draw.c - vx32 - Local 9vx git repository for patches.
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       ---
       draw.c (56885B)
       ---
            1 #include "u.h"
            2 #include "lib.h"
            3 #include "draw.h"
            4 #include "memdraw.h"
            5 
            6 int drawdebug;
            7 static int        tablesbuilt;
            8 
            9 /* perfect approximation to NTSC = .299r+.587g+.114b when 0 ≤ r,g,b < 256 */
           10 #define RGB2K(r,g,b)        ((156763*(r)+307758*(g)+59769*(b))>>19)
           11 
           12 /*
           13  * For 16-bit values, x / 255 == (t = x+1, (t+(t>>8)) >> 8).
           14  * We add another 127 to round to the nearest value rather
           15  * than truncate.
           16  *
           17  * CALCxy does x bytewise calculations on y input images (x=1,4; y=1,2).
           18  * CALC2x does two parallel 16-bit calculations on y input images (y=1,2).
           19  */
           20 #define CALC11(a, v, tmp) \
           21  (tmp=(a)*(v)+128, (tmp+(tmp>>8))>>8)
           22 #define CALC12(a1, v1, a2, v2, tmp) \
           23  (tmp=(a1)*(v1)+(a2)*(v2)+128, (tmp+(tmp>>8))>>8)
           24 #define MASK 0xFF00FF
           25 
           26 #define CALC21(a, vvuu, tmp) \
           27  (tmp=(a)*(vvuu)+0x00800080, ((tmp+((tmp>>8)&MASK))>>8)&MASK)
           28 
           29 #define CALC41(a, rgba, tmp1, tmp2) \
           30  (CALC21(a, rgba & MASK, tmp1) | \
           31  (CALC21(a, (rgba>>8)&MASK, tmp2)<<8))
           32 
           33 #define CALC22(a1, vvuu1, a2, vvuu2, tmp) \
           34  (tmp=(a1)*(vvuu1)+(a2)*(vvuu2)+0x00800080, ((tmp+((tmp>>8)&MASK))>>8)&MASK)
           35 
           36 #define CALC42(a1, rgba1, a2, rgba2, tmp1, tmp2) \
           37  (CALC22(a1, rgba1 & MASK, a2, rgba2 & MASK, tmp1) | \
           38  (CALC22(a1, (rgba1>>8) & MASK, a2, (rgba2>>8) & MASK, tmp2)<<8))
           39 
           40 static void mktables(void);
           41 typedef int Subdraw(Memdrawparam*);
           42 static Subdraw chardraw, alphadraw, memoptdraw;
           43 
           44 static Memimage*        memones;
           45 static Memimage*        memzeros;
           46 Memimage *memwhite;
           47 Memimage *memblack;
           48 Memimage *memtransparent;
           49 Memimage *memopaque;
           50 
           51 int        __ifmt(Fmt*);
           52 
           53 void
           54 _memimageinit(void)
           55 {
           56         static int didinit = 0;
           57 
           58         if(didinit)
           59                 return;
           60 
           61         didinit = 1;
           62 
           63 
           64         mktables();
           65         _memmkcmap();
           66 
           67         fmtinstall('R', Rfmt); 
           68         fmtinstall('P', Pfmt);
           69         fmtinstall('b', __ifmt);
           70 
           71         memones = allocmemimage(Rect(0,0,1,1), GREY1);
           72         memones->flags |= Frepl;
           73         memones->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
           74         *byteaddr(memones, ZP) = ~0;
           75 
           76         memzeros = allocmemimage(Rect(0,0,1,1), GREY1);
           77         memzeros->flags |= Frepl;
           78         memzeros->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
           79         *byteaddr(memzeros, ZP) = 0;
           80 
           81         if(memones == nil || memzeros == nil)
           82                 assert(0 /*cannot initialize memimage library */);        /* RSC BUG */
           83 
           84         memwhite = memones;
           85         memblack = memzeros;
           86         memopaque = memones;
           87         memtransparent = memzeros;
           88 }
           89 
           90 
           91 #define DBG if(0)
           92 Memdrawparam*
           93 _memimagedrawsetup(Memimage *dst, Rectangle r, Memimage *src, Point p0, Memimage *mask, Point p1, int op)
           94 {
           95         static Memdrawparam par;
           96 
           97         if(mask == nil)
           98                 mask = memopaque;
           99 
          100 DBG        print("memimagedraw %p/%luX %R @ %p %p/%luX %P %p/%luX %P... ", dst, dst->chan, r, dst->data->bdata, src, src->chan, p0, mask, mask->chan, p1);
          101 
          102         if(drawclip(dst, &r, src, &p0, mask, &p1, &par.sr, &par.mr) == 0){
          103 //                if(drawdebug)
          104 //                        iprint("empty clipped rectangle\n");
          105                 return nil;
          106         }
          107 
          108         if(op < Clear || op > SoverD){
          109 //                if(drawdebug)
          110 //                        iprint("op out of range: %d\n", op);
          111                 return nil;
          112         }
          113 
          114         par.op = op;
          115         par.dst = dst;
          116         par.r = r;
          117         par.src = src;
          118         /* par.sr set by drawclip */
          119         par.mask = mask;
          120         /* par.mr set by drawclip */
          121 
          122         par.state = 0;
          123         if(src->flags&Frepl){
          124                 par.state |= Replsrc;
          125                 if(Dx(src->r)==1 && Dy(src->r)==1){
          126                         par.sval = pixelbits(src, src->r.min);
          127                         par.state |= Simplesrc;
          128                         par.srgba = _imgtorgba(src, par.sval);
          129                         par.sdval = _rgbatoimg(dst, par.srgba);
          130                         if((par.srgba&0xFF) == 0xFF)
          131                                 par.state |= Fullsrc;
          132                         if((par.srgba&0xFF) == 0 && (op&DoutS)){
          133 //                                if (drawdebug) iprint("fill with transparent source\n");
          134                                 return nil;        /* no-op successfully handled */
          135                         }
          136                 }
          137         }
          138 
          139         if(mask->flags & Frepl){
          140                 par.state |= Replmask;
          141                 if(Dx(mask->r)==1 && Dy(mask->r)==1){
          142                         par.mval = pixelbits(mask, mask->r.min);
          143                         if(par.mval == 0 && (op&DoutS)){
          144 //                                if(drawdebug) iprint("fill with zero mask\n");
          145                                 return nil;        /* no-op successfully handled */
          146                         }
          147                         par.state |= Simplemask;
          148                         if(par.mval == ~0)
          149                                 par.state |= Fullmask;
          150                         par.mrgba = _imgtorgba(mask, par.mval);
          151                 }
          152         }
          153 
          154 //        if(drawdebug)
          155 //                iprint("dr %R sr %R mr %R...", r, par.sr, par.mr);
          156 DBG print("draw dr %R sr %R mr %R %lux\n", r, par.sr, par.mr, par.state);
          157 
          158         return &par;
          159 }
          160 
          161 void
          162 _memimagedraw(Memdrawparam *par)
          163 {
          164         if(par == nil)
          165                 return;
          166 
          167         /*
          168          * Now that we've clipped the parameters down to be consistent, we 
          169          * simply try sub-drawing routines in order until we find one that was able
          170          * to handle us.  If the sub-drawing routine returns zero, it means it was
          171          * unable to satisfy the request, so we do not return.
          172          */
          173 
          174         /*
          175          * Hardware support.  Each video driver provides this function,
          176          * which checks to see if there is anything it can help with.
          177          * There could be an if around this checking to see if dst is in video memory.
          178          */
          179 DBG print("test hwdraw\n");
          180         if(hwdraw(par)){
          181 //if(drawdebug) iprint("hw handled\n");
          182 DBG print("hwdraw handled\n");
          183                 return;
          184         }
          185         /*
          186          * Optimizations using memmove and memset.
          187          */
          188 DBG print("test memoptdraw\n");
          189         if(memoptdraw(par)){
          190 //if(drawdebug) iprint("memopt handled\n");
          191 DBG print("memopt handled\n");
          192                 return;
          193         }
          194 
          195         /*
          196          * Character drawing.
          197          * Solid source color being painted through a boolean mask onto a high res image.
          198          */
          199 DBG print("test chardraw\n");
          200         if(chardraw(par)){
          201 //if(drawdebug) iprint("chardraw handled\n");
          202 DBG print("chardraw handled\n");
          203                 return;
          204         }
          205 
          206         /*
          207          * General calculation-laden case that does alpha for each pixel.
          208          */
          209 DBG print("do alphadraw\n");
          210         alphadraw(par);
          211 //if(drawdebug) iprint("alphadraw handled\n");
          212 DBG print("alphadraw handled\n");
          213 }
          214 #undef DBG
          215 
          216 /*
          217  * Clip the destination rectangle further based on the properties of the 
          218  * source and mask rectangles.  Once the destination rectangle is properly
          219  * clipped, adjust the source and mask rectangles to be the same size.
          220  * Then if source or mask is replicated, move its clipped rectangle
          221  * so that its minimum point falls within the repl rectangle.
          222  *
          223  * Return zero if the final rectangle is null.
          224  */
          225 int
          226 drawclip(Memimage *dst, Rectangle *r, Memimage *src, Point *p0, Memimage *mask, Point *p1, Rectangle *sr, Rectangle *mr)
          227 {
          228         Point rmin, delta;
          229         int splitcoords;
          230         Rectangle omr;
          231 
          232         if(r->min.x>=r->max.x || r->min.y>=r->max.y)
          233                 return 0;
          234         splitcoords = (p0->x!=p1->x) || (p0->y!=p1->y);
          235         /* clip to destination */
          236         rmin = r->min;
          237         if(!rectclip(r, dst->r) || !rectclip(r, dst->clipr))
          238                 return 0;
          239         /* move mask point */
          240         p1->x += r->min.x-rmin.x;
          241         p1->y += r->min.y-rmin.y;
          242         /* move source point */
          243         p0->x += r->min.x-rmin.x;
          244         p0->y += r->min.y-rmin.y;
          245         /* map destination rectangle into source */
          246         sr->min = *p0;
          247         sr->max.x = p0->x+Dx(*r);
          248         sr->max.y = p0->y+Dy(*r);
          249         /* sr is r in source coordinates; clip to source */
          250         if(!(src->flags&Frepl) && !rectclip(sr, src->r))
          251                 return 0;
          252         if(!rectclip(sr, src->clipr))
          253                 return 0;
          254         /* compute and clip rectangle in mask */
          255         if(splitcoords){
          256                 /* move mask point with source */
          257                 p1->x += sr->min.x-p0->x;
          258                 p1->y += sr->min.y-p0->y;
          259                 mr->min = *p1;
          260                 mr->max.x = p1->x+Dx(*sr);
          261                 mr->max.y = p1->y+Dy(*sr);
          262                 omr = *mr;
          263                 /* mr is now rectangle in mask; clip it */
          264                 if(!(mask->flags&Frepl) && !rectclip(mr, mask->r))
          265                         return 0;
          266                 if(!rectclip(mr, mask->clipr))
          267                         return 0;
          268                 /* reflect any clips back to source */
          269                 sr->min.x += mr->min.x-omr.min.x;
          270                 sr->min.y += mr->min.y-omr.min.y;
          271                 sr->max.x += mr->max.x-omr.max.x;
          272                 sr->max.y += mr->max.y-omr.max.y;
          273                 *p1 = mr->min;
          274         }else{
          275                 if(!(mask->flags&Frepl) && !rectclip(sr, mask->r))
          276                         return 0;
          277                 if(!rectclip(sr, mask->clipr))
          278                         return 0;
          279                 *p1 = sr->min;
          280         }
          281 
          282         /* move source clipping back to destination */
          283         delta.x = r->min.x - p0->x;
          284         delta.y = r->min.y - p0->y;
          285         r->min.x = sr->min.x + delta.x;
          286         r->min.y = sr->min.y + delta.y;
          287         r->max.x = sr->max.x + delta.x;
          288         r->max.y = sr->max.y + delta.y;
          289 
          290         /* move source rectangle so sr->min is in src->r */
          291         if(src->flags&Frepl) {
          292                 delta.x = drawreplxy(src->r.min.x, src->r.max.x, sr->min.x) - sr->min.x;
          293                 delta.y = drawreplxy(src->r.min.y, src->r.max.y, sr->min.y) - sr->min.y;
          294                 sr->min.x += delta.x;
          295                 sr->min.y += delta.y;
          296                 sr->max.x += delta.x;
          297                 sr->max.y += delta.y;
          298         }
          299         *p0 = sr->min;
          300 
          301         /* move mask point so it is in mask->r */
          302         *p1 = drawrepl(mask->r, *p1);
          303         mr->min = *p1;
          304         mr->max.x = p1->x+Dx(*sr);
          305         mr->max.y = p1->y+Dy(*sr);
          306 
          307         assert(Dx(*sr) == Dx(*mr) && Dx(*mr) == Dx(*r));
          308         assert(Dy(*sr) == Dy(*mr) && Dy(*mr) == Dy(*r));
          309         assert(ptinrect(*p0, src->r));
          310         assert(ptinrect(*p1, mask->r));
          311         assert(ptinrect(r->min, dst->r));
          312 
          313         return 1;
          314 }
          315 
          316 /*
          317  * Conversion tables.
          318  */
          319 static uchar replbit[1+8][256];                /* replbit[x][y] is the replication of the x-bit quantity y to 8-bit depth */
          320 static uchar conv18[256][8];                /* conv18[x][y] is the yth pixel in the depth-1 pixel x */
          321 static uchar conv28[256][4];                /* ... */
          322 static uchar conv48[256][2];
          323 
          324 /*
          325  * bitmap of how to replicate n bits to fill 8, for 1 ≤ n ≤ 8.
          326  * the X's are where to put the bottom (ones) bit of the n-bit pattern.
          327  * only the top 8 bits of the result are actually used.
          328  * (the lower 8 bits are needed to get bits in the right place
          329  * when n is not a divisor of 8.)
          330  *
          331  * Should check to see if its easier to just refer to replmul than
          332  * use the precomputed values in replbit.  On PCs it may well
          333  * be; on machines with slow multiply instructions it probably isn't.
          334  */
          335 #define a ((((((((((((((((0
          336 #define X *2+1)
          337 #define _ *2)
          338 static int replmul[1+8] = {
          339         0,
          340         a X X X X X X X X X X X X X X X X,
          341         a _ X _ X _ X _ X _ X _ X _ X _ X,
          342         a _ _ X _ _ X _ _ X _ _ X _ _ X _,
          343         a _ _ _ X _ _ _ X _ _ _ X _ _ _ X,
          344         a _ _ _ _ X _ _ _ _ X _ _ _ _ X _,
          345         a _ _ _ _ _ X _ _ _ _ _ X _ _ _ _, 
          346         a _ _ _ _ _ _ X _ _ _ _ _ _ X _ _,
          347         a _ _ _ _ _ _ _ X _ _ _ _ _ _ _ X,
          348 };
          349 #undef a
          350 #undef X
          351 #undef _
          352 
          353 static void
          354 mktables(void)
          355 {
          356         int i, j, mask, sh, small;
          357                 
          358         if(tablesbuilt)
          359                 return;
          360 
          361         fmtinstall('R', Rfmt);
          362         fmtinstall('P', Pfmt);
          363         tablesbuilt = 1;
          364 
          365         /* bit replication up to 8 bits */
          366         for(i=0; i<256; i++){
          367                 for(j=0; j<=8; j++){        /* j <= 8 [sic] */
          368                         small = i & ((1<<j)-1);
          369                         replbit[j][i] = (small*replmul[j])>>8;
          370                 }
          371         }
          372 
          373         /* bit unpacking up to 8 bits, only powers of 2 */
          374         for(i=0; i<256; i++){
          375                 for(j=0, sh=7, mask=1; j<8; j++, sh--)
          376                         conv18[i][j] = replbit[1][(i>>sh)&mask];
          377 
          378                 for(j=0, sh=6, mask=3; j<4; j++, sh-=2)
          379                         conv28[i][j] = replbit[2][(i>>sh)&mask];
          380 
          381                 for(j=0, sh=4, mask=15; j<2; j++, sh-=4)
          382                         conv48[i][j] = replbit[4][(i>>sh)&mask];
          383         }
          384 }
          385 
          386 static uchar ones = 0xff;
          387 
          388 /*
          389  * General alpha drawing case.  Can handle anything.
          390  */
          391 typedef struct        Buffer        Buffer;
          392 struct Buffer {
          393         /* used by most routines */
          394         uchar        *red;
          395         uchar        *grn;
          396         uchar        *blu;
          397         uchar        *alpha;
          398         uchar        *grey;
          399         uint32        *rgba;
          400         int        delta;        /* number of bytes to add to pointer to get next pixel to the right */
          401 
          402         /* used by boolcalc* for mask data */
          403         uchar        *m;                /* ptr to mask data r.min byte; like p->bytermin */
          404         int                mskip;        /* no. of left bits to skip in *m */
          405         uchar        *bm;                /* ptr to mask data img->r.min byte; like p->bytey0s */
          406         int                bmskip;        /* no. of left bits to skip in *bm */
          407         uchar        *em;                /* ptr to mask data img->r.max.x byte; like p->bytey0e */
          408         int                emskip;        /* no. of right bits to skip in *em */
          409 };
          410 
          411 typedef struct        Param        Param;
          412 typedef Buffer        Readfn(Param*, uchar*, int);
          413 typedef void        Writefn(Param*, uchar*, Buffer);
          414 typedef Buffer        Calcfn(Buffer, Buffer, Buffer, int, int, int);
          415 
          416 enum {
          417         MAXBCACHE = 16
          418 };
          419 
          420 /* giant rathole to customize functions with */
          421 struct Param {
          422         Readfn        *replcall;
          423         Readfn        *greymaskcall;        
          424         Readfn        *convreadcall;
          425         Writefn        *convwritecall;
          426 
          427         Memimage *img;
          428         Rectangle        r;
          429         int        dx;        /* of r */
          430         int        needbuf;
          431         int        convgrey;
          432         int        alphaonly;
          433 
          434         uchar        *bytey0s;                /* byteaddr(Pt(img->r.min.x, img->r.min.y)) */
          435         uchar        *bytermin;        /* byteaddr(Pt(r.min.x, img->r.min.y)) */
          436         uchar        *bytey0e;                /* byteaddr(Pt(img->r.max.x, img->r.min.y)) */
          437         int                bwidth;
          438 
          439         int        replcache;        /* if set, cache buffers */
          440         Buffer        bcache[MAXBCACHE];
          441         uint32        bfilled;
          442         uchar        *bufbase;
          443         int        bufoff;
          444         int        bufdelta;
          445 
          446         int        dir;
          447 
          448         int        convbufoff;
          449         uchar        *convbuf;
          450         Param        *convdpar;
          451         int        convdx;
          452 };
          453 
          454 static Readfn        greymaskread, replread, readptr;
          455 static Writefn        nullwrite;
          456 static Calcfn        alphacalc0, alphacalc14, alphacalc2810, alphacalc3679, alphacalc5, alphacalc11, alphacalcS;
          457 static Calcfn        boolcalc14, boolcalc236789, boolcalc1011;
          458 
          459 static Readfn*        readfn(Memimage*);
          460 static Readfn*        readalphafn(Memimage*);
          461 static Writefn*        writefn(Memimage*);
          462 
          463 static Calcfn*        boolcopyfn(Memimage*, Memimage*);
          464 static Readfn*        convfn(Memimage*, Param*, Memimage*, Param*, int*);
          465 
          466 static Calcfn *alphacalc[Ncomp] = 
          467 {
          468         alphacalc0,                /* Clear */
          469         alphacalc14,                /* DoutS */
          470         alphacalc2810,                /* SoutD */
          471         alphacalc3679,                /* DxorS */
          472         alphacalc14,                /* DinS */
          473         alphacalc5,                /* D */
          474         alphacalc3679,                /* DatopS */
          475         alphacalc3679,                /* DoverS */
          476         alphacalc2810,                /* SinD */
          477         alphacalc3679,                /* SatopD */
          478         alphacalc2810,                /* S */
          479         alphacalc11,                /* SoverD */
          480 };
          481 
          482 static Calcfn *boolcalc[Ncomp] =
          483 {
          484         alphacalc0,                /* Clear */
          485         boolcalc14,                /* DoutS */
          486         boolcalc236789,                /* SoutD */
          487         boolcalc236789,                /* DxorS */
          488         boolcalc14,                /* DinS */
          489         alphacalc5,                /* D */
          490         boolcalc236789,                /* DatopS */
          491         boolcalc236789,                /* DoverS */
          492         boolcalc236789,                /* SinD */
          493         boolcalc236789,                /* SatopD */
          494         boolcalc1011,                /* S */
          495         boolcalc1011,                /* SoverD */
          496 };
          497 
          498 /*
          499  * Avoid standard Lock, QLock so that can be used in kernel.
          500  */
          501 typedef struct Dbuf Dbuf;
          502 struct Dbuf
          503 {
          504         uchar *p;
          505         int n;
          506         Param spar, mpar, dpar;
          507         int inuse;
          508 };
          509 static Dbuf dbuf[10];
          510 extern int _tas(int*);
          511 
          512 static Dbuf*
          513 allocdbuf(void)
          514 {
          515         int i;
          516 
          517         for(i=0; i<nelem(dbuf); i++){
          518                 if(dbuf[i].inuse)
          519                         continue;
          520                 if(!_tas(&dbuf[i].inuse))
          521                         return &dbuf[i];
          522         }
          523         return nil;
          524 }
          525 
          526 static void
          527 getparam(Param *p, Memimage *img, Rectangle r, int convgrey, int needbuf, int *ndrawbuf)
          528 {
          529         int nbuf;
          530 
          531         memset(p, 0, sizeof *p);
          532 
          533         p->img = img;
          534         p->r = r;
          535         p->dx = Dx(r);
          536         p->needbuf = needbuf;
          537         p->convgrey = convgrey;
          538 
          539         assert(img->r.min.x <= r.min.x && r.min.x < img->r.max.x);
          540 
          541         p->bytey0s = byteaddr(img, Pt(img->r.min.x, img->r.min.y));
          542         p->bytermin = byteaddr(img, Pt(r.min.x, img->r.min.y));
          543         p->bytey0e = byteaddr(img, Pt(img->r.max.x, img->r.min.y));
          544         p->bwidth = sizeof(uint32)*img->width;
          545 
          546         assert(p->bytey0s <= p->bytermin && p->bytermin <= p->bytey0e);
          547 
          548         if(p->r.min.x == p->img->r.min.x)
          549                 assert(p->bytermin == p->bytey0s);
          550 
          551         nbuf = 1;
          552         if((img->flags&Frepl) && Dy(img->r) <= MAXBCACHE && Dy(img->r) < Dy(r)){
          553                 p->replcache = 1;
          554                 nbuf = Dy(img->r);
          555         }
          556         p->bufdelta = 4*p->dx;
          557         p->bufoff = *ndrawbuf;
          558         *ndrawbuf += p->bufdelta*nbuf;
          559 }
          560 
          561 static void
          562 clipy(Memimage *img, int *y)
          563 {
          564         int dy;
          565 
          566         dy = Dy(img->r);
          567         if(*y == dy)
          568                 *y = 0;
          569         else if(*y == -1)
          570                 *y = dy-1;
          571         assert(0 <= *y && *y < dy);
          572 }
          573 
          574 static void
          575 dumpbuf(char *s, Buffer b, int n)
          576 {
          577         int i;
          578         uchar *p;
          579         
          580         print("%s", s);
          581         for(i=0; i<n; i++){
          582                 print(" ");
          583                 if((p=b.grey)){
          584                         print(" k%.2uX", *p);
          585                         b.grey += b.delta;
          586                 }else{        
          587                         if((p=b.red)){
          588                                 print(" r%.2uX", *p);
          589                                 b.red += b.delta;
          590                         }
          591                         if((p=b.grn)){
          592                                 print(" g%.2uX", *p);
          593                                 b.grn += b.delta;
          594                         }
          595                         if((p=b.blu)){
          596                                 print(" b%.2uX", *p);
          597                                 b.blu += b.delta;
          598                         }
          599                 }
          600                 if((p=b.alpha) != &ones){
          601                         print(" α%.2uX", *p);
          602                         b.alpha += b.delta;
          603                 }
          604         }
          605         print("\n");
          606 }
          607 
          608 /*
          609  * For each scan line, we expand the pixels from source, mask, and destination
          610  * into byte-aligned red, green, blue, alpha, and grey channels.  If buffering is not
          611  * needed and the channels were already byte-aligned (grey8, rgb24, rgba32, rgb32),
          612  * the readers need not copy the data: they can simply return pointers to the data.
          613  * If the destination image is grey and the source is not, it is converted using the NTSC
          614  * formula.
          615  *
          616  * Once we have all the channels, we call either rgbcalc or greycalc, depending on 
          617  * whether the destination image is color.  This is allowed to overwrite the dst buffer (perhaps
          618  * the actual data, perhaps a copy) with its result.  It should only overwrite the dst buffer
          619  * with the same format (i.e. red bytes with red bytes, etc.)  A new buffer is returned from
          620  * the calculator, and that buffer is passed to a function to write it to the destination.
          621  * If the buffer is already pointing at the destination, the writing function is a no-op.
          622  */
          623 #define DBG if(0)
          624 static int
          625 alphadraw(Memdrawparam *par)
          626 {
          627         int isgrey, starty, endy, op;
          628         int needbuf, dsty, srcy, masky;
          629         int y, dir, dx, dy, ndrawbuf;
          630         uchar *drawbuf;
          631         Buffer bsrc, bdst, bmask;
          632         Readfn *rdsrc, *rdmask, *rddst;
          633         Calcfn *calc;
          634         Writefn *wrdst;
          635         Memimage *src, *mask, *dst;
          636         Rectangle r, sr, mr;
          637         Dbuf *z;
          638 
          639         r = par->r;
          640         dx = Dx(r);
          641         dy = Dy(r);
          642 
          643         z = allocdbuf();
          644         if(z == nil)
          645                 return 0;
          646 
          647         src = par->src;
          648         mask = par->mask;        
          649         dst = par->dst;
          650         sr = par->sr;
          651         mr = par->mr;
          652         op = par->op;
          653 
          654         isgrey = dst->flags&Fgrey;
          655 
          656         /*
          657          * Buffering when src and dst are the same bitmap is sufficient but not 
          658          * necessary.  There are stronger conditions we could use.  We could
          659          * check to see if the rectangles intersect, and if simply moving in the
          660          * correct y direction can avoid the need to buffer.
          661          */
          662         needbuf = (src->data == dst->data);
          663 
          664         ndrawbuf = 0;
          665         getparam(&z->spar, src, sr, isgrey, needbuf, &ndrawbuf);
          666         getparam(&z->dpar, dst, r, isgrey, needbuf, &ndrawbuf);
          667         getparam(&z->mpar, mask, mr, 0, needbuf, &ndrawbuf);
          668 
          669         dir = (needbuf && byteaddr(dst, r.min) > byteaddr(src, sr.min)) ? -1 : 1;
          670         z->spar.dir = z->mpar.dir = z->dpar.dir = dir;
          671 
          672         /*
          673          * If the mask is purely boolean, we can convert from src to dst format
          674          * when we read src, and then just copy it to dst where the mask tells us to.
          675          * This requires a boolean (1-bit grey) mask and lack of a source alpha channel.
          676          *
          677          * The computation is accomplished by assigning the function pointers as follows:
          678          *        rdsrc - read and convert source into dst format in a buffer
          679          *         rdmask - convert mask to bytes, set pointer to it
          680          *         rddst - fill with pointer to real dst data, but do no reads
          681          *        calc - copy src onto dst when mask says to.
          682          *        wrdst - do nothing
          683          * This is slightly sleazy, since things aren't doing exactly what their names say,
          684          * but it avoids a fair amount of code duplication to make this a case here
          685          * rather than have a separate booldraw.
          686          */
          687 //if(drawdebug) iprint("flag %lud mchan %lux=?%x dd %d\n", src->flags&Falpha, mask->chan, GREY1, dst->depth);
          688         if(!(src->flags&Falpha) && mask->chan == GREY1 && dst->depth >= 8 && op == SoverD){
          689 //if(drawdebug) iprint("boolcopy...");
          690                 rdsrc = convfn(dst, &z->dpar, src, &z->spar, &ndrawbuf);
          691                 rddst = readptr;
          692                 rdmask = readfn(mask);
          693                 calc = boolcopyfn(dst, mask);
          694                 wrdst = nullwrite;
          695         }else{
          696                 /* usual alphadraw parameter fetching */
          697                 rdsrc = readfn(src);
          698                 rddst = readfn(dst);
          699                 wrdst = writefn(dst);
          700                 calc = alphacalc[op];
          701 
          702                 /*
          703                  * If there is no alpha channel, we'll ask for a grey channel
          704                  * and pretend it is the alpha.
          705                  */
          706                 if(mask->flags&Falpha){
          707                         rdmask = readalphafn(mask);
          708                         z->mpar.alphaonly = 1;
          709                 }else{
          710                         z->mpar.greymaskcall = readfn(mask);
          711                         z->mpar.convgrey = 1;
          712                         rdmask = greymaskread;
          713 
          714                         /*
          715                          * Should really be above, but then boolcopyfns would have
          716                          * to deal with bit alignment, and I haven't written that.
          717                          *
          718                          * This is a common case for things like ellipse drawing.
          719                          * When there's no alpha involved and the mask is boolean,
          720                          * we can avoid all the division and multiplication.
          721                          */
          722                         if(mask->chan == GREY1 && !(src->flags&Falpha))
          723                                 calc = boolcalc[op];
          724                         else if(op == SoverD && !(src->flags&Falpha))
          725                                 calc = alphacalcS;
          726                 }
          727         }
          728 
          729         /*
          730          * If the image has a small enough repl rectangle,
          731          * we can just read each line once and cache them.
          732          */
          733         if(z->spar.replcache){
          734                 z->spar.replcall = rdsrc;
          735                 rdsrc = replread;
          736         }
          737         if(z->mpar.replcache){
          738                 z->mpar.replcall = rdmask;
          739                 rdmask = replread;
          740         }
          741 
          742         if(z->n < ndrawbuf){
          743                 free(z->p);
          744                 if((z->p = mallocz(ndrawbuf, 0)) == nil){
          745                         z->inuse = 0;
          746                         return 0;
          747                 }
          748                 z->n = ndrawbuf;
          749         }
          750         drawbuf = z->p;
          751 
          752         /*
          753          * Before we were saving only offsets from drawbuf in the parameter
          754          * structures; now that drawbuf has been grown to accomodate us,
          755          * we can fill in the pointers.
          756          */
          757         z->spar.bufbase = drawbuf+z->spar.bufoff;
          758         z->mpar.bufbase = drawbuf+z->mpar.bufoff;
          759         z->dpar.bufbase = drawbuf+z->dpar.bufoff;
          760         z->spar.convbuf = drawbuf+z->spar.convbufoff;
          761 
          762         if(dir == 1){
          763                 starty = 0;
          764                 endy = dy;
          765         }else{
          766                 starty = dy-1;
          767                 endy = -1;
          768         }
          769 
          770         /*
          771          * srcy, masky, and dsty are offsets from the top of their
          772          * respective Rectangles.  they need to be contained within
          773          * the rectangles, so clipy can keep them there without division.
          774           */
          775         srcy = (starty + sr.min.y - src->r.min.y)%Dy(src->r);
          776         masky = (starty + mr.min.y - mask->r.min.y)%Dy(mask->r);
          777         dsty = starty + r.min.y - dst->r.min.y;
          778 
          779         assert(0 <= srcy && srcy < Dy(src->r));
          780         assert(0 <= masky && masky < Dy(mask->r));
          781         assert(0 <= dsty && dsty < Dy(dst->r));
          782 
          783         for(y=starty; y!=endy; y+=dir, srcy+=dir, masky+=dir, dsty+=dir){
          784                 clipy(src, &srcy);
          785                 clipy(dst, &dsty);
          786                 clipy(mask, &masky);
          787 
          788                 bsrc = rdsrc(&z->spar, z->spar.bufbase, srcy);
          789 DBG print("[");
          790                 bmask = rdmask(&z->mpar, z->mpar.bufbase, masky);
          791 DBG print("]\n");
          792                 bdst = rddst(&z->dpar, z->dpar.bufbase, dsty);
          793 DBG                dumpbuf("src", bsrc, dx);
          794 DBG                dumpbuf("mask", bmask, dx);
          795 DBG                dumpbuf("dst", bdst, dx);
          796                 bdst = calc(bdst, bsrc, bmask, dx, isgrey, op);
          797                 wrdst(&z->dpar, z->dpar.bytermin+dsty*z->dpar.bwidth, bdst);
          798         }
          799 
          800         z->inuse = 0;
          801         return 1;
          802 }
          803 #undef DBG
          804 
          805 static Buffer
          806 alphacalc0(Buffer bdst, Buffer b1, Buffer b2, int dx, int grey, int op)
          807 {
          808         USED(grey);
          809         USED(op);
          810         USED(b1);
          811         USED(b2);
          812         memset(bdst.rgba, 0, dx*bdst.delta);
          813         return bdst;
          814 }
          815 
          816 /*
          817  * Do the channels in the buffers match enough
          818  * that we can do word-at-a-time operations
          819  * on the pixels?
          820  */
          821 static int
          822 chanmatch(Buffer *bdst, Buffer *bsrc)
          823 {
          824         uchar *drgb, *srgb;
          825         
          826         /*
          827          * first, r, g, b must be in the same place
          828          * in the rgba word.
          829          */
          830         drgb = (uchar*)bdst->rgba;
          831         srgb = (uchar*)bsrc->rgba;
          832         if(bdst->red - drgb != bsrc->red - srgb
          833         || bdst->blu - drgb != bsrc->blu - srgb
          834         || bdst->grn - drgb != bsrc->grn - srgb)
          835                 return 0;
          836         
          837         /*
          838          * that implies alpha is in the same place,
          839          * if it is there at all (it might be == &ones).
          840          * if the destination is &ones, we can scribble
          841          * over the rgba slot just fine.
          842          */
          843         if(bdst->alpha == &ones)
          844                 return 1;
          845         
          846         /*
          847          * if the destination is not ones but the src is,
          848          * then the simultaneous calculation will use
          849          * bogus bytes from the src's rgba.  no good.
          850          */
          851         if(bsrc->alpha == &ones)
          852                 return 0;
          853         
          854         /*
          855          * otherwise, alphas are in the same place.
          856          */
          857         return 1;
          858 }
          859 
          860 static Buffer
          861 alphacalc14(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
          862 {
          863         Buffer obdst;
          864         int fd, sadelta;
          865         int i, sa, ma, q;
          866         uint32 t, t1;
          867 
          868         obdst = bdst;
          869         sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
          870         q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);
          871 
          872         for(i=0; i<dx; i++){
          873                 sa = *bsrc.alpha;
          874                 ma = *bmask.alpha;
          875                 fd = CALC11(sa, ma, t);
          876                 if(op == DoutS)
          877                         fd = 255-fd;
          878 
          879                 if(grey){
          880                         *bdst.grey = CALC11(fd, *bdst.grey, t);
          881                         bsrc.grey += bsrc.delta;
          882                         bdst.grey += bdst.delta;
          883                 }else{
          884                         if(q){
          885                                 *bdst.rgba = CALC41(fd, *bdst.rgba, t, t1);
          886                                 bsrc.rgba++;
          887                                 bdst.rgba++;
          888                                 bsrc.alpha += sadelta;
          889                                 bmask.alpha += bmask.delta;
          890                                 continue;
          891                         }
          892                         *bdst.red = CALC11(fd, *bdst.red, t);
          893                         *bdst.grn = CALC11(fd, *bdst.grn, t);
          894                         *bdst.blu = CALC11(fd, *bdst.blu, t);
          895                         bsrc.red += bsrc.delta;
          896                         bsrc.blu += bsrc.delta;
          897                         bsrc.grn += bsrc.delta;
          898                         bdst.red += bdst.delta;
          899                         bdst.blu += bdst.delta;
          900                         bdst.grn += bdst.delta;
          901                 }
          902                 if(bdst.alpha != &ones){
          903                         *bdst.alpha = CALC11(fd, *bdst.alpha, t);
          904                         bdst.alpha += bdst.delta;
          905                 }
          906                 bmask.alpha += bmask.delta;
          907                 bsrc.alpha += sadelta;
          908         }
          909         return obdst;
          910 }
          911 
          912 static Buffer
          913 alphacalc2810(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
          914 {
          915         Buffer obdst;
          916         int fs, sadelta;
          917         int i, ma, da, q;
          918         uint32 t, t1;
          919 
          920         obdst = bdst;
          921         sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
          922         q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);
          923 
          924         for(i=0; i<dx; i++){
          925                 ma = *bmask.alpha;
          926                 da = *bdst.alpha;
          927                 if(op == SoutD)
          928                         da = 255-da;
          929                 fs = ma;
          930                 if(op != S)
          931                         fs = CALC11(fs, da, t);
          932 
          933                 if(grey){
          934                         *bdst.grey = CALC11(fs, *bsrc.grey, t);
          935                         bsrc.grey += bsrc.delta;
          936                         bdst.grey += bdst.delta;
          937                 }else{
          938                         if(q){
          939                                 *bdst.rgba = CALC41(fs, *bsrc.rgba, t, t1);
          940                                 bsrc.rgba++;
          941                                 bdst.rgba++;
          942                                 bmask.alpha += bmask.delta;
          943                                 bdst.alpha += bdst.delta;
          944                                 continue;
          945                         }
          946                         *bdst.red = CALC11(fs, *bsrc.red, t);
          947                         *bdst.grn = CALC11(fs, *bsrc.grn, t);
          948                         *bdst.blu = CALC11(fs, *bsrc.blu, t);
          949                         bsrc.red += bsrc.delta;
          950                         bsrc.blu += bsrc.delta;
          951                         bsrc.grn += bsrc.delta;
          952                         bdst.red += bdst.delta;
          953                         bdst.blu += bdst.delta;
          954                         bdst.grn += bdst.delta;
          955                 }
          956                 if(bdst.alpha != &ones){
          957                         *bdst.alpha = CALC11(fs, *bsrc.alpha, t);
          958                         bdst.alpha += bdst.delta;
          959                 }
          960                 bmask.alpha += bmask.delta;
          961                 bsrc.alpha += sadelta;
          962         }
          963         return obdst;
          964 }
          965 
          966 static Buffer
          967 alphacalc3679(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
          968 {
          969         Buffer obdst;
          970         int fs, fd, sadelta;
          971         int i, sa, ma, da, q;
          972         uint32 t, t1;
          973 
          974         obdst = bdst;
          975         sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
          976         q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);
          977 
          978         for(i=0; i<dx; i++){
          979                 sa = *bsrc.alpha;
          980                 ma = *bmask.alpha;
          981                 da = *bdst.alpha;
          982                 if(op == SatopD)
          983                         fs = CALC11(ma, da, t);
          984                 else
          985                         fs = CALC11(ma, 255-da, t);
          986                 if(op == DoverS)
          987                         fd = 255;
          988                 else{
          989                         fd = CALC11(sa, ma, t);
          990                         if(op != DatopS)
          991                                 fd = 255-fd;
          992                 }
          993 
          994                 if(grey){
          995                         *bdst.grey = CALC12(fs, *bsrc.grey, fd, *bdst.grey, t);
          996                         bsrc.grey += bsrc.delta;
          997                         bdst.grey += bdst.delta;
          998                 }else{
          999                         if(q){
         1000                                 *bdst.rgba = CALC42(fs, *bsrc.rgba, fd, *bdst.rgba, t, t1);
         1001                                 bsrc.rgba++;
         1002                                 bdst.rgba++;
         1003                                 bsrc.alpha += sadelta;
         1004                                 bmask.alpha += bmask.delta;
         1005                                 bdst.alpha += bdst.delta;
         1006                                 continue;
         1007                         }
         1008                         *bdst.red = CALC12(fs, *bsrc.red, fd, *bdst.red, t);
         1009                         *bdst.grn = CALC12(fs, *bsrc.grn, fd, *bdst.grn, t);
         1010                         *bdst.blu = CALC12(fs, *bsrc.blu, fd, *bdst.blu, t);
         1011                         bsrc.red += bsrc.delta;
         1012                         bsrc.blu += bsrc.delta;
         1013                         bsrc.grn += bsrc.delta;
         1014                         bdst.red += bdst.delta;
         1015                         bdst.blu += bdst.delta;
         1016                         bdst.grn += bdst.delta;
         1017                 }
         1018                 if(bdst.alpha != &ones){
         1019                         *bdst.alpha = CALC12(fs, sa, fd, da, t);
         1020                         bdst.alpha += bdst.delta;
         1021                 }
         1022                 bmask.alpha += bmask.delta;
         1023                 bsrc.alpha += sadelta;
         1024         }
         1025         return obdst;
         1026 }
         1027 
         1028 static Buffer
         1029 alphacalc5(Buffer bdst, Buffer b1, Buffer b2, int dx, int grey, int op)
         1030 {
         1031         USED(dx);
         1032         USED(grey);
         1033         USED(op);
         1034         USED(b1);
         1035         USED(b2);
         1036         return bdst;
         1037 }
         1038 
         1039 static Buffer
         1040 alphacalc11(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
         1041 {
         1042         Buffer obdst;
         1043         int fd, sadelta;
         1044         int i, sa, ma, q;
         1045         uint32 t, t1;
         1046 
         1047         USED(op);
         1048         obdst = bdst;
         1049         sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
         1050         q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);
         1051 
         1052         for(i=0; i<dx; i++){
         1053                 sa = *bsrc.alpha;
         1054                 ma = *bmask.alpha;
         1055                 fd = 255-CALC11(sa, ma, t);
         1056 
         1057                 if(grey){
         1058                         *bdst.grey = CALC12(ma, *bsrc.grey, fd, *bdst.grey, t);
         1059                         bsrc.grey += bsrc.delta;
         1060                         bdst.grey += bdst.delta;
         1061                 }else{
         1062                         if(q){
         1063                                 *bdst.rgba = CALC42(ma, *bsrc.rgba, fd, *bdst.rgba, t, t1);
         1064                                 bsrc.rgba++;
         1065                                 bdst.rgba++;
         1066                                 bsrc.alpha += sadelta;
         1067                                 bmask.alpha += bmask.delta;
         1068                                 continue;
         1069                         }
         1070                         *bdst.red = CALC12(ma, *bsrc.red, fd, *bdst.red, t);
         1071                         *bdst.grn = CALC12(ma, *bsrc.grn, fd, *bdst.grn, t);
         1072                         *bdst.blu = CALC12(ma, *bsrc.blu, fd, *bdst.blu, t);
         1073                         bsrc.red += bsrc.delta;
         1074                         bsrc.blu += bsrc.delta;
         1075                         bsrc.grn += bsrc.delta;
         1076                         bdst.red += bdst.delta;
         1077                         bdst.blu += bdst.delta;
         1078                         bdst.grn += bdst.delta;
         1079                 }
         1080                 if(bdst.alpha != &ones){
         1081                         *bdst.alpha = CALC12(ma, sa, fd, *bdst.alpha, t);
         1082                         bdst.alpha += bdst.delta;
         1083                 }
         1084                 bmask.alpha += bmask.delta;
         1085                 bsrc.alpha += sadelta;
         1086         }
         1087         return obdst;
         1088 }
         1089 
         1090 /*
         1091 not used yet
         1092 source and mask alpha 1
         1093 static Buffer
         1094 alphacalcS0(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
         1095 {
         1096         Buffer obdst;
         1097         int i;
         1098 
         1099         USED(op);
         1100         obdst = bdst;
         1101         if(bsrc.delta == bdst.delta){
         1102                 memmove(bdst.rgba, bsrc.rgba, dx*bdst.delta);
         1103                 return obdst;
         1104         }
         1105         for(i=0; i<dx; i++){
         1106                 if(grey){
         1107                         *bdst.grey = *bsrc.grey;
         1108                         bsrc.grey += bsrc.delta;
         1109                         bdst.grey += bdst.delta;
         1110                 }else{
         1111                         *bdst.red = *bsrc.red;
         1112                         *bdst.grn = *bsrc.grn;
         1113                         *bdst.blu = *bsrc.blu;
         1114                         bsrc.red += bsrc.delta;
         1115                         bsrc.blu += bsrc.delta;
         1116                         bsrc.grn += bsrc.delta;
         1117                         bdst.red += bdst.delta;
         1118                         bdst.blu += bdst.delta;
         1119                         bdst.grn += bdst.delta;
         1120                 }
         1121                 if(bdst.alpha != &ones){
         1122                         *bdst.alpha = 255;
         1123                         bdst.alpha += bdst.delta;
         1124                 }
         1125         }
         1126         return obdst;
         1127 }
         1128 */
         1129 
         1130 /* source alpha 1 */
         1131 static Buffer
         1132 alphacalcS(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
         1133 {
         1134         Buffer obdst;
         1135         int fd;
         1136         int i, ma;
         1137         uint32 t;
         1138 
         1139         USED(op);
         1140         obdst = bdst;
         1141 
         1142         for(i=0; i<dx; i++){
         1143                 ma = *bmask.alpha;
         1144                 fd = 255-ma;
         1145 
         1146                 if(grey){
         1147                         *bdst.grey = CALC12(ma, *bsrc.grey, fd, *bdst.grey, t);
         1148                         bsrc.grey += bsrc.delta;
         1149                         bdst.grey += bdst.delta;
         1150                 }else{
         1151                         *bdst.red = CALC12(ma, *bsrc.red, fd, *bdst.red, t);
         1152                         *bdst.grn = CALC12(ma, *bsrc.grn, fd, *bdst.grn, t);
         1153                         *bdst.blu = CALC12(ma, *bsrc.blu, fd, *bdst.blu, t);
         1154                         bsrc.red += bsrc.delta;
         1155                         bsrc.blu += bsrc.delta;
         1156                         bsrc.grn += bsrc.delta;
         1157                         bdst.red += bdst.delta;
         1158                         bdst.blu += bdst.delta;
         1159                         bdst.grn += bdst.delta;
         1160                 }
         1161                 if(bdst.alpha != &ones){
         1162                         *bdst.alpha = ma+CALC11(fd, *bdst.alpha, t);
         1163                         bdst.alpha += bdst.delta;
         1164                 }
         1165                 bmask.alpha += bmask.delta;
         1166         }
         1167         return obdst;
         1168 }
         1169 
         1170 static Buffer
         1171 boolcalc14(Buffer bdst, Buffer b1, Buffer bmask, int dx, int grey, int op)
         1172 {
         1173         Buffer obdst;
         1174         int i, ma, zero;
         1175 
         1176         USED(b1);
         1177 
         1178         obdst = bdst;
         1179 
         1180         for(i=0; i<dx; i++){
         1181                 ma = *bmask.alpha;
         1182                 zero = ma ? op == DoutS : op == DinS;
         1183 
         1184                 if(grey){
         1185                         if(zero)
         1186                                 *bdst.grey = 0;
         1187                         bdst.grey += bdst.delta;
         1188                 }else{
         1189                         if(zero)
         1190                                 *bdst.red = *bdst.grn = *bdst.blu = 0;
         1191                         bdst.red += bdst.delta;
         1192                         bdst.blu += bdst.delta;
         1193                         bdst.grn += bdst.delta;
         1194                 }
         1195                 bmask.alpha += bmask.delta;
         1196                 if(bdst.alpha != &ones){
         1197                         if(zero)
         1198                                 *bdst.alpha = 0;
         1199                         bdst.alpha += bdst.delta;
         1200                 }
         1201         }
         1202         return obdst;
         1203 }
         1204 
         1205 static Buffer
         1206 boolcalc236789(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
         1207 {
         1208         Buffer obdst;
         1209         int fs, fd;
         1210         int i, ma, da, zero;
         1211         uint32 t;
         1212 
         1213         obdst = bdst;
         1214         zero = !(op&1);
         1215 
         1216         for(i=0; i<dx; i++){
         1217                 ma = *bmask.alpha;
         1218                 da = *bdst.alpha;
         1219                 fs = da;
         1220                 if(op&2)
         1221                         fs = 255-da;
         1222                 fd = 0;
         1223                 if(op&4)
         1224                         fd = 255;
         1225 
         1226                 if(grey){
         1227                         if(ma)
         1228                                 *bdst.grey = CALC12(fs, *bsrc.grey, fd, *bdst.grey, t);
         1229                         else if(zero)
         1230                                 *bdst.grey = 0;
         1231                         bsrc.grey += bsrc.delta;
         1232                         bdst.grey += bdst.delta;
         1233                 }else{
         1234                         if(ma){
         1235                                 *bdst.red = CALC12(fs, *bsrc.red, fd, *bdst.red, t);
         1236                                 *bdst.grn = CALC12(fs, *bsrc.grn, fd, *bdst.grn, t);
         1237                                 *bdst.blu = CALC12(fs, *bsrc.blu, fd, *bdst.blu, t);
         1238                         }
         1239                         else if(zero)
         1240                                 *bdst.red = *bdst.grn = *bdst.blu = 0;
         1241                         bsrc.red += bsrc.delta;
         1242                         bsrc.blu += bsrc.delta;
         1243                         bsrc.grn += bsrc.delta;
         1244                         bdst.red += bdst.delta;
         1245                         bdst.blu += bdst.delta;
         1246                         bdst.grn += bdst.delta;
         1247                 }
         1248                 bmask.alpha += bmask.delta;
         1249                 if(bdst.alpha != &ones){
         1250                         if(ma)
         1251                                 *bdst.alpha = fs+CALC11(fd, da, t);
         1252                         else if(zero)
         1253                                 *bdst.alpha = 0;
         1254                         bdst.alpha += bdst.delta;
         1255                 }
         1256         }
         1257         return obdst;
         1258 }
         1259 
         1260 static Buffer
         1261 boolcalc1011(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
         1262 {
         1263         Buffer obdst;
         1264         int i, ma, zero;
         1265 
         1266         obdst = bdst;
         1267         zero = !(op&1);
         1268 
         1269         for(i=0; i<dx; i++){
         1270                 ma = *bmask.alpha;
         1271 
         1272                 if(grey){
         1273                         if(ma)
         1274                                 *bdst.grey = *bsrc.grey;
         1275                         else if(zero)
         1276                                 *bdst.grey = 0;
         1277                         bsrc.grey += bsrc.delta;
         1278                         bdst.grey += bdst.delta;
         1279                 }else{
         1280                         if(ma){
         1281                                 *bdst.red = *bsrc.red;
         1282                                 *bdst.grn = *bsrc.grn;
         1283                                 *bdst.blu = *bsrc.blu;
         1284                         }
         1285                         else if(zero)
         1286                                 *bdst.red = *bdst.grn = *bdst.blu = 0;
         1287                         bsrc.red += bsrc.delta;
         1288                         bsrc.blu += bsrc.delta;
         1289                         bsrc.grn += bsrc.delta;
         1290                         bdst.red += bdst.delta;
         1291                         bdst.blu += bdst.delta;
         1292                         bdst.grn += bdst.delta;
         1293                 }
         1294                 bmask.alpha += bmask.delta;
         1295                 if(bdst.alpha != &ones){
         1296                         if(ma)
         1297                                 *bdst.alpha = 255;
         1298                         else if(zero)
         1299                                 *bdst.alpha = 0;
         1300                         bdst.alpha += bdst.delta;
         1301                 }
         1302         }
         1303         return obdst;
         1304 }
         1305 /*
         1306  * Replicated cached scan line read.  Call the function listed in the Param,
         1307  * but cache the result so that for replicated images we only do the work once.
         1308  */
         1309 static Buffer
         1310 replread(Param *p, uchar *s, int y)
         1311 {
         1312         Buffer *b;
         1313 
         1314         USED(s);
         1315         b = &p->bcache[y];
         1316         if((p->bfilled & (1<<y)) == 0){
         1317                 p->bfilled |= 1<<y;
         1318                 *b = p->replcall(p, p->bufbase+y*p->bufdelta, y);
         1319         }
         1320         return *b;
         1321 }
         1322 
         1323 /*
         1324  * Alpha reading function that simply relabels the grey pointer.
         1325  */
         1326 static Buffer
         1327 greymaskread(Param *p, uchar *buf, int y)
         1328 {
         1329         Buffer b;
         1330 
         1331         b = p->greymaskcall(p, buf, y);
         1332         b.alpha = b.grey;
         1333         return b;
         1334 }
         1335 
         1336 #define DBG if(0)
         1337 static Buffer
         1338 readnbit(Param *p, uchar *buf, int y)
         1339 {
         1340         Buffer b;
         1341         Memimage *img;
         1342         uchar *repl, *r, *w, *ow, bits;
         1343         memset(&b, 0, sizeof b); // shut up gcc
         1344         int i, n, sh, depth, x, dx, npack, nbits;
         1345 
         1346         b.rgba = (uint32*)buf;
         1347         b.grey = w = buf;
         1348         b.red = b.blu = b.grn = w;
         1349         b.alpha = &ones;
         1350         b.delta = 1;
         1351 
         1352         dx = p->dx;
         1353         img = p->img;
         1354         depth = img->depth;
         1355         repl = &replbit[depth][0];
         1356         npack = 8/depth;
         1357         sh = 8-depth;
         1358 
         1359         /* copy from p->r.min.x until end of repl rectangle */
         1360         x = p->r.min.x;
         1361         n = dx;
         1362         if(n > p->img->r.max.x - x)
         1363                 n = p->img->r.max.x - x;
         1364 
         1365         r = p->bytermin + y*p->bwidth;
         1366 DBG print("readnbit dx %d %p=%p+%d*%d, *r=%d fetch %d ", dx, r, p->bytermin, y, p->bwidth, *r, n);
         1367         bits = *r++;
         1368         nbits = 8;
         1369         if((i=x&(npack-1))){
         1370 DBG print("throwaway %d...", i);
         1371                 bits <<= depth*i;
         1372                 nbits -= depth*i;
         1373         }
         1374         for(i=0; i<n; i++){
         1375                 if(nbits == 0){
         1376 DBG print("(%.2ux)...", *r);
         1377                         bits = *r++;
         1378                         nbits = 8;
         1379                 }
         1380                 *w++ = repl[bits>>sh];
         1381 DBG print("bit %x...", repl[bits>>sh]);
         1382                 bits <<= depth;
         1383                 nbits -= depth;
         1384         }
         1385         dx -= n;
         1386         if(dx == 0)
         1387                 return b;
         1388 
         1389         assert(x+i == p->img->r.max.x);
         1390 
         1391         /* copy from beginning of repl rectangle until where we were before. */
         1392         x = p->img->r.min.x;
         1393         n = dx;
         1394         if(n > p->r.min.x - x)
         1395                 n = p->r.min.x - x;
         1396 
         1397         r = p->bytey0s + y*p->bwidth;
         1398 DBG print("x=%d r=%p...", x, r);
         1399         bits = *r++;
         1400         nbits = 8;
         1401         if((i=x&(npack-1))){
         1402                 bits <<= depth*i;
         1403                 nbits -= depth*i;
         1404         }
         1405 DBG print("nbits=%d...", nbits);
         1406         for(i=0; i<n; i++){
         1407                 if(nbits == 0){
         1408                         bits = *r++;
         1409                         nbits = 8;
         1410                 }
         1411                 *w++ = repl[bits>>sh];
         1412 DBG print("bit %x...", repl[bits>>sh]);
         1413                 bits <<= depth;
         1414                 nbits -= depth;
         1415 DBG print("bits %x nbits %d...", bits, nbits);
         1416         }
         1417         dx -= n;
         1418         if(dx == 0)
         1419                 return b;
         1420 
         1421         assert(dx > 0);
         1422         /* now we have exactly one full scan line: just replicate the buffer itself until we are done */
         1423         ow = buf;
         1424         while(dx--)
         1425                 *w++ = *ow++;
         1426 
         1427         return b;
         1428 }
         1429 #undef DBG
         1430 
         1431 #define DBG if(0)
         1432 static void
         1433 writenbit(Param *p, uchar *w, Buffer src)
         1434 {
         1435         uchar *r;
         1436         uint32 bits;
         1437         int i, sh, depth, npack, nbits, x, ex;
         1438 
         1439         assert(src.grey != nil && src.delta == 1);
         1440 
         1441         x = p->r.min.x;
         1442         ex = x+p->dx;
         1443         depth = p->img->depth;
         1444         npack = 8/depth;
         1445 
         1446         i=x&(npack-1);
         1447         bits = i ? (*w >> (8-depth*i)) : 0;
         1448         nbits = depth*i;
         1449         sh = 8-depth;
         1450         r = src.grey;
         1451 
         1452         for(; x<ex; x++){
         1453                 bits <<= depth;
         1454 DBG print(" %x", *r);
         1455                 bits |= (*r++ >> sh);
         1456                 nbits += depth;
         1457                 if(nbits == 8){
         1458                         *w++ = bits;
         1459                         nbits = 0;
         1460                 }
         1461         }
         1462 
         1463         if(nbits){
         1464                 sh = 8-nbits;
         1465                 bits <<= sh;
         1466                 bits |= *w & ((1<<sh)-1);
         1467                 *w = bits;
         1468         }
         1469 DBG print("\n");
         1470         return;
         1471 }
         1472 #undef DBG
         1473 
         1474 static Buffer
         1475 readcmap(Param *p, uchar *buf, int y)
         1476 {
         1477         Buffer b;
         1478         int a, convgrey, copyalpha, dx, i, m;
         1479         uchar *q, *cmap, *begin, *end, *r, *w;
         1480         memset(&b, 0, sizeof b); // shut up gcc
         1481 
         1482         begin = p->bytey0s + y*p->bwidth;
         1483         r = p->bytermin + y*p->bwidth;
         1484         end = p->bytey0e + y*p->bwidth;
         1485         cmap = p->img->cmap->cmap2rgb;
         1486         convgrey = p->convgrey;
         1487         copyalpha = (p->img->flags&Falpha) ? 1 : 0;
         1488 
         1489         w = buf;
         1490         dx = p->dx;
         1491         if(copyalpha){
         1492                 b.alpha = buf++;
         1493                 a = p->img->shift[CAlpha]/8;
         1494                 m = p->img->shift[CMap]/8;
         1495                 for(i=0; i<dx; i++){
         1496                         *w++ = r[a];
         1497                         q = cmap+r[m]*3;
         1498                         r += 2;
         1499                         if(r == end)
         1500                                 r = begin;
         1501                         if(convgrey){
         1502                                 *w++ = RGB2K(q[0], q[1], q[2]);
         1503                         }else{
         1504                                 *w++ = q[2];        /* blue */
         1505                                 *w++ = q[1];        /* green */
         1506                                 *w++ = q[0];        /* red */
         1507                         }
         1508                 }
         1509         }else{
         1510                 b.alpha = &ones;
         1511                 for(i=0; i<dx; i++){
         1512                         q = cmap+*r++*3;
         1513                         if(r == end)
         1514                                 r = begin;
         1515                         if(convgrey){
         1516                                 *w++ = RGB2K(q[0], q[1], q[2]);
         1517                         }else{
         1518                                 *w++ = q[2];        /* blue */
         1519                                 *w++ = q[1];        /* green */
         1520                                 *w++ = q[0];        /* red */
         1521                         }
         1522                 }
         1523         }
         1524 
         1525         b.rgba = (uint32*)(buf-copyalpha);
         1526 
         1527         if(convgrey){
         1528                 b.grey = buf;
         1529                 b.red = b.blu = b.grn = buf;
         1530                 b.delta = 1+copyalpha;
         1531         }else{
         1532                 b.blu = buf;
         1533                 b.grn = buf+1;
         1534                 b.red = buf+2;
         1535                 b.grey = nil;
         1536                 b.delta = 3+copyalpha;
         1537         }
         1538         return b;
         1539 }
         1540 
         1541 static void
         1542 writecmap(Param *p, uchar *w, Buffer src)
         1543 {
         1544         uchar *cmap, *red, *grn, *blu;
         1545         int i, dx, delta;
         1546 
         1547         cmap = p->img->cmap->rgb2cmap;
         1548         
         1549         delta = src.delta;
         1550         red= src.red;
         1551         grn = src.grn;
         1552         blu = src.blu;
         1553 
         1554         dx = p->dx;
         1555         for(i=0; i<dx; i++, red+=delta, grn+=delta, blu+=delta)
         1556                 *w++ = cmap[(*red>>4)*256+(*grn>>4)*16+(*blu>>4)];
         1557 }
         1558 
         1559 #define DBG if(0)
         1560 static Buffer
         1561 readbyte(Param *p, uchar *buf, int y)
         1562 {
         1563         Buffer b;
         1564         Memimage *img;
         1565         int dx, isgrey, convgrey, alphaonly, copyalpha, i, nb;
         1566         uchar *begin, *end, *r, *w, *rrepl, *grepl, *brepl, *arepl, *krepl;
         1567         uchar ured, ugrn, ublu;
         1568         uint32 u;
         1569 
         1570         img = p->img;
         1571         begin = p->bytey0s + y*p->bwidth;
         1572         r = p->bytermin + y*p->bwidth;
         1573         end = p->bytey0e + y*p->bwidth;
         1574 
         1575         w = buf;
         1576         dx = p->dx;
         1577         nb = img->depth/8;
         1578 
         1579         convgrey = p->convgrey;        /* convert rgb to grey */
         1580         isgrey = img->flags&Fgrey;
         1581         alphaonly = p->alphaonly;
         1582         copyalpha = (img->flags&Falpha) ? 1 : 0;
         1583 
         1584 DBG print("copyalpha %d alphaonly %d convgrey %d isgrey %d\n", copyalpha, alphaonly, convgrey, isgrey);
         1585         /* if we can, avoid processing everything */
         1586         if(!(img->flags&Frepl) && !convgrey && (img->flags&Fbytes)){
         1587                 memset(&b, 0, sizeof b);
         1588                 if(p->needbuf){
         1589                         memmove(buf, r, dx*nb);
         1590                         r = buf;
         1591                 }
         1592                 b.rgba = (uint32*)r;
         1593                 if(copyalpha)
         1594                         b.alpha = r+img->shift[CAlpha]/8;
         1595                 else
         1596                         b.alpha = &ones;
         1597                 if(isgrey){
         1598                         b.grey = r+img->shift[CGrey]/8;
         1599                         b.red = b.grn = b.blu = b.grey;
         1600                 }else{
         1601                         b.red = r+img->shift[CRed]/8;
         1602                         b.grn = r+img->shift[CGreen]/8;
         1603                         b.blu = r+img->shift[CBlue]/8;
         1604                 }
         1605                 b.delta = nb;
         1606                 return b;
         1607         }
         1608 
         1609 DBG print("2\n");
         1610         rrepl = replbit[img->nbits[CRed]];
         1611         grepl = replbit[img->nbits[CGreen]];
         1612         brepl = replbit[img->nbits[CBlue]];
         1613         arepl = replbit[img->nbits[CAlpha]];
         1614         krepl = replbit[img->nbits[CGrey]];
         1615 
         1616         for(i=0; i<dx; i++){
         1617                 u = r[0] | (r[1]<<8) | (r[2]<<16) | (r[3]<<24);
         1618                 if(copyalpha) {
         1619                         *w++ = arepl[(u>>img->shift[CAlpha]) & img->mask[CAlpha]];
         1620 DBG print("a %x\n", w[-1]);
         1621                 }
         1622 
         1623                 if(isgrey)
         1624                         *w++ = krepl[(u >> img->shift[CGrey]) & img->mask[CGrey]];
         1625                 else if(!alphaonly){
         1626                         ured = rrepl[(u >> img->shift[CRed]) & img->mask[CRed]];
         1627                         ugrn = grepl[(u >> img->shift[CGreen]) & img->mask[CGreen]];
         1628                         ublu = brepl[(u >> img->shift[CBlue]) & img->mask[CBlue]];
         1629                         if(convgrey){
         1630 DBG print("g %x %x %x\n", ured, ugrn, ublu);
         1631                                 *w++ = RGB2K(ured, ugrn, ublu);
         1632 DBG print("%x\n", w[-1]);
         1633                         }else{
         1634                                 *w++ = brepl[(u >> img->shift[CBlue]) & img->mask[CBlue]];
         1635                                 *w++ = grepl[(u >> img->shift[CGreen]) & img->mask[CGreen]];
         1636                                 *w++ = rrepl[(u >> img->shift[CRed]) & img->mask[CRed]];
         1637                         }
         1638                 }
         1639                 r += nb;
         1640                 if(r == end)
         1641                         r = begin;
         1642         }
         1643         
         1644         b.alpha = copyalpha ? buf : &ones;
         1645         b.rgba = (uint32*)buf;
         1646         if(alphaonly){
         1647                 b.red = b.grn = b.blu = b.grey = nil;
         1648                 if(!copyalpha)
         1649                         b.rgba = nil;
         1650                 b.delta = 1;
         1651         }else if(isgrey || convgrey){
         1652                 b.grey = buf+copyalpha;
         1653                 b.red = b.grn = b.blu = buf+copyalpha;
         1654                 b.delta = copyalpha+1;
         1655 DBG print("alpha %x grey %x\n", b.alpha ? *b.alpha : 0xFF, *b.grey);
         1656         }else{
         1657                 b.blu = buf+copyalpha;
         1658                 b.grn = buf+copyalpha+1;
         1659                 b.grey = nil;
         1660                 b.red = buf+copyalpha+2;
         1661                 b.delta = copyalpha+3;
         1662         }
         1663         return b;
         1664 }
         1665 #undef DBG
         1666 
         1667 #define DBG if(0)
         1668 static void
         1669 writebyte(Param *p, uchar *w, Buffer src)
         1670 {
         1671         Memimage *img;
         1672         int i, isalpha, isgrey, nb, delta, dx, adelta;
         1673         uchar ff, *red, *grn, *blu, *grey, *alpha;
         1674         uint32 u, mask;
         1675 
         1676         img = p->img;
         1677 
         1678         red = src.red;
         1679         grn = src.grn;
         1680         blu = src.blu;
         1681         alpha = src.alpha;
         1682         delta = src.delta;
         1683         grey = src.grey;
         1684         dx = p->dx;
         1685 
         1686         nb = img->depth/8;
         1687         mask = (nb==4) ? 0 : ~((1<<img->depth)-1);
         1688 
         1689         isalpha = img->flags&Falpha;
         1690         isgrey = img->flags&Fgrey;
         1691         adelta = src.delta;
         1692 
         1693         if(isalpha && (alpha == nil || alpha == &ones)){
         1694                 ff = 0xFF;
         1695                 alpha = &ff;
         1696                 adelta = 0;
         1697         }
         1698 
         1699         for(i=0; i<dx; i++){
         1700                 u = w[0] | (w[1]<<8) | (w[2]<<16) | (w[3]<<24);
         1701 DBG print("u %.8lux...", u);
         1702                 u &= mask;
         1703 DBG print("&mask %.8lux...", u);
         1704                 if(isgrey){
         1705                         u |= ((*grey >> (8-img->nbits[CGrey])) & img->mask[CGrey]) << img->shift[CGrey];
         1706 DBG print("|grey %.8lux...", u);
         1707                         grey += delta;
         1708                 }else{
         1709                         u |= ((*red >> (8-img->nbits[CRed])) & img->mask[CRed]) << img->shift[CRed];
         1710                         u |= ((*grn >> (8-img->nbits[CGreen])) & img->mask[CGreen]) << img->shift[CGreen];
         1711                         u |= ((*blu >> (8-img->nbits[CBlue])) & img->mask[CBlue]) << img->shift[CBlue];
         1712                         red += delta;
         1713                         grn += delta;
         1714                         blu += delta;
         1715 DBG print("|rgb %.8lux...", u);
         1716                 }
         1717 
         1718                 if(isalpha){
         1719                         u |= ((*alpha >> (8-img->nbits[CAlpha])) & img->mask[CAlpha]) << img->shift[CAlpha];
         1720                         alpha += adelta;
         1721 DBG print("|alpha %.8lux...", u);
         1722                 }
         1723 
         1724                 w[0] = u;
         1725                 w[1] = u>>8;
         1726                 w[2] = u>>16;
         1727                 w[3] = u>>24;
         1728                 w += nb;
         1729         }
         1730 }
         1731 #undef DBG
         1732 
         1733 static Readfn*
         1734 readfn(Memimage *img)
         1735 {
         1736         if(img->depth < 8)
         1737                 return readnbit;
         1738         if(img->nbits[CMap] == 8)
         1739                 return readcmap;
         1740         return readbyte;
         1741 }
         1742 
         1743 static Readfn*
         1744 readalphafn(Memimage *m)
         1745 {
         1746         USED(m);
         1747         return readbyte;
         1748 }
         1749 
         1750 static Writefn*
         1751 writefn(Memimage *img)
         1752 {
         1753         if(img->depth < 8)
         1754                 return writenbit;
         1755         if(img->chan == CMAP8)
         1756                 return writecmap;
         1757         return writebyte;
         1758 }
         1759 
         1760 static void
         1761 nullwrite(Param *p, uchar *s, Buffer b)
         1762 {
         1763         USED(p);
         1764         USED(s);
         1765         USED(b);
         1766 }
         1767 
         1768 static Buffer
         1769 readptr(Param *p, uchar *s, int y)
         1770 {
         1771         Buffer b;
         1772         uchar *q;
         1773 
         1774         memset(&b, 0, sizeof b); // shut up gcc
         1775         USED(s);
         1776         q = p->bytermin + y*p->bwidth;
         1777         b.red = q;        /* ptr to data */
         1778         b.grn = b.blu = b.grey = b.alpha = nil;
         1779         b.rgba = (uint32*)q;
         1780         b.delta = p->img->depth/8;
         1781         return b;
         1782 }
         1783 
         1784 static Buffer
         1785 boolmemmove(Buffer bdst, Buffer bsrc, Buffer b1, int dx, int i, int o)
         1786 {
         1787         USED(i);
         1788         USED(o);
         1789         USED(b1);
         1790         USED(bsrc);
         1791         memmove(bdst.red, bsrc.red, dx*bdst.delta);
         1792         return bdst;
         1793 }
         1794 
         1795 static Buffer
         1796 boolcopy8(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
         1797 {
         1798         uchar *m, *r, *w, *ew;
         1799 
         1800         USED(i);
         1801         USED(o);
         1802         m = bmask.grey;
         1803         w = bdst.red;
         1804         r = bsrc.red;
         1805         ew = w+dx;
         1806         for(; w < ew; w++,r++)
         1807                 if(*m++)
         1808                         *w = *r;
         1809         return bdst;        /* not used */
         1810 }
         1811 
         1812 static Buffer
         1813 boolcopy16(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
         1814 {
         1815         uchar *m;
         1816         ushort *r, *w, *ew;
         1817 
         1818         USED(i);
         1819         USED(o);
         1820         m = bmask.grey;
         1821         w = (ushort*)bdst.red;
         1822         r = (ushort*)bsrc.red;
         1823         ew = w+dx;
         1824         for(; w < ew; w++,r++)
         1825                 if(*m++)
         1826                         *w = *r;
         1827         return bdst;        /* not used */
         1828 }
         1829 
         1830 static Buffer
         1831 boolcopy24(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
         1832 {
         1833         uchar *m;
         1834         uchar *r, *w, *ew;
         1835 
         1836         USED(i);
         1837         USED(o);
         1838         m = bmask.grey;
         1839         w = bdst.red;
         1840         r = bsrc.red;
         1841         ew = w+dx*3;
         1842         while(w < ew){
         1843                 if(*m++){
         1844                         *w++ = *r++;
         1845                         *w++ = *r++;
         1846                         *w++ = *r++;
         1847                 }else{
         1848                         w += 3;
         1849                         r += 3;
         1850                 }
         1851         }
         1852         return bdst;        /* not used */
         1853 }
         1854 
         1855 static Buffer
         1856 boolcopy32(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
         1857 {
         1858         uchar *m;
         1859         uint32 *r, *w, *ew;
         1860 
         1861         USED(i);
         1862         USED(o);
         1863         m = bmask.grey;
         1864         w = (uint32*)bdst.red;
         1865         r = (uint32*)bsrc.red;
         1866         ew = w+dx;
         1867         for(; w < ew; w++,r++)
         1868                 if(*m++)
         1869                         *w = *r;
         1870         return bdst;        /* not used */
         1871 }
         1872 
         1873 static Buffer
         1874 genconv(Param *p, uchar *buf, int y)
         1875 {
         1876         Buffer b;
         1877         int nb;
         1878         uchar *r, *w, *ew;
         1879 
         1880         /* read from source into RGB format in convbuf */
         1881         b = p->convreadcall(p, p->convbuf, y);
         1882 
         1883         /* write RGB format into dst format in buf */
         1884         p->convwritecall(p->convdpar, buf, b);
         1885 
         1886         if(p->convdx){
         1887                 nb = p->convdpar->img->depth/8;
         1888                 r = buf;
         1889                 w = buf+nb*p->dx;
         1890                 ew = buf+nb*p->convdx;
         1891                 while(w<ew)
         1892                         *w++ = *r++;
         1893         }
         1894 
         1895         b.red = buf;
         1896         b.blu = b.grn = b.grey = b.alpha = nil;
         1897         b.rgba = (uint32*)buf;
         1898         b.delta = 0;
         1899         
         1900         return b;
         1901 }
         1902 
         1903 static Readfn*
         1904 convfn(Memimage *dst, Param *dpar, Memimage *src, Param *spar, int *ndrawbuf)
         1905 {
         1906         if(dst->chan == src->chan && !(src->flags&Frepl)){
         1907 //if(drawdebug) iprint("readptr...");
         1908                 return readptr;
         1909         }
         1910 
         1911         if(dst->chan==CMAP8 && (src->chan==GREY1||src->chan==GREY2||src->chan==GREY4)){
         1912                 /* cheat because we know the replicated value is exactly the color map entry. */
         1913 //if(drawdebug) iprint("Readnbit...");
         1914                 return readnbit;
         1915         }
         1916 
         1917         spar->convreadcall = readfn(src);
         1918         spar->convwritecall = writefn(dst);
         1919         spar->convdpar = dpar;
         1920 
         1921         /* allocate a conversion buffer */
         1922         spar->convbufoff = *ndrawbuf;
         1923         *ndrawbuf += spar->dx*4;
         1924 
         1925         if(spar->dx > Dx(spar->img->r)){
         1926                 spar->convdx = spar->dx;
         1927                 spar->dx = Dx(spar->img->r);
         1928         }
         1929 
         1930 //if(drawdebug) iprint("genconv...");
         1931         return genconv;
         1932 }
         1933 
         1934 uint32
         1935 _pixelbits(Memimage *i, Point pt)
         1936 {
         1937         uchar *p;
         1938         uint32 val;
         1939         int off, bpp, npack;
         1940 
         1941         val = 0;
         1942         p = byteaddr(i, pt);
         1943         switch(bpp=i->depth){
         1944         case 1:
         1945         case 2:
         1946         case 4:
         1947                 npack = 8/bpp;
         1948                 off = pt.x%npack;
         1949                 val = p[0] >> bpp*(npack-1-off);
         1950                 val &= (1<<bpp)-1;
         1951                 break;
         1952         case 8:
         1953                 val = p[0];
         1954                 break;
         1955         case 16:
         1956                 val = p[0]|(p[1]<<8);
         1957                 break;
         1958         case 24:
         1959                 val = p[0]|(p[1]<<8)|(p[2]<<16);
         1960                 break;
         1961         case 32:
         1962                 val = p[0]|(p[1]<<8)|(p[2]<<16)|(p[3]<<24);
         1963                 break;
         1964         }
         1965         while(bpp<32){
         1966                 val |= val<<bpp;
         1967                 bpp *= 2;
         1968         }
         1969         return val;
         1970 }
         1971 
         1972 static Calcfn*
         1973 boolcopyfn(Memimage *img, Memimage *mask)
         1974 {
         1975         if(mask->flags&Frepl && Dx(mask->r)==1 && Dy(mask->r)==1 && pixelbits(mask, mask->r.min)==~0)
         1976                 return boolmemmove;
         1977 
         1978         switch(img->depth){
         1979         case 8:
         1980                 return boolcopy8;
         1981         case 16:
         1982                 return boolcopy16;
         1983         case 24:
         1984                 return boolcopy24;
         1985         case 32:
         1986                 return boolcopy32;
         1987         default:
         1988                 assert(0 /* boolcopyfn */);
         1989         }
         1990         return nil;
         1991 }
         1992 
         1993 /*
         1994  * Optimized draw for filling and scrolling; uses memset and memmove.
         1995  */
         1996 #if 0
         1997 static void
         1998 memsetb(void *vp, uchar val, int n)
         1999 {
         2000         uchar *p, *ep;
         2001 
         2002         p = vp;
         2003         ep = p+n;
         2004         while(p<ep)
         2005                 *p++ = val;
         2006 }
         2007 #endif
         2008 
         2009 static void
         2010 memsets(void *vp, ushort val, int n)
         2011 {
         2012         ushort *p, *ep;
         2013 
         2014         p = vp;
         2015         ep = p+n;
         2016         while(p<ep)
         2017                 *p++ = val;
         2018 }
         2019 
         2020 static void
         2021 memsetl(void *vp, uint32 val, int n)
         2022 {
         2023         uint32 *p, *ep;
         2024 
         2025         p = vp;
         2026         ep = p+n;
         2027         while(p<ep)
         2028                 *p++ = val;
         2029 }
         2030 
         2031 static void
         2032 memset24(void *vp, uint32 val, int n)
         2033 {
         2034         uchar *p, *ep;
         2035         uchar a,b,c;
         2036 
         2037         p = vp;
         2038         ep = p+3*n;
         2039         a = val;
         2040         b = val>>8;
         2041         c = val>>16;
         2042         while(p<ep){
         2043                 *p++ = a;
         2044                 *p++ = b;
         2045                 *p++ = c;
         2046         }
         2047 }
         2048 
         2049 uint32
         2050 _imgtorgba(Memimage *img, uint32 val)
         2051 {
         2052         uchar r, g, b, a;
         2053         int nb, ov, v;
         2054         uint32 chan;
         2055         uchar *p;
         2056 
         2057         a = 0xFF;
         2058         r = g = b = 0xAA;        /* garbage */
         2059         for(chan=img->chan; chan; chan>>=8){
         2060                 nb = NBITS(chan);
         2061                 ov = v = val&((1<<nb)-1);
         2062                 val >>= nb;
         2063 
         2064                 while(nb < 8){
         2065                         v |= v<<nb;
         2066                         nb *= 2;
         2067                 }
         2068                 v >>= (nb-8);
         2069 
         2070                 switch(TYPE(chan)){
         2071                 case CRed:
         2072                         r = v;
         2073                         break;
         2074                 case CGreen:
         2075                         g = v;
         2076                         break;
         2077                 case CBlue:
         2078                         b = v;
         2079                         break;
         2080                 case CAlpha:
         2081                         a = v;
         2082                         break;
         2083                 case CGrey:
         2084                         r = g = b = v;
         2085                         break;
         2086                 case CMap:
         2087                         p = img->cmap->cmap2rgb+3*ov;
         2088                         r = *p++;
         2089                         g = *p++;        
         2090                         b = *p;
         2091                         break;
         2092                 }
         2093         }
         2094         return (r<<24)|(g<<16)|(b<<8)|a;        
         2095 }
         2096 
         2097 uint32
         2098 _rgbatoimg(Memimage *img, uint32 rgba)
         2099 {
         2100         uint32 chan;
         2101         int d, nb;
         2102         uint32 v;
         2103         uchar *p, r, g, b, a, m;
         2104 
         2105         v = 0;
         2106         r = rgba>>24;
         2107         g = rgba>>16;
         2108         b = rgba>>8;
         2109         a = rgba;
         2110         d = 0;
         2111         for(chan=img->chan; chan; chan>>=8){
         2112                 nb = NBITS(chan);
         2113                 switch(TYPE(chan)){
         2114                 case CRed:
         2115                         v |= (r>>(8-nb))<<d;
         2116                         break;
         2117                 case CGreen:
         2118                         v |= (g>>(8-nb))<<d;
         2119                         break;
         2120                 case CBlue:
         2121                         v |= (b>>(8-nb))<<d;
         2122                         break;
         2123                 case CAlpha:
         2124                         v |= (a>>(8-nb))<<d;
         2125                         break;
         2126                 case CMap:
         2127                         p = img->cmap->rgb2cmap;
         2128                         m = p[(r>>4)*256+(g>>4)*16+(b>>4)];
         2129                         v |= (m>>(8-nb))<<d;
         2130                         break;
         2131                 case CGrey:
         2132                         m = RGB2K(r,g,b);
         2133                         v |= (m>>(8-nb))<<d;
         2134                         break;
         2135                 }
         2136                 d += nb;
         2137         }
         2138 //        print("rgba2img %.8lux = %.*lux\n", rgba, 2*d/8, v);
         2139         return v;
         2140 }
         2141 
         2142 #define DBG if(0)
         2143 static int
         2144 memoptdraw(Memdrawparam *par)
         2145 {
         2146         int m, y, dy, dx, op;
         2147         uint32 v;
         2148         Memimage *src;
         2149         Memimage *dst;
         2150 
         2151         dx = Dx(par->r);
         2152         dy = Dy(par->r);
         2153         src = par->src;
         2154         dst = par->dst;
         2155         op = par->op;
         2156 
         2157 DBG print("state %lux mval %lux dd %d\n", par->state, par->mval, dst->depth);
         2158         /*
         2159          * If we have an opaque mask and source is one opaque pixel we can convert to the
         2160          * destination format and just replicate with memset.
         2161          */
         2162         m = Simplesrc|Simplemask|Fullmask;
         2163         if((par->state&m)==m && (par->srgba&0xFF) == 0xFF && (op ==S || op == SoverD)){
         2164                 uchar *dp, p[4];
         2165                 int d, dwid, ppb, np, nb;
         2166                 uchar lm, rm;
         2167 
         2168 DBG print("memopt, dst %p, dst->data->bdata %p\n", dst, dst->data->bdata);
         2169                 dwid = dst->width*sizeof(uint32);
         2170                 dp = byteaddr(dst, par->r.min);
         2171                 v = par->sdval;
         2172 DBG print("sdval %lud, depth %d\n", v, dst->depth);
         2173                 switch(dst->depth){
         2174                 case 1:
         2175                 case 2:
         2176                 case 4:
         2177                         for(d=dst->depth; d<8; d*=2)
         2178                                 v |= (v<<d);
         2179                         ppb = 8/dst->depth;        /* pixels per byte */
         2180                         m = ppb-1;
         2181                         /* left edge */
         2182                         np = par->r.min.x&m;                /* no. pixels unused on left side of word */
         2183                         dx -= (ppb-np);
         2184                         nb = 8 - np * dst->depth;                /* no. bits used on right side of word */
         2185                         lm = (1<<nb)-1;
         2186 DBG print("np %d x %d nb %d lm %ux ppb %d m %ux\n", np, par->r.min.x, nb, lm, ppb, m);        
         2187 
         2188                         /* right edge */
         2189                         np = par->r.max.x&m;        /* no. pixels used on left side of word */
         2190                         dx -= np;
         2191                         nb = 8 - np * dst->depth;                /* no. bits unused on right side of word */
         2192                         rm = ~((1<<nb)-1);
         2193 DBG print("np %d x %d nb %d rm %ux ppb %d m %ux\n", np, par->r.max.x, nb, rm, ppb, m);        
         2194 
         2195 DBG print("dx %d Dx %d\n", dx, Dx(par->r));
         2196                         /* lm, rm are masks that are 1 where we should touch the bits */
         2197                         if(dx < 0){        /* just one byte */
         2198                                 lm &= rm;
         2199                                 for(y=0; y<dy; y++, dp+=dwid)
         2200                                         *dp ^= (v ^ *dp) & lm;
         2201                         }else if(dx == 0){        /* no full bytes */
         2202                                 if(lm)
         2203                                         dwid--;
         2204 
         2205                                 for(y=0; y<dy; y++, dp+=dwid){
         2206                                         if(lm){
         2207 DBG print("dp %p v %lux lm %ux (v ^ *dp) & lm %lux\n", dp, v, lm, (v^*dp)&lm);
         2208                                                 *dp ^= (v ^ *dp) & lm;
         2209                                                 dp++;
         2210                                         }
         2211                                         *dp ^= (v ^ *dp) & rm;
         2212                                 }
         2213                         }else{                /* full bytes in middle */
         2214                                 dx /= ppb;
         2215                                 if(lm)
         2216                                         dwid--;
         2217                                 dwid -= dx;
         2218 
         2219                                 for(y=0; y<dy; y++, dp+=dwid){
         2220                                         if(lm){
         2221                                                 *dp ^= (v ^ *dp) & lm;
         2222                                                 dp++;
         2223                                         }
         2224                                         memset(dp, v, dx);
         2225                                         dp += dx;
         2226                                         *dp ^= (v ^ *dp) & rm;
         2227                                 }
         2228                         }
         2229                         return 1;
         2230                 case 8:
         2231                         for(y=0; y<dy; y++, dp+=dwid)
         2232                                 memset(dp, v, dx);
         2233                         return 1;
         2234                 case 16:
         2235                         p[0] = v;                /* make little endian */
         2236                         p[1] = v>>8;
         2237                         v = *(ushort*)p;
         2238 DBG print("dp=%p; dx=%d; for(y=0; y<%d; y++, dp+=%d)\nmemsets(dp, v, dx);\n",
         2239         dp, dx, dy, dwid);
         2240                         for(y=0; y<dy; y++, dp+=dwid)
         2241                                 memsets(dp, v, dx);
         2242                         return 1;
         2243                 case 24:
         2244                         for(y=0; y<dy; y++, dp+=dwid)
         2245                                 memset24(dp, v, dx);
         2246                         return 1;
         2247                 case 32:
         2248                         p[0] = v;                /* make little endian */
         2249                         p[1] = v>>8;
         2250                         p[2] = v>>16;
         2251                         p[3] = v>>24;
         2252                         v = *(uint32*)p;
         2253                         for(y=0; y<dy; y++, dp+=dwid)
         2254                                 memsetl(dp, v, dx);
         2255                         return 1;
         2256                 default:
         2257                         assert(0 /* bad dest depth in memoptdraw */);
         2258                 }
         2259         }
         2260 
         2261         /*
         2262          * If no source alpha, an opaque mask, we can just copy the
         2263          * source onto the destination.  If the channels are the same and
         2264          * the source is not replicated, memmove suffices.
         2265          */
         2266         m = Simplemask|Fullmask;
         2267         if((par->state&(m|Replsrc))==m && src->depth >= 8 
         2268         && src->chan == dst->chan && !(src->flags&Falpha) && (op == S || op == SoverD)){
         2269                 uchar *sp, *dp;
         2270                 long swid, dwid, nb;
         2271                 int dir;
         2272 
         2273                 if(src->data == dst->data && byteaddr(dst, par->r.min) > byteaddr(src, par->sr.min))
         2274                         dir = -1;
         2275                 else
         2276                         dir = 1;
         2277 
         2278                 swid = src->width*sizeof(uint32);
         2279                 dwid = dst->width*sizeof(uint32);
         2280                 sp = byteaddr(src, par->sr.min);
         2281                 dp = byteaddr(dst, par->r.min);
         2282                 if(dir == -1){
         2283                         sp += (dy-1)*swid;
         2284                         dp += (dy-1)*dwid;
         2285                         swid = -swid;
         2286                         dwid = -dwid;
         2287                 }
         2288                 nb = (dx*src->depth)/8;
         2289                 for(y=0; y<dy; y++, sp+=swid, dp+=dwid)
         2290                         memmove(dp, sp, nb);
         2291                 return 1;
         2292         }
         2293 
         2294         /*
         2295          * If we have a 1-bit mask, 1-bit source, and 1-bit destination, and
         2296          * they're all bit aligned, we can just use bit operators.  This happens
         2297          * when we're manipulating boolean masks, e.g. in the arc code.
         2298          */
         2299         if((par->state&(Simplemask|Simplesrc|Replmask|Replsrc))==0 
         2300         && dst->chan==GREY1 && src->chan==GREY1 && par->mask->chan==GREY1 
         2301         && (par->r.min.x&7)==(par->sr.min.x&7) && (par->r.min.x&7)==(par->mr.min.x&7)){
         2302                 uchar *sp, *dp, *mp;
         2303                 uchar lm, rm;
         2304                 long swid, dwid, mwid;
         2305                 int i, x, dir;
         2306 
         2307                 sp = byteaddr(src, par->sr.min);
         2308                 dp = byteaddr(dst, par->r.min);
         2309                 mp = byteaddr(par->mask, par->mr.min);
         2310                 swid = src->width*sizeof(uint32);
         2311                 dwid = dst->width*sizeof(uint32);
         2312                 mwid = par->mask->width*sizeof(uint32);
         2313 
         2314                 if(src->data == dst->data && byteaddr(dst, par->r.min) > byteaddr(src, par->sr.min)){
         2315                         dir = -1;
         2316                 }else
         2317                         dir = 1;
         2318 
         2319                 lm = 0xFF>>(par->r.min.x&7);
         2320                 rm = 0xFF<<(8-(par->r.max.x&7));
         2321                 dx -= (8-(par->r.min.x&7)) + (par->r.max.x&7);
         2322 
         2323                 if(dx < 0){        /* one byte wide */
         2324                         lm &= rm;
         2325                         if(dir == -1){
         2326                                 dp += dwid*(dy-1);
         2327                                 sp += swid*(dy-1);
         2328                                 mp += mwid*(dy-1);
         2329                                 dwid = -dwid;
         2330                                 swid = -swid;
         2331                                 mwid = -mwid;
         2332                         }
         2333                         for(y=0; y<dy; y++){
         2334                                 *dp ^= (*dp ^ *sp) & *mp & lm;
         2335                                 dp += dwid;
         2336                                 sp += swid;
         2337                                 mp += mwid;
         2338                         }
         2339                         return 1;
         2340                 }
         2341 
         2342                 dx /= 8;
         2343                 if(dir == 1){
         2344                         i = (lm!=0)+dx+(rm!=0);
         2345                         mwid -= i;
         2346                         swid -= i;
         2347                         dwid -= i;
         2348                         for(y=0; y<dy; y++, dp+=dwid, sp+=swid, mp+=mwid){
         2349                                 if(lm){
         2350                                         *dp ^= (*dp ^ *sp++) & *mp++ & lm;
         2351                                         dp++;
         2352                                 }
         2353                                 for(x=0; x<dx; x++){
         2354                                         *dp ^= (*dp ^ *sp++) & *mp++;
         2355                                         dp++;
         2356                                 }
         2357                                 if(rm){
         2358                                         *dp ^= (*dp ^ *sp++) & *mp++ & rm;
         2359                                         dp++;
         2360                                 }
         2361                         }
         2362                         return 1;
         2363                 }else{
         2364                 /* dir == -1 */
         2365                         i = (lm!=0)+dx+(rm!=0);
         2366                         dp += dwid*(dy-1)+i-1;
         2367                         sp += swid*(dy-1)+i-1;
         2368                         mp += mwid*(dy-1)+i-1;
         2369                         dwid = -dwid+i;
         2370                         swid = -swid+i;
         2371                         mwid = -mwid+i;
         2372                         for(y=0; y<dy; y++, dp+=dwid, sp+=swid, mp+=mwid){
         2373                                 if(rm){
         2374                                         *dp ^= (*dp ^ *sp--) & *mp-- & rm;
         2375                                         dp--;
         2376                                 }
         2377                                 for(x=0; x<dx; x++){
         2378                                         *dp ^= (*dp ^ *sp--) & *mp--;
         2379                                         dp--;
         2380                                 }
         2381                                 if(lm){
         2382                                         *dp ^= (*dp ^ *sp--) & *mp-- & lm;
         2383                                         dp--;
         2384                                 }
         2385                         }
         2386                 }
         2387                 return 1;
         2388         }
         2389         return 0;        
         2390 }
         2391 #undef DBG
         2392 
         2393 /*
         2394  * Boolean character drawing.
         2395  * Solid opaque color through a 1-bit greyscale mask.
         2396  */
         2397 #define DBG if(0)
         2398 static int
         2399 chardraw(Memdrawparam *par)
         2400 {
         2401         uint32 bits;
         2402         int i, ddepth, dy, dx, x, bx, ex, y, npack, bsh, depth, op;
         2403         uint32 v, maskwid, dstwid;
         2404         uchar *wp, *rp, *q, *wc;
         2405         ushort *ws;
         2406         uint32 *wl;
         2407         uchar sp[4];
         2408         Rectangle r, mr;
         2409         Memimage *mask, *src, *dst;
         2410 
         2411 if(0) if(drawdebug) iprint("chardraw? mf %lux md %d sf %lux dxs %d dys %d dd %d ddat %p sdat %p\n",
         2412                 par->mask->flags, par->mask->depth, par->src->flags, 
         2413                 Dx(par->src->r), Dy(par->src->r), par->dst->depth, par->dst->data, par->src->data);
         2414 
         2415         mask = par->mask;
         2416         src = par->src;
         2417         dst = par->dst;
         2418         r = par->r;
         2419         mr = par->mr;
         2420         op = par->op;
         2421 
         2422         if((par->state&(Replsrc|Simplesrc|Fullsrc|Replmask)) != (Replsrc|Simplesrc|Fullsrc)
         2423         || mask->depth != 1 || src->flags&Falpha || dst->depth<8 || dst->data==src->data
         2424         || op != SoverD)
         2425                 return 0;
         2426 
         2427 //if(drawdebug) iprint("chardraw...");
         2428 
         2429         depth = mask->depth;
         2430         maskwid = mask->width*sizeof(uint32);
         2431         rp = byteaddr(mask, mr.min);
         2432         npack = 8/depth;
         2433         bsh = (mr.min.x % npack) * depth;
         2434 
         2435         wp = byteaddr(dst, r.min);
         2436         dstwid = dst->width*sizeof(uint32);
         2437 DBG print("bsh %d\n", bsh);
         2438         dy = Dy(r);
         2439         dx = Dx(r);
         2440 
         2441         ddepth = dst->depth;
         2442 
         2443         /*
         2444          * for loop counts from bsh to bsh+dx
         2445          *
         2446          * we want the bottom bits to be the amount
         2447          * to shift the pixels down, so for n≡0 (mod 8) we want 
         2448          * bottom bits 7.  for n≡1, 6, etc.
         2449          * the bits come from -n-1.
         2450          */
         2451 
         2452         bx = -bsh-1;
         2453         ex = -bsh-1-dx;
         2454         bits=0;
         2455         v = par->sdval;
         2456 
         2457         /* make little endian */
         2458         sp[0] = v;
         2459         sp[1] = v>>8;
         2460         sp[2] = v>>16;
         2461         sp[3] = v>>24;
         2462 
         2463 //print("sp %x %x %x %x\n", sp[0], sp[1], sp[2], sp[3]);
         2464         for(y=0; y<dy; y++, rp+=maskwid, wp+=dstwid){
         2465                 q = rp;
         2466                 if(bsh)
         2467                         bits = *q++;
         2468                 switch(ddepth){
         2469                 case 8:
         2470 //if(drawdebug) iprint("8loop...");
         2471                         wc = wp;
         2472                         for(x=bx; x>ex; x--, wc++){
         2473                                 i = x&7;
         2474                                 if(i == 8-1)
         2475                                         bits = *q++;
         2476 DBG print("bits %lux sh %d...", bits, i);
         2477                                 if((bits>>i)&1)
         2478                                         *wc = v;
         2479                         }
         2480                         break;
         2481                 case 16:
         2482                         ws = (ushort*)wp;
         2483                         v = *(ushort*)sp;
         2484                         for(x=bx; x>ex; x--, ws++){
         2485                                 i = x&7;
         2486                                 if(i == 8-1)
         2487                                         bits = *q++;
         2488 DBG print("bits %lux sh %d...", bits, i);
         2489                                 if((bits>>i)&1)
         2490                                         *ws = v;
         2491                         }
         2492                         break;
         2493                 case 24:
         2494                         wc = wp;
         2495                         for(x=bx; x>ex; x--, wc+=3){
         2496                                 i = x&7;
         2497                                 if(i == 8-1)
         2498                                         bits = *q++;
         2499 DBG print("bits %lux sh %d...", bits, i);
         2500                                 if((bits>>i)&1){
         2501                                         wc[0] = sp[0];
         2502                                         wc[1] = sp[1];
         2503                                         wc[2] = sp[2];
         2504                                 }
         2505                         }
         2506                         break;
         2507                 case 32:
         2508                         wl = (uint32*)wp;
         2509                         v = *(uint32*)sp;
         2510                         for(x=bx; x>ex; x--, wl++){
         2511                                 i = x&7;
         2512                                 if(i == 8-1)
         2513                                         bits = *q++;
         2514 DBG iprint("bits %lux sh %d...", bits, i);
         2515                                 if((bits>>i)&1)
         2516                                         *wl = v;
         2517                         }
         2518                         break;
         2519                 }
         2520         }
         2521 
         2522 DBG print("\n");        
         2523         return 1;        
         2524 }
         2525 #undef DBG
         2526 
         2527 
         2528 /*
         2529  * Fill entire byte with replicated (if necessary) copy of source pixel,
         2530  * assuming destination ldepth is >= source ldepth.
         2531  *
         2532  * This code is just plain wrong for >8bpp.
         2533  *
         2534 uint32
         2535 membyteval(Memimage *src)
         2536 {
         2537         int i, val, bpp;
         2538         uchar uc;
         2539 
         2540         unloadmemimage(src, src->r, &uc, 1);
         2541         bpp = src->depth;
         2542         uc <<= (src->r.min.x&(7/src->depth))*src->depth;
         2543         uc &= ~(0xFF>>bpp);
         2544         // pixel value is now in high part of byte. repeat throughout byte 
         2545         val = uc;
         2546         for(i=bpp; i<8; i<<=1)
         2547                 val |= val>>i;
         2548         return val;
         2549 }
         2550  * 
         2551  */
         2552 
         2553 void
         2554 _memfillcolor(Memimage *i, uint32 val)
         2555 {
         2556         uint32 bits;
         2557         int d, y;
         2558 
         2559         if(val == DNofill)
         2560                 return;
         2561 
         2562         bits = _rgbatoimg(i, val);
         2563         switch(i->depth){
         2564         case 24:        /* 24-bit images suck */
         2565                 for(y=i->r.min.y; y<i->r.max.y; y++)
         2566                         memset24(byteaddr(i, Pt(i->r.min.x, y)), bits, Dx(i->r));
         2567                 break;
         2568         default:        /* 1, 2, 4, 8, 16, 32 */
         2569                 for(d=i->depth; d<32; d*=2)
         2570                         bits = (bits << d) | bits;
         2571                 memsetl(wordaddr(i, i->r.min), bits, i->width*Dy(i->r));
         2572                 break;
         2573         }
         2574 }
         2575