#include <X11/Xlib.h>
#include <X11/Xutil.h>
#define XK_MISCELLANY
#include <X11/keysymdef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <unistd.h>
#include <termios.h>
#include <signal.h>
#include <locale.h>
#include <errno.h>
#include <libutil.h>

#define BW 2

#define FONT_US "-ncd-terminal-medium-r-normal--18-*-iso646-us"
#define FONT_SE "-ncd-terminal-medium-r-normal--18-*-iso646-se2"

Display *d;
Window w;
GC tgc, fgc;
Pixmap wsave, csave;
Atom wm_protocols, wm_delete_window;

int cols = 80;
int lines = 25;
int pheight = 66;

int wx = 0, wy = 0, ww, wh;
char *fg = "#acaaac";
char *bg = "black";

char *font_us = FONT_US;
char *font_se = FONT_SE;
XFontStruct *fi_us, *fi_se;
int cw, ch, asc, desc;
int x, y;

char *shell;

int ptyfd, xfd;

int glass = 0;

int baud, delay;


static void wrestore()
{
    XCopyArea(d, wsave, w, tgc, 0, 0, ww + (BW*2), wh + (BW*2), 0, 0);
}

static void cur(int state)
{
    static int first = 1;

    if (state) {
	XCopyArea(d, w, csave, tgc, x, y - asc, cw, ch, 0, 0);
	XFillRectangle(d, w, tgc, x, y - asc, cw, ch);
	XCopyArea(d, wsave, csave, tgc, x, y - asc, cw, ch, 0, 0);
	XFillRectangle(d, wsave, tgc, x, y - asc, cw, ch);
	first = 0;
    } else {
	if (! first) {
	    XCopyArea(d, csave, w, tgc, 0, 0, cw, ch, x, y - asc);
	    XCopyArea(d, csave, wsave, tgc, 0, 0, cw, ch, x, y - asc);
	}
    }
}

static void feed(void)
{
    XCopyArea(d, w, w, tgc, BW, BW + ch, ww, wh - ch, BW, BW);
    XFillRectangle(d, w, fgc, BW, BW + wh - ch, ww, ch);
    XCopyArea(d, wsave, wsave, tgc, BW, BW + ch, ww, wh - ch, BW, BW);
    XFillRectangle(d, wsave, fgc, BW, BW + wh - ch, ww, ch);
}

static int read_pty(void)
{
    static int line = 0;
    int i, n;
    unsigned char c;

#define print() if (glass) { \
    XDrawImageString(d, w, tgc, x, y, &c, 1); \
    XDrawImageString(d, wsave, tgc, x, y, &c, 1); \
} else { \
    XDrawString(d, w, tgc, x, y, &c, 1); \
    XDrawString(d, wsave, tgc, x, y, &c, 1); \
}

    if ((n = read(ptyfd, &c, 1)) <= 0)
	return n;

    if (delay)
	usleep(delay);

    if (glass)
	cur(0);

    switch (c) {
	case 8:
	    if (x > BW)
		x -= cw;
	    break;
	case 10:
	    feed();
	    if (++line == pheight)
		line = 0;
	    break;
	case 12:
	    for (i = 0; i < (pheight - line); i++)
		feed();
	    line = 0;
	    break;
	case 13:
	    x = BW;
	    break;
	default:
	    if ((c < 32) || ((c > 126) && (c < 160))) 
		break;
	    if (x == BW + ww) {
		feed();
		x = BW;
	    }
	    print();
	    x += cw;
    }

    if (glass)
	cur(1);

    return n;
}

static void write_pty(XEvent *e)
{
    KeySym ks;
    unsigned char c;

    XLookupString((XKeyEvent *)e, &c, 1, &ks, NULL);
    switch (ks) {
	case XK_F9:
	    XSetFont(d, tgc, fi_us->fid);
	    return;
	case XK_F10:
	    XSetFont(d, tgc, fi_se->fid);
	    return;
    }
    if (c != 0) {
	if (delay)
	    usleep(delay);
	write(ptyfd, &c, 1);
    }
}

static void usage(char *name)
{
    fprintf(stderr, "usage: %s [-x xpos] [-y ypos] [-c columns] [-l lines] [-f us_font] [-s se_font] [-b baud]\n", name);
    exit(1);
}

static void init(int argc, char **argv)
{
    XColor fgcol, bgcol;
    XClassHint *chint;
    XSizeHints *shints;
    char *name;
    int pid;
    int c, mod;

    if ((name = strrchr(argv[0], '/')))
	name++;
    else
	name = argv[0];
    if (! strcmp(name, "ttyemu")) {
	fprintf(stderr, "Error: wrong invocation name\n");
	exit(1);
    }
    glass = ! strcmp(name, "glasstty");

    baud = glass ? 300 : 110;

    while ((c = getopt(argc, argv, ":x:y:c:l:f:s:b:")) != -1) {
	switch (c) {
	    case 'x':
		wx = atoi(optarg);
		break;
	    case 'y':
		wy = atoi(optarg);
		break;
	    case 'c':
		cols = atoi(optarg);
		break;
	    case 'l':
		lines = atoi(optarg);
		break;
	    case 'f':
		font_us = (char *)malloc(strlen(optarg) + 1);
		strcpy(font_us, optarg);
		break;
	    case 's':
		font_se = (char *)malloc(strlen(optarg) + 1);
		strcpy(font_se, optarg);
		break;
	    case 'b':
		baud = atoi(optarg);
		break;
	    case ':':
	    case '?':
	    default:
		usage(name);
	}
    }

    if (! (pid = forkpty(&ptyfd, NULL, NULL, NULL))) {
	char *shell, *tail, shminus[80];
	setenv(glass ? "GLASSTTY" : "HCTTY", "1", 1);
	if (! (shell = getenv("SHELL")))
	    shell = "/bin/sh";
	tail = strrchr(shell, '/') + 1;
	sprintf(shminus, "-%s", tail);
	execl(shell, shminus, (char *)NULL);
	perror("execl");
	_exit(1);
    } else if (pid < 0) {
	perror("fork");
	exit(1);
    }

    setlocale(LC_ALL, "");

    if (! (d = XOpenDisplay(NULL))) {
	fprintf(stderr, "Error opening display!\n");
	exit(1);
    }

    xfd = ConnectionNumber(d);

    if (! (fi_us = XLoadQueryFont(d, font_us))) {
	fprintf(stderr, "Error loading font!\n");
	exit(1);
    }

    if (! (fi_se = XLoadQueryFont(d, font_se))) {
	fprintf(stderr, "Error loading font!\n");
	exit(1);
    }

    cw = fi_us->per_char[32].width;
    ch = fi_us->ascent + fi_us->descent;

    XAllocNamedColor(d, DefaultColormap(d, 0), fg, &fgcol, &fgcol);
    XAllocNamedColor(d, DefaultColormap(d, 0), bg, &bgcol, &bgcol);

    ww = cw * cols;
    wh = ch * lines;

    if (! (w = XCreateSimpleWindow(d, DefaultRootWindow(d), wx, wy,
	    ww + (BW*2), wh + (BW*2), 0, bgcol.pixel, bgcol.pixel)) ) {
	printf("Error creating window!\n");
	exit(1);
    }

    XSelectInput(d, w, KeyPressMask|ExposureMask);

    chint = XAllocClassHint();
    chint->res_name = (glass ? "glasstty" : "hctty");
    chint->res_class = (glass ? "Glasstty" : "Hctty");
    XSetClassHint(d, w, chint);
    XStoreName(d, w, glass ? "Glass TTY" : "Hardcopy TTY");

    shints = XAllocSizeHints();
    shints->x = wx;
    shints->y = wy;
    shints->flags = USPosition;
    XSetWMNormalHints(d, w, shints);

    wm_protocols = XInternAtom(d, "WM_PROTOCOLS", False);
    wm_delete_window = XInternAtom(d, "WM_DELETE_WINDOW", False);
    XSetWMProtocols(d, w, &wm_delete_window, 1);

    tgc = XCreateGC(d, w, 0, NULL);
    XSetForeground(d, tgc, fgcol.pixel);
    XSetBackground(d, tgc, bgcol.pixel);
    XSetFont(d, tgc, fi_us->fid);

    fgc = XCreateGC(d, w, 0, NULL);
    XSetForeground(d, fgc, bgcol.pixel);

    wsave = XCreatePixmap(d, w, ww + (BW*2), wh + (BW*2), DefaultDepth(d, 0));
    XFillRectangle(d, wsave, fgc, 0, 0, ww + (BW*2), wh + (BW*2));

    if (glass)
	csave = XCreatePixmap(d, w, cw, ch, DefaultDepth(d, 0));

    x = BW;
    y = BW + wh - fi_us->descent;
    asc = fi_us->ascent;
    desc = fi_us->descent;

    delay = 1000000 / ((double)baud / (glass ? 10. : 11.));
    mod = delay % 10000;
    delay = (mod > 5000 ? delay + (10000 - mod) : delay - mod) - 10000;
    if (delay < 0)
	delay = 0;

    XMapWindow(d, w);
}

static void quit()
{
    XDestroyWindow(d, w);
    XCloseDisplay(d);
    exit(0);
}

int main(int argc, char **argv)
{
    init(argc, argv);

    for (;;) {
	XEvent e;
	fd_set io_set;
	struct timeval timeout;

	while (XPending(d)) {
	    XNextEvent(d, &e);
	    switch (e.type) {
		case Expose:
		    if (! e.xexpose.count)
			wrestore();
		    break;
		case KeyPress:
		    write_pty(&e);
		    break;
		case ClientMessage:
		    if (e.xclient.message_type == wm_protocols &&
			    e.xclient.data.l[0] == wm_delete_window)
			quit();
		    break;
	    }
	}

	FD_ZERO(&io_set);
	FD_SET(ptyfd, &io_set);
	FD_SET(xfd, &io_set);
	timeout.tv_sec = 0;
	timeout.tv_usec = 5000;

	if (select(xfd + 1, &io_set, NULL, NULL, &timeout) <= 0)
	    continue;

	if (FD_ISSET(ptyfd, &io_set)) {
	    if (read_pty() <= 0)
		quit();
	}
    }
}
.