blind-dissolve.c - blind - suckless command-line video editing utility
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       ---
       blind-dissolve.c (1255B)
       ---
            1 /* See LICENSE file for copyright and license details. */
            2 #include "common.h"
            3 
            4 USAGE("[-r]")
            5 
            6 static size_t fm;
            7 static double fm_double;
            8 static float fm_float;
            9 static int reverse = 0;
           10 
           11 #define PROCESS(TYPE)\
           12         do {\
           13                 size_t i = (size_t)(stream->alpha_chan) * stream->chan_size;\
           14                 TYPE a = fm ? (TYPE)(reverse ? f : fm - f) / fm_##TYPE : (TYPE)0.5;\
           15                 for (; i < n; i += stream->pixel_size)\
           16                         *(TYPE *)(stream->buf + i) *= a;\
           17         } while (0)
           18 
           19 static void process_lf(struct stream *stream, size_t n, size_t f) {PROCESS(double);}
           20 static void process_f (struct stream *stream, size_t n, size_t f) {PROCESS(float);}
           21 
           22 int
           23 main(int argc, char *argv[])
           24 {
           25         struct stream stream;
           26         void (*process)(struct stream *stream, size_t n, size_t f);
           27 
           28         ARGBEGIN {
           29         case 'r':
           30                 reverse = 1;
           31                 break;
           32         default:
           33                 usage();
           34         } ARGEND;
           35 
           36         if (argc)
           37                 usage();
           38 
           39         eopen_stream(&stream, NULL);
           40 
           41         SELECT_PROCESS_FUNCTION(&stream);
           42         CHECK_CHANS(&stream, != -1, == stream.luma_chan);
           43 
           44         if (!stream.frames)
           45                 eprintf("video's length is not recorded");
           46 
           47         fprint_stream_head(stdout, &stream);
           48         efflush(stdout, "<stdout>");
           49         fm_double = (double)(fm = stream.frames - 1);
           50         fm_float = (float)fm_double;
           51         process_each_frame_segmented(&stream, STDOUT_FILENO, "<stdout>", process);
           52         return 0;
           53 }