1 files changed, 94 insertions, 0 deletions
diff --git a/jpg/z2.c b/jpg/z2.c
new file mode 100644
index 0000000..1f29d7f
--- /dev/null
+++ b/jpg/z2.c
@@ -0,0 +1,94 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "jpg.h"
+
+int main(int argc, char **argv)
+{
+  int fd, i, width, height;
+  unsigned char *jpg = malloc(1 << 20);
+  unsigned char *img, *p;
+  struct jpeg_decdata jdd;
+  unsigned bits = 16;
+  unsigned char pixel[3];
+  unsigned x;
+  unsigned x0, x1, y0, y1;
+
+  if(argc < 2) return 1;
+
+  fd = open(argv[1], O_RDONLY);
+
+  if(fd == -1) return 2;
+
+  i = read(fd, jpg, 1 << 20);
+
+  if(i < 0) return 3;
+
+  close(fd);
+
+  jpg = realloc(jpg, i);
+
+  jpeg_get_size(jpg, &width, &height);
+
+  fprintf(stderr, "size = %d bytes, width = %d, height = %d\n", i, width, height);
+
+  img = malloc(width * height * 4);
+
+  x0 = 10;
+  x1 = 170;
+  y0 = 20;
+  y1 = 177;
+
+  i = jpeg_decode(jpg, img, &jdd, x0, x1, y0, y1);
+
+  width = x1 - x0;
+  height = y1 - y0;
+
+  fprintf(stderr, "decode = %d\n", i);
+
+  if(argc >= 3) {
+
+    fd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+
+    if(fd >= 0) {
+      char *s = NULL;
+
+      i = asprintf(&s, "P6\n%d %d\n255\n", width, height);
+      if(i > 0) write(fd, s, i);
+
+      free(s);
+
+      for(i = 0, p = img; i < width * height; i++) {
+        if(bits == 24) {
+          pixel[0] = *p++;
+          pixel[1] = *p++;
+          pixel[2] = *p++;
+        }
+        else {
+          x = p[1] + (p[0] << 8);
+          p += 2;
+
+          pixel[0] = ((x >> 11) & 0x1f) << 3;
+          pixel[0] += pixel[0] >> 5;
+          pixel[1] = ((x >> 5) & 0x3f) << 2;
+          pixel[1] += pixel[1] >> 6;
+          pixel[2] = (x & 0x1f) << 3;
+          pixel[2] += pixel[2] >> 5;
+        }
+
+        write(fd, &pixel, 3);
+      }
+
+      close(fd);
+    }
+  }
+
+  return 0;
+}
+
+