Implement functions for loading palettes, and slightly improve the image reader.

[liblbx.git] / src / image.c

diff --git a/src/image.c b/src/image.c
index a5b8b058557cc6f6179d27477eb1abd3cf2346b0..9b9b1dde323e6b0c5de1aa978b3ed97616ab4669 100644 (file)
--- a/src/image.c
+++ b/src/image.c
@@ -119,14 +119,17 @@ static int _lbx_drawrow(int first, struct lbx_image *img)
                img->currenty += yval;
                img->currentx  = xval;
        } else {
-               count = 0;
-/*
+               if (fread(&yval,  sizeof yval,  1, img->f) != 1) goto readerr;
+               yval = letohs(yval); img->foff += sizeof yval;
+
+               /* FIXME Still have to figure out what to do here. */
+
                count = type;
+
                if (count > img->width - img->currentx) {
                        lbx_errno = LBX_EFORMAT;
                        return -1;
                }
-*/
        }
 
        pos = &img->framedata[img->currenty][img->currentx];
@@ -215,6 +218,76 @@ unsigned char **lbximg_getframe(struct lbx_image *img, int frame)
        return img->framedata;
 }
 
+int lbximg_loadpalette(FILE *f, struct lbx_colour palette[static 256])
+{
+       uint8_t entry[4];
+       int i;
+
+       for (i = 0; i < 256; i++) {
+               if (fread(entry, sizeof entry, 1, f) != 1) {
+                       lbx_errno = (feof(f)) ? LBX_EEOF : -errno;
+                       return -1;
+               }
+
+               if (entry[0] != 1) {
+                       lbx_errno = LBX_EFORMAT;
+                       return -1;
+               }
+
+               palette[i] = (struct lbx_colour){
+                       .red   = entry[1] << 2,
+                       .green = entry[2] << 2,
+                       .blue  = entry[3] << 2,
+               };
+       }
+
+       return 0;
+}
+
+int
+lbximg_getpalette(struct lbx_image *img, struct lbx_colour palette[static 256])
+{
+       int index = 0;
+       size_t rc;
+       size_t hdrlen = 6*(sizeof img->width)
+                       + (img->offs)*(sizeof *img->offsets);
+       
+       uint8_t entry[4];
+
+       /* Palette data is located right after the header. */
+       if (_lbx_fseek(img->f, &img->foff, hdrlen) == -1)
+               return -1;
+       
+       while (img->foff + sizeof entry <= img->offsets[0]) {
+               rc = fread(entry, 1, sizeof entry, img->f);
+               img->foff += rc;
+
+               if (rc < sizeof entry) {
+                       goto readerr;
+               }
+
+               if (entry[0] == 0) {
+                       index++;
+               } else {
+                       index = entry[0];
+               }
+
+               palette[index] = (struct lbx_colour){
+                       .red   = entry[1] << 2,
+                       .green = entry[2] << 2,
+                       .blue  = entry[3] << 2,
+               };
+       }
+
+       return 0;
+readerr:
+       if (feof(img->f))
+               lbx_errno = LBX_EEOF;
+       else
+               lbx_errno = -errno;
+       return -1;
+}
+
 void lbximg_close(struct lbx_image *img)
 {
        if (!img) return;