handle alpha

1 files changed, 5 insertions, 3 deletions

diff --git a/pximg.c b/pximg.c
index 2eec9b8..c5afbc4 100644
--- a/pximg.c
+++ b/pximg.c
@@ -89,13 +89,13 @@ indexed(char **argv)
 	/* read image */
 	int img_w, img_h, img_col_chans;
 	uint8_t *const img_data =
-	    stbi_load(argv[2], &img_w, &img_h, &img_col_chans, 3);
+	    stbi_load(argv[2], &img_w, &img_h, &img_col_chans, 4);
 
 	if (img_data == NULL) {
 		fprintf(stderr, "error: failed to load image\n");
 		return 1;
 	}
-	if (pal_col_chans != 3) {
+	if (pal_col_chans != 4) {
 		fprintf(stderr, "error: image isn't RBG\n");
 		stbi_image_free(img_data);
 		return 1;
@@ -111,10 +111,12 @@ indexed(char **argv)
 	for (int i = 0; i < img_w * img_h; i++) {
 		int col = -1;
 		for (int k = 0; k < pal_size; k++)
-			if (memcmp(pal + k * 3, img_data + i * 3, 3) == 0) {
+			if (memcmp(pal + k * 3, img_data + i * 4, 3) == 0) {
 				col = k;
 				break;
 			}
+		if (img_data[i * 4 + 3] == 0)
+			col = 0;
 		if (col == -1) {
 			fprintf(stderr,
 			        "color at pixel %d:%d not found in palette\n",