xscreenshot

commit 09f10196b609f477adfd6d1692508434954c3566
parent b0165f794fa7eee32c3c29933f60d05e122e9c4d
Author: z3bra <willyatmailoodotorg>
Date:   Tue, 17 Nov 2015 22:40:45 +0100

Make conversion from RGB8 to RGB16 more accurate

Each value has to be multiplied by 257 (65535/255), and not left-rotated
by 8 bits. Thanks FRIGN!

Diffstat:
M
xscreenshot.c
 | 
6
+++---

1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/xscreenshot.c b/xscreenshot.c
@@ -76,9 +76,9 @@ main(int argc, char *argv[])
 	for (h = 0; h < (uint32_t)img->height; h++) {
 		for (w = 0; w < (uint32_t)img->width; w++) {
 			tmp = XGetPixel(img, w, h);
-			rgba[0] = htons((tmp & img->red_mask) >> 8);
-			rgba[1] = htons(tmp & img->green_mask);
-			rgba[2] = htons((tmp & img->blue_mask) << 8);
+			rgba[0] = htons(((tmp & img->red_mask) >> 16) * 257);
+			rgba[1] = htons(((tmp & img->green_mask) >>  8) * 257);
+			rgba[2] = htons((tmp & img->blue_mask) * 257);
 			rgba[3] = htons(65535);
 
 			if (fwrite(&rgba, 4 * sizeof(uint16_t), 1, stdout) != 1)