xscreenshot

commit 895ec4bf5e0ff2ff52e27d62a88f7927d8fc470c
parent d8f8fff9489a4e0521b682d2d9ab0698ad2b6422
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Wed, 24 Feb 2016 20:01:13 +0100

add 16-bit colour support (only 5-6-5 format).

Add 16-bit bpp colour support, only 5-6-6 format is assumed and supported.
Check explcitly for 16-bit, 24-bit and 32-bit.

Thanks Dwight Hower for the idea/feedback!

Diffstat:
M
xscreenshot.c
 | 
26
++++++++++++++++++++++----

1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/xscreenshot.c b/xscreenshot.c
@@ -21,6 +21,7 @@ main(int argc, char *argv[])
 	XWindowAttributes attr;
 	uint32_t tmp, w, h;
 	uint16_t rgba[4];
+	int sr, sg, fr, fg, fb;
 	char *ep;
 
 	if (!(dpy = XOpenDisplay(NULL)))
@@ -53,7 +54,24 @@ main(int argc, char *argv[])
 	XUngrabServer(dpy);
 	XCloseDisplay(dpy);
 	if (!img)
-		die("Can't XGetImage");
+		errx(1, "XGetImage\n");
+
+	switch (img->bits_per_pixel) {
+	case 16: /* only 5-6-5 format supported */
+		sr = 11;
+		sg = 5;
+		fr = fb = 2047;
+		fg = 1023;
+		break;
+	case 24:
+	case 32: /* ignore alpha in case of 32-bit */
+		sr = 16;
+		sg = 8;
+		fr = fg = fb = 257;
+		break;
+	default:
+		errx(1, "unsupported bpp: %d\n", img->bits_per_pixel);
+	}
 
 	/* write header with big endian width and height-values */
 	fprintf(stdout, "farbfeld");
@@ -66,9 +84,9 @@ 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) >> 16) * 257);
-			rgba[1] = htons(((tmp & img->green_mask) >>  8) * 257);
-			rgba[2] = htons((tmp & img->blue_mask) * 257);
+			rgba[0] = htons(((tmp & img->red_mask) >> sr) * fr);
+			rgba[1] = htons(((tmp & img->green_mask) >> sg) * fg);
+			rgba[2] = htons((tmp & img->blue_mask) * fb);
 			rgba[3] = htons(65535);
 
 			if (fwrite(&rgba, 4 * sizeof(uint16_t), 1, stdout) != 1)