[hackers] [sent] support transparent images || Markus Teich

From: <git_AT_suckless.org>
Date: Tue, 8 Dec 2015 22:08:01 +0100 (CET)

commit 0798e82d2326fc330168733997006020cc59e215
Author: Markus Teich <markus.teich_AT_stusta.mhn.de>
AuthorDate: Tue Dec 8 21:46:18 2015 +0100
Commit: Markus Teich <markus.teich_AT_stusta.mhn.de>
CommitDate: Tue Dec 8 21:46:18 2015 +0100

    support transparent images

diff --git a/sent.c b/sent.c
index eb3aadc..e10e8ca 100644
--- a/sent.c
+++ b/sent.c
_AT_@ -215,6 +215,8 @@ int ffread(Image *img)
 {
         uint32_t y, x;
         uint16_t *row;
+ uint8_t opac;
+ uint8_t fg_r, fg_g, fg_b, bg_r, bg_g, bg_b;
         size_t rowlen, off, nbytes;
         ssize_t r;
 
_AT_@ -239,6 +241,11 @@ int ffread(Image *img)
                 return 0;
         }
 
+ /* extract window background color channels for transparency */
+ bg_r = (sc->bg.pix >> 16) % 256;
+ bg_g = (sc->bg.pix >> 8) % 256;
+ bg_b = (sc->bg.pix >> 0) % 256;
+
         for (off = 0, y = 0; y < img->bufheight; y++) {
                 nbytes = 0;
                 while (nbytes < rowlen) {
_AT_@ -248,9 +255,15 @@ int ffread(Image *img)
                         nbytes += r;
                 }
                 for (x = 0; x < rowlen / 2; x += 4) {
- img->buf[off++] = ntohs(row[x + 0]) / 257;
- img->buf[off++] = ntohs(row[x + 1]) / 257;
- img->buf[off++] = ntohs(row[x + 2]) / 257;
+ fg_r = ntohs(row[x + 0]) / 256;
+ fg_g = ntohs(row[x + 1]) / 256;
+ fg_b = ntohs(row[x + 2]) / 256;
+ opac = ntohs(row[x + 3]) / 256;
+ /* blend opaque part of image data with window background color to
+ * emulate transparency */
+ img->buf[off++] = (fg_r * opac + bg_r * (255 - opac)) / 256;
+ img->buf[off++] = (fg_g * opac + bg_g * (255 - opac)) / 256;
+ img->buf[off++] = (fg_b * opac + bg_b * (255 - opac)) / 256;
                 }
         }
 
Received on Tue Dec 08 2015 - 22:08:01 CET