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Premultiply background RGB values if alpha is used

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This commit is contained in:
Lucas Lugao 2019-05-21 17:17:13 +02:00
parent d06bf1fd7e
commit ffcacfa98d
1 changed files with 9 additions and 3 deletions
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12
x.c
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@ -784,9 +784,15 @@ xloadcols(void)
/* set alpha value of bg color */
if (opt_alpha)
alpha = strtof(opt_alpha, NULL);
dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * alpha);
dc.col[defaultbg].pixel &= 0x00FFFFFF;
dc.col[defaultbg].pixel |= (unsigned char)(0xff * alpha) << 24;
dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * alpha);
dc.col[defaultbg].color.red =
((unsigned short)(dc.col[defaultbg].color.red * alpha)) & 0xff00;
dc.col[defaultbg].color.green =
((unsigned short)(dc.col[defaultbg].color.green * alpha)) & 0xff00;
dc.col[defaultbg].color.blue =
((unsigned short)(dc.col[defaultbg].color.blue * alpha)) & 0xff00;
dc.col[defaultbg].pixel &= 0x00FFFFFF;
dc.col[defaultbg].pixel |= (unsigned char)(0xff * alpha) << 24;
loaded = 1;
}