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libmemdraw: update drawtest to use same rounding in alpha calculation as libmemdraw

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This commit is contained in:
cinap_lenrek 2014-09-14 17:03:56 +02:00
parent e9fddbaad8
commit fdf3883ce4
1 changed files with 7 additions and 7 deletions
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14
sys/src/libmemdraw/drawtest.c
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@ -974,7 +974,7 @@ drawonepixel(Memimage *dst, Point dp, Memimage *src, Point sp, Memimage *mask, P
pixtorgba(getpixel(dst, dp), &dr, &dg, &db, &da);
pixtorgba(getpixel(src, sp), &sr, &sg, &sb, &sa);
m = getmask(mask, mp);
M = 255-(sa*m)/255;
M = 255-(sa*m + 127)/255;
DBG print("dst %x %x %x %x src %x %x %x %x m %x = ", dr,dg,db,da, sr,sg,sb,sa, m);
if(dst->flags&Fgrey){
@ -985,18 +985,18 @@ DBG print("dst %x %x %x %x src %x %x %x %x m %x = ", dr,dg,db,da, sr,sg,sb,sa, m
*/
sk = RGB2K(sr, sg, sb);
dk = RGB2K(dr, dg, db);
dk = (sk*m + dk*M)/255;
dk = (sk*m + dk*M + 127)/255;
dr = dg = db = dk;
da = (sa*m + da*M)/255;
da = (sa*m + da*M + 127)/255;
}else{
/*
* True color alpha calculation treats all channels (including alpha)
* the same. It might have been nice to use an array, but oh well.
*/
dr = (sr*m + dr*M)/255;
dg = (sg*m + dg*M)/255;
db = (sb*m + db*M)/255;
da = (sa*m + da*M)/255;
dr = (sr*m + dr*M + 127)/255;
dg = (sg*m + dg*M + 127)/255;
db = (sb*m + db*M + 127)/255;
da = (sa*m + da*M + 127)/255;
}
DBG print("%x %x %x %x\n", dr,dg,db,da);