colorspace: clamp intermediates when dithering

This commit is contained in:
David Schleef 2012-02-19 00:15:47 -08:00
parent 8f8d7bf781
commit e0db2faa12

View file

@ -1823,10 +1823,14 @@ colorspace_dither_verterr (ColorspaceConvert * convert, int j)
int i;
guint16 *tmpline = convert->tmpline16;
guint16 *errline = convert->errline;
unsigned int mask = 0xff;
for (i = 0; i < 4 * convert->width; i++) {
tmpline[i] += errline[i];
errline[i] = tmpline[i] & 0xff;
int x = tmpline[i] + errline[i];
if (x > 65535)
x = 65535;
tmpline[i] = x;
errline[i] = x & mask;
}
}
@ -1847,7 +1851,11 @@ colorspace_dither_halftone (ColorspaceConvert * convert, int j)
};
for (i = 0; i < convert->width * 4; i++) {
tmpline[i] += halftone[(i >> 2) & 7][j & 7];
int x;
x = tmpline[i] + halftone[(i >> 2) & 7][j & 7];
if (x > 65535)
x = 65535;
tmpline[i] = x;
}
}