[cairo-commit] src/cairo-image-compositor.c
Chris Wilson
ickle at kemper.freedesktop.org
Sat Apr 28 15:17:59 PDT 2012
src/cairo-image-compositor.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
New commits:
commit ec400daf9ec3bbd8403324db7fcdaf175e185e7b
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date: Sat Apr 28 23:15:52 2012 +0100
image: Avoid overflow when computing lerp spans for a8
Reported-by: Benjamin Otte <otte at redhat.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
diff --git a/src/cairo-image-compositor.c b/src/cairo-image-compositor.c
index f9ef031..fb4b2fb 100644
--- a/src/cairo-image-compositor.c
+++ b/src/cairo-image-compositor.c
@@ -1950,12 +1950,12 @@ _fill_a8_lerp_opaque_spans (void *abstract_renderer, int y, int h,
if (a == 0xff) {
memset(d + spans[0].x, r->u.fill.pixel, len);
} else {
- uint16_t p = (uint16_t)a * r->u.fill.pixel + 0x7f;
- uint16_t ia = ~a;
+ uint8_t s = mul8_8(a, r->u.fill.pixel);
uint8_t *dst = d + spans[0].x;
+ a = ~a;
while (len--) {
- uint16_t t = *dst*ia + p;
- *dst++ = (t + (t>>8)) >> 8;
+ uint8_t t = mul8_8(*dst, a);
+ *dst++ = t + s;
}
}
}
@@ -1974,14 +1974,14 @@ _fill_a8_lerp_opaque_spans (void *abstract_renderer, int y, int h,
yy++;
} while (--hh);
} else {
- uint16_t p = (uint16_t)a * r->u.fill.pixel + 0x7f;
- uint16_t ia = ~a;
+ uint8_t s = mul8_8(a, r->u.fill.pixel);
+ a = ~a;
do {
int len = spans[1].x - spans[0].x;
uint8_t *d = r->u.fill.data + r->u.fill.stride*yy + spans[0].x;
while (len--) {
- uint16_t t = *d*ia + p;
- *d++ = (t + (t>>8)) >> 8;
+ uint8_t t = mul8_8(*d, a);
+ *d++ = t + s;
}
yy++;
} while (--hh);
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