diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2012-01-23 11:40:13 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2012-01-23 11:40:13 +0000 |
| commit | c67e6a05ff729c0ddb26775e1c8533be1144d85a (patch) | |
| tree | b07f82970df8d0015be9904c9750b4917cdd96e2 | |
| parent | 9267da93969d1727cb95956c3f63643f0039c60d (diff) | |
sna: Align the origin of downsampling subregion to an even pixel
In order for us to produce stable downsampled images across multiple
frames, we need to sample the same pairs of pixels every time. This
requires us to align the origin of the sample region to an even pixel.
Reported-by: Clemens Eisserer <linuxhippy@gmail.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=45086
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
| -rw-r--r-- | src/sna/sna_render.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/sna/sna_render.c b/src/sna/sna_render.c index 5f79e04c..4f861379 100644 --- a/src/sna/sna_render.c +++ b/src/sna/sna_render.c @@ -643,6 +643,12 @@ static int sna_render_picture_downsample(struct sna *sna, oy = v.vector[1] / v.vector[2]; } + /* Align the origin to an even pixel so that the sampling of + * partial images is stable. + */ + box.x1 &= ~1; + box.y1 &= ~1; + if (channel->repeat == RepeatNone || channel->repeat == RepeatPad) { if (box.x1 < 0) box.x1 = 0; |