Avoid unnecessary clipping of gradient/generated images

Avoid unnecessary clipping of gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com

Committed: https://crrev.com/26528184b3b96533811a96106193d33dd8693e87
Cr-Commit-Position: refs/heads/master@{#392145}

[f(malita), 2016-05-05 20:42:20]

Description was changed from

==========
Avoid clipping when drawing gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com
==========

to

==========
Avoid unnecessary clipping of gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com
==========

[f(malita), 2016-05-06 12:47:40]

Splitting the straightforward bits from http://crrev.com/1949253004.

This removes the inner clipRect and save/restore from the convoluted gradient
circle draw sequence (see http://crbug.com/603966):

   save
     clipRect(AA: false)
     clipRRect(AA: true)
>    save
>      clipRect(AA: false)
       drawRect()
>    restore
  retore

A couple of trivial rebaselines due to edge AA no longer being chopped off by
aliased clip:
https://storage.googleapis.com/chromium-layout-test-archives/linux_chromium_r...

[reed1, 2016-05-06 18:28:17]

lgtm

[bsalomon, 2016-05-06 18:33:29]

On 2016/05/06 12:47:40, f(malita) wrote:
> Splitting the straightforward bits from http://crrev.com/1949253004.
> 
> This removes the inner clipRect and save/restore from the convoluted gradient
> circle draw sequence (see http://crbug.com/603966):
> 
>    save
>      clipRect(AA: false)
>      clipRRect(AA: true)
> >    save
> >      clipRect(AA: false)
>        drawRect()
> >    restore
>   retore
> 
> A couple of trivial rebaselines due to edge AA no longer being chopped off by
> aliased clip:
>
https://storage.googleapis.com/chromium-layout-test-archives/linux_chromium_r...

I think for Ganesh to see a real benefit the circular clip has to become a
circle draw.

[f(malita), 2016-05-06 18:43:26]

On 2016/05/06 18:33:29, bsalomon wrote:
> On 2016/05/06 12:47:40, f(malita) wrote:
> > Splitting the straightforward bits from http://crrev.com/1949253004.
> > 
> > This removes the inner clipRect and save/restore from the convoluted
gradient
> > circle draw sequence (see http://crbug.com/603966):
> > 
> >    save
> >      clipRect(AA: false)
> >      clipRRect(AA: true)
> > >    save
> > >      clipRect(AA: false)
> >        drawRect()
> > >    restore
> >   retore
> > 
> > A couple of trivial rebaselines due to edge AA no longer being chopped off
by
> > aliased clip:
> >
>
https://storage.googleapis.com/chromium-layout-test-archives/linux_chromium_r...
> 
> I think for Ganesh to see a real benefit the circular clip has to become a
> circle draw.

Yup, that would be http://crrev.com/1949253004 which shows a 12x improvement,
bit will take some serious massaging to land :)

[f(malita), 2016-05-06 20:44:22]

The CQ bit was checked by fmalita@chromium.org

[commit-bot: I haz the power, 2016-05-06 20:44:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1955683002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1955683002/40001

[commit-bot: I haz the power, 2016-05-06 20:48:57]

Description was changed from

==========
Avoid unnecessary clipping of gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com
==========

to

==========
Avoid unnecessary clipping of gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com
==========

[commit-bot: I haz the power, 2016-05-06 20:48:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-06 20:50:25]

Description was changed from

==========
Avoid unnecessary clipping of gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com
==========

to

==========
Avoid unnecessary clipping of gradient/generated images

Refactor GradientGeneratedImage::draw() to

a) use an adjusted draw rect instead of explicit/unconditional clipping

b) completely avoid save/restores when not needed (identity transform)

This speeds up Animometer/CSS Bouncing Gradient Circles by ~25% in
software mode (no noticeable improvement for Ganesh).

BUG=603966
R=schenney@chromium.org,reed@google.com

Committed: https://crrev.com/26528184b3b96533811a96106193d33dd8693e87
Cr-Commit-Position: refs/heads/master@{#392145}
==========

[commit-bot: I haz the power, 2016-05-06 20:50:26]

Patchset 3 (id:??) landed as
https://crrev.com/26528184b3b96533811a96106193d33dd8693e87
Cr-Commit-Position: refs/heads/master@{#392145}