Clamp background tiles when possible

Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
R=reed@google.com,fs@opera.com,schenney@chromium.org

Committed: https://crrev.com/a7e84a029b10a5a8c0b0faf4bda87e54187840fb
Cr-Commit-Position: refs/heads/master@{#439529}

[f(malita), 2016-12-19 14:49:12]

The CQ bit was checked by fmalita@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-19 14:49:24]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[f(malita), 2016-12-19 14:50:20]

Description was changed from

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

BUG=673261
==========

to

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
==========

[f(malita), 2016-12-19 16:27:07]

The CQ bit was checked by fmalita@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-19 16:27:23]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[f(malita), 2016-12-19 16:27:57]

fmalita@chromium.org changed reviewers:
+ fs@opera.com, reed@google.com, schenney@chromium.org

[f(malita), 2016-12-19 16:29:12]

Description was changed from

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
==========

to

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
R=reed@google.com,fs@opera.com,schenney@chromium.org
==========

[f(malita), 2016-12-19 16:30:06]

A handful of minor diffs:
https://storage.googleapis.com/chromium-layout-test-archives/mac_chromium_rel...

with one noticeable improvement:
https://storage.googleapis.com/chromium-layout-test-archives/mac_chromium_rel...

[Stephen Chennney, 2016-12-19 16:36:45]

lgtm

[fs, 2016-12-19 16:49:22]

lgtm

https://codereview.chromium.org/2582383002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/platform/graphics/Image.cpp (right):

https://codereview.chromium.org/2582383002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/platform/graphics/Image.cpp:247: SkShader::TileMode
computeTileMode(float destOffset,
Maybe structure this as an interval containment check instead. Same but
different, just putting the idea on the table...

(i.e: computeTileMode(destRect.x(), destRect.maxX(), ...) et.c)

[f(malita), 2016-12-19 17:34:56]

https://codereview.chromium.org/2582383002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/platform/graphics/Image.cpp (right):

https://codereview.chromium.org/2582383002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/platform/graphics/Image.cpp:247: SkShader::TileMode
computeTileMode(float destOffset,
On 2016/12/19 16:49:22, fs wrote:
> Maybe structure this as an interval containment check instead. Same but
> different, just putting the idea on the table...
> 
> (i.e: computeTileMode(destRect.x(), destRect.maxX(), ...) et.c)

Done.

[f(malita), 2016-12-19 17:35:00]

The CQ bit was checked by fmalita@chromium.org

[f(malita), 2016-12-19 17:35:01]

The patchset sent to the CQ was uploaded after l-g-t-m from
schenney@chromium.org, fs@opera.com
Link to the patchset: https://codereview.chromium.org/2582383002/#ps60001
(title: "asserts")

[commit-bot: I haz the power, 2016-12-19 17:35:23]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[f(malita), 2016-12-19 18:03:51]

The CQ bit was checked by fmalita@chromium.org

[f(malita), 2016-12-19 18:03:51]

The patchset sent to the CQ was uploaded after l-g-t-m from
schenney@chromium.org, fs@opera.com
Link to the patchset: https://codereview.chromium.org/2582383002/#ps80001
(title: "relax asserts")

[commit-bot: I haz the power, 2016-12-19 18:04:07]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-19 19:59:18]

CQ is committing da patch.

Bot data: {"patchset_id": 80001, "attempt_start_ts": 1482170631122190,
"parent_rev": "a78fc12e855de783f0254ed1fe7c4439e08c9130", "commit_rev":
"663e6267e3457ac0ad16c3f36dd1b27b1b4b49d4"}

[commit-bot: I haz the power, 2016-12-19 19:59:45]

Description was changed from

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
R=reed@google.com,fs@opera.com,schenney@chromium.org
==========

to

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
R=reed@google.com,fs@opera.com,schenney@chromium.org

Review-Url: https://codereview.chromium.org/2582383002
==========

[commit-bot: I haz the power, 2016-12-19 19:59:47]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2016-12-19 20:01:54]

Description was changed from

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
R=reed@google.com,fs@opera.com,schenney@chromium.org

Review-Url: https://codereview.chromium.org/2582383002
==========

to

==========
Clamp background tiles when possible

We're currently always drawing tiled backgrounds in repeat/repeat mode,
even if we need tiling in one dimension only.

This has the unexpected side effect of opposite edge bleed, in the
dimension which doesn't require tiling, when rasterized for hidpi
devices (DSF causing Skia to sample across the tile boundary).

Detect cases where tile repetition is not needed, and strength-reduce the
shader tile mode accordingly.

Also make Image::drawPattern() protected, as it is only used in subclasses.

BUG=673261
R=reed@google.com,fs@opera.com,schenney@chromium.org

Committed: https://crrev.com/a7e84a029b10a5a8c0b0faf4bda87e54187840fb
Cr-Commit-Position: refs/heads/master@{#439529}
==========

[commit-bot: I haz the power, 2016-12-19 20:01:55]

Patchset 5 (id:??) landed as
https://crrev.com/a7e84a029b10a5a8c0b0faf4bda87e54187840fb
Cr-Commit-Position: refs/heads/master@{#439529}