cc: Fix a bug where filter outsets for drop-shadow could be negative.

cc: Fix a bug where filter outsets for drop-shadow could be negative.

The drop shadow filter draws the original content as well as its shadow, so it
should never have negative filter outsets (i.e. applying the filter always
produces output with bounds enclosing the original content).

While FilterOperations::GetOutsets will likely be removed shortly, there is
still code relying on it. Additionally, this gives a good excuse to add a unit
test for FilterOperations::MapRect/MapRectReverse, confirming that it does not
have the same issue.

BUG=600821
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Committed: https://crrev.com/e29d64cfae00a48483cc6497d39fb822c807a83a
Cr-Commit-Position: refs/heads/master@{#404009}

[jbroman, 2016-07-01 23:59:55]

Description was changed from

==========
cc: Fix a bug where filter outsets for drop-shadow could be negative.

The drop shadow filter draws the original content as well as its shadow, so it
should never have negative filter outsets (i.e. applying the filter always
produces output with bounds enclosing the original content).

While FilterOperations::GetOutsets will likely be removed shortly, there is
still code relying on it. Additionally, this gives a good excuse to add a unit
test for FilterOperations::MapRect/MapRectReverse, confirming that it does not
have the same issue.

BUG=600821
==========

to

==========
cc: Fix a bug where filter outsets for drop-shadow could be negative.

The drop shadow filter draws the original content as well as its shadow, so it
should never have negative filter outsets (i.e. applying the filter always
produces output with bounds enclosing the original content).

While FilterOperations::GetOutsets will likely be removed shortly, there is
still code relying on it. Additionally, this gives a good excuse to add a unit
test for FilterOperations::MapRect/MapRectReverse, confirming that it does not
have the same issue.

BUG=600821
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
==========

[jbroman, 2016-07-02 00:02:48]

Patchset #1 (id:1) has been deleted

[jbroman, 2016-07-02 00:59:48]

jbroman@chromium.org changed reviewers:
+ enne@chromium.org

[enne (OOO), 2016-07-06 17:34:57]

https://codereview.chromium.org/2115163002/diff/20001/cc/output/filter_operat...
File cc/output/filter_operations.cc (right):

https://codereview.chromium.org/2115163002/diff/20001/cc/output/filter_operat...
cc/output/filter_operations.cc:113: *top += std::max(0, spread -
op.drop_shadow_offset().y());
What if your drop shadow is up and to the left instead of down and to the right?
Does (-3, -8) really have the same outsets as (3, 8)?

[jbroman, 2016-07-06 17:37:32]

https://codereview.chromium.org/2115163002/diff/20001/cc/output/filter_operat...
File cc/output/filter_operations.cc (right):

https://codereview.chromium.org/2115163002/diff/20001/cc/output/filter_operat...
cc/output/filter_operations.cc:113: *top += std::max(0, spread -
op.drop_shadow_offset().y());
On 2016/07/06 at 17:34:57, enne wrote:
> What if your drop shadow is up and to the left instead of down and to the
right? Does (-3, -8) really have the same outsets as (3, 8)?

I don't understand your question. No, it doesn't have the same outsets; it has
opposite outsets. For example, in the test below, the outsets for (-3, -8) would
be top=8, right=0, bottom=0, left=3.

This isn't std::abs(x); it's std::max(0, x). It only ensures that no edge gets
negative outsets.

[enne (OOO), 2016-07-06 17:57:18]

lgtm

https://codereview.chromium.org/2115163002/diff/20001/cc/output/filter_operat...
File cc/output/filter_operations.cc (right):

https://codereview.chromium.org/2115163002/diff/20001/cc/output/filter_operat...
cc/output/filter_operations.cc:113: *top += std::max(0, spread -
op.drop_shadow_offset().y());
*drinks more coffee* Oops, sorry about misreading that.

[jbroman, 2016-07-06 17:59:26]

The CQ bit was checked by jbroman@chromium.org

[commit-bot: I haz the power, 2016-07-06 17:59:59]

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, 2016-07-06 21:06:46]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-06 21:06:47]

Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[jbroman, 2016-07-06 21:20:47]

The CQ bit was checked by jbroman@chromium.org

[commit-bot: I haz the power, 2016-07-06 21:21:35]

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, 2016-07-07 00:28:11]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-07-07 00:28:31]

CQ bit was unchecked.

[commit-bot: I haz the power, 2016-07-07 00:31:02]

Description was changed from

==========
cc: Fix a bug where filter outsets for drop-shadow could be negative.

The drop shadow filter draws the original content as well as its shadow, so it
should never have negative filter outsets (i.e. applying the filter always
produces output with bounds enclosing the original content).

While FilterOperations::GetOutsets will likely be removed shortly, there is
still code relying on it. Additionally, this gives a good excuse to add a unit
test for FilterOperations::MapRect/MapRectReverse, confirming that it does not
have the same issue.

BUG=600821
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
==========

to

==========
cc: Fix a bug where filter outsets for drop-shadow could be negative.

The drop shadow filter draws the original content as well as its shadow, so it
should never have negative filter outsets (i.e. applying the filter always
produces output with bounds enclosing the original content).

While FilterOperations::GetOutsets will likely be removed shortly, there is
still code relying on it. Additionally, this gives a good excuse to add a unit
test for FilterOperations::MapRect/MapRectReverse, confirming that it does not
have the same issue.

BUG=600821
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Committed: https://crrev.com/e29d64cfae00a48483cc6497d39fb822c807a83a
Cr-Commit-Position: refs/heads/master@{#404009}
==========

[commit-bot: I haz the power, 2016-07-07 00:31:03]

Patchset 1 (id:??) landed as
https://crrev.com/e29d64cfae00a48483cc6497d39fb822c807a83a
Cr-Commit-Position: refs/heads/master@{#404009}