[SVGDom] Initial linear gradient support

[SVGDom] Initial linear gradient support

Kind of a big change, to connect several new bits into something useful:

  * ID tracking & lookup
  * new asPaint() node virtual to support shader (and in the future filter) based paint servers
  * <defs>, <linearGradient> and <stop> element support
  * 'href', 'offset', 'stop-color', 'stop-opacity' attribute support
  * IRI/FuncIRI and rgb(...) parsing


BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003

Committed: https://skia.googlesource.com/skia/+/28d5b72d86fdfae20dc47ba548748f119c7273e3

[f(malita), 2016-09-09 22:02:02]

Description was changed from

==========
[SVGDom] Linear gradient support

WIP

BUG=skia:
==========

to

==========
[SVGDom] Linear gradient support

WIP

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003
==========

[f(malita), 2016-09-12 15:06:00]

Description was changed from

==========
[SVGDom] Linear gradient support

WIP

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003
==========

to

==========
[SVGDom] Initial linear gradient support

Kind of a big change, to connect several new bits into something useful:

  * ID tracking & lookup
  * new asPaint() node virtual to support shader (and in the future filter)
based paint servers
  * <defs>, <linearGradient> and <stop> element support
  * 'href', 'offset', 'stop-color', 'stop-opacity' attribute support
  * IRI/FuncIRI and rgb(...) parsing


BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003
==========

[f(malita), 2016-09-12 15:06:00]

fmalita@chromium.org changed reviewers:
+ reed@google.com, robertphillips@google.com, stephana@google.com

[f(malita), 2016-09-12 15:07:09]

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

[commit-bot: I haz the power, 2016-09-12 15:07:17]

Dry run: 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, 2016-09-12 15:49:08]

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

[commit-bot: I haz the power, 2016-09-12 15:49:09]

Dry run: This issue passed the CQ dry run.

[robertphillips, 2016-09-12 19:31:52]

lgtm

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGContainer.h (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGContainer.h:24: 
Hmm, very trusting ...

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGLinearGradient.cpp (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGLinearGradient.cpp:86: 
Shouldn't this test be more like:

if ((pos->count() < 2 || colors->count() < 2) && !....

?

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGLinearGradient.h (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGLinearGradient.h:41: SkSVGLength fX2 =
SkSVGLength(100, SkSVGLength::Unit::kPercentage);
fY2 isn't 100 too ?

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGRenderContext.cpp (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGRenderContext.cpp:204: SkCanvas dummyCanvas(0, 0);
overlength line ?

[f(malita), 2016-09-12 19:52:09]

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGContainer.h (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGContainer.h:24: 
On 2016/09/12 19:31:52, robertphillips wrote:
> Hmm, very trusting ...

Added a TODO for some sort of child iterator instead of protected container.

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGLinearGradient.cpp (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGLinearGradient.cpp:86: 
On 2016/09/12 19:31:52, robertphillips wrote:
> Shouldn't this test be more like:
> 
> if ((pos->count() < 2 || colors->count() < 2) && !....
> 
> ?

pos->count should always match colors->count because we always insert in
lock-step.  Added an assert to document.

Then for count == 1, I think we don't need to recurse:

a) "if one stop is defined, then paint with the solid color fill using the color
defined for that gradient stop."
(https://www.w3.org/TR/SVG/pservers.html#StopOpacityProperty)

b) "if this element has no defined gradient stops, and the referenced element
does (possibly due to its own ‘xlink:href’ attribute), then this element
inherits the gradient stop from the referenced element. Inheritance can be
indirect to an arbitrary level;"
(https://www.w3.org/TR/SVG/pservers.html#LinearGradientElementHrefAttribute)

Sounds like they want to inherit only for an empty list.

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGLinearGradient.h (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGLinearGradient.h:41: SkSVGLength fX2 =
SkSVGLength(100, SkSVGLength::Unit::kPercentage);
On 2016/09/12 19:31:52, robertphillips wrote:
> fY2 isn't 100 too ?

Heh, you would think so (and that's how I wrote it initially), but no :P

https://www.w3.org/TR/SVG/pservers.html#LinearGradientElementY2Attribute

(I'm assuming to default to horizontal left->right gradient)

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
File experimental/svg/model/SkSVGRenderContext.cpp (right):

https://codereview.chromium.org/2327233003/diff/60001/experimental/svg/model/...
experimental/svg/model/SkSVGRenderContext.cpp:204: SkCanvas dummyCanvas(0, 0);
On 2016/09/12 19:31:52, robertphillips wrote:
> overlength line ?

Done.

[f(malita), 2016-09-12 19:52:15]

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

[commit-bot: I haz the power, 2016-09-12 19:52:24]

Dry run: 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, 2016-09-12 20:45:35]

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

[commit-bot: I haz the power, 2016-09-12 20:45:35]

Dry run: This issue passed the CQ dry run.

[f(malita), 2016-09-13 00:05:16]

The CQ bit was checked by fmalita@chromium.org

[f(malita), 2016-09-13 00:05:16]

The patchset sent to the CQ was uploaded after l-g-t-m from
robertphillips@google.com
Link to the patchset: https://codereview.chromium.org/2327233003/#ps80001
(title: "review")

[commit-bot: I haz the power, 2016-09-13 00:05:26]

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, 2016-09-13 00:06:49]

Description was changed from

==========
[SVGDom] Initial linear gradient support

Kind of a big change, to connect several new bits into something useful:

  * ID tracking & lookup
  * new asPaint() node virtual to support shader (and in the future filter)
based paint servers
  * <defs>, <linearGradient> and <stop> element support
  * 'href', 'offset', 'stop-color', 'stop-opacity' attribute support
  * IRI/FuncIRI and rgb(...) parsing


BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003
==========

to

==========
[SVGDom] Initial linear gradient support

Kind of a big change, to connect several new bits into something useful:

  * ID tracking & lookup
  * new asPaint() node virtual to support shader (and in the future filter)
based paint servers
  * <defs>, <linearGradient> and <stop> element support
  * 'href', 'offset', 'stop-color', 'stop-opacity' attribute support
  * IRI/FuncIRI and rgb(...) parsing


BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003

Committed:
https://skia.googlesource.com/skia/+/28d5b72d86fdfae20dc47ba548748f119c7273e3
==========

[commit-bot: I haz the power, 2016-09-13 00:06:50]

Committed patchset #5 (id:80001) as
https://skia.googlesource.com/skia/+/28d5b72d86fdfae20dc47ba548748f119c7273e3