Make swizzler optional for SkPngCodec, refactor xforms

Make swizzler optional for SkPngCodec, refactor xforms

I think is a good redesign that will allow us to handle more png
xforms more efficiently.  And I also think it reduces a bit of
complexity.

PNGs can be RGBA, RGB, Gray, GrayAlpha, Index8.

The swizzler handles all of those input formats and all Skia
output formats.  Swizzler also provides sampling/subsetting.

Color xforms currently only handles RGBA.  So we use the
swizzler to convert to RGBA first.  I've started thinking
about adding RGB, Gray, etc. support for color xforms.
In this case (and the RGBA case), we should skip the
swizzling step.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2279313003

Committed: https://skia.googlesource.com/skia/+/400a93bd6c5a07aa8c83de9e31e224243e59089e

[msarett, 2016-08-26 16:32:14]

Description was changed from

==========
Make swizzler optional for SkPngCodec, refactor xforms

I think is a good redesign that will allow us to handle more png
xforms more efficiently.  And I also think it reduces a bit of
complexity.

PNGs can be RGBA, RGB, Gray, GrayAlpha, Index8.

The swizzler handles all of those input formats and all Skia
output formats.  Swizzler also provides sampling/subsetting.

Color xforms currently only handles RGBA.  So we use the
swizzler to convert to RGBA first.  I've started thinking
about adding RGB, Gray, etc. support for color xforms.
In this case (and the RGBA case), we should skip the
swizzling step.

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

to

==========
Make swizzler optional for SkPngCodec, refactor xforms

I think is a good redesign that will allow us to handle more png
xforms more efficiently.  And I also think it reduces a bit of
complexity.

PNGs can be RGBA, RGB, Gray, GrayAlpha, Index8.

The swizzler handles all of those input formats and all Skia
output formats.  Swizzler also provides sampling/subsetting.

Color xforms currently only handles RGBA.  So we use the
swizzler to convert to RGBA first.  I've started thinking
about adding RGB, Gray, etc. support for color xforms.
In this case (and the RGBA case), we should skip the
swizzling step.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2279313003
==========

[msarett, 2016-08-26 16:37:44]

msarett@google.com changed reviewers:
+ mtklein@google.com

[msarett, 2016-08-26 16:37:45]

https://codereview.chromium.org/2279313003/diff/1/src/codec/SkPngCodec.h
File src/codec/SkPngCodec.h (right):

https://codereview.chromium.org/2279313003/diff/1/src/codec/SkPngCodec.h#newc...
src/codec/SkPngCodec.h:80: enum XformMode {
There are two more cases where we are not quite optimal.
(1) When we could decode directly to dst and skip swizzling and color xforms.
(2) When we could perform the color xform in place (don't need an extra row
buffer).

I considered adding both of these modes, but ultimately decided the gain wasn't
worth the complexity.

[msarett, 2016-08-30 18:40:40]

Any thoughts?

[mtklein, 2016-09-01 18:57:50]

lgtm

https://codereview.chromium.org/2279313003/diff/20001/src/codec/SkPngCodec.h
File src/codec/SkPngCodec.h (right):

https://codereview.chromium.org/2279313003/diff/20001/src/codec/SkPngCodec.h#...
src/codec/SkPngCodec.h:94: XformMode                          fXformMode;
probably clearer with less space between type and name

[msarett, 2016-09-02 00:48:55]

The CQ bit was checked by msarett@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-09-02 00:49:01]

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

[msarett, 2016-09-02 00:52:54]

https://codereview.chromium.org/2279313003/diff/20001/src/codec/SkPngCodec.h
File src/codec/SkPngCodec.h (right):

https://codereview.chromium.org/2279313003/diff/20001/src/codec/SkPngCodec.h#...
src/codec/SkPngCodec.h:94: XformMode                          fXformMode;
On 2016/09/01 18:57:49, mtklein wrote:
> probably clearer with less space between type and name

Done.

[commit-bot: I haz the power, 2016-09-02 01:14:25]

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

[commit-bot: I haz the power, 2016-09-02 01:14:26]

Dry run: This issue passed the CQ dry run.

[msarett, 2016-09-02 01:31:56]

The CQ bit was checked by msarett@google.com

[msarett, 2016-09-02 01:31:57]

The patchset sent to the CQ was uploaded after l-g-t-m from mtklein@google.com
Link to the patchset: https://codereview.chromium.org/2279313003/#ps40001
(title: "Less spacing")

[commit-bot: I haz the power, 2016-09-02 01:32:00]

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, 2016-09-02 01:32:55]

Description was changed from

==========
Make swizzler optional for SkPngCodec, refactor xforms

I think is a good redesign that will allow us to handle more png
xforms more efficiently.  And I also think it reduces a bit of
complexity.

PNGs can be RGBA, RGB, Gray, GrayAlpha, Index8.

The swizzler handles all of those input formats and all Skia
output formats.  Swizzler also provides sampling/subsetting.

Color xforms currently only handles RGBA.  So we use the
swizzler to convert to RGBA first.  I've started thinking
about adding RGB, Gray, etc. support for color xforms.
In this case (and the RGBA case), we should skip the
swizzling step.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2279313003
==========

to

==========
Make swizzler optional for SkPngCodec, refactor xforms

I think is a good redesign that will allow us to handle more png
xforms more efficiently.  And I also think it reduces a bit of
complexity.

PNGs can be RGBA, RGB, Gray, GrayAlpha, Index8.

The swizzler handles all of those input formats and all Skia
output formats.  Swizzler also provides sampling/subsetting.

Color xforms currently only handles RGBA.  So we use the
swizzler to convert to RGBA first.  I've started thinking
about adding RGB, Gray, etc. support for color xforms.
In this case (and the RGBA case), we should skip the
swizzling step.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2279313003

Committed:
https://skia.googlesource.com/skia/+/400a93bd6c5a07aa8c83de9e31e224243e59089e
==========

[commit-bot: I haz the power, 2016-09-02 01:32:56]

Committed patchset #3 (id:40001) as
https://skia.googlesource.com/skia/+/400a93bd6c5a07aa8c83de9e31e224243e59089e