Track nested picture xform state for layer hoisting

Track nested picture xform state for layer hoisting

The accumulated matrix state of any enclosing SkPictures must be stored separate from the picture-local CTM. Any setMatrix calls inside a layer need to replace the picture-local CTM but concatenate with the enclosing SkPicture transform state (and the transform state needed to translate the layer to the correct location in the cached GrTexture).

Committed: https://skia.googlesource.com/skia/+/9e6835da41e344ef3c4c35036fabfdb0a4146c33

[robertphillips, 2014-10-21 16:44:28]

robertphillips@google.com changed reviewers:
+ jvanverth@google.com

[jvanverth1, 2014-10-21 18:40:04]

lgtm + comments

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.cpp
File src/gpu/GrPictureUtils.cpp (right):

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.cpp#n...
src/gpu/GrPictureUtils.cpp:129: dst.fInitialMat.preConcat(*fCTM);
Not postConcat?

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.h
File src/gpu/GrPictureUtils.h (right):

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.h#new...
src/gpu/GrPictureUtils.h:35: SkMatrix fInitialMat;
This name is confusing -- I keep thinking it's the matrix we first start with.
Maybe fAccumulatedMat? fPreMat?

[robertphillips, 2014-10-21 19:54:47]

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.cpp
File src/gpu/GrPictureUtils.cpp (right):

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.cpp#n...
src/gpu/GrPictureUtils.cpp:129: dst.fInitialMat.preConcat(*fCTM);
I believe preConcat is correct. fCTM is the CTM of the current picture while
src.fPreMat is the prefix matrix of the arbitrarily nested child picture. I
would expect the true CTM of the child saveLayer to be: fCTM * src.fPreMat *
src.fLocalMat.

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.h
File src/gpu/GrPictureUtils.h (right):

https://codereview.chromium.org/639863005/diff/1/src/gpu/GrPictureUtils.h#new...
src/gpu/GrPictureUtils.h:35: SkMatrix fInitialMat;
On 2014/10/21 18:40:04, jvanverth1 wrote:
> This name is confusing -- I keep thinking it's the matrix we first start with.
> Maybe fAccumulatedMat? fPreMat?

Done. Went with fPreMat.

[robertphillips, 2014-10-22 12:25:46]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2014-10-22 12:26:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/639863005/20001

[commit-bot: I haz the power, 2014-10-22 12:33:56]

Committed patchset #2 (id:20001) as 9e6835da41e344ef3c4c35036fabfdb0a4146c33