Compile-time initialize special SkMatrices.

Compile-time initialize special SkMatrices.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/ada3635c8e83739f45cd52459d3e052783d1a40e

[bungeman-skia, 2014-06-02 16:35:15]

https://codereview.chromium.org/303263011/diff/20001/src/core/SkMatrix.cpp
File src/core/SkMatrix.cpp (right):

https://codereview.chromium.org/303263011/diff/20001/src/core/SkMatrix.cpp#ne...
src/core/SkMatrix.cpp:1568: SK_COMPILE_ASSERT(sizeof(PODMatrix) ==
sizeof(SkMatrix), PODMatrixSizeMismatch);
In addition to this, it would be nice for SkMatrix to SK_COMPILE_ASSERT that the
offsetof its matrix and typemask are where an equivalent POD would put them.

[mtklein, 2014-06-02 17:31:47]

On 2014/06/02 16:35:15, bungeman1 wrote:
> https://codereview.chromium.org/303263011/diff/20001/src/core/SkMatrix.cpp
> File src/core/SkMatrix.cpp (right):
> 
>
https://codereview.chromium.org/303263011/diff/20001/src/core/SkMatrix.cpp#ne...
> src/core/SkMatrix.cpp:1568: SK_COMPILE_ASSERT(sizeof(PODMatrix) ==
> sizeof(SkMatrix), PODMatrixSizeMismatch);
> In addition to this, it would be nice for SkMatrix to SK_COMPILE_ASSERT that
the
> offsetof its matrix and typemask are where an equivalent POD would put them.

done.  ptal?

[bungeman-skia, 2014-06-02 17:46:31]

I shall go out on a limb and say lgtm.

https://codereview.chromium.org/303263011/diff/40001/src/core/SkMatrix.cpp
File src/core/SkMatrix.cpp (right):

https://codereview.chromium.org/303263011/diff/40001/src/core/SkMatrix.cpp#ne...
src/core/SkMatrix.cpp:1568: const SkMatrix& asSkMatrix() const { return
*reinterpret_cast<const SkMatrix*>(this); }
This cast is implementation defined. Of course, we'd break all over the place if
this didn't work. We already assert that they have the same sizeof, so they
should have the same alignment constraints as well.

[mtklein, 2014-06-02 17:54:56]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-06-02 17:55:24]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/303263011/40001

[commit-bot: I haz the power, 2014-06-02 17:59:39]

Change committed as ada3635c8e83739f45cd52459d3e052783d1a40e

[reed1, 2014-06-02 18:39:50]

https://codereview.chromium.org/303263011/diff/40001/src/core/SkMatrix.cpp
File src/core/SkMatrix.cpp (right):

https://codereview.chromium.org/303263011/diff/40001/src/core/SkMatrix.cpp#ne...
src/core/SkMatrix.cpp:12: #include <stddef.h>
is this not already included (directly/indirectly) by SkTypes.h?

[mtklein, 2014-06-02 18:40:31]

https://codereview.chromium.org/303263011/diff/40001/src/core/SkMatrix.cpp
File src/core/SkMatrix.cpp (right):

https://codereview.chromium.org/303263011/diff/40001/src/core/SkMatrix.cpp#ne...
src/core/SkMatrix.cpp:12: #include <stddef.h>
On 2014/06/02 18:39:50, reed1 wrote:
> is this not already included (directly/indirectly) by SkTypes.h?

Nope.  offsetof wasn't defined until I included this.