Add SkBitmap::getColor(int x, int y).

Add SkBitmap::getColor(int x, int y) - return the color of a pixel in a bitmap.

Committed: http://code.google.com/p/skia/source/detail?r=854

[reed1, 2011-02-24 17:45:39]

Lets just call SkColorSetARGB instead of SkColorSetARGBMacro or
SkColorSetARGBInline. I think both of those latter ones should not be public
anyway.

http://codereview.appspot.com/4230041/diff/1/include/core/SkBitmap.h
File include/core/SkBitmap.h (right):

http://codereview.appspot.com/4230041/diff/1/include/core/SkBitmap.h#newcode404
include/core/SkBitmap.h:404: /** Return the color of the specified pixel. */
Lets emphasis in the comment that we are returning a color, not a SkPMColor, and
so there will (sometimes) be a conversion as we have to unpremultiply the color
components.

Also lets document what we return for weird configs like kNone (either say its
undefined, or say its 0. Also document that alpha-only configs (kA1 and kA8)
return black with the alpha set.

http://codereview.appspot.com/4230041/diff/1/src/core/SkBitmap.cpp
File src/core/SkBitmap.cpp (right):

http://codereview.appspot.com/4230041/diff/1/src/core/SkBitmap.cpp#newcode633
src/core/SkBitmap.cpp:633: uint16_t* addr = getAddr16(x, y);
Need to call unpremultiply on the values from a 4444 bitmap.

http://codereview.appspot.com/4230041/diff/1/src/core/SkBitmap.cpp#newcode641
src/core/SkBitmap.cpp:641: uint32_t* addr = getAddr32(x, y);
Need to call unpremultiply on these values

[Steve VanDeBogart, 2011-02-24 19:27:36]

Hmm, I didn't realize that bitmap configs with alpha where pre multiplied.  It
should be all fixed here (and cleaned up a bit).  Now that I know, I need to
clean up SkPDFImage.cpp as well.

http://codereview.appspot.com/4230041/diff/1/include/core/SkBitmap.h
File include/core/SkBitmap.h (right):

http://codereview.appspot.com/4230041/diff/1/include/core/SkBitmap.h#newcode404
include/core/SkBitmap.h:404: /** Return the color of the specified pixel. */
On 2011/02/24 17:45:39, reed1 wrote:
> Lets emphasis in the comment that we are returning a color, not a SkPMColor,
and
> so there will (sometimes) be a conversion as we have to unpremultiply the
color
> components.
> 
> Also lets document what we return for weird configs like kNone (either say its
> undefined, or say its 0. Also document that alpha-only configs (kA1 and kA8)
> return black with the alpha set.

Done.

http://codereview.appspot.com/4230041/diff/1/src/core/SkBitmap.cpp
File src/core/SkBitmap.cpp (right):

http://codereview.appspot.com/4230041/diff/1/src/core/SkBitmap.cpp#newcode633
src/core/SkBitmap.cpp:633: uint16_t* addr = getAddr16(x, y);
On 2011/02/24 17:45:39, reed1 wrote:
> Need to call unpremultiply on the values from a 4444 bitmap.

Done.

http://codereview.appspot.com/4230041/diff/1/src/core/SkBitmap.cpp#newcode641
src/core/SkBitmap.cpp:641: uint32_t* addr = getAddr32(x, y);
On 2011/02/24 17:45:39, reed1 wrote:
> Need to call unpremultiply on these values

Done.

[reed1, 2011-02-24 22:18:43]

LGTM

Lets consider a unittest for this call, either in BitmapCopyTest.cpp or in a new
file. I'm OK to do that later (in another CL).

http://codereview.appspot.com/4230041/diff/4001/include/core/SkBitmap.h
File include/core/SkBitmap.h (right):

http://codereview.appspot.com/4230041/diff/4001/include/core/SkBitmap.h#newco...
include/core/SkBitmap.h:407: for KNone_Config or if x or y are out of bounds.
KNone -> kNone

[Steve VanDeBogart, 2011-02-24 22:52:07]

On 2011/02/24 22:18:43, reed1 wrote:
> LGTM

Thanks.

> Lets consider a unittest for this call, either in BitmapCopyTest.cpp or in a
new
> file. I'm OK to do that later (in another CL).

Sure, put it on my todo list.

http://codereview.appspot.com/4230041/diff/4001/include/core/SkBitmap.h
File include/core/SkBitmap.h (right):

http://codereview.appspot.com/4230041/diff/4001/include/core/SkBitmap.h#newco...
include/core/SkBitmap.h:407: for KNone_Config or if x or y are out of bounds.
On 2011/02/24 22:18:43, reed1 wrote:
> KNone -> kNone

Done.