This mirrors the behavior in onGetPixels, and allows the implementation
to share code for handling calls to rewindIfNeeded.
This also fixes a bug where getScanlineDecoder was calling
rewindIfNeeded and treating the result as a bool.
In SkPngCodec, factor out the code to call rewindIfNeeded, and call it
in both onGetPixels and onGetScanlineDecoder.
Update the test to include testing the scanline decoder. Rename "gen"
to "codec" now that it must be an SkCodec.
BUG=skia:3257
Depends on https://codereview.chromium.org/1048423003/ (DIFFERENT ISSUE).
Review URL: https://codereview.chromium.org/1050893002
Add an interface for decoding scanlines, and implement that interface
in the PNG decoder.
Use a separate method to determine whether an image that used a type
with alpha was actually opaque.
SkScanlineDecoder.h:
New interface for decoding scanlines.
SkCodec.h:
Add getScanlineDecoder.
Add a virtual function (with non-virtual caller) for determining
whether the image truly had alpha. The client can call this to
determine if the image was actually opaque if it reported having alpha.
Remove code to sneakily change the passed in alpha type.
SkCodec_libpng.*:
Split up code onGetPixels into helper functions that can be shared with
the scanline decoder.
Implement scanline decoding.
Implement onReallyHasAlpha.
SkSwizzler.*:
Add a new SrcConfig as a default, which is invalid.
Add a function for setting fDstRow directly.
Assert fDstRow is not NULL.
BUG=skia:3257
Review URL: https://codereview.chromium.org/1010903003
DM:
Add a flag to use SkCodec instead of SkImageDecoder.
SkCodec:
Base class for codecs, allowing creation from an SkStream or an SkData.
An SkCodec, on creation, knows properties of the data like its width and height. Further calls can be used to generate the image.
TODO: Add scanline iterator
SkPngCodec:
New decoder for png. Wraps libpng. The code has been repurposed from SkImageDecoder_libpng.
TODO: Handle other destination colortypes
TODO: Substitute the transpose color
TODO: Allow silencing warnings
TODO: Use RGB instead of filler?
TODO: sRGB
SkSwizzler:
Simplified version of SkScaledSampler. Unlike the sampler, this object does no sampling.
TODO: Implement other swizzles.
Requires a gclient sync to pull down libpng.
BUG=skia:3257
Committed: https://skia.googlesource.com/skia/+/ca358852b4fed656d11107b2aaf28318a4518b49
(and then reverted)
Review URL: https://codereview.chromium.org/930283002
Reason for revert:
Breaking windows bots all over the place :(
Original issue's description:
> Add SkCodec, including PNG implementation.
>
> DM:
> Add a flag to use SkCodec instead of SkImageDecoder.
>
> SkCodec:
> Base class for codecs, allowing creation from an SkStream or an SkData.
> An SkCodec, on creation, knows properties of the data like its width and height. Further calls can be used to generate the image.
> TODO: Add scanline iterator
>
> SkPngCodec:
> New decoder for png. Wraps libpng. The code has been repurposed from SkImageDecoder_libpng.
> TODO: Handle other destination colortypes
> TODO: Substitute the transpose color
> TODO: Allow silencing warnings
> TODO: Use RGB instead of filler?
> TODO: sRGB
>
> SkSwizzler:
> Simplified version of SkScaledSampler. Unlike the sampler, this object does no sampling.
> TODO: Implement other swizzles.
>
> BUG=skia:3257
>
> Committed: https://skia.googlesource.com/skia/+/ca358852b4fed656d11107b2aaf28318a4518b49TBR=reed@google.com,djsollen@google.com,msarett@google.com,mtklein@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:3257
Review URL: https://codereview.chromium.org/972743003
DM:
Add a flag to use SkCodec instead of SkImageDecoder.
SkCodec:
Base class for codecs, allowing creation from an SkStream or an SkData.
An SkCodec, on creation, knows properties of the data like its width and height. Further calls can be used to generate the image.
TODO: Add scanline iterator
SkPngCodec:
New decoder for png. Wraps libpng. The code has been repurposed from SkImageDecoder_libpng.
TODO: Handle other destination colortypes
TODO: Substitute the transpose color
TODO: Allow silencing warnings
TODO: Use RGB instead of filler?
TODO: sRGB
SkSwizzler:
Simplified version of SkScaledSampler. Unlike the sampler, this object does no sampling.
TODO: Implement other swizzles.
BUG=skia:3257
Review URL: https://codereview.chromium.org/930283002
