- Hide SkImageEncoder class in private header.
- SkImageEncoder::Type becomes SkEncodedImageFormat
- SkEncodedFormat becomes SkEncodedImageFormat
- SkImageEncoder static functions replaced with
single function EncodeImage()
- utility wrappers for EncodeImage() are in
sk_tool_utils.h
TODO: remove link-time registration mechanism.
TODO: clean up clients use of API and flip the flag.
TODO: implement EncodeImage() in chromeium/skia/ext
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4909
Change-Id: Ib48b31fdc05cf23cda7f56ebfd67c841c149ce70
Reviewed-on: https://skia-review.googlesource.com/4909
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
This was always intended to be a temporary dependency to use for
testing. It has served its purpose.
Also, this has already been dropped (accidentally, I think) by
the new GN build.
TBR=reed@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4220
Change-Id: Ic72ee08bbfaf86ed86a4122fd38be2921eb1327e
Reviewed-on: https://skia-review.googlesource.com/4220
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
Add a new accessor to retrieve the repetition count.
Remove constants (and corresponding copyright) in SkCodecAnimation.
These may make sense for the calling code, but are not needed here.
kRepetitionCountInfinite corresponds to Blink's kAnimationLoopInfinite.
Move cLoopCountNotSeen to private. It is used to determine whether we
still need to parse. Add a new enum to the parse query - only parse
enough to determine the repetition count.
Unlike Chromium, SkGifCodec does not account for deleting the reader
(which SkGifCodec does not do) or failed decodes.
Add a test.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2447863002
Review-Url: https://codereview.chromium.org/2447863002
Unmarked images should be treated as sRGB.
BUG=skia:4895
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4151
Change-Id: I5f8c308d22fd2d069cbfa89c5a5bb19ae6fde8bd
Reviewed-on: https://skia-review.googlesource.com/4151
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
This also makes the required changed to src, tests, and tools. The few
public APIs modified by this change appear to be unused outside of Skia.
Removing these from the public API makes it easier to ensure users are
no longer using them.
This also updates GrGpu::wrapBackendXXX and the
::onWrapBackendXXX methods to clarify ownership.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2448593002
Review-Url: https://codereview.chromium.org/2448593002
Add an interface to decode frames beyond the first in SkCodec, and
add an implementation for SkGifCodec.
Add getFrameData to SkCodec. This method reads ahead in the stream
to return a vector containing meta data about each frame in the image.
This is not required in order to decode frames beyond the first, but
it allows a client to learn extra information:
- how long the frame should be displayed
- whether a frame should be blended with a prior frame, allowing the
client to provide the prior frame to speed up decoding
Add a new fields to SkCodec::Options:
- fFrameIndex
- fHasPriorFrame
The API is designed so that SkCodec never caches frames. If a
client wants a frame beyond the first, they specify the frame in
Options.fFrameIndex. If the client does not have the
frame's required frame (the frame that this frame must be blended on
top of) cached, they pass false for
Options.fHasPriorFrame. Unless the frame is
independent, the codec will then recursively decode all frames
necessary to decode fFrameIndex. If the client has the required frame
cached, they can put it in the dst they pass to the codec, and the
codec will only draw fFrameIndex onto it.
Replace SkGifCodec's scanline decoding support with progressive
decoding, and update the tests accordingly.
Implement new APIs in SkGifCodec. Instead of using gif_lib, use
GIFImageReader, imported from Chromium (along with its copyright
headers) with the following changes:
- SkGifCodec is now the client
- Replace blink types
- Combine GIFColorMap::buildTable and ::getTable into a method that
creates and returns an SkColorTable
- Input comes from an SkStream, instead of a SegmentReader. Add
SkStreamBuffer, which buffers the (potentially partial) stream in
order to decode progressively.
(FIXME: This requires copying data that previously was read directly
from the SegmentReader. Does this hurt performance? If so, can we
fix it?)
- Remove UMA code
- Instead of reporting screen width and height to the client, allow the
client to query for it
- Fail earlier if the first frame AND screen have size of zero
- Compute required previous frame when adding a new one
- Move GIFParseQuery from GIFImageDecoder to GIFImageReader
- Allow parsing up to a specific frame (to skip parsing the rest of the
stream if a client only wants the first frame)
- Compute whether the first frame has alpha and supports index 8, to
create the SkImageInfo. This happens before reporting that the size
has been decoded.
Add GIFImageDecoder::haveDecodedRow to SkGifCodec, imported from
Chromium (along with its copyright header), with the following changes:
- Add support for sampling
- Use the swizzler
- Keep track of the rows decoded
- Do *not* keep track of whether we've seen alpha
Remove SkCodec::kOutOfOrder_SkScanlineOrder, which was only used by GIF
scanline decoding.
Call onRewind even if there is no stream (SkGifCodec needs to clear its
decoded state so it will decode from the beginning).
Add a method to SkSwizzler to access the offset into the dst, taking
subsetting into account.
Add a GM that animates a GIF.
Add tests for the new APIs.
*** Behavior changes:
* Previously, we reported that an image with a subset frame and no transparent
index was opaque and used the background index (if present) to fill the
background. This is necessary in order to support index 8, but it does not
match viewers/browsers I have seen. Examples:
- Chromium and Gimp render the background transparent
- Firefox, Safari, Linux Image Viewer, Safari Preview clip to the frame (for
a single frame image)
This CL matches Chromium's behavior and renders the background transparent.
This allows us to have consistent behavior across products and simplifies
the code (relative to what we would have to do to continue the old behavior
on Android). It also means that we will no longer support index 8 for some
GIFs.
* Stop checking for GIFSTAMP - all GIFs should be either 89a or 87a.
This matches Chromium. I suspect that bugs would have been reported if valid
GIFs started with "GIFVER" instead of "GIF89a" or "GIF87a" (but did not decode
in Chromium).
*** Future work not included in this CL:
* Move some checks out of haveDecodedRow, since they are the same for the
entire frame e.g.
- intersecting the frameRect with the full image size
- whether there is a color table
* Change when we write transparent pixels
- In some cases, Chromium deemed this unnecessary, but I suspect it is slower
than the fallback case. There will continue to be cases where we should
*not* write them, but for e.g. the first pass where we have already
cleared to transparent (which we may also be able to skip) writing the
transparent pixels will not make anything incorrect.
* Report color type and alpha type per frame
- Depending on alpha values, disposal methods, frame rects, etc, subsequent
frames may have different properties than the first.
* Skip copies of the encoded data
- We copy the encoded data in case the stream is one that cannot be rewound,
so we can parse and then decode (possibly not immediately). For some input
streams, this is unnecessary.
- I was concerned this cause a performance regression, but on average the
new code is faster than the old for the images I tested [1].
- It may cause a performance regression for Chromium, though, where we can
always move back in the stream, so this should be addressed.
Design doc:
https://docs.google.com/a/google.com/document/d/12Qhf9T92MWfdWujQwCIjhCO3sw6pTJB5pJBwDM1T7Kc/
[1] https://docs.google.com/a/google.com/spreadsheets/d/19V-t9BfbFw5eiwBTKA1qOBkZbchjlTC5EIz6HFy-6RI/
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=2045293002
Review-Url: https://codereview.chromium.org/2045293002
(1) The transformation code *should* support any src SkColorSpace
that we successfully parse. This is agreed upon internally and
by clients. The fact that we currently don't is just a bug...
(2) We cannot and will not support all SkColorSpaces as dsts.
So if we fail to make a SkColorSpaceXform, we should assume that
it was caused by a bad dst color space. The correct response in
this case is to return kInvalidConversion. I've rewritten the CL
to do this.
The fact that weird src spaces will sometimes trigger a
kInvalidConversion is just a bug that is being actively worked on.
TBR=reed@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3661
Change-Id: Iac2b45120507ec71b1b3d555c61931f7348dad9e
Reviewed-on: https://skia-review.googlesource.com/3661
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Robert Aftias <raftias@google.com>
This is a step towards using SkCodec in Chromium, where progressive
decoding is necessary.
Switch from using png_read_row (which expects all the data to be
available) to png_process_data, which uses callbacks when rows are
available.
Create a new API for SkCodec, which supports progressive decoding and
scanline decoding. Future changes will switch the other clients off of
startScanlineDecode and get/skip-Scanlines to the new API.
Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
updateCurrScanline(), which was only used by the old implementation for
interlaced PNG.
DMSrcSink:
- In CodecSrc::kScanline_Mode, use the new method for scanline decoding
for the supported formats (just PNG and PNG-in-ICO for now).
fuzz.cpp:
- Remove reference to kNone_ScanlineOrder
SkCodec:
- Add new APIs:
- startIncrementalDecode
- incrementalDecode
- Remove kNone_SkScanlineOrder and updateCurrScanline()
- Set fDstInfo and fOptions in getPixels(). This may not be necessary
for all implementations, but it simplifies things for SkPngCodec.
SkPngCodec:
- Implement new APIs
- Switch from sk_read_fn/png_read_row etc to png_process_data
- Expand AutoCleanPng's role to decode the header and create the
SkPngCodec
- Make the interlaced PNG decoder report how many lines were
initialized during an incomplete decode
SkIcoCodec:
- Implement the new APIs; supported for PNG in ICO
SkSampledCodec:
- Call the new method for decoding scanlines, and fall back to the old
method if the new version is unimplemented
- Remove references to kNone_SkScanlineOrder
tests/CodecPartial:
- Add a test which decodes part of an image, then finishes the decode,
and compares it to the straightforward method
tests/CodecTest:
- Add a test which decodes all scanlines using the new method
- Repurpose the Codec_stripes test to decode using the new method in
sections rather than all at once
- In the method check(), add a parameter for whether the image supports
the new method of scanline decoding, and be explicit about whether an
image supports incomplete
- Test incomplete PNG decodes. We should have been doing it anyway for
non-interlaced (except for an image that is too small - one row), but
the new method supports interlaced incomplete as well
- Make test_invalid_parameters test the new method
- Add a test to ensure that it's safe to fall back to scanline decoding without
rewinding
BUG=skia:4211
The new version was generally faster than the old version (but not significantly so).
Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
Review-Url: https://codereview.chromium.org/1997703003
Reason for revert:
Still causing problems in Google3, e.g.
https://test.corp.google.com/ui#cl=124138817&flags=CAMQBQ==&id=OCL:124138817:BASE:124139560:1465227435491:219ffbdb&t=//third_party/skia/HEAD:dm
Original issue's description:
> Make SkPngCodec decode progressively.
>
> This is a step towards using SkCodec in Chromium, where progressive
> decoding is necessary.
>
> Switch from using png_read_row (which expects all the data to be
> available) to png_process_data, which uses callbacks when rows are
> available.
>
> Create a new API for SkCodec, which supports progressive decoding and
> scanline decoding. Future changes will switch the other clients off of
> startScanlineDecode and get/skip-Scanlines to the new API.
>
> Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
> PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
> updateCurrScanline(), which was only used by the old implementation for
> interlaced PNG.
>
> DMSrcSink:
> - In CodecSrc::kScanline_Mode, use the new method for scanline decoding
> for the supported formats (just PNG and PNG-in-ICO for now).
>
> fuzz.cpp:
> - Remove reference to kNone_ScanlineOrder
>
> SkCodec:
> - Add new APIs:
> - startIncrementalDecode
> - incrementalDecode
> - Remove kNone_SkScanlineOrder and updateCurrScanline()
>
> SkPngCodec:
> - Implement new APIs
> - Switch from sk_read_fn/png_read_row etc to png_process_data
> - Expand AutoCleanPng's role to decode the header and create the
> SkPngCodec
> - Make the interlaced PNG decoder report how many lines were
> initialized during an incomplete decode
> - Make initializeSwizzler return a bool instead of an SkCodec::Result
> (It only returned kSuccess or kInvalidInput anyway)
>
> SkIcoCodec:
> - Implement the new APIs; supported for PNG in ICO
>
> SkSampledCodec:
> - Call the new method for decoding scanlines, and fall back to the old
> method if the new version is unimplemented
> - Remove references to kNone_SkScanlineOrder
>
> tests/CodecPartial:
> - Add a test which decodes part of an image, then finishes the decode,
> and compares it to the straightforward method
>
> tests/CodecTest:
> - Add a test which decodes all scanlines using the new method
> - Repurpose the Codec_stripes test to decode using the new method in
> sections rather than all at once
> - In the method check(), add a parameter for whether the image supports
> the new method of scanline decoding, and be explicit about whether an
> image supports incomplete
> - Test incomplete PNG decodes. We should have been doing it anyway for
> non-interlaced (except for an image that is too small - one row), but
> the new method supports interlaced incomplete as well
> - Make test_invalid_parameters test the new method
> - Add a test to ensure that it's safe to fall back to scanline decoding without
> rewinding
>
> BUG=skia:4211
>
> The new version was generally faster than the old version (but not significantly so).
>
> Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
>
> Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
>
> Committed: https://skia.googlesource.com/skia/+/a4b09a117d4d1ba5dda372e6a2323e653766539e
>
> Committed: https://skia.googlesource.com/skia/+/30e78c9737ff4861dc4e3fa1e4cd010680ed6965
>
> Committed: https://skia.googlesource.com/skia/+/6fb2391b2cc83ee2160b4e994faa8128975acc1fTBR=reed@google.com,msarett@google.com,scroggo@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=skia:4211
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2044573002
Review-Url: https://codereview.chromium.org/2044573002
This is a step towards using SkCodec in Chromium, where progressive
decoding is necessary.
Switch from using png_read_row (which expects all the data to be
available) to png_process_data, which uses callbacks when rows are
available.
Create a new API for SkCodec, which supports progressive decoding and
scanline decoding. Future changes will switch the other clients off of
startScanlineDecode and get/skip-Scanlines to the new API.
Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
updateCurrScanline(), which was only used by the old implementation for
interlaced PNG.
DMSrcSink:
- In CodecSrc::kScanline_Mode, use the new method for scanline decoding
for the supported formats (just PNG and PNG-in-ICO for now).
fuzz.cpp:
- Remove reference to kNone_ScanlineOrder
SkCodec:
- Add new APIs:
- startIncrementalDecode
- incrementalDecode
- Remove kNone_SkScanlineOrder and updateCurrScanline()
SkPngCodec:
- Implement new APIs
- Switch from sk_read_fn/png_read_row etc to png_process_data
- Expand AutoCleanPng's role to decode the header and create the
SkPngCodec
- Make the interlaced PNG decoder report how many lines were
initialized during an incomplete decode
- Make initializeSwizzler return a bool instead of an SkCodec::Result
(It only returned kSuccess or kInvalidInput anyway)
SkIcoCodec:
- Implement the new APIs; supported for PNG in ICO
SkSampledCodec:
- Call the new method for decoding scanlines, and fall back to the old
method if the new version is unimplemented
- Remove references to kNone_SkScanlineOrder
tests/CodecPartial:
- Add a test which decodes part of an image, then finishes the decode,
and compares it to the straightforward method
tests/CodecTest:
- Add a test which decodes all scanlines using the new method
- Repurpose the Codec_stripes test to decode using the new method in
sections rather than all at once
- In the method check(), add a parameter for whether the image supports
the new method of scanline decoding, and be explicit about whether an
image supports incomplete
- Test incomplete PNG decodes. We should have been doing it anyway for
non-interlaced (except for an image that is too small - one row), but
the new method supports interlaced incomplete as well
- Make test_invalid_parameters test the new method
- Add a test to ensure that it's safe to fall back to scanline decoding without
rewinding
BUG=skia:4211
The new version was generally faster than the old version (but not significantly so).
Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
Committed: https://skia.googlesource.com/skia/+/a4b09a117d4d1ba5dda372e6a2323e653766539e
Committed: https://skia.googlesource.com/skia/+/30e78c9737ff4861dc4e3fa1e4cd010680ed6965
Review-Url: https://codereview.chromium.org/1997703003
Reason for revert:
Still breaking Google3 e.g.:
https://sponge.corp.google.com/target?id=9261d31b-34fc-4f0f-981e-f92f7c5cea2c&target=//third_party/skia/HEAD:dm#shard=1|run=1|attempt=1|page=-1
https://test.corp.google.com/ui#cl=123773095&flags=CAMQBQ==&id=OCL:123773095:BASE:123773415:1464804876959:b0ea9b1c&t=//third_party/skia/HEAD:dm
Original issue's description:
> Make SkPngCodec decode progressively.
>
> This is a step towards using SkCodec in Chromium, where progressive
> decoding is necessary.
>
> Switch from using png_read_row (which expects all the data to be
> available) to png_process_data, which uses callbacks when rows are
> available.
>
> Create a new API for SkCodec, which supports progressive decoding and
> scanline decoding. Future changes will switch the other clients off of
> startScanlineDecode and get/skip-Scanlines to the new API.
>
> Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
> PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
> updateCurrScanline(), which was only used by the old implementation for
> interlaced PNG.
>
> DMSrcSink:
> - In CodecSrc::kScanline_Mode, use the new method for scanline decoding
> for the supported formats (just PNG and PNG-in-ICO for now).
>
> fuzz.cpp:
> - Remove reference to kNone_ScanlineOrder
>
> SkCodec:
> - Add new APIs:
> - startIncrementalDecode
> - incrementalDecode
> - Remove kNone_SkScanlineOrder and updateCurrScanline()
>
> SkPngCodec:
> - Implement new APIs
> - Switch from sk_read_fn/png_read_row etc to png_process_data
> - Expand AutoCleanPng's role to decode the header and create the
> SkPngCodec
> - Make the interlaced PNG decoder report how many lines were
> initialized during an incomplete decode
> - Make initializeSwizzler return a bool instead of an SkCodec::Result
> (It only returned kSuccess or kInvalidInput anyway)
>
> SkIcoCodec:
> - Implement the new APIs; supported for PNG in ICO
>
> SkSampledCodec:
> - Call the new method for decoding scanlines, and fall back to the old
> method if the new version is unimplemented
> - Remove references to kNone_SkScanlineOrder
>
> tests/CodecPartial:
> - Add a test which decodes part of an image, then finishes the decode,
> and compares it to the straightforward method
>
> tests/CodecTest:
> - Add a test which decodes all scanlines using the new method
> - Repurpose the Codec_stripes test to decode using the new method in
> sections rather than all at once
> - In the method check(), add a parameter for whether the image supports
> the new method of scanline decoding, and be explicit about whether an
> image supports incomplete
> - Test incomplete PNG decodes. We should have been doing it anyway for
> non-interlaced (except for an image that is too small - one row), but
> the new method supports interlaced incomplete as well
> - Make test_invalid_parameters test the new method
> - Add a test to ensure that it's safe to fall back to scanline decoding without
> rewinding
>
> BUG=skia:4211
>
> The new version was generally faster than the old version (but not significantly so).
>
> Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
>
> Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
>
> Committed: https://skia.googlesource.com/skia/+/a4b09a117d4d1ba5dda372e6a2323e653766539e
>
> Committed: https://skia.googlesource.com/skia/+/30e78c9737ff4861dc4e3fa1e4cd010680ed6965TBR=reed@google.com,msarett@google.com,scroggo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4211
Review-Url: https://codereview.chromium.org/2026383002
This is a step towards using SkCodec in Chromium, where progressive
decoding is necessary.
Switch from using png_read_row (which expects all the data to be
available) to png_process_data, which uses callbacks when rows are
available.
Create a new API for SkCodec, which supports progressive decoding and
scanline decoding. Future changes will switch the other clients off of
startScanlineDecode and get/skip-Scanlines to the new API.
Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
updateCurrScanline(), which was only used by the old implementation for
interlaced PNG.
DMSrcSink:
- In CodecSrc::kScanline_Mode, use the new method for scanline decoding
for the supported formats (just PNG and PNG-in-ICO for now).
fuzz.cpp:
- Remove reference to kNone_ScanlineOrder
SkCodec:
- Add new APIs:
- startIncrementalDecode
- incrementalDecode
- Remove kNone_SkScanlineOrder and updateCurrScanline()
SkPngCodec:
- Implement new APIs
- Switch from sk_read_fn/png_read_row etc to png_process_data
- Expand AutoCleanPng's role to decode the header and create the
SkPngCodec
- Make the interlaced PNG decoder report how many lines were
initialized during an incomplete decode
- Make initializeSwizzler return a bool instead of an SkCodec::Result
(It only returned kSuccess or kInvalidInput anyway)
SkIcoCodec:
- Implement the new APIs; supported for PNG in ICO
SkSampledCodec:
- Call the new method for decoding scanlines, and fall back to the old
method if the new version is unimplemented
- Remove references to kNone_SkScanlineOrder
tests/CodecPartial:
- Add a test which decodes part of an image, then finishes the decode,
and compares it to the straightforward method
tests/CodecTest:
- Add a test which decodes all scanlines using the new method
- Repurpose the Codec_stripes test to decode using the new method in
sections rather than all at once
- In the method check(), add a parameter for whether the image supports
the new method of scanline decoding, and be explicit about whether an
image supports incomplete
- Test incomplete PNG decodes. We should have been doing it anyway for
non-interlaced (except for an image that is too small - one row), but
the new method supports interlaced incomplete as well
- Make test_invalid_parameters test the new method
- Add a test to ensure that it's safe to fall back to scanline decoding without
rewinding
BUG=skia:4211
The new version was generally faster than the old version (but not significantly so).
Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
Committed: https://skia.googlesource.com/skia/+/a4b09a117d4d1ba5dda372e6a2323e653766539e
Review-Url: https://codereview.chromium.org/1997703003
Reason for revert:
This is failing tests and then crashing on Google3 [1]. The crashes are fixed by crrev.com/2026873002, but to fix the builder we'll need to upgrade its version of libpng.
[1] https://sponge.corp.google.com/target?id=e545ef55-4da4-4931-9524-1ac92acb61b1&target=//third_party/skia/HEAD:dm#shard=1|run=1|attempt=1|page=-1
Original issue's description:
> Make SkPngCodec decode progressively.
>
> This is a step towards using SkCodec in Chromium, where progressive
> decoding is necessary.
>
> Switch from using png_read_row (which expects all the data to be
> available) to png_process_data, which uses callbacks when rows are
> available.
>
> Create a new API for SkCodec, which supports progressive decoding and
> scanline decoding. Future changes will switch the other clients off of
> startScanlineDecode and get/skip-Scanlines to the new API.
>
> Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
> PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
> updateCurrScanline(), which was only used by the old implementation for
> interlaced PNG.
>
> DMSrcSink:
> - In CodecSrc::kScanline_Mode, use the new method for scanline decoding
> for the supported formats (just PNG and PNG-in-ICO for now).
>
> fuzz.cpp:
> - Remove reference to kNone_ScanlineOrder
>
> SkCodec:
> - Add new APIs:
> - startIncrementalDecode
> - incrementalDecode
> - Remove kNone_SkScanlineOrder and updateCurrScanline()
>
> SkPngCodec:
> - Implement new APIs
> - Switch from sk_read_fn/png_read_row etc to png_process_data
> - Expand AutoCleanPng's role to decode the header and create the
> SkPngCodec
> - Make the interlaced PNG decoder report how many lines were
> initialized during an incomplete decode
> - Make initializeSwizzler return a bool instead of an SkCodec::Result
> (It only returned kSuccess or kInvalidInput anyway)
>
> SkIcoCodec:
> - Implement the new APIs; supported for PNG in ICO
>
> SkSampledCodec:
> - Call the new method for decoding scanlines, and fall back to the old
> method if the new version is unimplemented
> - Remove references to kNone_SkScanlineOrder
>
> tests/CodecPartial:
> - Add a test which decodes part of an image, then finishes the decode,
> and compares it to the straightforward method
>
> tests/CodecTest:
> - Add a test which decodes all scanlines using the new method
> - Repurpose the Codec_stripes test to decode using the new method in
> sections rather than all at once
> - In the method check(), add a parameter for whether the image supports
> the new method of scanline decoding, and be explicit about whether an
> image supports incomplete
> - Test incomplete PNG decodes. We should have been doing it anyway for
> non-interlaced (except for an image that is too small - one row), but
> the new method supports interlaced incomplete as well
> - Make test_invalid_parameters test the new method
> - Add a test to ensure that it's safe to fall back to scanline decoding without
> rewinding
>
> BUG=skia:4211
>
> The new version was generally faster than the old version (but not significantly so).
>
> Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
>
> Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
>
> Committed: https://skia.googlesource.com/skia/+/a4b09a117d4d1ba5dda372e6a2323e653766539eTBR=reed@google.com,msarett@google.com,scroggo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4211
Review-Url: https://codereview.chromium.org/2023103002
This is a step towards using SkCodec in Chromium, where progressive
decoding is necessary.
Switch from using png_read_row (which expects all the data to be
available) to png_process_data, which uses callbacks when rows are
available.
Create a new API for SkCodec, which supports progressive decoding and
scanline decoding. Future changes will switch the other clients off of
startScanlineDecode and get/skip-Scanlines to the new API.
Remove SkCodec::kNone_ScanlineOrder, which was only used for interlaced
PNG images. In the new API, interlaced PNG fits kTopDown. Also remove
updateCurrScanline(), which was only used by the old implementation for
interlaced PNG.
DMSrcSink:
- In CodecSrc::kScanline_Mode, use the new method for scanline decoding
for the supported formats (just PNG and PNG-in-ICO for now).
fuzz.cpp:
- Remove reference to kNone_ScanlineOrder
SkCodec:
- Add new APIs:
- startIncrementalDecode
- incrementalDecode
- Remove kNone_SkScanlineOrder and updateCurrScanline()
SkPngCodec:
- Implement new APIs
- Switch from sk_read_fn/png_read_row etc to png_process_data
- Expand AutoCleanPng's role to decode the header and create the
SkPngCodec
- Make the interlaced PNG decoder report how many lines were
initialized during an incomplete decode
- Make initializeSwizzler return a bool instead of an SkCodec::Result
(It only returned kSuccess or kInvalidInput anyway)
SkIcoCodec:
- Implement the new APIs; supported for PNG in ICO
SkSampledCodec:
- Call the new method for decoding scanlines, and fall back to the old
method if the new version is unimplemented
- Remove references to kNone_SkScanlineOrder
tests/CodecPartial:
- Add a test which decodes part of an image, then finishes the decode,
and compares it to the straightforward method
tests/CodecTest:
- Add a test which decodes all scanlines using the new method
- Repurpose the Codec_stripes test to decode using the new method in
sections rather than all at once
- In the method check(), add a parameter for whether the image supports
the new method of scanline decoding, and be explicit about whether an
image supports incomplete
- Test incomplete PNG decodes. We should have been doing it anyway for
non-interlaced (except for an image that is too small - one row), but
the new method supports interlaced incomplete as well
- Make test_invalid_parameters test the new method
- Add a test to ensure that it's safe to fall back to scanline decoding without
rewinding
BUG=skia:4211
The new version was generally faster than the old version (but not significantly so).
Some raw performance differences can be found at https://docs.google.com/a/google.com/spreadsheets/d/1Gis3aRCEa72qBNDRMgGDg3jD-pMgO-FXldlNF9ejo4o/
Design doc can be found at https://docs.google.com/a/google.com/document/d/11Mn8-ePDKwVEMCjs3nWwSjxcSpJ_Cu8DF57KNtUmgLM/
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1997703003
Review-Url: https://codereview.chromium.org/1997703003
Reason for revert:
Lots of bots failing
Original issue's description:
> Add SkEncodedInfo to report properties of encoded image data
>
> All this does is build an SkEncodedInfo for each codec, and
> then convert it to an SkImageInfo.
>
> In future steps I intend to:
> (1) Use SkEncodedInfo in place of SrcConfig in SkSwizzler.
> (2) Support more conversions in SkSwizzler (non-native
> BGRA/RGBA, 16-bit components, float, fixed point)
> (3) Investigate optimizing conversions from encoded data
> to linear color spaces.
>
> BUG=skia:4133
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1820073002
>
> Committed: https://skia.googlesource.com/skia/+/f682d9ad70d690a343bc15e26ef321d86770be41TBR=scroggo@google.com,reed@google.com,msarett@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4133
Review URL: https://codereview.chromium.org/1895383002
All this does is build an SkEncodedInfo for each codec, and
then convert it to an SkImageInfo.
In future steps I intend to:
(1) Use SkEncodedInfo in place of SrcConfig in SkSwizzler.
(2) Support more conversions in SkSwizzler (non-native
BGRA/RGBA, 16-bit components, float, fixed point)
(3) Investigate optimizing conversions from encoded data
to linear color spaces.
BUG=skia:4133
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1820073002
Review URL: https://codereview.chromium.org/1820073002
This is a synonym for the version of getAndroidPixels that accepts
only three parameters (i.e. no AndroidOptions). It is very similar
to SkCodec::getPixels, so I think the motivation for naming the
version with options differently does not apply here.
Add comments to the header describing defaults.
Update the test to use a template, and delete a lot of redundant code.
Rename a variable to stop shadowing another variable.
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1647153002
Review URL: https://codereview.chromium.org/1647153002
If a client requests unpremul or premul from an opaque SkCodec,
support it. The opaque image can be treated as any of them, though
it will be less efficient to draw than if the client had used
opaque.
Change the filling code (i.e. for incomplete images) to base its color on
the source alpha type. Prior to adding the support to decode opaque to
any, it was fine to use either source or dest (which would have yielded
the same result). If the client requests non-opaque, we do not want this
to switch the fill value from black to transparent. This also allows
simplifying the signatures for getFillValue and onGetFillValue.
In CodexTest, expect the same result when decoding opaque to *premul,
and compare to the opaque version.
BUG=skia:4616
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1641273003
Review URL: https://codereview.chromium.org/1641273003
If the client requests a color type or alpha type that is
not supported, we should decode to the default/appropriate
color and alpha types to match existing behavior in Android.
BUG=skia:
Review URL: https://codereview.chromium.org/1513023002
- Update SkCodec's dox to point out that some of the data must be
read twice in order to decode
- Add an accessor that reports how much is needed for reading twice
- Make SkCodec default to use peek()
If an input stream supports peek()ing, peek() instead of reading.
This way the stream need not implement rewind()
- Make SkCodec use read() + rewind() as a backup
So that streams without peek() implemented can still function
properly (assuming they can rewind).
- read everything we may need to determine the format once
In SkCodec::NewFromStream, peek()/read() 14 bytes, which is enough
to read all of the types we support. Pass the buffer to each subtype,
which will have enough info to determine whether it is the right
type. This simplifies the code and results in less reading and
rewinding.
- NOTE: SkWbmpCodec needs the following number of bytes for the header
+ 1 (type)
+ 1 (reserved)
+ 3 (width - bytes needed to support up to 0xFFFF)
+ 3 (height - bytes needed to support up to 0xFFFF)
= 8
- in SkWebpCodec, support using read + rewind as a backup if peek does
not work.
A change in Android will add peek() to JavaInputStreamAdapter.
BUG=skia:3257
Review URL: https://codereview.chromium.org/1472123002
This is more correct than using nextScanline() for the
SkGifCodec scanline decoder (since we will get a strange
result in the interlaced case) and is necessary if we want
to add scanline decoding to SkIcoCodec.
This does not actually fix bugs or change behavior.
BUG=skia:
Review URL: https://codereview.chromium.org/1489163002
This class allows a client of SkCodec to read chunks in the data
stream that are not recognized by libpng. This is used by Android
to specify ninepatch data.
Taken from SkImageDecoder::Peeker. Modify the name of the class
and its method to be more specific to their use. Make
SkImageDecoder::Peeker a subclass of the new class, to help stage
the change in Android.
Add a test to verify that it works.
BUG=skia:4574
BUG=skia:3257
Committed: https://skia.googlesource.com/skia/+/3389e00136188800b98ca69488c0418c374fd78b
Review URL: https://codereview.chromium.org/1040453002
Reason for revert:
Busted Chromium builds:
../../third_party/skia/src/ports/SkImageDecoder_empty.cpp:63:17: error: no type
named 'Peeker' in 'SkImageDecoder'
SkImageDecoder::Peeker* SkImageDecoder::setPeeker(Peeker*) {
~~~~~~~~~~~~~~~~^
../../third_party/skia/src/ports/SkImageDecoder_empty.cpp:63:51: error: unknown
type name 'Peeker'
SkImageDecoder::Peeker* SkImageDecoder::setPeeker(Peeker*) {
Original issue's description:
> Add SkPngChunkReader.
>
> This class allows a client of SkCodec to read chunks in the data
> stream that are not recognized by libpng. This is used by Android
> to specify ninepatch data.
>
> Taken from SkImageDecoder::Peeker. Modify the name of the class
> and its method to be more specific to their use. Make
> SkImageDecoder::Peeker a subclass of the new class, to help stage
> the change in Android.
>
> Add a test to verify that it works.
>
> BUG=skia:4574
> BUG=skia:3257
>
> Committed: https://skia.googlesource.com/skia/+/3389e00136188800b98ca69488c0418c374fd78bTBR=djsollen@google.com,reed@google.com,msarett@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4574
Review URL: https://codereview.chromium.org/1472863003
This class allows a client of SkCodec to read chunks in the data
stream that are not recognized by libpng. This is used by Android
to specify ninepatch data.
Taken from SkImageDecoder::Peeker. Modify the name of the class
and its method to be more specific to their use. Make
SkImageDecoder::Peeker a subclass of the new class, to help stage
the change in Android.
Add a test to verify that it works.
BUG=skia:4574
BUG=skia:3257
Review URL: https://codereview.chromium.org/1040453002
Make the struct passed to SkAndroidCodec::getAndroidPixels const. This
matches SkCodec, and makes sense, since it is not used as an output.
Brought up in crrev.com/1417583009
Review URL: https://codereview.chromium.org/1411693005
We will implement this API using SkCodecs.
SkAndroidCodecs will be used to implement the
BitmapRegionDecoder Java API (and possibly
BitmapFactory).
BUG=skia:
Review URL: https://codereview.chromium.org/1406223002
This CL allows the SkScanlineDecoder to decode partial
scanlines.
This is a first step in efficiently implementing subsetting
in SkScaledCodec.
BUG=skia:4209
Review URL: https://codereview.chromium.org/1390213002
Rather than implementing some sort of "fill" in every
SkCodec subclass for incomplete images, let's make the
parent class handle this situation.
This includes an API change to SkCodec.h
SkCodec::getScanlines() now returns the number of lines it
read successfully, rather than an SkCodec::Result enum.
getScanlines() most often fails on an incomplete input, in
which case it is useful to know how many lines were
successfully decoded - this provides more information than
kIncomplete vs kSuccess. We do lose information when the
API is used improperly, as we are no longer able to return
kInvalidParameter or kScanlineNotStarted.
Known Issues:
Does not work for incomplete fFrameIsSubset gifs.
Does not work for incomplete icos.
BUG=skia:
Review URL: https://codereview.chromium.org/1332053002
Prior to this CL, each SkCodec subclass that allows sampling does an
extra check in onStartScanlineDecode to determine whether the X dimension
is supported for sampling. Remove this check, and provide a way for
SkScaledCodec to directly access the SkSwizzler, and update it to do
sampling. This way, the SkCodec knows nothing of sampling, but we can
still save the extra step of sampling afterwards.
FIXME: SkBmpRLECodec still calls SkScaledCodec::DimensionsSupported. It
seems like it could directly support sampling, rather than dealing with
SkScaledCodec (partially).
Add a new base class for SkSwizzler. It allows updating the swizzler
after it was created, which is done by SkScaledCodec. Modify SkSwizzler's
constructor/factory function to stop taking any info about sampling,
assume the sample size is one, and move modifying that into a virtual
function overridden from the base class.
BUG=skia:4284
Review URL: https://codereview.chromium.org/1372973002
Rather than calling it in each subclass, call it once in the base
class. Call it first, since other steps may modify internal structures
which would be replaced by a call to onRewind.
BUG=skia:4284
Review URL: https://codereview.chromium.org/1381483002
Benefits:
- This mimics other decoding APIs (including the ones SkCodec relies
on, e.g. a png_struct, which can be used to decode an entire image or
one line at a time).
- It allows a client to ask us to do what we can do efficiently - i.e.
start from encoded data and either decode the whole thing or scanlines.
- It removes the duplicate methods which appeared in both SkCodec and
SkScanlineDecoder (some of which, e.g. in SkJpegScanlineDecoder, just
call fCodec->sameMethod()).
- It simplifies moving more checks into the base class (e.g. the
examples in skbug.com/4284).
BUG=skia:4175
BUG=skia:4284
=====================================================================
SkScanlineDecoder.h/.cpp:
Removed.
SkCodec.h/.cpp:
Add methods, enums, and variables which were previously in
SkScanlineDecoder.
Default fCurrScanline to -1, as a sentinel that start has not been
called.
General changes:
Convert SkScanlineDecoders to SkCodecs.
General changes in SkCodec subclasses:
Merge SkScanlineDecoder implementation into SkCodec. Most (all?) owned
an SkCodec, so they now call this-> instead of fCodec->.
SkBmpCodec.h/.cpp:
Replace the unused rowOrder method with an override for
onGetScanlineOrder.
Make getDstRow const, since it is called by onGetY, which is const.
SkCodec_libpng.h/.cpp:
Make SkPngCodec an abstract class, with two subclasses which handle
scanline decoding separately (they share code for decoding the entire
image). Reimplement onReallyHasAlpha so that it can return the most
recent result (e.g. after a scanline decode which only decoded part
of the image) or a better answer (e.g. if the whole image is known to
be opaque).
Compute fNumberPasses early, so we know which subclass to instantiate.
Make SkPngInterlaceScanlineDecoder use the base class' fCurrScanline
rather than a separate variable.
CodexTest.cpp:
Add tests for the state changes in SkCodec (need to call start before
decoding scanlines; calling getPixels means that start will need to
be called again before decoding more scanlines).
Add a test which decodes in stripes, currently only used for an
interlaced PNG.
TODO: Add tests for onReallyHasAlpha.
Review URL: https://codereview.chromium.org/1365313002
Redesigns SkScanlineDecoder.h to indicate the ordering
in which the scanlines are provided
Refactors SkSwizzler::Fill() to include the zeroInit check
and to actually be correct.
BUG=skia:3257
BUG=skia:4198
Review URL: https://codereview.chromium.org/1287423002
SkTemplates.h contains a number of Skia specific utilities which are
not designed for external use. In addition to reducing the external
support burden, this will allow Skia to freely refactor this file.
Review URL: https://codereview.chromium.org/1272293004
We don't want to test small images on Gold because they are
not interested to look at. Instead, I wrote a unit test to
verify that scaling small images does not cause crashes.
BUG=skia:
Review URL: https://codereview.chromium.org/1287863004
Previously, many of our codec implementations followed the same
pattern (often in a function named handleRewind):
switch (this->rewindIfNeeded()) {
case CouldNotRewind:
return CouldNotRewind;
case NoRewindNecessary:
// keep going
break;
case Rewound:
<re-read header etc>
break;
}
In this CL, remove the enum, and put the piece that happens in the
Rewound case into a virtual function, onRewind. rewindIfNeeded now
contains the common pieces from various functions named handleRewind.
In SkBmpCodec, add a function that returns whether the BMP is in ICO,
so it can have a common implementation for onRewind.
BUG=skia:3257
Review URL: https://codereview.chromium.org/1288483002
Prior to this CL, if a client wanted to decode scanlines, they had to
create an SkCodec in order to get an SkScanlineDecoder. This introduces
complications if input data is not easily shared between the two
objects.
Instead, add methods to SkScanlineDecoder for creating a new one from
input data, and remove the creation functions from SkCodec.
Update DM and tests.
Review URL: https://codereview.chromium.org/1267583002
This allows codecs that support subsets natively (i.e. WEBP) to do so.
Add a field on SkCodec::Options representing the subset.
Add a method on SkCodec to find a valid subset which approximately
matches a desired subset.
Implement subset decodes in SkWebpCodec.
Add a test in DM for decoding subsets.
Notice that we only start on even boundaries. This is due to the
way libwebp's API works. SkWEBPImageDecoder does not take this into
account, which results in visual artifacts.
FIXME: Subsets with scaling are not pixel identical, but close. (This
may be fine, though - they are not perceptually different. We'll just
need to mark another set of images in gold as valid, once
https://skbug.com/4038 is fixed, so we can tests scaled webp without
generating new images on each run.)
Review URL: https://codereview.chromium.org/1240143002
Make getScanlineDecoder return a new object each time, which is
owned by the caller, and independent from any existing scanline
decoders and the SkCodec itself.
Since the SkCodec already contains the entire state machine, and it
is used by the scanline decoders, simply create a new SkCodec which
is now owned by the scanline decoder.
Move code that cleans up after using a scanline decoder into its
destructor
One side effect is that creating the first scanline decoder requires
a duplication of the stream and re-reading the header. (With some
more complexity/changes, we could pass the state machine to the
scanline decoder and make the SkCodec recreate its own state machine
instead.) The typical client of the scanline decoder (region decoder)
uses an SkMemoryStream, so the duplication is cheap, although we
should consider the extra time to reread the header/recreate the state
machine. (If/when we use the scanline decoder for other purposes,
where the stream may not be cheaply duplicated, we should consider
passing the state machine.)
One (intended) result of this change is that a client can create a
new scanline decoder in a new thread, and decode different pieces of
the image simultaneously.
In SkPngCodec::decodePalette, use fBitDepth rather than a parameter.
Review URL: https://codereview.chromium.org/1230033004
SkImageGenerator makes some assumptions that are not necessarily valid
for SkCodec. For example, SkCodec does not assume that it can always be
rewound.
We also have an ongoing question of what an SkCodec should report as
its default settings (i.e. the return from getInfo). It makes sense for
an SkCodec to report that its pixels are unpremultiplied, if that is
the case for the underlying data, but if a client of SkImageGenerator
uses the default settings (as many do), they will receive
unpremultiplied pixels which cannot (currently) be drawn with Skia. We
may ultimately decide to revisit SkCodec reporting an SkImageInfo, but
I have left it unchanged for now.
Import features of SkImageGenerator used by SkCodec into SkCodec.
I have left SkImageGenerator unchanged for now, but it no longer needs
Result or Options. This will require changes to Chromium.
Manually handle the lifetime of fScanlineDecoder, so SkScanlineDecoder.h
can include SkCodec.h (where Result is), and SkCodec.h does not need
to include it (to delete fScanlineDecoder).
In many places, make the following simple changes:
- Now include SkScanlineDecoder.h, which is no longer included by
SkCodec.h
- Use the enums in SkCodec, rather than SkImageGenerator
- Stop including SkImageGenerator.h where no longer needed
Review URL: https://codereview.chromium.org/1220733013
the bottom of the image. In our code before this patch,
this would result in cleanup code in onFinish() never being
called.
We can allow subclasses to take ownership of the
SkScanlineDecoder in order to make sure that it is
finished/deleted before deleting the decode manager.
BUG=skia:
Review URL: https://codereview.chromium.org/1212593003
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
