Commit Graph

9 Commits

Author SHA1 Message Date
Leon Scroggins III
33deb7ed4d Make SkCodec more flexible about its required frame
SkCodec sets fRequiredFrame to be the earliest possible frame that a
given frame can depend on. e.g.

- Frame A fills the screen, Keep
- Frame B does not cover A, Keep
- Frame C covers B but not A, and is opaque

Frame C can depend on either A or B. SkCodec already reports that C
depends on A. This CL allows a client of SkCodec to use either A or
B to create C.

Also expose the DisposalMethod. Since any frame between A and C can
be used to create C except for DisposePrevious frames, the client
needs to be able to know the disposal method so they do not try to
use such a frame to create C.

Further, the disposal method can be used to give the client a better
idea whether they will continue to need a frame. (e.g. if frame i is
DisposePrevious and depends on i-1, the client may not want to steal
i-1 to create i, since i+1 may also depend on i-1.)

TODO: Share code for decoding prior frames between GIF and WEBP

Change-Id: I91a5ae22ba3d8dfbe0bde833fa67ae3da0d81ed6
Reviewed-on: https://skia-review.googlesource.com/13722
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Chris Blume <cblume@chromium.org>
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
2017-06-07 20:15:17 +00:00
Cary Clark
2a475eae62 add drawString helper to canvas
Many tests and examples use drawText with
a guess of how long the text is in bytes,
or a call to strlen(). Add a helper to
SkCanvas to simplify these examples.

Add another helper for SkString.

R=reed@google.com

Change-Id: I0204a31e938f065606f08ee7cd9a6b36db791ee2
Reviewed-on: https://skia-review.googlesource.com/13642
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Cary Clark <caryclark@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Cary Clark <caryclark@skia.org>
2017-04-28 20:41:04 +00:00
Matt Sarett
68b8e3d50d Revert "Revert "Delete copyTo(Allocator), hide copyTo() behind flag""
This reverts commit 0122af08f6.

Reason for revert: Fixed Android callsite

Original change's description:
> Revert "Delete copyTo(Allocator), hide copyTo() behind flag"
> 
> This reverts commit d4a338f4d0.
> 
> Reason for revert: Looks like I missed something I was supposed to delete in Android.
> 
> Original change's description:
> > Delete copyTo(Allocator), hide copyTo() behind flag
> > 
> > Replace uses of copyTo() in Skia.
> > 
> > Bug: skia:6464
> > Change-Id: I921dc53a1c29a5176d18f05741f7c0b5a008e548
> > Reviewed-on: https://skia-review.googlesource.com/14502
> > Commit-Queue: Matt Sarett <msarett@google.com>
> > Reviewed-by: Mike Reed <reed@google.com>
> > 
> 
> TBR=msarett@google.com,reed@google.com
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> 
> Change-Id: I4d252940cc6a2462b030007055ea6c229471fc6e
> Reviewed-on: https://skia-review.googlesource.com/14602
> Reviewed-by: Matt Sarett <msarett@google.com>
> Commit-Queue: Matt Sarett <msarett@google.com>
> 

TBR=msarett@google.com,reviews@skia.org,reed@google.com

Change-Id: I81659a820f79f1958fda23cb62513065b57db99d
Reviewed-on: https://skia-review.googlesource.com/14640
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
2017-04-28 15:49:04 +00:00
Matt Sarett
0122af08f6 Revert "Delete copyTo(Allocator), hide copyTo() behind flag"
This reverts commit d4a338f4d0.

Reason for revert: Looks like I missed something I was supposed to delete in Android.

Original change's description:
> Delete copyTo(Allocator), hide copyTo() behind flag
> 
> Replace uses of copyTo() in Skia.
> 
> Bug: skia:6464
> Change-Id: I921dc53a1c29a5176d18f05741f7c0b5a008e548
> Reviewed-on: https://skia-review.googlesource.com/14502
> Commit-Queue: Matt Sarett <msarett@google.com>
> Reviewed-by: Mike Reed <reed@google.com>
> 

TBR=msarett@google.com,reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I4d252940cc6a2462b030007055ea6c229471fc6e
Reviewed-on: https://skia-review.googlesource.com/14602
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>
2017-04-27 20:08:45 +00:00
Matt Sarett
d4a338f4d0 Delete copyTo(Allocator), hide copyTo() behind flag
Replace uses of copyTo() in Skia.

Bug: skia:6464
Change-Id: I921dc53a1c29a5176d18f05741f7c0b5a008e548
Reviewed-on: https://skia-review.googlesource.com/14502
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2017-04-27 17:18:03 +00:00
Leon Scroggins III
249b8e3a2b Switch SkCodec to int for counts and indices
This matches other Skia APIs. size_t was adopted from blink/
GIFImageReader.

Change-Id: Ic83e59f0942f597c4fb834e623acd9886ad483fe
Reviewed-on: https://skia-review.googlesource.com/13274
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Chris Blume <cblume@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
2017-04-17 17:38:35 +00:00
Jim Van Verth
3cfdf6c8b1 Fix some Windows warnings
BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3980

Change-Id: Icfc5dfb985b966c625d9bc81f61719ac5549085e
Reviewed-on: https://skia-review.googlesource.com/3980
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
2016-10-26 14:16:28 +00:00
scroggo
cf280a484a Clear background to white in animatedGif GM
White looks the same in 565, reducing the number of differences in gold
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2447793002

Review-Url: https://codereview.chromium.org/2447793002
2016-10-24 09:59:53 -07:00
scroggo
19b91531e9 Add support for multiple frames in SkCodec
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
2016-10-24 09:03:26 -07:00