diff options
author | scroggo <scroggo@google.com> | 2015-11-23 07:20:57 -0800 |
---|---|---|
committer | Commit bot <commit-bot@chromium.org> | 2015-11-23 07:20:57 -0800 |
commit | 3389e00136188800b98ca69488c0418c374fd78b (patch) | |
tree | 6cbb5b6bc005e618daca29be3873f7211780ebbc /include/core/SkPngChunkReader.h | |
parent | a98419be092cce2a7ef27a09b6fd8065ff709cff (diff) |
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
Review URL: https://codereview.chromium.org/1040453002
Diffstat (limited to 'include/core/SkPngChunkReader.h')
-rw-r--r-- | include/core/SkPngChunkReader.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/include/core/SkPngChunkReader.h b/include/core/SkPngChunkReader.h new file mode 100644 index 0000000000..f424dd8cfc --- /dev/null +++ b/include/core/SkPngChunkReader.h @@ -0,0 +1,45 @@ +/* + * Copyright 2015 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#ifndef SkPngChunkReader_DEFINED +#define SkPngChunkReader_DEFINED + +#include "SkTypes.h" +#include "SkRefCnt.h" + +/** + * SkPngChunkReader + * + * Base class for optional callbacks to retrieve meta/chunk data out of a PNG + * encoded image as it is being decoded. + * Used by SkImageDecoder and SkCodec. + */ +class SkPngChunkReader : public SkRefCnt { +public: + /** + * This will be called by the decoder when it sees an unknown chunk. + * + * Use by SkCodec: + * Depending on the location of the unknown chunks, this callback may be + * called by + * - the factory (NewFromStream/NewFromData) + * - getPixels + * - startScanlineDecode + * - the first call to getScanlines/skipScanlines + * The callback may be called from a different thread (e.g. if the SkCodec + * is passed to another thread), and it may be called multiple times, if + * the SkCodec is used multiple times. + * + * @param tag Name for this type of chunk. + * @param data Data to be interpreted by the subclass. + * @param length Number of bytes of data in the chunk. + * @return true to continue decoding, or false to indicate an error, which + * will cause the decoder to not return the image. + */ + virtual bool readChunk(const char tag[], const void* data, size_t length) = 0; +}; +#endif // SkPngChunkReader_DEFINED |