| /* |
| * 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 SkCodec_DEFINED |
| #define SkCodec_DEFINED |
| |
| #include "SkImageGenerator.h" |
| #include "SkImageInfo.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkTemplates.h" |
| #include "SkTypes.h" |
| |
| class SkData; |
| |
| /** |
| * Abstraction layer directly on top of an image codec. |
| */ |
| class SkCodec : public SkImageGenerator { |
| public: |
| /** |
| * If this stream represents an encoded image that we know how to decode, |
| * return an SkCodec that can decode it. Otherwise return NULL. |
| * |
| * If NULL is returned, the stream is deleted immediately. Otherwise, the |
| * SkCodec takes ownership of it, and will delete it when done with it. |
| */ |
| static SkCodec* NewFromStream(SkStream*); |
| |
| /** |
| * If this data represents an encoded image that we know how to decode, |
| * return an SkCodec that can decode it. Otherwise return NULL. |
| * |
| * Will take a ref if it returns a codec, else will not affect the data. |
| */ |
| static SkCodec* NewFromData(SkData*); |
| |
| /** |
| * Return a size that approximately supports the desired scale factor. |
| * The codec may not be able to scale efficiently to the exact scale |
| * factor requested, so return a size that approximates that scale. |
| * |
| * FIXME: Move to SkImageGenerator? |
| */ |
| SkISize getScaledDimensions(float desiredScale) const { |
| return this->onGetScaledDimensions(desiredScale); |
| } |
| |
| protected: |
| SkCodec(const SkImageInfo&, SkStream*); |
| |
| /** |
| * The SkAlphaType is a conservative answer. i.e. it is possible that it |
| * initially returns a non-opaque answer, but completing the decode |
| * reveals that the image is actually opaque. |
| */ |
| #ifdef SK_SUPPORT_LEGACY_BOOL_ONGETINFO |
| bool onGetInfo(SkImageInfo* info) SK_OVERRIDE { |
| *info = fInfo; |
| return true; |
| } |
| #endif |
| |
| // Helper for subclasses. |
| const SkImageInfo& getOriginalInfo() { return fInfo; } |
| |
| virtual SkISize onGetScaledDimensions(float /* desiredScale */) const { |
| // By default, scaling is not supported. |
| return fInfo.dimensions(); |
| } |
| |
| /** |
| * If the stream was previously read, attempt to rewind. |
| * @returns: |
| * true |
| * - if the stream needed to be rewound, and the rewind |
| * succeeded. |
| * - if the stream did not need to be rewound. |
| * false |
| * - if the stream needed to be rewound, and rewind failed. |
| * Subclasses MUST call this function before reading the stream (e.g. in |
| * onGetPixels). If it returns false, onGetPixels should return |
| * kCouldNotRewind. |
| */ |
| bool SK_WARN_UNUSED_RESULT rewindIfNeeded(); |
| |
| /* |
| * |
| * Get method for the input stream |
| * |
| */ |
| SkStream* stream() { |
| return fStream.get(); |
| } |
| |
| private: |
| const SkImageInfo fInfo; |
| SkAutoTDelete<SkStream> fStream; |
| bool fNeedsRewind; |
| |
| typedef SkImageGenerator INHERITED; |
| }; |
| #endif // SkCodec_DEFINED |