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Diffstat (limited to 'include/images/SkImageDecoder.h')
| -rw-r--r-- | include/images/SkImageDecoder.h | 263 |
1 files changed, 0 insertions, 263 deletions
diff --git a/include/images/SkImageDecoder.h b/include/images/SkImageDecoder.h deleted file mode 100644 index 3ea6198..0000000 --- a/include/images/SkImageDecoder.h +++ /dev/null @@ -1,263 +0,0 @@ -/* - * Copyright (C) 2006 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#ifndef SkImageDecoder_DEFINED -#define SkImageDecoder_DEFINED - -#include "SkBitmap.h" -#include "SkRefCnt.h" - -class SkStream; - -/** \class SkImageDecoder - - Base class for decoding compressed images into a SkBitmap -*/ -class SkImageDecoder { -public: - virtual ~SkImageDecoder(); - - enum Format { - kUnknown_Format, - kBMP_Format, - kGIF_Format, - kICO_Format, - kJPEG_Format, - kPNG_Format, - kWBMP_Format, - - kLastKnownFormat = kWBMP_Format - }; - - /** Return the compressed data's format (see Format enum) - */ - virtual Format getFormat() const; - - /** Returns true if the decoder should try to dither the resulting image. - The default setting is true. - */ - bool getDitherImage() const { return fDitherImage; } - - /** Set to true if the the decoder should try to dither the resulting image. - The default setting is true. - */ - void setDitherImage(bool dither) { fDitherImage = dither; } - - /** \class Peeker - - Base class for optional callbacks to retrieve meta/chunk data out of - an image as it is being decoded. - */ - class Peeker : public SkRefCnt { - public: - /** Return true to continue decoding, or false to indicate an error, which - will cause the decoder to not return the image. - */ - virtual bool peek(const char tag[], const void* data, size_t length) = 0; - }; - - Peeker* getPeeker() const { return fPeeker; } - Peeker* setPeeker(Peeker*); - - /** \class Peeker - - Base class for optional callbacks to retrieve meta/chunk data out of - an image as it is being decoded. - */ - class Chooser : public SkRefCnt { - public: - virtual void begin(int count) {} - virtual void inspect(int index, SkBitmap::Config config, int width, int height) {} - /** Return the index of the subimage you want, or -1 to choose none of them. - */ - virtual int choose() = 0; - }; - - Chooser* getChooser() const { return fChooser; } - Chooser* setChooser(Chooser*); - - SkBitmap::Allocator* getAllocator() const { return fAllocator; } - SkBitmap::Allocator* setAllocator(SkBitmap::Allocator*); - - // sample-size, if set to > 1, tells the decoder to return a smaller than - // original bitmap, sampling 1 pixel for every size pixels. e.g. if sample - // size is set to 3, then the returned bitmap will be 1/3 as wide and high, - // and will contain 1/9 as many pixels as the original. - // Note: this is a hint, and the codec may choose to ignore this, or only - // approximate the sample size. - int getSampleSize() const { return fSampleSize; } - void setSampleSize(int size); - - /** Reset the sampleSize to its default of 1 - */ - void resetSampleSize() { this->setSampleSize(1); } - - /** Decoding is synchronous, but for long decodes, a different thread can - call this method safely. This sets a state that the decoders will - periodically check, and if they see it changed to cancel, they will - cancel. This will result in decode() returning false. However, there is - no guarantee that the decoder will see the state change in time, so - it is possible that cancelDecode() will be called, but will be ignored - and decode() will return true (assuming no other problems were - encountered). - - This state is automatically reset at the beginning of decode(). - */ - void cancelDecode() { - // now the subclass must query shouldCancelDecode() to be informed - // of the request - fShouldCancelDecode = true; - } - - /** Passed to the decode method. If kDecodeBounds_Mode is passed, then - only the bitmap's width/height/config need be set. If kDecodePixels_Mode - is passed, then the bitmap must have pixels or a pixelRef. - */ - enum Mode { - kDecodeBounds_Mode, //!< only return width/height/config in bitmap - kDecodePixels_Mode //!< return entire bitmap (including pixels) - }; - - /** Given a stream, decode it into the specified bitmap. - If the decoder can decompress the image, it calls bitmap.setConfig(), - and then if the Mode is kDecodePixels_Mode, call allocPixelRef(), - which will allocated a pixelRef. To access the pixel memory, the codec - needs to call lockPixels/unlockPixels on the - bitmap. It can then set the pixels with the decompressed image. - If the image cannot be decompressed, return false. - - note: document use of Allocator, Peeker and Chooser - */ - bool decode(SkStream*, SkBitmap* bitmap, SkBitmap::Config pref, Mode); - - /** Given a stream, this will try to find an appropriate decoder object. - If none is found, the method returns NULL. - */ - static SkImageDecoder* Factory(SkStream*); - - /** Decode the image stored in the specified file, and store the result - in bitmap. Return true for success or false on failure. - - If pref is kNo_Config, then the decoder is free to choose the most natural - config given the image data. If pref something other than kNo_Config, - the decoder will attempt to decode the image into that format, unless - there is a conflict (e.g. the image has per-pixel alpha and the bitmap's - config does not support that), in which case the decoder will choose a - closest match configuration. - */ - static bool DecodeFile(const char file[], SkBitmap* bitmap, - SkBitmap::Config prefConfig, Mode); - static bool DecodeFile(const char file[], SkBitmap* bitmap) - { - return DecodeFile(file, bitmap, SkBitmap::kNo_Config, kDecodePixels_Mode); - } - /** Decode the image stored in the specified memory buffer, and store the - result in bitmap. Return true for success or false on failure. - - If pref is kNo_Config, then the decoder is free to choose the most natural - config given the image data. If pref something other than kNo_Config, - the decoder will attempt to decode the image into that format, unless - there is a conflict (e.g. the image has per-pixel alpha and the bitmap's - config does not support that), in which case the decoder will choose a - closest match configuration. - */ - static bool DecodeMemory(const void* buffer, size_t size, SkBitmap* bitmap, - SkBitmap::Config prefConfig, Mode); - static bool DecodeMemory(const void* buffer, size_t size, SkBitmap* bitmap) - { - return DecodeMemory(buffer, size, bitmap, SkBitmap::kNo_Config, - kDecodePixels_Mode); - } - /** Decode the image stored in the specified SkStream, and store the result - in bitmap. Return true for success or false on failure. - - If pref is kNo_Config, then the decoder is free to choose the most - natural config given the image data. If pref something other than - kNo_Config, the decoder will attempt to decode the image into that - format, unless there is a conflict (e.g. the image has per-pixel alpha - and the bitmap's config does not support that), in which case the - decoder will choose a closest match configuration. - */ - static bool DecodeStream(SkStream* stream, SkBitmap* bitmap, - SkBitmap::Config prefConfig, Mode); - static bool DecodeStream(SkStream* stream, SkBitmap* bitmap) - { - return DecodeStream(stream, bitmap, SkBitmap::kNo_Config, - kDecodePixels_Mode); - } - - /** Return the default config for the running device. - Currently this used as a suggestion to image decoders that need to guess - what config they should decode into. - Default is kNo_Config, but this can be changed with SetDeviceConfig() - */ - static SkBitmap::Config GetDeviceConfig(); - /** Set the default config for the running device. - Currently this used as a suggestion to image decoders that need to guess - what config they should decode into. - Default is kNo_Config. - This can be queried with GetDeviceConfig() - */ - static void SetDeviceConfig(SkBitmap::Config); - - /** @cond UNIT_TEST */ - SkDEBUGCODE(static void UnitTest();) - /** @endcond */ - -protected: - // must be overridden in subclasses. This guy is called by decode(...) - virtual bool onDecode(SkStream*, SkBitmap* bitmap, SkBitmap::Config pref, - Mode) = 0; - - /** Can be queried from within onDecode, to see if the user (possibly in - a different thread) has requested the decode to cancel. If this returns - true, your onDecode() should stop and return false. - Each subclass needs to decide how often it can query this, to balance - responsiveness with performance. - - Calling this outside of onDecode() may return undefined values. - */ - -public: - bool shouldCancelDecode() const { return fShouldCancelDecode; } - -protected: - SkImageDecoder(); - - // helper function for decoders to handle the (common) case where there is only - // once choice available in the image file. - bool chooseFromOneChoice(SkBitmap::Config config, int width, int height) const; - - /* Helper for subclasses. Call this to allocate the pixel memory given the bitmap's - width/height/rowbytes/config. Returns true on success. This method handles checking - for an optional Allocator. - */ - bool allocPixelRef(SkBitmap*, SkColorTable*) const; - -private: - Peeker* fPeeker; - Chooser* fChooser; - SkBitmap::Allocator* fAllocator; - int fSampleSize; - bool fDitherImage; - mutable bool fShouldCancelDecode; - - // illegal - SkImageDecoder(const SkImageDecoder&); - SkImageDecoder& operator=(const SkImageDecoder&); -}; - -#endif |