2bbc2c945b
Currently they cannot be used directly by Skia, but the pixels can be used elsewhere. SkImageDecoder: Add functions to require unpremultiplied output and query the presence of the requirement SkImageDecoder_libpng: SkImageDecoder_libwebp: SkImageDecoder_WIC: Respect the requirement for unpremultiplied output. TODO: Fix SkImageDecoder_CG. SkScaledBitmapSampler: Add procs to skip premultiplication and a boolean parameter to use those procs. ImageDecodingTest: Test unpremultiplied bitmap decoding. SampleUnpremul: Add a sample which allows visually comparing between the unpremultiplied version (copied into a premultiplied bitmap, since drawing unpremultiplied is not currently supported) and a premultiplied version of image files. gm.h: Add a getter for the resource path, so Samples can use it. As of patch set 13, https://codereview.chromium.org/16816016/ and https://codereview.chromium.org/16983004/, which were approved separately. R=reed@google.com Review URL: https://codereview.chromium.org/16410009 git-svn-id: http://skia.googlecode.com/svn/trunk@9612 2bbb7eff-a529-9590-31e7-b0007b416f81
501 lines
20 KiB
C++
501 lines
20 KiB
C++
|
|
/*
|
|
* Copyright 2006 The Android Open Source Project
|
|
*
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*/
|
|
|
|
|
|
#ifndef SkImageDecoder_DEFINED
|
|
#define SkImageDecoder_DEFINED
|
|
|
|
#include "SkBitmap.h"
|
|
#include "SkBitmapFactory.h"
|
|
#include "SkImage.h"
|
|
#include "SkRect.h"
|
|
#include "SkRefCnt.h"
|
|
#include "SkTypes.h"
|
|
|
|
class SkStream;
|
|
|
|
/** \class SkImageDecoder
|
|
|
|
Base class for decoding compressed images into a SkBitmap
|
|
*/
|
|
class SkImageDecoder : public SkNoncopyable {
|
|
public:
|
|
virtual ~SkImageDecoder();
|
|
|
|
enum Format {
|
|
kUnknown_Format,
|
|
kBMP_Format,
|
|
kGIF_Format,
|
|
kICO_Format,
|
|
kJPEG_Format,
|
|
kPNG_Format,
|
|
kWBMP_Format,
|
|
kWEBP_Format,
|
|
|
|
kLastKnownFormat = kWEBP_Format,
|
|
};
|
|
|
|
/** Return the format of image this decoder can decode. If this decoder can decode multiple
|
|
formats, kUnknown_Format will be returned.
|
|
*/
|
|
virtual Format getFormat() const;
|
|
|
|
/** Return the format of the SkStream or kUnknown_Format if it cannot be determined. Rewinds the
|
|
stream before returning.
|
|
*/
|
|
static Format GetStreamFormat(SkStream*);
|
|
|
|
/** Return a readable string of the Format provided.
|
|
*/
|
|
static const char* GetFormatName(Format);
|
|
|
|
/** Return a readable string of the value returned by getFormat().
|
|
*/
|
|
const char* getFormatName() 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; }
|
|
|
|
/** Returns true if the decoder should try to decode the
|
|
resulting image to a higher quality even at the expense of
|
|
the decoding speed.
|
|
*/
|
|
bool getPreferQualityOverSpeed() const { return fPreferQualityOverSpeed; }
|
|
|
|
/** Set to true if the the decoder should try to decode the
|
|
resulting image to a higher quality even at the expense of
|
|
the decoding speed.
|
|
*/
|
|
void setPreferQualityOverSpeed(bool qualityOverSpeed) {
|
|
fPreferQualityOverSpeed = qualityOverSpeed;
|
|
}
|
|
|
|
/** Set to true to require the decoder to return a bitmap with unpremultiplied
|
|
colors. The default is false, meaning the resulting bitmap will have its
|
|
colors premultiplied.
|
|
NOTE: Passing true to this function may result in a bitmap which cannot
|
|
be properly used by Skia.
|
|
*/
|
|
void setRequireUnpremultipliedColors(bool request) {
|
|
fRequireUnpremultipliedColors = request;
|
|
}
|
|
|
|
/** Returns true if the decoder will only return bitmaps with unpremultiplied
|
|
colors.
|
|
*/
|
|
bool getRequireUnpremultipliedColors() const { return fRequireUnpremultipliedColors; }
|
|
|
|
/** \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:
|
|
SK_DECLARE_INST_COUNT(Peeker)
|
|
|
|
/** 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;
|
|
private:
|
|
typedef SkRefCnt INHERITED;
|
|
};
|
|
|
|
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:
|
|
SK_DECLARE_INST_COUNT(Chooser)
|
|
|
|
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;
|
|
|
|
private:
|
|
typedef SkRefCnt INHERITED;
|
|
};
|
|
|
|
Chooser* getChooser() const { return fChooser; }
|
|
Chooser* setChooser(Chooser*);
|
|
|
|
/** This optional table describes the caller's preferred config based on
|
|
information about the src data. For this table, the src attributes are
|
|
described in terms of depth (index (8), 16, 32/24) and if there is
|
|
per-pixel alpha. These inputs combine to create an index into the
|
|
pref[] table, which contains the caller's preferred config for that
|
|
input, or kNo_Config if there is no preference.
|
|
|
|
To specify no preferrence, call setPrefConfigTable(NULL), which is
|
|
the default.
|
|
|
|
Note, it is still at the discretion of the codec as to what output
|
|
config is actually returned, as it may not be able to support the
|
|
caller's preference.
|
|
|
|
Here is how the index into the table is computed from the src:
|
|
depth [8, 16, 32/24] -> 0, 2, 4
|
|
alpha [no, yes] -> 0, 1
|
|
The two index values are OR'd together.
|
|
src: 8-index, no-alpha -> 0
|
|
src: 8-index, yes-alpha -> 1
|
|
src: 16bit, no-alpha -> 2 // e.g. 565
|
|
src: 16bit, yes-alpha -> 3 // e.g. 1555
|
|
src: 32/24, no-alpha -> 4
|
|
src: 32/24, yes-alpha -> 5
|
|
*/
|
|
void setPrefConfigTable(const SkBitmap::Config pref[6]);
|
|
|
|
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. After the
|
|
* decoding, the function converts the decoded config in bitmap
|
|
* to pref if possible. Whether a conversion is feasible is
|
|
* tested by Bitmap::canCopyTo(pref).
|
|
|
|
note: document use of Allocator, Peeker and Chooser
|
|
*/
|
|
bool decode(SkStream*, SkBitmap* bitmap, SkBitmap::Config pref, Mode, bool reuseBitmap = false);
|
|
bool decode(SkStream* stream, SkBitmap* bitmap, Mode mode, bool reuseBitmap = false) {
|
|
return this->decode(stream, bitmap, SkBitmap::kNo_Config, mode, reuseBitmap);
|
|
}
|
|
|
|
/**
|
|
* Given a stream, build an index for doing tile-based decode.
|
|
* The built index will be saved in the decoder, and the image size will
|
|
* be returned in width and height.
|
|
*
|
|
* Return true for success or false on failure.
|
|
*/
|
|
bool buildTileIndex(SkStream*, int *width, int *height);
|
|
|
|
/**
|
|
* Decode a rectangle subset in the image.
|
|
* The method can only be called after buildTileIndex().
|
|
*
|
|
* Return true for success.
|
|
* Return false if the index is never built or failing in decoding.
|
|
*/
|
|
bool decodeSubset(SkBitmap* bm, const SkIRect& subset, SkBitmap::Config pref);
|
|
|
|
/**
|
|
* @Deprecated
|
|
* Use decodeSubset instead.
|
|
*/
|
|
bool decodeRegion(SkBitmap* bitmap, const SkIRect& rect, SkBitmap::Config pref) {
|
|
return this->decodeSubset(bitmap, rect, pref);
|
|
}
|
|
|
|
/** 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.
|
|
|
|
@param format On success, if format is non-null, it is set to the format
|
|
of the decoded file. On failure it is ignored.
|
|
*/
|
|
static bool DecodeFile(const char file[], SkBitmap* bitmap,
|
|
SkBitmap::Config prefConfig, Mode,
|
|
Format* format = NULL);
|
|
static bool DecodeFile(const char file[], SkBitmap* bitmap) {
|
|
return DecodeFile(file, bitmap, SkBitmap::kNo_Config,
|
|
kDecodePixels_Mode, NULL);
|
|
}
|
|
/** 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.
|
|
|
|
@param format On success, if format is non-null, it is set to the format
|
|
of the decoded buffer. On failure it is ignored.
|
|
*/
|
|
static bool DecodeMemory(const void* buffer, size_t size, SkBitmap* bitmap,
|
|
SkBitmap::Config prefConfig, Mode,
|
|
Format* format = NULL);
|
|
static bool DecodeMemory(const void* buffer, size_t size, SkBitmap* bitmap){
|
|
return DecodeMemory(buffer, size, bitmap, SkBitmap::kNo_Config,
|
|
kDecodePixels_Mode, NULL);
|
|
}
|
|
|
|
/**
|
|
* Decode memory.
|
|
* @param info Output parameter. Returns info about the encoded image.
|
|
* @param target Contains the address of pixel memory to decode into
|
|
* (which must be large enough to hold the width in info) and
|
|
* the row bytes to use. If NULL, returns info and does not
|
|
* decode pixels.
|
|
* @return bool Whether the function succeeded.
|
|
*
|
|
* Sample usage:
|
|
* <code>
|
|
* // Determine the image's info: width/height/config
|
|
* SkImage::Info info;
|
|
* bool success = DecodeMemoryToTarget(src, size, &info, NULL);
|
|
* if (!success) return;
|
|
* // Allocate space for the result:
|
|
* SkBitmapFactory::Target target;
|
|
* target.fAddr = malloc/other allocation
|
|
* target.fRowBytes = ...
|
|
* // Now decode the actual pixels into target. &info is optional,
|
|
* // and could be NULL
|
|
* success = DecodeMemoryToTarget(src, size, &info, &target);
|
|
* </code>
|
|
*/
|
|
static bool DecodeMemoryToTarget(const void* buffer, size_t size, SkImage::Info* info,
|
|
const SkBitmapFactory::Target* target);
|
|
|
|
/** 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.
|
|
|
|
@param format On success, if format is non-null, it is set to the format
|
|
of the decoded stream. On failure it is ignored.
|
|
*/
|
|
static bool DecodeStream(SkStream* stream, SkBitmap* bitmap,
|
|
SkBitmap::Config prefConfig, Mode,
|
|
Format* format = NULL);
|
|
static bool DecodeStream(SkStream* stream, SkBitmap* bitmap) {
|
|
return DecodeStream(stream, bitmap, SkBitmap::kNo_Config,
|
|
kDecodePixels_Mode, NULL);
|
|
}
|
|
|
|
/** 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);
|
|
|
|
protected:
|
|
// must be overridden in subclasses. This guy is called by decode(...)
|
|
virtual bool onDecode(SkStream*, SkBitmap* bitmap, Mode) = 0;
|
|
|
|
// If the decoder wants to support tiled based decoding,
|
|
// this method must be overridden. This guy is called by buildTileIndex(...)
|
|
virtual bool onBuildTileIndex(SkStream*, int *width, int *height) {
|
|
return false;
|
|
}
|
|
|
|
// If the decoder wants to support tiled based decoding,
|
|
// this method must be overridden. This guy is called by decodeRegion(...)
|
|
virtual bool onDecodeSubset(SkBitmap* bitmap, const SkIRect& rect) {
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Crop a rectangle from the src Bitmap to the dest Bitmap. src and dst are
|
|
* both sampled by sampleSize from an original Bitmap.
|
|
*
|
|
* @param dst the destination bitmap.
|
|
* @param src the source bitmap that is sampled by sampleSize from the
|
|
* original bitmap.
|
|
* @param sampleSize the sample size that src is sampled from the original bitmap.
|
|
* @param (dstX, dstY) the upper-left point of the dest bitmap in terms of
|
|
* the coordinate in the original bitmap.
|
|
* @param (width, height) the width and height of the unsampled dst.
|
|
* @param (srcX, srcY) the upper-left point of the src bitmap in terms of
|
|
* the coordinate in the original bitmap.
|
|
* @return bool Whether or not it succeeded.
|
|
*/
|
|
bool cropBitmap(SkBitmap *dst, SkBitmap *src, int sampleSize,
|
|
int dstX, int dstY, int width, int height,
|
|
int srcX, int srcY);
|
|
|
|
|
|
|
|
/** 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;
|
|
|
|
enum SrcDepth {
|
|
kIndex_SrcDepth,
|
|
k16Bit_SrcDepth,
|
|
k32Bit_SrcDepth
|
|
};
|
|
/** The subclass, inside onDecode(), calls this to determine the config of
|
|
the returned bitmap. SrcDepth and hasAlpha reflect the raw data of the
|
|
src image. This routine returns the caller's preference given
|
|
srcDepth and hasAlpha, or kNo_Config if there is no preference.
|
|
|
|
Note: this also takes into account GetDeviceConfig(), so the subclass
|
|
need not call that.
|
|
*/
|
|
SkBitmap::Config getPrefConfig(SrcDepth, bool hasAlpha) const;
|
|
|
|
private:
|
|
Peeker* fPeeker;
|
|
Chooser* fChooser;
|
|
SkBitmap::Allocator* fAllocator;
|
|
int fSampleSize;
|
|
SkBitmap::Config fDefaultPref; // use if fUsePrefTable is false
|
|
SkBitmap::Config fPrefTable[6]; // use if fUsePrefTable is true
|
|
bool fDitherImage;
|
|
bool fUsePrefTable;
|
|
mutable bool fShouldCancelDecode;
|
|
bool fPreferQualityOverSpeed;
|
|
bool fRequireUnpremultipliedColors;
|
|
};
|
|
|
|
/** Calling newDecoder with a stream returns a new matching imagedecoder
|
|
instance, or NULL if none can be found. The caller must manage its ownership
|
|
of the stream as usual, calling unref() when it is done, as the returned
|
|
decoder may have called ref() (and if so, the decoder is responsible for
|
|
balancing its ownership when it is destroyed).
|
|
*/
|
|
class SkImageDecoderFactory : public SkRefCnt {
|
|
public:
|
|
SK_DECLARE_INST_COUNT(SkImageDecoderFactory)
|
|
|
|
virtual SkImageDecoder* newDecoder(SkStream*) = 0;
|
|
|
|
private:
|
|
typedef SkRefCnt INHERITED;
|
|
};
|
|
|
|
class SkDefaultImageDecoderFactory : SkImageDecoderFactory {
|
|
public:
|
|
// calls SkImageDecoder::Factory(stream)
|
|
virtual SkImageDecoder* newDecoder(SkStream* stream) {
|
|
return SkImageDecoder::Factory(stream);
|
|
}
|
|
};
|
|
|
|
// This macro declares a global (i.e., non-class owned) creation entry point
|
|
// for each decoder (e.g., CreateJPEGImageDecoder)
|
|
#define DECLARE_DECODER_CREATOR(codec) \
|
|
SkImageDecoder *Create ## codec ();
|
|
|
|
// This macro defines the global creation entry point for each decoder. Each
|
|
// decoder implementation that registers with the decoder factory must call it.
|
|
#define DEFINE_DECODER_CREATOR(codec) \
|
|
SkImageDecoder *Create ## codec () { \
|
|
return SkNEW( Sk ## codec ); \
|
|
}
|
|
|
|
// All the decoders known by Skia. Note that, depending on the compiler settings,
|
|
// not all of these will be available
|
|
DECLARE_DECODER_CREATOR(BMPImageDecoder);
|
|
DECLARE_DECODER_CREATOR(GIFImageDecoder);
|
|
DECLARE_DECODER_CREATOR(ICOImageDecoder);
|
|
DECLARE_DECODER_CREATOR(JPEGImageDecoder);
|
|
DECLARE_DECODER_CREATOR(PNGImageDecoder);
|
|
DECLARE_DECODER_CREATOR(WBMPImageDecoder);
|
|
DECLARE_DECODER_CREATOR(WEBPImageDecoder);
|
|
|
|
#endif
|