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/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkCodec.h"
#include "SkColorTable.h"
#include "SkEncodedFormat.h"
#include "SkImageInfo.h"
#include "SkMaskSwizzler.h"
#include "SkStream.h"
#include "SkSwizzler.h"
#include "SkTypes.h"
// TODO: rename SkCodec_libbmp files to SkBmpCodec
// TODO: define a wrapper for SkDebugf that doesn't always print
/*
*
* This class implements the decoding for bmp images
*
*/
class SkBmpCodec : public SkCodec {
public:
/*
*
* Describes if rows of the input start at the top or bottom of the image
*
*/
enum RowOrder {
kTopDown_RowOrder,
kBottomUp_RowOrder
};
/*
*
* Checks the start of the stream to see if the image is a bitmap
*
*/
static bool IsBmp(SkStream*);
/*
*
* Assumes IsBmp was called and returned true
* Creates a bitmap decoder
* Reads enough of the stream to determine the image format
*
*/
static SkCodec* NewFromStream(SkStream*);
protected:
/*
*
* Initiates the bitmap decode
*
*/
virtual Result onGetPixels(const SkImageInfo& dstInfo, void* dst,
size_t dstRowBytes, const Options&, SkPMColor*,
int*) SK_OVERRIDE;
SkEncodedFormat onGetEncodedFormat() const SK_OVERRIDE { return kBMP_SkEncodedFormat; }
private:
/*
*
* Used to define the input format of the bitmap
*
*/
enum BitmapInputFormat {
kStandard_BitmapInputFormat,
kRLE_BitmapInputFormat,
kBitMask_BitmapInputFormat,
kUnknown_BitmapInputFormat
};
/*
*
* Creates the color table
*
*/
bool createColorTable(SkAlphaType alphaType);
/*
*
* Performs the bitmap decoding for bit masks input format
*
*/
Result decodeMask(const SkImageInfo& dstInfo, void* dst,
size_t dstRowBytes);
/*
*
* Set an RLE pixel using the color table
*
*/
void setRLEPixel(SkPMColor* dst, size_t dstRowBytes,
const SkImageInfo& dstInfo, uint32_t x, uint32_t y,
uint8_t index);
/*
*
* Set an RLE24 pixel from R, G, B values
*
*/
void setRLE24Pixel(SkPMColor* dst, size_t dstRowBytes,
const SkImageInfo& dstInfo, uint32_t x, uint32_t y,
uint8_t red, uint8_t green, uint8_t blue);
/*
*
* Performs the bitmap decoding for RLE input format
*
*/
Result decodeRLE(const SkImageInfo& dstInfo, void* dst,
size_t dstRowBytes);
/*
*
* Performs the bitmap decoding for standard input format
*
*/
Result decode(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes);
/*
*
* Creates an instance of the decoder
* Called only by NewFromStream
*
* @param srcInfo contains the source width and height
* @param stream the stream of image data
* @param bitsPerPixel the number of bits used to store each pixel
* @param format the format of the bmp file
* @param masks optional color masks for certain bmp formats, passes
ownership to SkBmpCodec
* @param numColors the number of colors in the color table
* @param bytesPerColor the number of bytes in the stream used to represent
each color in the color table
* @param offset the offset of the image pixel data from the end of the
* headers
* @param rowOrder indicates whether rows are ordered top-down or bottom-up
* @param RLEBytes used only for RLE decodes, as we must decode all
* of the data at once rather than row by row
* it indicates the amount of data left in the stream
* after decoding the headers
*
*/
SkBmpCodec(const SkImageInfo& srcInfo, SkStream* stream,
uint16_t bitsPerPixel, BitmapInputFormat format,
SkMasks* masks, uint32_t numColors, uint32_t bytesPerColor,
uint32_t offset, RowOrder rowOrder, size_t RLEByes);
// Fields
const uint16_t fBitsPerPixel;
const BitmapInputFormat fInputFormat;
SkAutoTDelete<SkMasks> fMasks; // owned
SkAutoTDelete<SkColorTable> fColorTable; // owned
uint32_t fNumColors;
const uint32_t fBytesPerColor;
const uint32_t fOffset;
const RowOrder fRowOrder;
const size_t fRLEBytes;
typedef SkCodec INHERITED;
};
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