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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 "SkBmpCodec.h"
#include "SkColorTable.h"
#include "SkImageInfo.h"
#include "SkSampler.h"
#include "SkTypes.h"
* This class implements the decoding for bmp images that use an RLE encoding
class SkBmpRLECodec : public SkBmpCodec {
* Creates an instance of the decoder
* Called only by SkBmpCodec::NewFromStream
* There should be no other callers despite this being public
* @param info contains properties of the encoded data
* @param stream the stream of encoded image data
* @param bitsPerPixel the number of bits used to store each pixel
* @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 indicates the amount of data left in the stream
* after decoding the headers
SkBmpRLECodec(int width, int height, const SkEncodedInfo& info, SkStream* stream,
uint16_t bitsPerPixel, uint32_t numColors, uint32_t bytesPerColor,
uint32_t offset, SkCodec::SkScanlineOrder rowOrder,
size_t RLEBytes);
int setSampleX(int);
Result onGetPixels(const SkImageInfo& dstInfo, void* dst,
size_t dstRowBytes, const Options&, SkPMColor*,
int*, int*) override;
SkCodec::Result onPrepareToDecode(const SkImageInfo& dstInfo,
const SkCodec::Options& options, SkPMColor inputColorPtr[],
int* inputColorCount) override;
* Creates the color table
* Sets colorCount to the new color count if it is non-nullptr
bool createColorTable(SkColorType dstColorType, int* colorCount);
bool initializeStreamBuffer();
* Before signalling kIncompleteInput, we should attempt to load the
* stream buffer with additional data.
* @return the number of bytes remaining in the stream buffer after
* attempting to read more bytes from the stream
size_t checkForMoreData();
* Set an RLE pixel using the color table
void setPixel(void* 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 setRGBPixel(void* dst, size_t dstRowBytes,
const SkImageInfo& dstInfo, uint32_t x, uint32_t y,
uint8_t red, uint8_t green, uint8_t blue);
* If dst is NULL, this is a signal to skip the rows.
int decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes,
const Options& opts) override;
int decodeRLE(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes);
bool skipRows(int count) override;
SkSampler* getSampler(bool createIfNecessary) override;
sk_sp<SkColorTable> fColorTable;
// fNumColors is the number specified in the header, or 0 if not present in the header.
const uint32_t fNumColors;
const uint32_t fBytesPerColor;
const uint32_t fOffset;
std::unique_ptr<uint8_t[]> fStreamBuffer;
size_t fRLEBytes;
const size_t fOrigRLEBytes;
uint32_t fCurrRLEByte;
int fSampleX;
std::unique_ptr<SkSampler> fSampler;
// Scanline decodes allow the client to ask for a single scanline at a time.
// This can be tricky when the RLE encoding instructs the decoder to jump down
// multiple lines. This field keeps track of lines that need to be skipped
// on subsequent calls to decodeRows().
int fLinesToSkip;
typedef SkBmpCodec INHERITED;