SkWbmpCodec.h

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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.
 */
 
#ifndef SkCodec_wbmp_DEFINED
#define SkCodec_wbmp_DEFINED
 
#include "include/codec/SkCodec.h"
#include "include/core/SkTypes.h"
#include "include/private/base/SkTemplates.h"
#include "src/codec/SkSwizzler.h"
 
#include <cstddef>
#include <cstdint>
#include <memory>
 
class SkSampler;
class SkStream;
enum class SkEncodedImageFormat;
struct SkEncodedInfo;
struct SkImageInfo;
 
class SkWbmpCodec final : public SkCodec {
public:
    static bool IsWbmp(const void*, size_t);
 
    /*
     * Assumes IsWbmp was called and returned true
     * Creates a wbmp codec
     * Takes ownership of the stream
     */
    static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*);
 
protected:
    SkEncodedImageFormat onGetEncodedFormat() const override;
    Result onGetPixels(const SkImageInfo&, void*, size_t,
                       const Options&, int*) override;
    bool onRewind() override;
    bool conversionSupported(const SkImageInfo& dst, bool srcIsOpaque,
                             bool needsXform) override;
    // No need to Xform; all pixels are either black or white.
    bool usesColorXform() const override { return false; }
private:
    SkSampler* getSampler(bool createIfNecessary) override {
        SkASSERT(fSwizzler || !createIfNecessary);
        return fSwizzler.get();
    }
 
    /*
     * Read a src row from the encoded stream
     */
    bool readRow(uint8_t* row);
 
    SkWbmpCodec(SkEncodedInfo&&, std::unique_ptr<SkStream>);
 
    const size_t                fSrcRowBytes;
 
    // Used for scanline decodes:
    std::unique_ptr<SkSwizzler> fSwizzler;
    skia_private::AutoTMalloc<uint8_t>      fSrcBuffer;
 
    int onGetScanlines(void* dst, int count, size_t dstRowBytes) override;
    bool onSkipScanlines(int count) override;
    Result onStartScanlineDecode(const SkImageInfo& dstInfo,
            const Options& options) override;
 
    using INHERITED = SkCodec;
};
 
#endif  // SkCodec_wbmp_DEFINED