Home | History | Annotate | Download | only in codec 
      1 /*
      2  * Copyright 2015 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 #ifndef SkIcoCodec_DEFINED
      8 #define SkIcoCodec_DEFINED
      9 
     10 #include "SkCodec.h"
     11 #include "SkImageInfo.h"
     12 #include "SkStream.h"
     13 #include "SkTArray.h"
     14 #include "SkTypes.h"
     15 
     16 /*
     17  * This class implements the decoding for bmp images
     18  */
     19 class SkIcoCodec : public SkCodec {
     20 public:
     21     static bool IsIco(const void*, size_t);
     22 
     23     /*
     24      * Assumes IsIco was called and returned true
     25      * Creates an Ico decoder
     26      * Reads enough of the stream to determine the image format
     27      */
     28     static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*);
     29 
     30 protected:
     31 
     32     /*
     33      * Chooses the best dimensions given the desired scale
     34      */
     35     SkISize onGetScaledDimensions(float desiredScale) const override;
     36 
     37     bool onDimensionsSupported(const SkISize&) override;
     38 
     39     /*
     40      * Initiates the Ico decode
     41      */
     42     Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
     43             int*) override;
     44 
     45     SkEncodedImageFormat onGetEncodedFormat() const override {
     46         return SkEncodedImageFormat::kICO;
     47     }
     48 
     49     SkScanlineOrder onGetScanlineOrder() const override;
     50 
     51     bool conversionSupported(const SkImageInfo&, SkColorType, bool,
     52                              const SkColorSpace*) const override {
     53         // This will be checked by the embedded codec.
     54         return true;
     55     }
     56 
     57     // Handled by the embedded codec.
     58     bool usesColorXform() const override { return false; }
     59 private:
     60 
     61     Result onStartScanlineDecode(const SkImageInfo& dstInfo,
     62             const SkCodec::Options& options) override;
     63 
     64     int onGetScanlines(void* dst, int count, size_t rowBytes) override;
     65 
     66     bool onSkipScanlines(int count) override;
     67 
     68     Result onStartIncrementalDecode(const SkImageInfo& dstInfo, void* pixels, size_t rowBytes,
     69             const SkCodec::Options&) override;
     70 
     71     Result onIncrementalDecode(int* rowsDecoded) override;
     72 
     73     SkSampler* getSampler(bool createIfNecessary) override;
     74 
     75     /*
     76      * Searches fEmbeddedCodecs for a codec that matches requestedSize.
     77      * The search starts at startIndex and ends when an appropriate codec
     78      * is found, or we have reached the end of the array.
     79      *
     80      * @return the index of the matching codec or -1 if there is no
     81      *         matching codec between startIndex and the end of
     82      *         the array.
     83      */
     84     int chooseCodec(const SkISize& requestedSize, int startIndex);
     85 
     86     /*
     87      * Constructor called by NewFromStream
     88      * @param embeddedCodecs codecs for the embedded images, takes ownership
     89      */
     90     SkIcoCodec(int width, int height, const SkEncodedInfo& info,
     91             SkTArray<std::unique_ptr<SkCodec>, true>* embeddedCodecs, sk_sp<SkColorSpace> colorSpace);
     92 
     93     std::unique_ptr<SkTArray<std::unique_ptr<SkCodec>, true>> fEmbeddedCodecs;
     94 
     95     // fCurrCodec is owned by this class, but should not be an
     96     // std::unique_ptr.  It will be deleted by the destructor of fEmbeddedCodecs.
     97     SkCodec* fCurrCodec;
     98 
     99     typedef SkCodec INHERITED;
    100 };
    101 #endif  // SkIcoCodec_DEFINED
    102