msarett | 8c8f22a | 2015-04-01 06:58:48 -0700 | [diff] [blame^] | 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 | |
| 8 | #include "SkCodec.h" |
| 9 | #include "SkImageInfo.h" |
| 10 | |
| 11 | #include "gif_lib.h" |
| 12 | |
| 13 | /* |
| 14 | * |
| 15 | * This class implements the decoding for gif images |
| 16 | * |
| 17 | */ |
| 18 | class SkGifCodec : public SkCodec { |
| 19 | public: |
| 20 | |
| 21 | /* |
| 22 | * Checks the start of the stream to see if the image is a gif |
| 23 | */ |
| 24 | static bool IsGif(SkStream*); |
| 25 | |
| 26 | /* |
| 27 | * Assumes IsGif was called and returned true |
| 28 | * Creates a gif decoder |
| 29 | * Reads enough of the stream to determine the image format |
| 30 | */ |
| 31 | static SkCodec* NewFromStream(SkStream*); |
| 32 | |
| 33 | |
| 34 | protected: |
| 35 | |
| 36 | /* |
| 37 | * Initiates the gif decode |
| 38 | */ |
| 39 | Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, |
| 40 | SkPMColor*, int32_t*) override; |
| 41 | |
| 42 | SkEncodedFormat onGetEncodedFormat() const override { |
| 43 | return kGIF_SkEncodedFormat; |
| 44 | } |
| 45 | |
| 46 | private: |
| 47 | |
| 48 | /* |
| 49 | * This function cleans up the gif object after the decode completes |
| 50 | * It is used in a SkAutoTCallIProc template |
| 51 | */ |
| 52 | static int32_t CloseGif(GifFileType* gif); |
| 53 | |
| 54 | /* |
| 55 | * Frees any extension data used in the decode |
| 56 | * Used in a SkAutoTCallVProc |
| 57 | */ |
| 58 | static void FreeExtension(SavedImage* image); |
| 59 | |
| 60 | /* |
| 61 | * Creates an instance of the decoder |
| 62 | * Called only by NewFromStream |
| 63 | * |
| 64 | * @param srcInfo contains the source width and height |
| 65 | * @param stream the stream of image data |
| 66 | * @param gif pointer to library type that manages gif decode |
| 67 | * takes ownership |
| 68 | */ |
| 69 | SkGifCodec(const SkImageInfo& srcInfo, SkStream* stream, GifFileType* gif); |
| 70 | |
| 71 | SkAutoTCallIProc<GifFileType, CloseGif> fGif; // owned |
| 72 | |
| 73 | typedef SkCodec INHERITED; |
| 74 | }; |