commit-bot@chromium.org | 6e3e422 | 2013-11-06 10:08:30 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2013 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 | #ifndef SkLazyCachingPixelRef_DEFINED |
| 9 | #define SkLazyCachingPixelRef_DEFINED |
| 10 | |
| 11 | #include "SkBitmapFactory.h" |
| 12 | #include "SkCachingPixelRef.h" |
| 13 | |
| 14 | class SkData; |
| 15 | |
| 16 | /** |
| 17 | * PixelRef which defers decoding until SkBitmap::lockPixels() is |
| 18 | * called. Makes use of a supplied decode procedure. Will decode at |
| 19 | * the procedure's preferred size. |
| 20 | */ |
| 21 | class SkLazyCachingPixelRef : public SkCachingPixelRef { |
| 22 | public: |
| 23 | /** |
| 24 | * @param data Encoded data representing the pixels. NULL is |
| 25 | * equivalent to an empty data, and will be passed to |
| 26 | * DecodeProc with length zero. |
| 27 | * |
| 28 | * @param procedure Called to decode the pixels when |
| 29 | * needed. If NULL, use SkImageDecoder::DecodeMemoryToTarget. |
| 30 | */ |
| 31 | SkLazyCachingPixelRef(SkData* data, |
| 32 | SkBitmapFactory::DecodeProc procedure); |
| 33 | |
| 34 | virtual ~SkLazyCachingPixelRef(); |
| 35 | |
| 36 | virtual SkData* onRefEncodedData() SK_OVERRIDE { return SkSafeRef(fData); } |
| 37 | |
| 38 | /** |
| 39 | * A simplified version of SkBitmapFactory. Installs a new |
| 40 | * SkLazyCachingPixelRef into the provided bitmap. Will |
| 41 | * immediately call onDecodeInfo() to configure the bitmap, but |
| 42 | * will defer decoding until the first time the bitmap's pixels |
| 43 | * are locked. |
| 44 | * |
| 45 | * @param data Encoded data representing the pixels. NULL is |
| 46 | * equivalent to an empty data, and will be passed to |
| 47 | * DecodeProc with length zero. |
| 48 | * |
| 49 | * @param procedure Called to decode the pixels when |
| 50 | * needed. If NULL, use SkImageDecoder::DecodeMemoryToTarget. |
| 51 | * |
| 52 | * @param destination Bitmap that will be modified on success. |
| 53 | * |
| 54 | * @returns true on success. |
| 55 | */ |
| 56 | static bool Install(SkBitmapFactory::DecodeProc procedure, |
| 57 | SkData* data, |
| 58 | SkBitmap* destination); |
| 59 | |
| 60 | // No need to flatten this object. When flattening an SkBitmap, |
| 61 | // SkOrderedWriteBuffer will check the encoded data and write that |
| 62 | // instead. |
| 63 | // Future implementations of SkFlattenableWriteBuffer will need to |
| 64 | // special case for onRefEncodedData as well. |
| 65 | SK_DECLARE_UNFLATTENABLE_OBJECT() |
| 66 | |
| 67 | protected: |
| 68 | /** |
| 69 | * Return some information about the pixels, allowing this class |
| 70 | * to allocate pixels. @return false if anything goes wrong. |
| 71 | * |
| 72 | * This implementation calls SkBitmapFactory::DecodeProc with a |
| 73 | * NULL target. |
| 74 | */ |
| 75 | virtual bool onDecodeInfo(SkImageInfo* info) SK_OVERRIDE; |
| 76 | /** |
| 77 | * Decode into the given pixels, a block of memory of size |
| 78 | * (info.fHeight * rowBytes) bytes. |
| 79 | * |
| 80 | * @param info Should be identical to the info returned by |
| 81 | * onDecodeInfo so that the implementation can confirm |
| 82 | * that the caller knows what its asking for (config, |
| 83 | * size). |
| 84 | * |
| 85 | * @return false if anything goes wrong. |
| 86 | */ |
| 87 | virtual bool onDecodePixels(const SkImageInfo& info, |
| 88 | void* pixels, |
| 89 | size_t rowBytes) SK_OVERRIDE; |
| 90 | |
| 91 | private: |
| 92 | SkData* fData; |
| 93 | SkBitmapFactory::DecodeProc fDecodeProc; |
| 94 | |
| 95 | typedef SkCachingPixelRef INHERITED; |
| 96 | }; |
| 97 | |
| 98 | #endif // SkLazyCachingPixelRef_DEFINED |
| 99 | |