halcanary@google.com | ad04eb4 | 2013-11-21 15:32:08 +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 SkImageGenerator_DEFINED |
| 9 | #define SkImageGenerator_DEFINED |
| 10 | |
| 11 | #include "SkImageInfo.h" |
| 12 | |
| 13 | class SkData; |
| 14 | |
| 15 | /** |
| 16 | * An interface that allows a purgeable PixelRef (such as a |
| 17 | * SkDiscardablePixelRef) to decode and re-decode an image as needed. |
| 18 | */ |
| 19 | class SkImageGenerator { |
| 20 | public: |
| 21 | /** |
| 22 | * The PixelRef which takes ownership of this SkImageGenerator |
| 23 | * will call the image generator's destructor. |
| 24 | */ |
| 25 | virtual ~SkImageGenerator() { } |
| 26 | |
| 27 | /** |
| 28 | * Return a ref to the encoded (i.e. compressed) representation, |
| 29 | * of this data. |
| 30 | * |
| 31 | * If non-NULL is returned, the caller is responsible for calling |
| 32 | * unref() on the data when it is finished. |
| 33 | */ |
| 34 | virtual SkData* refEncodedData() { return NULL; } |
| 35 | |
| 36 | /** |
| 37 | * Return some information about the image, allowing the owner of |
| 38 | * this object to allocate pixels. |
| 39 | * |
| 40 | * @return false if anything goes wrong. |
| 41 | */ |
| 42 | virtual bool getInfo(SkImageInfo* info) = 0; |
| 43 | |
| 44 | /** |
| 45 | * Decode into the given pixels, a block of memory of size at |
| 46 | * least (info.fHeight - 1) * rowBytes + (info.fWidth * |
| 47 | * bytesPerPixel) |
| 48 | * |
| 49 | * @param info A description of the format (config, size) |
| 50 | * expected by the caller. This can simply be identical |
| 51 | * to the info returned by getInfo(). |
| 52 | * |
| 53 | * This contract also allows the caller to specify |
| 54 | * different output-configs, which the implementation can |
| 55 | * decide to support or not. |
| 56 | * |
| 57 | * @return false if anything goes wrong or if the image info is |
| 58 | * unsupported. |
| 59 | */ |
| 60 | virtual bool getPixels(const SkImageInfo& info, |
| 61 | void* pixels, |
| 62 | size_t rowBytes) = 0; |
| 63 | }; |
| 64 | |
| 65 | #endif // SkImageGenerator_DEFINED |