msarett | a5783ae | 2015-09-08 15:35:32 -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 | #ifndef SkBitmapRegionDecoder_DEFINED |
| 9 | #define SkBitmapRegionDecoder_DEFINED |
| 10 | |
| 11 | #include "SkBitmap.h" |
| 12 | #include "SkStream.h" |
| 13 | |
| 14 | /* |
| 15 | * This class aims to provide an interface to test multiple implementations of |
| 16 | * SkBitmapRegionDecoder. |
| 17 | */ |
| 18 | class SkBitmapRegionDecoderInterface { |
| 19 | public: |
| 20 | |
| 21 | enum Strategy { |
| 22 | kCanvas_Strategy, // Draw to the canvas, uses SkCodec |
| 23 | kOriginal_Strategy, // Sampling, uses SkImageDecoder |
| 24 | // TODO (msarett): Add strategy for SkScaledCodec |
| 25 | }; |
| 26 | |
| 27 | /* |
| 28 | * @param stream Encoded image stream, takes ownership |
| 29 | * @param strategy Strategy used for scaling and subsetting |
| 30 | * @return Tries to create an SkBitmapRegionDecoder, returns NULL |
| 31 | * on failure |
| 32 | */ |
| 33 | static SkBitmapRegionDecoderInterface* CreateBitmapRegionDecoder( |
| 34 | SkStreamRewindable* stream, Strategy strategy); |
| 35 | |
| 36 | /* |
| 37 | * Decode a scaled region of the encoded image stream |
| 38 | * |
| 39 | * @param start_x X-coordinate of upper-left corner of region. |
| 40 | * This coordinate is unscaled, relative to the original dimensions. |
| 41 | * @param start_y Y-coordinate of upper-left corner of region. |
| 42 | * This coordinate is unscaled, relative to the original dimensions. |
| 43 | * @param width Width of the region to decode. |
| 44 | * This distance is unscaled, relative to the original dimensions. |
| 45 | * @param height Height of the region to decode. |
| 46 | * This distance is unscaled, relative to the original dimensions. |
| 47 | * @param sampleSize An integer downscaling factor for the decode. |
| 48 | * @param colorType Preferred output colorType. |
| 49 | * New implementations should return NULL if they do not support |
| 50 | * decoding to this color type. |
| 51 | * The old kOriginal_Strategy will decode to a default color type |
| 52 | * if this color type is unsupported. |
| 53 | * @return Pointer to a bitmap of the decoded region on success, NULL on |
| 54 | * failure. |
| 55 | */ |
| 56 | virtual SkBitmap* decodeRegion(int start_x, int start_y, int width, |
| 57 | int height, int sampleSize, |
| 58 | SkColorType colorType) = 0; |
msarett | 04965c6 | 2015-10-12 10:24:38 -0700 | [diff] [blame] | 59 | /* |
| 60 | * @param Requested destination color type |
| 61 | * @return true if we support the requested color type and false otherwise |
| 62 | */ |
| 63 | virtual bool conversionSupported(SkColorType colorType) = 0; |
msarett | a5783ae | 2015-09-08 15:35:32 -0700 | [diff] [blame] | 64 | |
| 65 | int width() const { return fWidth; } |
| 66 | int height() const { return fHeight; } |
| 67 | |
| 68 | virtual ~SkBitmapRegionDecoderInterface() {} |
| 69 | |
| 70 | protected: |
| 71 | |
| 72 | SkBitmapRegionDecoderInterface(int width, int height) |
| 73 | : fWidth(width) |
| 74 | , fHeight(height) |
| 75 | {} |
| 76 | |
| 77 | private: |
| 78 | const int fWidth; |
| 79 | const int fHeight; |
| 80 | }; |
| 81 | |
| 82 | #endif |