The Tor Browser / file comparison
comparison: gfx/skia/trunk/src/core/SkBitmapScaler.h
gfx/skia/trunk/src/core/SkBitmapScaler.h
- changeset 0
- 6474c204b198
equal
deleted
inserted
replaced
| -1:000000000000 | 0:dc0ed537cbdb |
|---|---|
| 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 SkBitmapScaler_DEFINED | |
| 9 #define SkBitmapScaler_DEFINED | |
| 10 | |
| 11 #include "SkBitmap.h" | |
| 12 #include "SkConvolver.h" | |
| 13 | |
| 14 /** \class SkBitmapScaler | |
| 15 | |
| 16 Provides the interface for high quality image resampling. | |
| 17 */ | |
| 18 | |
| 19 class SK_API SkBitmapScaler { | |
| 20 public: | |
| 21 enum ResizeMethod { | |
| 22 // Quality Methods | |
| 23 // | |
| 24 // Those enumeration values express a desired quality/speed tradeoff. | |
| 25 // They are translated into an algorithm-specific method that depends | |
| 26 // on the capabilities (CPU, GPU) of the underlying platform. | |
| 27 // It is possible for all three methods to be mapped to the same | |
| 28 // algorithm on a given platform. | |
| 29 | |
| 30 // Good quality resizing. Fastest resizing with acceptable visual quality. | |
| 31 // This is typically intended for use during interactive layouts | |
| 32 // where slower platforms may want to trade image quality for large | |
| 33 // increase in resizing performance. | |
| 34 // | |
| 35 // For example the resizing implementation may devolve to linear | |
| 36 // filtering if this enables GPU acceleration to be used. | |
| 37 // | |
| 38 // Note that the underlying resizing method may be determined | |
| 39 // on the fly based on the parameters for a given resize call. | |
| 40 // For example an implementation using a GPU-based linear filter | |
| 41 // in the common case may still use a higher-quality software-based | |
| 42 // filter in cases where using the GPU would actually be slower - due | |
| 43 // to too much latency - or impossible - due to image format or size | |
| 44 // constraints. | |
| 45 RESIZE_GOOD, | |
| 46 | |
| 47 // Medium quality resizing. Close to high quality resizing (better | |
| 48 // than linear interpolation) with potentially some quality being | |
| 49 // traded-off for additional speed compared to RESIZE_BEST. | |
| 50 // | |
| 51 // This is intended, for example, for generation of large thumbnails | |
| 52 // (hundreds of pixels in each dimension) from large sources, where | |
| 53 // a linear filter would produce too many artifacts but where | |
| 54 // a RESIZE_HIGH might be too costly time-wise. | |
| 55 RESIZE_BETTER, | |
| 56 | |
| 57 // High quality resizing. The algorithm is picked to favor image quality. | |
| 58 RESIZE_BEST, | |
| 59 | |
| 60 // | |
| 61 // Algorithm-specific enumerations | |
| 62 // | |
| 63 | |
| 64 // Box filter. This is a weighted average of all of the pixels touching | |
| 65 // the destination pixel. For enlargement, this is nearest neighbor. | |
| 66 // | |
| 67 // You probably don't want this, it is here for testing since it is easy to | |
| 68 // compute. Use RESIZE_LANCZOS3 instead. | |
| 69 RESIZE_BOX, | |
| 70 RESIZE_TRIANGLE, | |
| 71 RESIZE_LANCZOS3, | |
| 72 RESIZE_HAMMING, | |
| 73 RESIZE_MITCHELL, | |
| 74 | |
| 75 // enum aliases for first and last methods by algorithm or by quality. | |
| 76 RESIZE_FIRST_QUALITY_METHOD = RESIZE_GOOD, | |
| 77 RESIZE_LAST_QUALITY_METHOD = RESIZE_BEST, | |
| 78 RESIZE_FIRST_ALGORITHM_METHOD = RESIZE_BOX, | |
| 79 RESIZE_LAST_ALGORITHM_METHOD = RESIZE_MITCHELL, | |
| 80 }; | |
| 81 | |
| 82 // Resizes the given source bitmap using the specified resize method, so that | |
| 83 // the entire image is (dest_size) big. The dest_subset is the rectangle in | |
| 84 // this destination image that should actually be returned. | |
| 85 // | |
| 86 // The output image will be (dest_subset.width(), dest_subset.height()). This | |
| 87 // will save work if you do not need the entire bitmap. | |
| 88 // | |
| 89 // The destination subset must be smaller than the destination image. | |
| 90 static bool Resize(SkBitmap* result, | |
| 91 const SkBitmap& source, | |
| 92 ResizeMethod method, | |
| 93 int dest_width, int dest_height, | |
| 94 const SkIRect& dest_subset, | |
| 95 const SkConvolutionProcs&, | |
| 96 SkBitmap::Allocator* allocator = NULL); | |
| 97 | |
| 98 // Alternate version for resizing and returning the entire bitmap rather than | |
| 99 // a subset. | |
| 100 static bool Resize(SkBitmap* result, | |
| 101 const SkBitmap& source, | |
| 102 ResizeMethod method, | |
| 103 int dest_width, int dest_height, | |
| 104 const SkConvolutionProcs&, | |
| 105 SkBitmap::Allocator* allocator = NULL); | |
| 106 }; | |
| 107 | |
| 108 #endif |
