Matt Sarett | cb6266b | 2017-01-17 10:48:53 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2017 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 | /** |
| 9 | * Returns true if |info| contains a valid combination of width, height, colorType, alphaType, |
| 10 | * colorSpace. Returns false otherwise. |
| 11 | */ |
| 12 | static inline bool SkImageInfoIsValid(const SkImageInfo& info) { |
| 13 | if (info.width() <= 0 || info.height() <= 0) { |
| 14 | return false; |
| 15 | } |
| 16 | |
| 17 | if (kUnknown_SkColorType == info.colorType() || kUnknown_SkAlphaType == info.alphaType()) { |
| 18 | return false; |
| 19 | } |
| 20 | |
| 21 | if (kOpaque_SkAlphaType != info.alphaType() && |
| 22 | (kRGB_565_SkColorType == info.colorType() || kGray_8_SkColorType == info.colorType())) { |
| 23 | return false; |
| 24 | } |
| 25 | |
| 26 | if (kRGBA_F16_SkColorType == info.colorType() && |
| 27 | (!info.colorSpace() || !info.colorSpace()->gammaIsLinear())) { |
| 28 | return false; |
| 29 | } |
| 30 | |
| 31 | if (info.colorSpace() && |
| 32 | (!info.colorSpace()->gammaCloseToSRGB() && !info.colorSpace()->gammaIsLinear())) { |
| 33 | return false; |
| 34 | } |
| 35 | |
| 36 | return true; |
| 37 | } |
| 38 | |
| 39 | /** |
| 40 | * Returns true if Skia has defined a pixel conversion from the |src| to the |dst|. |
| 41 | * Returns false otherwise. Some discussion of false cases: |
| 42 | * We will not convert to kIndex8 unless |src| is kIndex8. This is possible only |
| 43 | * in some cases and likley inefficient. |
| 44 | * We do not convert to kGray8 when the |src| is not kGray8. We may add this |
| 45 | * feature - it just requires some work to convert to luminance while handling color |
| 46 | * spaces correctly. Currently no one is asking for this. |
| 47 | * We will not convert from kAlpha8 when the |dst| is not kAlpha8. This would require |
| 48 | * inventing color information. |
| 49 | * We will not convert to kOpaque when the |src| is not kOpaque. This could be |
| 50 | * implemented to set all the alpha values to 1, but there is still some ambiguity - |
| 51 | * should we use kPremul or kUnpremul color values with the opaque alphas? Or should |
| 52 | * we just use whatever the |src| alpha is? In the future, we could choose to clearly |
| 53 | * define this, but currently no one is asking for this feature. |
| 54 | */ |
| 55 | static inline bool SkImageInfoValidConversion(const SkImageInfo& dst, const SkImageInfo& src) { |
| 56 | if (!SkImageInfoIsValid(dst) || !SkImageInfoIsValid(src)) { |
| 57 | return false; |
| 58 | } |
| 59 | |
| 60 | if (kIndex_8_SkColorType == dst.colorType() && kIndex_8_SkColorType != src.colorType()) { |
| 61 | return false; |
| 62 | } |
| 63 | |
| 64 | if (kGray_8_SkColorType == dst.colorType() && kGray_8_SkColorType != src.colorType()) { |
| 65 | return false; |
| 66 | } |
| 67 | |
| 68 | if (kAlpha_8_SkColorType != dst.colorType() && kAlpha_8_SkColorType == src.colorType()) { |
| 69 | return false; |
| 70 | } |
| 71 | |
Matt Sarett | 8dadd9e | 2017-01-18 13:39:39 +0000 | [diff] [blame^] | 72 | // FIXME (msarett): This is commented out until a fix to Chrome's gfx_unittest lands. |
| 73 | // In those tests, they write kPremul pixels to a kOpaque canvas. |
| 74 | //if (kOpaque_SkAlphaType == dst.alphaType() && kOpaque_SkAlphaType != src.alphaType()) { |
| 75 | // return false; |
| 76 | //} |
Matt Sarett | cb6266b | 2017-01-17 10:48:53 -0500 | [diff] [blame] | 77 | |
| 78 | return true; |
| 79 | } |