The Tor Browser / file comparison
comparison: gfx/layers/LayerUtils.cpp
gfx/layers/LayerUtils.cpp
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
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| -1:000000000000 | 0:cce5b1195b4e |
|---|---|
| 1 /* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #include "LayerUtils.h" | |
| 7 #include "PremultiplyTables.h" | |
| 8 #include "mozilla/Endian.h" | |
| 9 | |
| 10 namespace mozilla { | |
| 11 namespace layers { | |
| 12 | |
| 13 using namespace mozilla::gfx; | |
| 14 | |
| 15 static inline const uint8_t PremultiplyValue(uint8_t a, uint8_t v) { | |
| 16 return PremultiplyTable[a*256+v]; | |
| 17 } | |
| 18 | |
| 19 static inline const uint8_t UnpremultiplyValue(uint8_t a, uint8_t v) { | |
| 20 return UnpremultiplyTable[a*256+v]; | |
| 21 } | |
| 22 | |
| 23 #ifdef DEBUG | |
| 24 static bool IsLittleEndian() | |
| 25 { | |
| 26 // Violate strict aliasing, because violating strict aliasing is how | |
| 27 // we always pack and unpack between uint32_t and uint8_t[]. | |
| 28 uint16_t testShort; | |
| 29 static const uint8_t testBytes[2] = { 0xAA, 0xBB }; | |
| 30 memcpy(&testShort, testBytes, sizeof(testBytes)); | |
| 31 return testShort == 0xBBAA; | |
| 32 } | |
| 33 #endif // DEBUG | |
| 34 | |
| 35 #ifdef MOZ_LITTLE_ENDIAN | |
| 36 #define ASSERT_ENDIAN() MOZ_ASSERT(IsLittleEndian(), "Defined as little endian, but actually big!") | |
| 37 #else | |
| 38 #define ASSERT_ENDIAN() MOZ_ASSERT(!IsLittleEndian(), "Defined as big endian, but actually little!") | |
| 39 #endif | |
| 40 | |
| 41 void | |
| 42 PremultiplySurface(DataSourceSurface* srcSurface, | |
| 43 DataSourceSurface* destSurface) | |
| 44 { | |
| 45 if (!destSurface) | |
| 46 destSurface = srcSurface; | |
| 47 | |
| 48 IntSize srcSize = srcSurface->GetSize(); | |
| 49 MOZ_ASSERT(srcSurface->GetFormat() == destSurface->GetFormat() && | |
| 50 srcSize.width == destSurface->GetSize().width && | |
| 51 srcSize.height == destSurface->GetSize().height && | |
| 52 srcSurface->Stride() == destSurface->Stride(), | |
| 53 "Source and destination surfaces don't have identical characteristics"); | |
| 54 | |
| 55 MOZ_ASSERT(srcSurface->Stride() == srcSize.width * 4, | |
| 56 "Source surface stride isn't tightly packed"); | |
| 57 | |
| 58 // Only premultiply ARGB32 | |
| 59 if (srcSurface->GetFormat() != SurfaceFormat::B8G8R8A8) { | |
| 60 if (destSurface != srcSurface) { | |
| 61 memcpy(destSurface->GetData(), srcSurface->GetData(), | |
| 62 srcSurface->Stride() * srcSize.height); | |
| 63 } | |
| 64 return; | |
| 65 } | |
| 66 | |
| 67 uint8_t *src = srcSurface->GetData(); | |
| 68 uint8_t *dst = destSurface->GetData(); | |
| 69 | |
| 70 // Assert that our endian define is correct. | |
| 71 ASSERT_ENDIAN(); | |
| 72 | |
| 73 uint32_t dim = srcSize.width * srcSize.height; | |
| 74 for (uint32_t i = 0; i < dim; ++i) { | |
| 75 #ifdef MOZ_LITTLE_ENDIAN | |
| 76 uint8_t b = *src++; | |
| 77 uint8_t g = *src++; | |
| 78 uint8_t r = *src++; | |
| 79 uint8_t a = *src++; | |
| 80 | |
| 81 *dst++ = PremultiplyValue(a, b); | |
| 82 *dst++ = PremultiplyValue(a, g); | |
| 83 *dst++ = PremultiplyValue(a, r); | |
| 84 *dst++ = a; | |
| 85 #else | |
| 86 uint8_t a = *src++; | |
| 87 uint8_t r = *src++; | |
| 88 uint8_t g = *src++; | |
| 89 uint8_t b = *src++; | |
| 90 | |
| 91 *dst++ = a; | |
| 92 *dst++ = PremultiplyValue(a, r); | |
| 93 *dst++ = PremultiplyValue(a, g); | |
| 94 *dst++ = PremultiplyValue(a, b); | |
| 95 #endif | |
| 96 } | |
| 97 } | |
| 98 | |
| 99 | |
| 100 } | |
| 101 } |
