The Tor Browser / file comparison
comparison: gfx/skia/trunk/src/utils/SkUnitMappers.cpp
gfx/skia/trunk/src/utils/SkUnitMappers.cpp
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:04079e66d91a |
|---|---|
| 1 | |
| 2 /* | |
| 3 * Copyright 2011 Google Inc. | |
| 4 * | |
| 5 * Use of this source code is governed by a BSD-style license that can be | |
| 6 * found in the LICENSE file. | |
| 7 */ | |
| 8 #include "SkUnitMappers.h" | |
| 9 #include "SkReadBuffer.h" | |
| 10 #include "SkWriteBuffer.h" | |
| 11 | |
| 12 | |
| 13 SkDiscreteMapper::SkDiscreteMapper(int segments) { | |
| 14 if (segments < 2) { | |
| 15 fSegments = 0; | |
| 16 fScale = 0; | |
| 17 } else { | |
| 18 if (segments > 0xFFFF) { | |
| 19 segments = 0xFFFF; | |
| 20 } | |
| 21 fSegments = segments; | |
| 22 fScale = (1 << 30) / (segments - 1); | |
| 23 } | |
| 24 } | |
| 25 | |
| 26 uint16_t SkDiscreteMapper::mapUnit16(uint16_t input) { | |
| 27 SkFixed x = input * fSegments >> 16; | |
| 28 x = x * fScale >> 14; | |
| 29 x += x << 15 >> 31; // map 0x10000 to 0xFFFF | |
| 30 return SkToU16(x); | |
| 31 } | |
| 32 | |
| 33 SkDiscreteMapper::SkDiscreteMapper(SkReadBuffer& rb) | |
| 34 : SkUnitMapper(rb) { | |
| 35 fSegments = rb.readInt(); | |
| 36 fScale = rb.read32(); | |
| 37 } | |
| 38 | |
| 39 void SkDiscreteMapper::flatten(SkWriteBuffer& wb) const { | |
| 40 this->INHERITED::flatten(wb); | |
| 41 | |
| 42 wb.writeInt(fSegments); | |
| 43 wb.write32(fScale); | |
| 44 } | |
| 45 | |
| 46 /////////////////////////////////////////////////////////////////////////////// | |
| 47 | |
| 48 uint16_t SkCosineMapper::mapUnit16(uint16_t input) | |
| 49 { | |
| 50 /* we want to call cosine(input * pi/2) treating input as [0...1) | |
| 51 however, the straight multitply would overflow 32bits since input is | |
| 52 16bits and pi/2 is 17bits, so we shift down our pi const before we mul | |
| 53 */ | |
| 54 SkFixed rads = (unsigned)(input * (SK_FixedPI >> 2)) >> 15; | |
| 55 SkFixed x = SkFixedCos(rads); | |
| 56 x += x << 15 >> 31; // map 0x10000 to 0xFFFF | |
| 57 return SkToU16(x); | |
| 58 } | |
| 59 | |
| 60 SkCosineMapper::SkCosineMapper(SkReadBuffer& rb) | |
| 61 : SkUnitMapper(rb) {} |
