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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 SkPx_DEFINED | |
9 #define SkPx_DEFINED | |
10 | |
11 #include "SkTypes.h" | |
12 #include "SkColorPriv.h" | |
13 | |
14 // We'll include one of src/opts/SkPx_{sse,neon,none}.h to define a type SkPx. | |
15 // | |
16 // SkPx represents up to SkPx::N 8888 pixels. It's agnostic to whether these | |
17 // are SkColors or SkPMColors; it only assumes that alpha is the high byte. | |
18 static_assert(SK_A32_SHIFT == 24, "For both SkColor and SkPMColor, alpha is alwa
ys the high byte."); | |
19 // | |
20 // SkPx::Alpha represents up to SkPx::N 8-bit values, usually coverage or alpha. | |
21 // SkPx::Wide represents up to SkPx::N pixels with 16 bits per component. | |
22 // | |
23 // SkPx supports the following methods: | |
24 // static SkPx Dup(uint32_t); | |
25 // static SkPx Load(const uint32_t*); | |
26 // static SkPx Load(const uint32_t*, int n); // where 0<n<SkPx::N | |
27 // void store(uint32_t*) const; | |
28 // void store(uint32_t*, int n) const; // where 0<n<SkPx::N | |
29 // | |
30 // Alpha alpha() const; // argb -> a | |
31 // Wide widenLo() const; // argb -> 0a0r0g0b | |
32 // Wide widenHi() const; // argb -> a0r0g0b0 | |
33 // Wide widenLoHi() const; // argb -> aarrggbb | |
34 // | |
35 // SkPx operator+(const SkPx&) const; | |
36 // SkPx operator-(const SkPx&) const; | |
37 // SkPx saturatedAdd(const SkPx&) const; | |
38 // | |
39 // Wide operator*(const Alpha&) const; // argb * A -> (a*A)(r*A)(g*A)(b*A) | |
40 // | |
41 // // Fast approximate (px*a+127)/255. | |
42 // // Never off by more than 1, and always correct when px or a is 0 or 255. | |
43 // // We use the approximation (px*a+px)/256. | |
44 // SkPx approxMulDiv255(const Alpha&) const; | |
45 // | |
46 // SkPx addAlpha(const Alpha&) const; // argb + A -> (a+A)rgb | |
47 // | |
48 // SkPx::Alpha supports the following methods: | |
49 // static Alpha Dup(uint8_t); | |
50 // static Alpha Load(const uint8_t*); | |
51 // static Alpha Load(const uint8_t*, int n); // where 0<n<SkPx::N | |
52 // | |
53 // Alpha inv() const; // a -> 255-a | |
54 // | |
55 // SkPx::Wide supports the following methods: | |
56 // Wide operator+(const Wide&); | |
57 // Wide operator-(const Wide&); | |
58 // Wide shl<int bits>(); | |
59 // Wide shr<int bits>(); | |
60 // | |
61 // // Return the high byte of each component of (*this + o.widenLo()). | |
62 // SkPx addNarrowHi(const SkPx& o); | |
63 // | |
64 // Methods left unwritten, but certainly to come: | |
65 // SkPx SkPx::operator<(const SkPx&) const; | |
66 // SkPx SkPx::thenElse(const SkPx& then, const SkPx& else) const; | |
67 // Wide Wide::operator<(const Wide&) const; | |
68 // Wide Wide::thenElse(const Wide& then, const Wide& else) const; | |
69 // | |
70 // SkPx Wide::div255() const; // Rounds, think (*this + 127) / 255. | |
71 // | |
72 // The different implementations of SkPx have complete freedom to choose | |
73 // SkPx::N and how they represent SkPx, SkPx::Alpha, and SkPx::Wide. | |
74 // | |
75 // All observable math must remain identical. | |
76 | |
77 #if defined(SKNX_NO_SIMD) | |
78 #include "../opts/SkPx_none.h" | |
79 #else | |
80 #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2 | |
81 #include "../opts/SkPx_sse.h" | |
82 #elif defined(SK_ARM_HAS_NEON) | |
83 #include "../opts/SkPx_neon.h" | |
84 #else | |
85 #include "../opts/SkPx_none.h" | |
86 #endif | |
87 #endif | |
88 | |
89 #endif//SkPx_DEFINED | |
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