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 Sk4pxXfermode_DEFINED
9#define Sk4pxXfermode_DEFINED
10
11#include "include/private/SkNx.h"
12#include "src/core/Sk4px.h"
13#include "src/core/SkMSAN.h"
14#include "src/core/SkXfermodePriv.h"
15
16#ifdef SK_FORCE_RASTER_PIPELINE_BLITTER
17
18namespace SK_OPTS_NS {
19 /*not static*/ inline SkXfermode* create_xfermode(SkBlendMode) { return nullptr; }
20}
21
22#else
23
24namespace { // NOLINT(google-build-namespaces)
25
26// Most xfermodes can be done most efficiently 4 pixels at a time in 8 or 16-bit fixed point.
27#define XFERMODE(Xfermode) \
28 struct Xfermode { Sk4px operator()(const Sk4px&, const Sk4px&) const; }; \
29 inline Sk4px Xfermode::operator()(const Sk4px& d, const Sk4px& s) const
30
31XFERMODE(Clear) { return Sk4px::DupPMColor(0); }
32XFERMODE(Src) { return s; }
33XFERMODE(Dst) { return d; }
34XFERMODE(SrcIn) { return s.approxMulDiv255(d.alphas() ); }
35XFERMODE(SrcOut) { return s.approxMulDiv255(d.alphas().inv()); }
36XFERMODE(SrcOver) { return s + d.approxMulDiv255(s.alphas().inv()); }
37XFERMODE(DstIn) { return SrcIn ()(s,d); }
38XFERMODE(DstOut) { return SrcOut ()(s,d); }
39XFERMODE(DstOver) { return SrcOver()(s,d); }
40
41// [ S * Da + (1 - Sa) * D]
42XFERMODE(SrcATop) { return (s * d.alphas() + d * s.alphas().inv()).div255(); }
43XFERMODE(DstATop) { return SrcATop()(s,d); }
44//[ S * (1 - Da) + (1 - Sa) * D ]
45XFERMODE(Xor) { return (s * d.alphas().inv() + d * s.alphas().inv()).div255(); }
46// [S + D ]
47XFERMODE(Plus) { return s.saturatedAdd(d); }
48// [S * D ]
49XFERMODE(Modulate) { return s.approxMulDiv255(d); }
50// [S + D - S * D]
51XFERMODE(Screen) {
52 // Doing the math as S + (1-S)*D or S + (D - S*D) means the add and subtract can be done
53 // in 8-bit space without overflow. S + (1-S)*D is a touch faster because inv() is cheap.
54 return s + d.approxMulDiv255(s.inv());
55}
56
57#undef XFERMODE
58
59// A reasonable fallback mode for doing AA is to simply apply the transfermode first,
60// then linearly interpolate the AA.
61template <typename Xfermode>
62static Sk4px xfer_aa(const Sk4px& d, const Sk4px& s, const Sk4px& aa) {
63 Sk4px bw = Xfermode()(d, s);
64 return (bw * aa + d * aa.inv()).div255();
65}
66
67// For some transfermodes we specialize AA, either for correctness or performance.
68#define XFERMODE_AA(Xfermode) \
69 template <> Sk4px xfer_aa<Xfermode>(const Sk4px& d, const Sk4px& s, const Sk4px& aa)
70
71// Plus' clamp needs to happen after AA. skia:3852
72XFERMODE_AA(Plus) { // [ clamp( (1-AA)D + (AA)(S+D) ) == clamp(D + AA*S) ]
73 return d.saturatedAdd(s.approxMulDiv255(aa));
74}
75
76#undef XFERMODE_AA
77
78// Src and Clear modes are safe to use with unitialized dst buffers,
79// even if the implementation branches based on bytes from dst (e.g. asserts in Debug mode).
80// For those modes, just lie to MSAN that dst is always intialized.
81template <typename Xfermode> static void mark_dst_initialized_if_safe(void*, void*) {}
82template <> void mark_dst_initialized_if_safe<Src>(void* dst, void* end) {
83 sk_msan_mark_initialized(dst, end, "Src doesn't read dst.");
84}
85template <> void mark_dst_initialized_if_safe<Clear>(void* dst, void* end) {
86 sk_msan_mark_initialized(dst, end, "Clear doesn't read dst.");
87}
88
89template <typename Xfermode>
90class Sk4pxXfermode : public SkXfermode {
91public:
92 Sk4pxXfermode() {}
93
94 void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
95 mark_dst_initialized_if_safe<Xfermode>(dst, dst+n);
96 if (nullptr == aa) {
97 Sk4px::MapDstSrc(n, dst, src, Xfermode());
98 } else {
99 Sk4px::MapDstSrcAlpha(n, dst, src, aa, xfer_aa<Xfermode>);
100 }
101 }
102};
103
104} // namespace
105
106namespace SK_OPTS_NS {
107
108/*not static*/ inline SkXfermode* create_xfermode(SkBlendMode mode) {
109 switch (mode) {
110#define CASE(Xfermode) \
111 case SkBlendMode::k##Xfermode: return new Sk4pxXfermode<Xfermode>()
112 CASE(Clear);
113 CASE(Src);
114 CASE(Dst);
115 CASE(SrcOver);
116 CASE(DstOver);
117 CASE(SrcIn);
118 CASE(DstIn);
119 CASE(SrcOut);
120 CASE(DstOut);
121 CASE(SrcATop);
122 CASE(DstATop);
123 CASE(Xor);
124 CASE(Plus);
125 CASE(Modulate);
126 CASE(Screen);
127 #undef CASE
128
129 default: break;
130 }
131 return nullptr;
132}
133
134} // namespace SK_OPTS_NS
135
136#endif // #ifdef SK_FORCE_RASTER_PIPELINE_BLITTER
137
138#endif//Sk4pxXfermode_DEFINED
139