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