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 "Sk4px.h"
12 #include "SkMSAN.h"
13 #include "SkNx.h"
14 #include "SkXfermodePriv.h"
15
16 #ifdef SK_FORCE_RASTER_PIPELINE_BLITTER
17
18 namespace SK_OPTS_NS {
create_xfermode(SkBlendMode)19 /*not static*/ inline SkXfermode* create_xfermode(SkBlendMode) { return nullptr; }
20 }
21
22 #else
23
24 namespace { // 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
XFERMODE(Clear)31 XFERMODE(Clear) { return Sk4px::DupPMColor(0); }
XFERMODE(Src)32 XFERMODE(Src) { return s; }
XFERMODE(Dst)33 XFERMODE(Dst) { return d; }
XFERMODE(SrcIn)34 XFERMODE(SrcIn) { return s.approxMulDiv255(d.alphas() ); }
XFERMODE(SrcOut)35 XFERMODE(SrcOut) { return s.approxMulDiv255(d.alphas().inv()); }
XFERMODE(SrcOver)36 XFERMODE(SrcOver) { return s + d.approxMulDiv255(s.alphas().inv()); }
XFERMODE(DstIn)37 XFERMODE(DstIn) { return SrcIn ()(s,d); }
XFERMODE(DstOut)38 XFERMODE(DstOut) { return SrcOut ()(s,d); }
XFERMODE(DstOver)39 XFERMODE(DstOver) { return SrcOver()(s,d); }
40
41 // [ S * Da + (1 - Sa) * D]
XFERMODE(SrcATop)42 XFERMODE(SrcATop) { return (s * d.alphas() + d * s.alphas().inv()).div255(); }
XFERMODE(DstATop)43 XFERMODE(DstATop) { return SrcATop()(s,d); }
44 //[ S * (1 - Da) + (1 - Sa) * D ]
XFERMODE(Xor)45 XFERMODE(Xor) { return (s * d.alphas().inv() + d * s.alphas().inv()).div255(); }
46 // [S + D ]
XFERMODE(Plus)47 XFERMODE(Plus) { return s.saturatedAdd(d); }
48 // [S * D ]
XFERMODE(Modulate)49 XFERMODE(Modulate) { return s.approxMulDiv255(d); }
50 // [S + D - S * D]
XFERMODE(Screen)51 XFERMODE(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.
61 template <typename Xfermode>
xfer_aa(const Sk4px & d,const Sk4px & s,const Sk4px & aa)62 static 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
XFERMODE_AA(Plus)72 XFERMODE_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.
mark_dst_initialized_if_safe(void *,void *)81 template <typename Xfermode> static void mark_dst_initialized_if_safe(void*, void*) {}
82 template <> void mark_dst_initialized_if_safe<Src>(void* dst, void* end) {
83 sk_msan_mark_initialized(dst, end, "Src doesn't read dst.");
84 }
85 template <> 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
89 template <typename Xfermode>
90 class Sk4pxXfermode : public SkXfermode {
91 public:
Sk4pxXfermode()92 Sk4pxXfermode() {}
93
xfer32(SkPMColor dst[],const SkPMColor src[],int n,const SkAlpha aa[])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
106 namespace SK_OPTS_NS {
107
create_xfermode(SkBlendMode mode)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