/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef Sk4pxXfermode_DEFINED
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#define Sk4pxXfermode_DEFINED
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#include "Sk4px.h"
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#include "SkMSAN.h"
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#include "SkNx.h"
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#include "SkXfermodePriv.h"
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#ifdef SK_FORCE_RASTER_PIPELINE_BLITTER
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namespace SK_OPTS_NS {
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/*not static*/ inline SkXfermode* create_xfermode(SkBlendMode) { return nullptr; }
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}
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#else
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namespace { // NOLINT(google-build-namespaces)
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// Most xfermodes can be done most efficiently 4 pixels at a time in 8 or 16-bit fixed point.
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#define XFERMODE(Xfermode) \
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struct Xfermode { Sk4px operator()(const Sk4px&, const Sk4px&) const; }; \
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inline Sk4px Xfermode::operator()(const Sk4px& d, const Sk4px& s) const
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XFERMODE(Clear) { return Sk4px::DupPMColor(0); }
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XFERMODE(Src) { return s; }
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XFERMODE(Dst) { return d; }
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XFERMODE(SrcIn) { return s.approxMulDiv255(d.alphas() ); }
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XFERMODE(SrcOut) { return s.approxMulDiv255(d.alphas().inv()); }
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XFERMODE(SrcOver) { return s + d.approxMulDiv255(s.alphas().inv()); }
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XFERMODE(DstIn) { return SrcIn ()(s,d); }
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XFERMODE(DstOut) { return SrcOut ()(s,d); }
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XFERMODE(DstOver) { return SrcOver()(s,d); }
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// [ S * Da + (1 - Sa) * D]
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XFERMODE(SrcATop) { return (s * d.alphas() + d * s.alphas().inv()).div255(); }
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XFERMODE(DstATop) { return SrcATop()(s,d); }
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//[ S * (1 - Da) + (1 - Sa) * D ]
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XFERMODE(Xor) { return (s * d.alphas().inv() + d * s.alphas().inv()).div255(); }
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// [S + D ]
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XFERMODE(Plus) { return s.saturatedAdd(d); }
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// [S * D ]
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XFERMODE(Modulate) { return s.approxMulDiv255(d); }
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// [S + D - S * D]
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XFERMODE(Screen) {
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// Doing the math as S + (1-S)*D or S + (D - S*D) means the add and subtract can be done
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// in 8-bit space without overflow. S + (1-S)*D is a touch faster because inv() is cheap.
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return s + d.approxMulDiv255(s.inv());
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}
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#undef XFERMODE
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// A reasonable fallback mode for doing AA is to simply apply the transfermode first,
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// then linearly interpolate the AA.
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template <typename Xfermode>
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static Sk4px xfer_aa(const Sk4px& d, const Sk4px& s, const Sk4px& aa) {
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Sk4px bw = Xfermode()(d, s);
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return (bw * aa + d * aa.inv()).div255();
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}
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// For some transfermodes we specialize AA, either for correctness or performance.
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#define XFERMODE_AA(Xfermode) \
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template <> Sk4px xfer_aa<Xfermode>(const Sk4px& d, const Sk4px& s, const Sk4px& aa)
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// Plus' clamp needs to happen after AA. skia:3852
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XFERMODE_AA(Plus) { // [ clamp( (1-AA)D + (AA)(S+D) ) == clamp(D + AA*S) ]
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return d.saturatedAdd(s.approxMulDiv255(aa));
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}
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#undef XFERMODE_AA
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// Src and Clear modes are safe to use with unitialized dst buffers,
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// even if the implementation branches based on bytes from dst (e.g. asserts in Debug mode).
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// For those modes, just lie to MSAN that dst is always intialized.
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template <typename Xfermode> static void mark_dst_initialized_if_safe(void*, void*) {}
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template <> void mark_dst_initialized_if_safe<Src>(void* dst, void* end) {
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sk_msan_mark_initialized(dst, end, "Src doesn't read dst.");
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}
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template <> void mark_dst_initialized_if_safe<Clear>(void* dst, void* end) {
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sk_msan_mark_initialized(dst, end, "Clear doesn't read dst.");
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}
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template <typename Xfermode>
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class Sk4pxXfermode : public SkXfermode {
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public:
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Sk4pxXfermode() {}
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void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
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mark_dst_initialized_if_safe<Xfermode>(dst, dst+n);
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if (nullptr == aa) {
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Sk4px::MapDstSrc(n, dst, src, Xfermode());
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} else {
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Sk4px::MapDstSrcAlpha(n, dst, src, aa, xfer_aa<Xfermode>);
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}
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}
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};
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} // namespace
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namespace SK_OPTS_NS {
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/*not static*/ inline SkXfermode* create_xfermode(SkBlendMode mode) {
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switch (mode) {
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#define CASE(Xfermode) \
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case SkBlendMode::k##Xfermode: return new Sk4pxXfermode<Xfermode>()
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CASE(Clear);
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CASE(Src);
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CASE(Dst);
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CASE(SrcOver);
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CASE(DstOver);
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CASE(SrcIn);
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CASE(DstIn);
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CASE(SrcOut);
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CASE(DstOut);
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CASE(SrcATop);
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CASE(DstATop);
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CASE(Xor);
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CASE(Plus);
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CASE(Modulate);
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CASE(Screen);
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#undef CASE
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default: break;
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}
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return nullptr;
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}
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} // namespace SK_OPTS_NS
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#endif // #ifdef SK_FORCE_RASTER_PIPELINE_BLITTER
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#endif//Sk4pxXfermode_DEFINED
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