| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef Sk4pxXfermode_DEFINED |
| #define Sk4pxXfermode_DEFINED |
| |
| #include "Sk4px.h" |
| #include "SkMSAN.h" |
| #include "SkNx.h" |
| #include "SkXfermodePriv.h" |
| |
| namespace { |
| |
| // Most xfermodes can be done most efficiently 4 pixels at a time in 8 or 16-bit fixed point. |
| #define XFERMODE(Xfermode) \ |
| struct Xfermode { Sk4px operator()(const Sk4px&, const Sk4px&) const; }; \ |
| inline Sk4px Xfermode::operator()(const Sk4px& d, const Sk4px& s) const |
| |
| XFERMODE(Clear) { return Sk4px::DupPMColor(0); } |
| XFERMODE(Src) { return s; } |
| XFERMODE(Dst) { return d; } |
| XFERMODE(SrcIn) { return s.approxMulDiv255(d.alphas() ); } |
| XFERMODE(SrcOut) { return s.approxMulDiv255(d.alphas().inv()); } |
| XFERMODE(SrcOver) { return s + d.approxMulDiv255(s.alphas().inv()); } |
| XFERMODE(DstIn) { return SrcIn ()(s,d); } |
| XFERMODE(DstOut) { return SrcOut ()(s,d); } |
| XFERMODE(DstOver) { return SrcOver()(s,d); } |
| |
| // [ S * Da + (1 - Sa) * D] |
| XFERMODE(SrcATop) { return (s * d.alphas() + d * s.alphas().inv()).div255(); } |
| XFERMODE(DstATop) { return SrcATop()(s,d); } |
| //[ S * (1 - Da) + (1 - Sa) * D ] |
| XFERMODE(Xor) { return (s * d.alphas().inv() + d * s.alphas().inv()).div255(); } |
| // [S + D ] |
| XFERMODE(Plus) { return s.saturatedAdd(d); } |
| // [S * D ] |
| XFERMODE(Modulate) { return s.approxMulDiv255(d); } |
| // [S + D - S * D] |
| XFERMODE(Screen) { |
| // Doing the math as S + (1-S)*D or S + (D - S*D) means the add and subtract can be done |
| // in 8-bit space without overflow. S + (1-S)*D is a touch faster because inv() is cheap. |
| return s + d.approxMulDiv255(s.inv()); |
| } |
| XFERMODE(Multiply) { return (s * d.alphas().inv() + d * s.alphas().inv() + s*d).div255(); } |
| // [ Sa + Da - Sa*Da, Sc + Dc - 2*min(Sc*Da, Dc*Sa) ] (And notice Sa*Da == min(Sa*Da, Da*Sa).) |
| XFERMODE(Difference) { |
| auto m = Sk4px::Wide::Min(s * d.alphas(), d * s.alphas()).div255(); |
| // There's no chance of underflow, and if we subtract m before adding s+d, no overflow. |
| return (s - m) + (d - m.zeroAlphas()); |
| } |
| // [ Sa + Da - Sa*Da, Sc + Dc - 2*Sc*Dc ] |
| XFERMODE(Exclusion) { |
| auto p = s.approxMulDiv255(d); |
| // There's no chance of underflow, and if we subtract p before adding src+dst, no overflow. |
| return (s - p) + (d - p.zeroAlphas()); |
| } |
| |
| // We take care to use exact math for these next few modes where alphas |
| // and colors are calculated using significantly different math. We need |
| // to preserve premul invariants, and exact math makes this easier. |
| // |
| // TODO: Some of these implementations might be able to be sped up a bit |
| // while maintaining exact math, but let's follow up with that. |
| |
| XFERMODE(HardLight) { |
| auto sa = s.alphas(), |
| da = d.alphas(); |
| |
| auto srcover = s + (d * sa.inv()).div255(); |
| |
| auto isLite = ((sa-s) < s).widenLoHi(); |
| |
| auto lite = sa*da - ((da-d)*(sa-s) << 1), |
| dark = s*d << 1, |
| both = s*da.inv() + d*sa.inv(); |
| |
| auto alphas = srcover; |
| auto colors = (both + isLite.thenElse(lite, dark)).div255(); |
| return alphas.zeroColors() + colors.zeroAlphas(); |
| } |
| XFERMODE(Overlay) { return HardLight()(s,d); } |
| |
| XFERMODE(Darken) { |
| auto sa = s.alphas(), |
| da = d.alphas(); |
| |
| auto sda = (s*da).div255(), |
| dsa = (d*sa).div255(); |
| |
| auto srcover = s + (d * sa.inv()).div255(), |
| dstover = d + (s * da.inv()).div255(); |
| auto alphas = srcover, |
| colors = (sda < dsa).thenElse(srcover, dstover); |
| return alphas.zeroColors() + colors.zeroAlphas(); |
| } |
| XFERMODE(Lighten) { |
| auto sa = s.alphas(), |
| da = d.alphas(); |
| |
| auto sda = (s*da).div255(), |
| dsa = (d*sa).div255(); |
| |
| auto srcover = s + (d * sa.inv()).div255(), |
| dstover = d + (s * da.inv()).div255(); |
| auto alphas = srcover, |
| colors = (dsa < sda).thenElse(srcover, dstover); |
| return alphas.zeroColors() + colors.zeroAlphas(); |
| } |
| #undef XFERMODE |
| |
| // Some xfermodes use math like divide or sqrt that's best done in floats 1 pixel at a time. |
| #define XFERMODE(Xfermode) \ |
| struct Xfermode { Sk4f operator()(const Sk4f&, const Sk4f&) const; }; \ |
| inline Sk4f Xfermode::operator()(const Sk4f& d, const Sk4f& s) const |
| |
| static inline Sk4f a_rgb(const Sk4f& a, const Sk4f& rgb) { |
| static_assert(SK_A32_SHIFT == 24, ""); |
| return a * Sk4f(0,0,0,1) + rgb * Sk4f(1,1,1,0); |
| } |
| static inline Sk4f alphas(const Sk4f& f) { |
| return f[SK_A32_SHIFT/8]; |
| } |
| |
| XFERMODE(ColorDodge) { |
| auto sa = alphas(s), |
| da = alphas(d), |
| isa = Sk4f(1)-sa, |
| ida = Sk4f(1)-da; |
| |
| auto srcover = s + d*isa, |
| dstover = d + s*ida, |
| otherwise = sa * Sk4f::Min(da, (d*sa)*(sa-s).invert()) + s*ida + d*isa; |
| |
| // Order matters here, preferring d==0 over s==sa. |
| auto colors = (d == Sk4f(0)).thenElse(dstover, |
| (s == sa).thenElse(srcover, |
| otherwise)); |
| return a_rgb(srcover, colors); |
| } |
| XFERMODE(ColorBurn) { |
| auto sa = alphas(s), |
| da = alphas(d), |
| isa = Sk4f(1)-sa, |
| ida = Sk4f(1)-da; |
| |
| auto srcover = s + d*isa, |
| dstover = d + s*ida, |
| otherwise = sa*(da-Sk4f::Min(da, (da-d)*sa*s.invert())) + s*ida + d*isa; |
| |
| // Order matters here, preferring d==da over s==0. |
| auto colors = (d == da).thenElse(dstover, |
| (s == Sk4f(0)).thenElse(srcover, |
| otherwise)); |
| return a_rgb(srcover, colors); |
| } |
| XFERMODE(SoftLight) { |
| auto sa = alphas(s), |
| da = alphas(d), |
| isa = Sk4f(1)-sa, |
| ida = Sk4f(1)-da; |
| |
| // Some common terms. |
| auto m = (da > Sk4f(0)).thenElse(d / da, Sk4f(0)), |
| s2 = Sk4f(2)*s, |
| m4 = Sk4f(4)*m; |
| |
| // The logic forks three ways: |
| // 1. dark src? |
| // 2. light src, dark dst? |
| // 3. light src, light dst? |
| auto darkSrc = d*(sa + (s2 - sa)*(Sk4f(1) - m)), // Used in case 1. |
| darkDst = (m4*m4 + m4)*(m - Sk4f(1)) + Sk4f(7)*m, // Used in case 2. |
| liteDst = m.sqrt() - m, // Used in case 3. |
| liteSrc = d*sa + da*(s2-sa)*(Sk4f(4)*d <= da).thenElse(darkDst, liteDst); // Case 2 or 3? |
| |
| auto alpha = s + d*isa; |
| auto colors = s*ida + d*isa + (s2 <= sa).thenElse(darkSrc, liteSrc); // Case 1 or 2/3? |
| |
| return a_rgb(alpha, colors); |
| } |
| #undef XFERMODE |
| |
| // A reasonable fallback mode for doing AA is to simply apply the transfermode first, |
| // then linearly interpolate the AA. |
| template <typename Xfermode> |
| static Sk4px xfer_aa(const Sk4px& d, const Sk4px& s, const Sk4px& aa) { |
| Sk4px bw = Xfermode()(d, s); |
| return (bw * aa + d * aa.inv()).div255(); |
| } |
| |
| // For some transfermodes we specialize AA, either for correctness or performance. |
| #define XFERMODE_AA(Xfermode) \ |
| template <> Sk4px xfer_aa<Xfermode>(const Sk4px& d, const Sk4px& s, const Sk4px& aa) |
| |
| // Plus' clamp needs to happen after AA. skia:3852 |
| XFERMODE_AA(Plus) { // [ clamp( (1-AA)D + (AA)(S+D) ) == clamp(D + AA*S) ] |
| return d.saturatedAdd(s.approxMulDiv255(aa)); |
| } |
| |
| #undef XFERMODE_AA |
| |
| // Src and Clear modes are safe to use with unitialized dst buffers, |
| // even if the implementation branches based on bytes from dst (e.g. asserts in Debug mode). |
| // For those modes, just lie to MSAN that dst is always intialized. |
| template <typename Xfermode> static void mark_dst_initialized_if_safe(void*, void*) {} |
| template <> void mark_dst_initialized_if_safe<Src>(void* dst, void* end) { |
| sk_msan_mark_initialized(dst, end, "Src doesn't read dst."); |
| } |
| template <> void mark_dst_initialized_if_safe<Clear>(void* dst, void* end) { |
| sk_msan_mark_initialized(dst, end, "Clear doesn't read dst."); |
| } |
| |
| template <typename Xfermode> |
| class Sk4pxXfermode : public SkXfermode { |
| public: |
| Sk4pxXfermode() {} |
| |
| void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override { |
| mark_dst_initialized_if_safe<Xfermode>(dst, dst+n); |
| if (nullptr == aa) { |
| Sk4px::MapDstSrc(n, dst, src, Xfermode()); |
| } else { |
| Sk4px::MapDstSrcAlpha(n, dst, src, aa, xfer_aa<Xfermode>); |
| } |
| } |
| }; |
| |
| template <typename Xfermode> |
| class Sk4fXfermode : public SkXfermode { |
| public: |
| Sk4fXfermode() {} |
| |
| void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override { |
| for (int i = 0; i < n; i++) { |
| dst[i] = Xfer32_1(dst[i], src[i], aa ? aa+i : nullptr); |
| } |
| } |
| |
| private: |
| static SkPMColor Xfer32_1(SkPMColor dst, const SkPMColor src, const SkAlpha* aa) { |
| Sk4f d = Load(dst), |
| s = Load(src), |
| b = Xfermode()(d, s); |
| if (aa) { |
| Sk4f a = Sk4f(*aa) * Sk4f(1.0f/255); |
| b = b*a + d*(Sk4f(1)-a); |
| } |
| return Round(b); |
| } |
| |
| static Sk4f Load(SkPMColor c) { |
| return SkNx_cast<float>(Sk4b::Load(&c)) * Sk4f(1.0f/255); |
| } |
| |
| static SkPMColor Round(const Sk4f& f) { |
| SkPMColor c; |
| SkNx_cast<uint8_t>(f * Sk4f(255) + Sk4f(0.5f)).store(&c); |
| return c; |
| } |
| }; |
| |
| } // namespace |
| |
| namespace SK_OPTS_NS { |
| |
| static SkXfermode* create_xfermode(SkBlendMode mode) { |
| switch (mode) { |
| #define CASE(Xfermode) \ |
| case SkBlendMode::k##Xfermode: return new Sk4pxXfermode<Xfermode>() |
| CASE(Clear); |
| CASE(Src); |
| CASE(Dst); |
| CASE(SrcOver); |
| CASE(DstOver); |
| CASE(SrcIn); |
| CASE(DstIn); |
| CASE(SrcOut); |
| CASE(DstOut); |
| CASE(SrcATop); |
| CASE(DstATop); |
| CASE(Xor); |
| CASE(Plus); |
| CASE(Modulate); |
| CASE(Screen); |
| CASE(Multiply); |
| CASE(Difference); |
| CASE(Exclusion); |
| CASE(HardLight); |
| CASE(Overlay); |
| CASE(Darken); |
| CASE(Lighten); |
| #undef CASE |
| |
| #define CASE(Xfermode) \ |
| case SkBlendMode::k##Xfermode: return new Sk4fXfermode<Xfermode>() |
| CASE(ColorDodge); |
| CASE(ColorBurn); |
| CASE(SoftLight); |
| #undef CASE |
| |
| default: break; |
| } |
| return nullptr; |
| } |
| |
| } // namespace SK_OPTS_NS |
| |
| #endif//Sk4pxXfermode_DEFINED |