| mtklein | 4a37d08 | 2015-09-10 10:38:02 -0700 | [diff] [blame] | 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 SkBlitRow_opts_DEFINED |
| 9 | #define SkBlitRow_opts_DEFINED |
| 10 | |
| 11 | #include "Sk4px.h" |
| 12 | |
| 13 | namespace SK_OPTS_NS { |
| 14 | |
| 15 | // Color32 uses the blend_256_round_alt algorithm from tests/BlendTest.cpp. |
| 16 | // It's not quite perfect, but it's never wrong in the interesting edge cases, |
| 17 | // and it's quite a bit faster than blend_perfect. |
| 18 | // |
| 19 | // blend_256_round_alt is our currently blessed algorithm. Please use it or an analogous one. |
| 20 | static void blit_row_color32(SkPMColor* dst, const SkPMColor* src, int count, SkPMColor color) { |
| 21 | unsigned invA = 255 - SkGetPackedA32(color); |
| 22 | invA += invA >> 7; |
| 23 | SkASSERT(invA < 256); // We've should have already handled alpha == 0 externally. |
| 24 | |
| 25 | Sk16h colorHighAndRound = Sk4px::DupPMColor(color).widenHi() + Sk16h(128); |
| 26 | Sk16b invA_16x(invA); |
| 27 | |
| 28 | Sk4px::MapSrc(count, dst, src, [&](const Sk4px& src4) -> Sk4px { |
| 29 | return (src4 * invA_16x).addNarrowHi(colorHighAndRound); |
| 30 | }); |
| 31 | } |
| 32 | |
| 33 | } // SK_OPTS_NS |
| 34 | |
| 35 | #endif//SkBlitRow_opts_DEFINED |