diff options
| -rw-r--r-- | src/core/SkRasterPipelineBlitter.cpp | 33 | ||||
| -rw-r--r-- | src/core/SkSRGB.h | 27 |
2 files changed, 47 insertions, 13 deletions
diff --git a/src/core/SkRasterPipelineBlitter.cpp b/src/core/SkRasterPipelineBlitter.cpp index 169bb9f74b..9d89b4dcfc 100644 --- a/src/core/SkRasterPipelineBlitter.cpp +++ b/src/core/SkRasterPipelineBlitter.cpp @@ -9,7 +9,6 @@ #include "SkColor.h" #include "SkColorFilter.h" #include "SkPM4f.h" -#include "SkPM4fPriv.h" #include "SkRasterPipeline.h" #include "SkShader.h" #include "SkSRGB.h" @@ -57,6 +56,22 @@ SkBlitter* SkCreateRasterPipelineBlitter(const SkPixmap& dst, return SkRasterPipelineBlitter::Create(dst, paint, alloc); } +// Clamp colors into [0,1] premul (e.g. just before storing back to memory). +static void SK_VECTORCALL clamp_01_premul(SkRasterPipeline::Stage* st, size_t x, + Sk4f r, Sk4f g, Sk4f b, Sk4f a, + Sk4f dr, Sk4f dg, Sk4f db, Sk4f da) { + a = Sk4f::Max(a, 0.0f); + r = Sk4f::Max(r, 0.0f); + g = Sk4f::Max(g, 0.0f); + b = Sk4f::Max(b, 0.0f); + + a = Sk4f::Min(a, 1.0f); + r = Sk4f::Min(r, a); + g = Sk4f::Min(g, a); + b = Sk4f::Min(b, a); + + st->next(x, r,g,b,a, dr,dg,db,da); +} // The default shader produces a constant color (from the SkPaint). static void SK_VECTORCALL constant_color(SkRasterPipeline::Stage* st, size_t x, @@ -255,10 +270,10 @@ static void SK_VECTORCALL store_srgb(SkRasterPipeline::Stage* st, size_t x, Sk4f r, Sk4f g, Sk4f b, Sk4f a, Sk4f dr, Sk4f dg, Sk4f db, Sk4f da) { auto dst = st->ctx<uint32_t*>() + x; - ( sk_linear_to_srgb(r) << SK_R32_SHIFT - | sk_linear_to_srgb(g) << SK_G32_SHIFT - | sk_linear_to_srgb(b) << SK_B32_SHIFT - | Sk4f_round(255.0f*a) << SK_A32_SHIFT).store(dst); + ( sk_linear_to_srgb_noclamp(r) << SK_R32_SHIFT + | sk_linear_to_srgb_noclamp(g) << SK_G32_SHIFT + | sk_linear_to_srgb_noclamp(b) << SK_B32_SHIFT + | Sk4f_round(255.0f * a) << SK_A32_SHIFT).store(dst); } // Tail variant of store_srgb() handling 1 pixel at a time. @@ -266,7 +281,12 @@ static void SK_VECTORCALL store_srgb_1(SkRasterPipeline::Stage* st, size_t x, Sk4f r, Sk4f g, Sk4f b, Sk4f a, Sk4f dr, Sk4f dg, Sk4f db, Sk4f da) { auto dst = st->ctx<uint32_t*>() + x; - *dst = Sk4f_toS32(swizzle_rb_if_bgra({ r[0], g[0], b[0], a[0] })); + Sk4i rgb = sk_linear_to_srgb_noclamp(swizzle_rb_if_bgra({ r[0], g[0], b[0], 0.0f })); + + uint32_t rgba; + SkNx_cast<uint8_t>(rgb).store(&rgba); + rgba |= (uint32_t)(255.0f * a[0] + 0.5f) << 24; + *dst = rgba; } static bool supported(const SkImageInfo& info) { @@ -343,6 +363,7 @@ void SkRasterPipelineBlitter::append_load_d(SkRasterPipeline* p, const void* dst void SkRasterPipelineBlitter::append_store(SkRasterPipeline* p, void* dst) const { SkASSERT(supported(fDst.info())); + p->append(clamp_01_premul); switch (fDst.info().colorType()) { case kN32_SkColorType: if (fDst.info().gammaCloseToSRGB()) { diff --git a/src/core/SkSRGB.h b/src/core/SkSRGB.h index 08ba860e4a..31fd4aec5e 100644 --- a/src/core/SkSRGB.h +++ b/src/core/SkSRGB.h @@ -28,14 +28,15 @@ static inline Sk4f sk_clamp_0_255(const Sk4f& x) { return Sk4f::Min(Sk4f::Max(x, 0.0f), 255.0f); } -static inline Sk4i sk_linear_to_srgb(const Sk4f& x) { +// This should probably only be called from sk_linear_to_srgb() or sk_linear_to_srgb_noclamp(). +// It generally doesn't make sense to work with sRGB floats. +static inline Sk4f sk_linear_to_srgb_needs_trunc(const Sk4f& x) { // Approximation of the sRGB gamma curve (within 1 when scaled to 8-bit pixels). // - // Tuned by brute force to minimize the number of bytes that fail to round trip, - // here 0 (of 256), and then to minimize the number of points halfway between bytes - // (in linear space) that fail to hit the right byte, here 131 (of 255), and to - // minimize the number of monotonicity regressions over the range [0,1], here 0. - + // Constants tuned by brute force to minimize (in order of importance) after truncation: + // 1) the number of bytes that fail to round trip (0 of 256); + // 2) the number of points in [FLT_MIN, 1.0f] that are non-monotonic (0 of ~1 billion); + // 3) the number of points halfway between bytes that hit the wrong byte (131 of 255). auto rsqrt = x.rsqrt(), sqrt = rsqrt.invert(), ftrt = rsqrt.rsqrt(); @@ -45,8 +46,20 @@ static inline Sk4i sk_linear_to_srgb(const Sk4f& x) { auto hi = (-0.0974983f * 255.0f) + (+0.687999f * 255.0f) * sqrt + (+0.412999f * 255.0f) * ftrt; + return (x < 0.0048f).thenElse(lo, hi); +} + +static inline Sk4i sk_linear_to_srgb(const Sk4f& x) { + Sk4f f = sk_linear_to_srgb_needs_trunc(x); + return SkNx_cast<int>(sk_clamp_0_255(f)); +} - return SkNx_cast<int>(sk_clamp_0_255((x < 0.0048f).thenElse(lo, hi))); +static inline Sk4i sk_linear_to_srgb_noclamp(const Sk4f& x) { + Sk4f f = sk_linear_to_srgb_needs_trunc(x); + for (int i = 0; i < 4; i++) { + SkASSERTF(0.0f <= f[i] && f[i] < 256.0f, "f[%d] was %g, outside [0,256)\n", i, f[i]); + } + return SkNx_cast<int>(f); } #endif//SkSRGB_DEFINED |