diff options
author | 2017-08-28 12:50:26 -0400 | |
---|---|---|
committer | 2017-08-29 17:10:36 +0000 | |
commit | aa0ce825b877871f73532beb6fde6bf2f80e99dd (patch) | |
tree | 6cc4c265c8ccb84e1408b5b9cfe6068e9abc6fec /src/shaders/gradients/Sk4fLinearGradient.cpp | |
parent | 9d7e57d509149dd2fcb3ba73ea8f4cdce11f84bd (diff) |
Use the 4f impl for legacy/8888 linear gradients
This is a partial revert of https://skia-review.googlesource.com/c/20280,
adding back L32 support for 4f gradients and switching off the legacy
impl.
If it sticks, we should be able to completely delete the legacy gradient
code.
Change-Id: Iaa6d722ea4dfd8e4d959bb76eca815a30ca7098f
Reviewed-on: https://skia-review.googlesource.com/31425
Reviewed-by: Herb Derby <herb@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Diffstat (limited to 'src/shaders/gradients/Sk4fLinearGradient.cpp')
-rw-r--r-- | src/shaders/gradients/Sk4fLinearGradient.cpp | 125 |
1 files changed, 89 insertions, 36 deletions
diff --git a/src/shaders/gradients/Sk4fLinearGradient.cpp b/src/shaders/gradients/Sk4fLinearGradient.cpp index 700b7fb13e..11bf96d98f 100644 --- a/src/shaders/gradients/Sk4fLinearGradient.cpp +++ b/src/shaders/gradients/Sk4fLinearGradient.cpp @@ -12,20 +12,21 @@ namespace { -template<ApplyPremul premul> -void ramp(const Sk4f& c, const Sk4f& dc, SkPM4f dst[], int n) { +template<typename dstType, ApplyPremul premul> +void ramp(const Sk4f& c, const Sk4f& dc, dstType dst[], int n, + const Sk4f& bias0, const Sk4f& bias1) { SkASSERT(n > 0); - const Sk4f dc2 = dc + dc; - const Sk4f dc4 = dc2 + dc2; + const Sk4f dc2 = dc + dc, + dc4 = dc2 + dc2; - Sk4f c0 = c ; - Sk4f c1 = c + dc; - Sk4f c2 = c0 + dc2; - Sk4f c3 = c1 + dc2; + Sk4f c0 = c + DstTraits<dstType, premul>::pre_lerp_bias(bias0), + c1 = c + dc + DstTraits<dstType, premul>::pre_lerp_bias(bias1), + c2 = c0 + dc2, + c3 = c1 + dc2; while (n >= 4) { - DstTraits<premul>::store4x(c0, c1, c2, c3, dst); + DstTraits<dstType, premul>::store4x(c0, c1, c2, c3, dst, bias0, bias1); dst += 4; c0 = c0 + dc4; @@ -35,12 +36,12 @@ void ramp(const Sk4f& c, const Sk4f& dc, SkPM4f dst[], int n) { n -= 4; } if (n & 2) { - DstTraits<premul>::store(c0, dst++); - DstTraits<premul>::store(c1, dst++); + DstTraits<dstType, premul>::store(c0, dst++, bias0); + DstTraits<dstType, premul>::store(c1, dst++, bias1); c0 = c0 + dc2; } if (n & 1) { - DstTraits<premul>::store(c0, dst); + DstTraits<dstType, premul>::store(c0, dst, bias0); } } @@ -141,37 +142,81 @@ SkLinearGradient::LinearGradient4fContext::findInterval(SkScalar fx) const { } } + +void SkLinearGradient:: +LinearGradient4fContext::shadeSpan(int x, int y, SkPMColor dst[], int count) { + SkASSERT(count > 0); + + float bias0 = 0, + bias1 = 0; + + if (fDither) { + static constexpr float dither_cell[] = { + -3/8.0f, 1/8.0f, + 3/8.0f, -1/8.0f, + }; + + const int rowIndex = (y & 1) << 1; + bias0 = dither_cell[rowIndex + 0]; + bias1 = dither_cell[rowIndex + 1]; + + if (x & 1) { + SkTSwap(bias0, bias1); + } + } + + if (fColorsArePremul) { + // In premul interpolation mode, components are pre-scaled by 255 and the store + // op is truncating. We pre-bias here to achieve rounding. + bias0 += 0.5f; + bias1 += 0.5f; + + this->shadePremulSpan<SkPMColor, ApplyPremul::False>(x, y, dst, count, bias0, bias1); + } else { + // In unpremul interpolation mode, Components are not pre-scaled. + bias0 *= 1/255.0f; + bias1 *= 1/255.0f; + + this->shadePremulSpan<SkPMColor, ApplyPremul::True >(x, y, dst, count, bias0, bias1); + } +} + void SkLinearGradient:: LinearGradient4fContext::shadeSpan4f(int x, int y, SkPM4f dst[], int count) { SkASSERT(count > 0); + + // 4f dests are dithered at a later stage, if needed. + static constexpr float bias0 = 0, + bias1 = 0; if (fColorsArePremul) { - this->shadePremulSpan<ApplyPremul::False>(x, y, dst, count); + this->shadePremulSpan<SkPM4f, ApplyPremul::False>(x, y, dst, count, bias0, bias1); } else { - this->shadePremulSpan<ApplyPremul::True>(x, y, dst, count); + this->shadePremulSpan<SkPM4f, ApplyPremul::True >(x, y, dst, count, bias0, bias1); } } -template<ApplyPremul premul> +template<typename dstType, ApplyPremul premul> void SkLinearGradient:: -LinearGradient4fContext::shadePremulSpan(int x, int y, SkPM4f dst[], int count) const { - const SkLinearGradient& shader = - static_cast<const SkLinearGradient&>(fShader); +LinearGradient4fContext::shadePremulSpan(int x, int y, dstType dst[], int count, + float bias0, float bias1) const { + const SkLinearGradient& shader = static_cast<const SkLinearGradient&>(fShader); switch (shader.fTileMode) { case kClamp_TileMode: - this->shadeSpanInternal<premul, kClamp_TileMode>(x, y, dst, count); + this->shadeSpanInternal<dstType, premul, kClamp_TileMode >(x, y, dst, count, bias0, bias1); break; case kRepeat_TileMode: - this->shadeSpanInternal<premul, kRepeat_TileMode>(x, y, dst, count); + this->shadeSpanInternal<dstType, premul, kRepeat_TileMode>(x, y, dst, count, bias0, bias1); break; case kMirror_TileMode: - this->shadeSpanInternal<premul, kMirror_TileMode>(x, y, dst, count); + this->shadeSpanInternal<dstType, premul, kMirror_TileMode>(x, y, dst, count, bias0, bias1); break; } } -template<ApplyPremul premul, SkShader::TileMode tileMode> +template<typename dstType, ApplyPremul premul, SkShader::TileMode tileMode> void SkLinearGradient:: -LinearGradient4fContext::shadeSpanInternal(int x, int y, SkPM4f dst[], int count) const { +LinearGradient4fContext::shadeSpanInternal(int x, int y, dstType dst[], int count, + float bias0, float bias1) const { SkPoint pt; fDstToPosProc(fDstToPos, x + SK_ScalarHalf, @@ -179,12 +224,15 @@ LinearGradient4fContext::shadeSpanInternal(int x, int y, SkPM4f dst[], int count &pt); const SkScalar fx = pinFx<tileMode>(pt.x()); const SkScalar dx = fDstToPos.getScaleX(); - LinearIntervalProcessor<premul, tileMode> proc(fIntervals->begin(), - fIntervals->end() - 1, - this->findInterval(fx), - fx, - dx, - SkScalarNearlyZero(dx * count)); + LinearIntervalProcessor<dstType, premul, tileMode> proc(fIntervals->begin(), + fIntervals->end() - 1, + this->findInterval(fx), + fx, + dx, + SkScalarNearlyZero(dx * count)); + Sk4f bias4f0(bias0), + bias4f1(bias1); + while (count > 0) { // What we really want here is SkTPin(advance, 1, count) // but that's a significant perf hit for >> stops; investigate. @@ -199,18 +247,23 @@ LinearGradient4fContext::shadeSpanInternal(int x, int y, SkPM4f dst[], int count || (n == count && proc.currentRampIsZero())); if (proc.currentRampIsZero()) { - DstTraits<premul>::store(proc.currentColor(), dst, n); + DstTraits<dstType, premul>::store(proc.currentColor(), dst, n); } else { - ramp<premul>(proc.currentColor(), proc.currentColorGrad(), dst, n); + ramp<dstType, premul>(proc.currentColor(), proc.currentColorGrad(), dst, n, + bias4f0, bias4f1); } proc.advance(SkIntToScalar(n)); count -= n; dst += n; + + if (n & 1) { + SkTSwap(bias4f0, bias4f1); + } } } -template<ApplyPremul premul, SkShader::TileMode tileMode> +template<typename dstType, ApplyPremul premul, SkShader::TileMode tileMode> class SkLinearGradient:: LinearGradient4fContext::LinearIntervalProcessor { public: @@ -275,8 +328,8 @@ private: void compute_interval_props(SkScalar t) { SkASSERT(in_range(t, fInterval->fT0, fInterval->fT1)); - const Sk4f dc = DstTraits<premul>::load(fInterval->fCg); - fCc = DstTraits<premul>::load(fInterval->fCb) + dc * Sk4f(t); + const Sk4f dc = DstTraits<dstType, premul>::load(fInterval->fCg); + fCc = DstTraits<dstType, premul>::load(fInterval->fCb) + dc * Sk4f(t); fDcDx = dc * fDx; fZeroRamp = fIsVertical || (dc == 0).allTrue(); } @@ -295,8 +348,8 @@ private: // // Avg += C * (t1 - t0) // - const auto c = DstTraits<premul>::load(i->fCb) - + DstTraits<premul>::load(i->fCg) * (i->fT0 + i->fT1) * 0.5f; + const auto c = DstTraits<dstType, premul>::load(i->fCb) + + DstTraits<dstType, premul>::load(i->fCg) * (i->fT0 + i->fT1) * 0.5f; fCc = fCc + c * (i->fT1 - i->fT0); } } |