| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "src/shaders/gradients/SkLinearGradient.h" |
| |
| #include "include/core/SkColor.h" |
| #include "include/core/SkColorSpace.h" |
| #include "include/core/SkMatrix.h" |
| #include "include/core/SkRefCnt.h" |
| #include "include/core/SkScalar.h" |
| #include "include/core/SkShader.h" |
| #include "include/effects/SkGradientShader.h" |
| #include "include/private/base/SkFloatingPoint.h" |
| #include "include/private/base/SkTArray.h" |
| #include "src/core/SkReadBuffer.h" |
| #include "src/core/SkWriteBuffer.h" |
| #include "src/shaders/SkShaderBase.h" |
| |
| #include <cstdint> |
| #include <utility> |
| |
| class SkArenaAlloc; |
| class SkRasterPipeline; |
| enum class SkTileMode; |
| |
| static SkMatrix pts_to_unit_matrix(const SkPoint pts[2]) { |
| SkVector vec = pts[1] - pts[0]; |
| SkScalar mag = vec.length(); |
| SkScalar inv = mag ? SkScalarInvert(mag) : 0; |
| |
| vec.scale(inv); |
| SkMatrix matrix; |
| matrix.setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY); |
| matrix.postTranslate(-pts[0].fX, -pts[0].fY); |
| matrix.postScale(inv, inv); |
| return matrix; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| SkLinearGradient::SkLinearGradient(const SkPoint pts[2], const Descriptor& desc) |
| : SkGradientBaseShader(desc, pts_to_unit_matrix(pts)), fStart(pts[0]), fEnd(pts[1]) {} |
| |
| sk_sp<SkFlattenable> SkLinearGradient::CreateProc(SkReadBuffer& buffer) { |
| DescriptorScope desc; |
| SkMatrix legacyLocalMatrix, *lmPtr = nullptr; |
| if (!desc.unflatten(buffer, &legacyLocalMatrix)) { |
| return nullptr; |
| } |
| if (!legacyLocalMatrix.isIdentity()) { |
| lmPtr = &legacyLocalMatrix; |
| } |
| SkPoint pts[2]; |
| pts[0] = buffer.readPoint(); |
| pts[1] = buffer.readPoint(); |
| return SkGradientShader::MakeLinear(pts, |
| desc.fColors, |
| std::move(desc.fColorSpace), |
| desc.fPositions, |
| desc.fColorCount, |
| desc.fTileMode, |
| desc.fInterpolation, |
| lmPtr); |
| } |
| |
| void SkLinearGradient::flatten(SkWriteBuffer& buffer) const { |
| this->INHERITED::flatten(buffer); |
| buffer.writePoint(fStart); |
| buffer.writePoint(fEnd); |
| } |
| |
| void SkLinearGradient::appendGradientStages(SkArenaAlloc*, SkRasterPipeline*, |
| SkRasterPipeline*) const { |
| // No extra stage needed for linear gradients. |
| } |
| |
| SkShaderBase::GradientType SkLinearGradient::asGradient(GradientInfo* info, |
| SkMatrix* localMatrix) const { |
| if (info) { |
| commonAsAGradient(info); |
| info->fPoint[0] = fStart; |
| info->fPoint[1] = fEnd; |
| } |
| if (localMatrix) { |
| *localMatrix = SkMatrix::I(); |
| } |
| return GradientType::kLinear; |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeLinear(const SkPoint pts[2], |
| const SkColor4f colors[], |
| sk_sp<SkColorSpace> colorSpace, |
| const SkScalar pos[], |
| int colorCount, |
| SkTileMode mode, |
| const Interpolation& interpolation, |
| const SkMatrix* localMatrix) { |
| if (!pts || !SkIsFinite((pts[1] - pts[0]).length())) { |
| return nullptr; |
| } |
| if (!SkGradientBaseShader::ValidGradient(colors, colorCount, mode, interpolation)) { |
| return nullptr; |
| } |
| if (1 == colorCount) { |
| return SkShaders::Color(colors[0], std::move(colorSpace)); |
| } |
| if (localMatrix && !localMatrix->invert(nullptr)) { |
| return nullptr; |
| } |
| |
| if (SkScalarNearlyZero((pts[1] - pts[0]).length(), |
| SkGradientBaseShader::kDegenerateThreshold)) { |
| // Degenerate gradient, the only tricky complication is when in clamp mode, the limit of |
| // the gradient approaches two half planes of solid color (first and last). However, they |
| // are divided by the line perpendicular to the start and end point, which becomes undefined |
| // once start and end are exactly the same, so just use the end color for a stable solution. |
| return SkGradientBaseShader::MakeDegenerateGradient( |
| colors, pos, colorCount, std::move(colorSpace), mode); |
| } |
| |
| SkGradientBaseShader::Descriptor desc( |
| colors, std::move(colorSpace), pos, colorCount, mode, interpolation); |
| |
| sk_sp<SkShader> s = sk_make_sp<SkLinearGradient>(pts, desc); |
| return s->makeWithLocalMatrix(localMatrix ? *localMatrix : SkMatrix::I()); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeLinear(const SkPoint pts[2], |
| const SkColor colors[], |
| const SkScalar pos[], |
| int colorCount, |
| SkTileMode mode, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| SkColorConverter converter(colors, colorCount); |
| return MakeLinear(pts, converter.fColors4f.begin(), nullptr, pos, colorCount, mode, flags, |
| localMatrix); |
| } |
| |
| void SkRegisterLinearGradientShaderFlattenable() { |
| SK_REGISTER_FLATTENABLE(SkLinearGradient); |
| } |