| /* |
| * 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 "SkTwoPointConicalGradient.h" |
| |
| #include "SkRasterPipeline.h" |
| #include "../../jumper/SkJumper.h" |
| |
| struct TwoPtRadialContext { |
| const TwoPtRadial& fRec; |
| float fRelX, fRelY; |
| const float fIncX, fIncY; |
| float fB; |
| const float fDB; |
| |
| TwoPtRadialContext(const TwoPtRadial& rec, SkScalar fx, SkScalar fy, |
| SkScalar dfx, SkScalar dfy); |
| SkFixed nextT(); |
| }; |
| |
| static int valid_divide(float numer, float denom, float* ratio) { |
| SkASSERT(ratio); |
| if (0 == denom) { |
| return 0; |
| } |
| *ratio = numer / denom; |
| return 1; |
| } |
| |
| // Return the number of distinct real roots, and write them into roots[] in |
| // ascending order |
| static int find_quad_roots(float A, float B, float C, float roots[2], bool descendingOrder = false) { |
| SkASSERT(roots); |
| |
| if (A == 0) { |
| return valid_divide(-C, B, roots); |
| } |
| |
| float R = B*B - 4*A*C; |
| if (R < 0) { |
| return 0; |
| } |
| R = sk_float_sqrt(R); |
| |
| #if 1 |
| float Q = B; |
| if (Q < 0) { |
| Q -= R; |
| } else { |
| Q += R; |
| } |
| #else |
| // on 10.6 this was much slower than the above branch :( |
| float Q = B + copysignf(R, B); |
| #endif |
| Q *= -0.5f; |
| if (0 == Q) { |
| roots[0] = 0; |
| return 1; |
| } |
| |
| float r0 = Q / A; |
| float r1 = C / Q; |
| roots[0] = r0 < r1 ? r0 : r1; |
| roots[1] = r0 > r1 ? r0 : r1; |
| if (descendingOrder) { |
| SkTSwap(roots[0], roots[1]); |
| } |
| return 2; |
| } |
| |
| static float lerp(float x, float dx, float t) { |
| return x + t * dx; |
| } |
| |
| static float sqr(float x) { return x * x; } |
| |
| void TwoPtRadial::init(const SkPoint& center0, SkScalar rad0, |
| const SkPoint& center1, SkScalar rad1, |
| bool flipped) { |
| fCenterX = SkScalarToFloat(center0.fX); |
| fCenterY = SkScalarToFloat(center0.fY); |
| fDCenterX = SkScalarToFloat(center1.fX) - fCenterX; |
| fDCenterY = SkScalarToFloat(center1.fY) - fCenterY; |
| fRadius = SkScalarToFloat(rad0); |
| fDRadius = SkScalarToFloat(rad1) - fRadius; |
| |
| fA = sqr(fDCenterX) + sqr(fDCenterY) - sqr(fDRadius); |
| fRadius2 = sqr(fRadius); |
| fRDR = fRadius * fDRadius; |
| |
| fFlipped = flipped; |
| } |
| |
| TwoPtRadialContext::TwoPtRadialContext(const TwoPtRadial& rec, SkScalar fx, SkScalar fy, |
| SkScalar dfx, SkScalar dfy) |
| : fRec(rec) |
| , fRelX(SkScalarToFloat(fx) - rec.fCenterX) |
| , fRelY(SkScalarToFloat(fy) - rec.fCenterY) |
| , fIncX(SkScalarToFloat(dfx)) |
| , fIncY(SkScalarToFloat(dfy)) |
| , fB(-2 * (rec.fDCenterX * fRelX + rec.fDCenterY * fRelY + rec.fRDR)) |
| , fDB(-2 * (rec.fDCenterX * fIncX + rec.fDCenterY * fIncY)) {} |
| |
| SkFixed TwoPtRadialContext::nextT() { |
| float roots[2]; |
| |
| float C = sqr(fRelX) + sqr(fRelY) - fRec.fRadius2; |
| int countRoots = find_quad_roots(fRec.fA, fB, C, roots, fRec.fFlipped); |
| |
| fRelX += fIncX; |
| fRelY += fIncY; |
| fB += fDB; |
| |
| if (0 == countRoots) { |
| return TwoPtRadial::kDontDrawT; |
| } |
| |
| // Prefer the bigger t value if both give a radius(t) > 0 |
| // find_quad_roots returns the values sorted, so we start with the last |
| float t = roots[countRoots - 1]; |
| float r = lerp(fRec.fRadius, fRec.fDRadius, t); |
| if (r < 0) { |
| t = roots[0]; // might be the same as roots[countRoots-1] |
| r = lerp(fRec.fRadius, fRec.fDRadius, t); |
| if (r < 0) { |
| return TwoPtRadial::kDontDrawT; |
| } |
| } |
| return SkFloatToFixed(t); |
| } |
| |
| typedef void (*TwoPointConicalProc)(TwoPtRadialContext* rec, SkPMColor* dstC, |
| const SkPMColor* cache, int toggle, int count); |
| |
| static void twopoint_clamp(TwoPtRadialContext* rec, SkPMColor* SK_RESTRICT dstC, |
| const SkPMColor* SK_RESTRICT cache, int toggle, |
| int count) { |
| for (; count > 0; --count) { |
| SkFixed t = rec->nextT(); |
| if (TwoPtRadial::DontDrawT(t)) { |
| *dstC++ = 0; |
| } else { |
| SkFixed index = SkClampMax(t, 0xFFFF); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[toggle + |
| (index >> SkGradientShaderBase::kCache32Shift)]; |
| } |
| toggle = next_dither_toggle(toggle); |
| } |
| } |
| |
| static void twopoint_repeat(TwoPtRadialContext* rec, SkPMColor* SK_RESTRICT dstC, |
| const SkPMColor* SK_RESTRICT cache, int toggle, |
| int count) { |
| for (; count > 0; --count) { |
| SkFixed t = rec->nextT(); |
| if (TwoPtRadial::DontDrawT(t)) { |
| *dstC++ = 0; |
| } else { |
| SkFixed index = repeat_tileproc(t); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[toggle + |
| (index >> SkGradientShaderBase::kCache32Shift)]; |
| } |
| toggle = next_dither_toggle(toggle); |
| } |
| } |
| |
| static void twopoint_mirror(TwoPtRadialContext* rec, SkPMColor* SK_RESTRICT dstC, |
| const SkPMColor* SK_RESTRICT cache, int toggle, |
| int count) { |
| for (; count > 0; --count) { |
| SkFixed t = rec->nextT(); |
| if (TwoPtRadial::DontDrawT(t)) { |
| *dstC++ = 0; |
| } else { |
| SkFixed index = mirror_tileproc(t); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[toggle + |
| (index >> SkGradientShaderBase::kCache32Shift)]; |
| } |
| toggle = next_dither_toggle(toggle); |
| } |
| } |
| |
| ///////////////////////////////////////////////////////////////////// |
| |
| SkTwoPointConicalGradient::SkTwoPointConicalGradient( |
| const SkPoint& start, SkScalar startRadius, |
| const SkPoint& end, SkScalar endRadius, |
| bool flippedGrad, const Descriptor& desc) |
| : SkGradientShaderBase(desc, SkMatrix::I()) |
| , fCenter1(start) |
| , fCenter2(end) |
| , fRadius1(startRadius) |
| , fRadius2(endRadius) |
| , fFlippedGrad(flippedGrad) |
| { |
| // this is degenerate, and should be caught by our caller |
| SkASSERT(fCenter1 != fCenter2 || fRadius1 != fRadius2); |
| fRec.init(fCenter1, fRadius1, fCenter2, fRadius2, fFlippedGrad); |
| } |
| |
| bool SkTwoPointConicalGradient::isOpaque() const { |
| // Because areas outside the cone are left untouched, we cannot treat the |
| // shader as opaque even if the gradient itself is opaque. |
| // TODO(junov): Compute whether the cone fills the plane crbug.com/222380 |
| return false; |
| } |
| |
| SkShaderBase::Context* SkTwoPointConicalGradient::onMakeContext( |
| const ContextRec& rec, SkArenaAlloc* alloc) const { |
| return CheckedMakeContext<TwoPointConicalGradientContext>(alloc, *this, rec); |
| } |
| |
| SkTwoPointConicalGradient::TwoPointConicalGradientContext::TwoPointConicalGradientContext( |
| const SkTwoPointConicalGradient& shader, const ContextRec& rec) |
| : INHERITED(shader, rec) |
| { |
| // in general, we might discard based on computed-radius, so clear |
| // this flag (todo: sometimes we can detect that we never discard...) |
| fFlags &= ~kOpaqueAlpha_Flag; |
| } |
| |
| void SkTwoPointConicalGradient::TwoPointConicalGradientContext::shadeSpan( |
| int x, int y, SkPMColor* dstCParam, int count) { |
| const SkTwoPointConicalGradient& twoPointConicalGradient = |
| static_cast<const SkTwoPointConicalGradient&>(fShader); |
| |
| int toggle = init_dither_toggle(x, y); |
| |
| SkASSERT(count > 0); |
| |
| SkPMColor* SK_RESTRICT dstC = dstCParam; |
| |
| SkMatrix::MapXYProc dstProc = fDstToIndexProc; |
| |
| const SkPMColor* SK_RESTRICT cache = fCache->getCache32(); |
| |
| TwoPointConicalProc shadeProc = twopoint_repeat; |
| if (SkShader::kClamp_TileMode == twoPointConicalGradient.fTileMode) { |
| shadeProc = twopoint_clamp; |
| } else if (SkShader::kMirror_TileMode == twoPointConicalGradient.fTileMode) { |
| shadeProc = twopoint_mirror; |
| } else { |
| SkASSERT(SkShader::kRepeat_TileMode == twoPointConicalGradient.fTileMode); |
| } |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) { |
| SkPoint srcPt; |
| dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf, |
| SkIntToScalar(y) + SK_ScalarHalf, &srcPt); |
| SkScalar dx, fx = srcPt.fX; |
| SkScalar dy, fy = srcPt.fY; |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) { |
| const auto step = fDstToIndex.fixedStepInX(SkIntToScalar(y)); |
| dx = step.fX; |
| dy = step.fY; |
| } else { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = fDstToIndex.getScaleX(); |
| dy = fDstToIndex.getSkewY(); |
| } |
| |
| TwoPtRadialContext rec(twoPointConicalGradient.fRec, fx, fy, dx, dy); |
| (*shadeProc)(&rec, dstC, cache, toggle, count); |
| } else { // perspective case |
| SkScalar dstX = SkIntToScalar(x) + SK_ScalarHalf; |
| SkScalar dstY = SkIntToScalar(y) + SK_ScalarHalf; |
| for (; count > 0; --count) { |
| SkPoint srcPt; |
| dstProc(fDstToIndex, dstX, dstY, &srcPt); |
| TwoPtRadialContext rec(twoPointConicalGradient.fRec, srcPt.fX, srcPt.fY, 0, 0); |
| (*shadeProc)(&rec, dstC, cache, toggle, 1); |
| |
| dstX += SK_Scalar1; |
| toggle = next_dither_toggle(toggle); |
| dstC += 1; |
| } |
| } |
| } |
| |
| // Returns the original non-sorted version of the gradient |
| SkShader::GradientType SkTwoPointConicalGradient::asAGradient( |
| GradientInfo* info) const { |
| if (info) { |
| commonAsAGradient(info, fFlippedGrad); |
| info->fPoint[0] = fCenter1; |
| info->fPoint[1] = fCenter2; |
| info->fRadius[0] = fRadius1; |
| info->fRadius[1] = fRadius2; |
| if (fFlippedGrad) { |
| SkTSwap(info->fPoint[0], info->fPoint[1]); |
| SkTSwap(info->fRadius[0], info->fRadius[1]); |
| } |
| } |
| return kConical_GradientType; |
| } |
| |
| sk_sp<SkFlattenable> SkTwoPointConicalGradient::CreateProc(SkReadBuffer& buffer) { |
| DescriptorScope desc; |
| if (!desc.unflatten(buffer)) { |
| return nullptr; |
| } |
| SkPoint c1 = buffer.readPoint(); |
| SkPoint c2 = buffer.readPoint(); |
| SkScalar r1 = buffer.readScalar(); |
| SkScalar r2 = buffer.readScalar(); |
| |
| if (buffer.readBool()) { // flipped |
| SkTSwap(c1, c2); |
| SkTSwap(r1, r2); |
| |
| SkColor4f* colors = desc.mutableColors(); |
| SkScalar* pos = desc.mutablePos(); |
| const int last = desc.fCount - 1; |
| const int half = desc.fCount >> 1; |
| for (int i = 0; i < half; ++i) { |
| SkTSwap(colors[i], colors[last - i]); |
| if (pos) { |
| SkScalar tmp = pos[i]; |
| pos[i] = SK_Scalar1 - pos[last - i]; |
| pos[last - i] = SK_Scalar1 - tmp; |
| } |
| } |
| if (pos) { |
| if (desc.fCount & 1) { |
| pos[half] = SK_Scalar1 - pos[half]; |
| } |
| } |
| } |
| |
| return SkGradientShader::MakeTwoPointConical(c1, r1, c2, r2, desc.fColors, |
| std::move(desc.fColorSpace), desc.fPos, |
| desc.fCount, desc.fTileMode, desc.fGradFlags, |
| desc.fLocalMatrix); |
| } |
| |
| void SkTwoPointConicalGradient::flatten(SkWriteBuffer& buffer) const { |
| this->INHERITED::flatten(buffer); |
| buffer.writePoint(fCenter1); |
| buffer.writePoint(fCenter2); |
| buffer.writeScalar(fRadius1); |
| buffer.writeScalar(fRadius2); |
| buffer.writeBool(fFlippedGrad); |
| } |
| |
| #if SK_SUPPORT_GPU |
| |
| #include "SkGr.h" |
| #include "SkTwoPointConicalGradient_gpu.h" |
| |
| sk_sp<GrFragmentProcessor> SkTwoPointConicalGradient::asFragmentProcessor( |
| const AsFPArgs& args) const { |
| SkASSERT(args.fContext); |
| SkASSERT(fPtsToUnit.isIdentity()); |
| sk_sp<GrColorSpaceXform> colorSpaceXform = GrColorSpaceXform::Make(fColorSpace.get(), |
| args.fDstColorSpace); |
| sk_sp<GrFragmentProcessor> inner(Gr2PtConicalGradientEffect::Make( |
| GrGradientEffect::CreateArgs(args.fContext, this, args.fLocalMatrix, fTileMode, |
| std::move(colorSpaceXform), SkToBool(args.fDstColorSpace)))); |
| if (!inner) { |
| return nullptr; |
| } |
| return GrFragmentProcessor::MulOutputByInputAlpha(std::move(inner)); |
| } |
| |
| #endif |
| |
| sk_sp<SkShader> SkTwoPointConicalGradient::onMakeColorSpace(SkColorSpaceXformer* xformer) const { |
| SkSTArray<8, SkColor> origColorsStorage(fColorCount); |
| SkSTArray<8, SkScalar> origPosStorage(fColorCount); |
| SkSTArray<8, SkColor> xformedColorsStorage(fColorCount); |
| SkColor* origColors = origColorsStorage.begin(); |
| SkScalar* origPos = fOrigPos ? origPosStorage.begin() : nullptr; |
| SkColor* xformedColors = xformedColorsStorage.begin(); |
| |
| // Flip if necessary |
| SkPoint center1 = fFlippedGrad ? fCenter2 : fCenter1; |
| SkPoint center2 = fFlippedGrad ? fCenter1 : fCenter2; |
| SkScalar radius1 = fFlippedGrad ? fRadius2 : fRadius1; |
| SkScalar radius2 = fFlippedGrad ? fRadius1 : fRadius2; |
| for (int i = 0; i < fColorCount; i++) { |
| origColors[i] = fFlippedGrad ? fOrigColors[fColorCount - i - 1] : fOrigColors[i]; |
| if (origPos) { |
| origPos[i] = fFlippedGrad ? 1.0f - fOrigPos[fColorCount - i - 1] : fOrigPos[i]; |
| } |
| } |
| |
| xformer->apply(xformedColors, origColors, fColorCount); |
| return SkGradientShader::MakeTwoPointConical(center1, radius1, center2, radius2, xformedColors, |
| origPos, fColorCount, fTileMode, fGradFlags, |
| &this->getLocalMatrix()); |
| } |
| |
| |
| #ifndef SK_IGNORE_TO_STRING |
| void SkTwoPointConicalGradient::toString(SkString* str) const { |
| str->append("SkTwoPointConicalGradient: ("); |
| |
| str->append("center1: ("); |
| str->appendScalar(fCenter1.fX); |
| str->append(", "); |
| str->appendScalar(fCenter1.fY); |
| str->append(") radius1: "); |
| str->appendScalar(fRadius1); |
| str->append(" "); |
| |
| str->append("center2: ("); |
| str->appendScalar(fCenter2.fX); |
| str->append(", "); |
| str->appendScalar(fCenter2.fY); |
| str->append(") radius2: "); |
| str->appendScalar(fRadius2); |
| str->append(" "); |
| |
| this->INHERITED::toString(str); |
| |
| str->append(")"); |
| } |
| #endif |
| |
| bool SkTwoPointConicalGradient::adjustMatrixAndAppendStages(SkArenaAlloc* alloc, |
| SkMatrix* matrix, |
| SkRasterPipeline* p, |
| SkRasterPipeline* postPipeline) const { |
| const auto dCenter = (fCenter1 - fCenter2).length(); |
| const auto dRadius = fRadius2 - fRadius1; |
| SkASSERT(dRadius >= 0); |
| |
| // When the two circles are concentric, we can pretend we're radial (with a tiny *twist). |
| if (SkScalarNearlyZero(dCenter)) { |
| matrix->postTranslate(-fCenter1.fX, -fCenter1.fY); |
| matrix->postScale(1 / fRadius2, 1 / fRadius2); |
| p->append(SkRasterPipeline::xy_to_radius); |
| |
| // Tiny twist: radial computes a t for [0, r2], but we want a t for [r1, r2]. |
| auto scale = fRadius2 / dRadius; |
| auto bias = -fRadius1 / dRadius; |
| |
| auto mad_matrix = SkMatrix::Concat(SkMatrix::MakeTrans(bias, 0), |
| SkMatrix::MakeScale(scale, 1)); |
| auto m = alloc->makeArrayDefault<float>(6); |
| SkAssertResult(mad_matrix.asAffine(m)); |
| p->append(SkRasterPipeline::matrix_2x3, m); |
| |
| return true; |
| } |
| |
| // To simplify the stage math, we transform the universe (translate/scale/rotate) |
| // such that fCenter1 -> (0, 0) and fCenter2 -> (1, 0). |
| SkMatrix map_to_unit_vector; |
| const SkPoint centers[2] = { fCenter1, fCenter2 }; |
| const SkPoint unitvec[2] = { {0, 0}, {1, 0} }; |
| SkAssertResult(map_to_unit_vector.setPolyToPoly(centers, unitvec, 2)); |
| matrix->postConcat(map_to_unit_vector); |
| |
| // Since we've squashed the centers into a unit vector, we must also scale |
| // all the coefficient variables by (1 / dCenter). |
| const auto coeffA = 1 - dRadius * dRadius / (dCenter * dCenter); |
| auto* ctx = alloc->make<SkJumper_2PtConicalCtx>(); |
| ctx->fCoeffA = coeffA; |
| ctx->fInvCoeffA = 1 / coeffA; |
| ctx->fR0 = fRadius1 / dCenter; |
| ctx->fDR = dRadius / dCenter; |
| |
| // Is the solver guaranteed to not produce degenerates? |
| bool isWellBehaved = true; |
| |
| if (SkScalarNearlyZero(coeffA)) { |
| // The focal point is on the edge of the end circle. |
| p->append(SkRasterPipeline::xy_to_2pt_conical_linear, ctx); |
| isWellBehaved = false; |
| } else { |
| if (dCenter + fRadius1 > fRadius2) { |
| // The focal point is outside the end circle. |
| |
| // We want the larger root, per spec: |
| // "For all values of ω where r(ω) > 0, starting with the value of ω nearest |
| // to positive infinity and ending with the value of ω nearest to negative |
| // infinity, draw the circumference of the circle with radius r(ω) at position |
| // (x(ω), y(ω)), with the color at ω, but only painting on the parts of the |
| // bitmap that have not yet been painted on by earlier circles in this step for |
| // this rendering of the gradient." |
| // (https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-createradialgradient) |
| p->append(fFlippedGrad ? SkRasterPipeline::xy_to_2pt_conical_quadratic_min |
| : SkRasterPipeline::xy_to_2pt_conical_quadratic_max, ctx); |
| isWellBehaved = false; |
| } else { |
| // The focal point is inside (well-behaved case). |
| p->append(SkRasterPipeline::xy_to_2pt_conical_quadratic_max, ctx); |
| } |
| } |
| |
| if (!isWellBehaved) { |
| p->append(SkRasterPipeline::mask_2pt_conical_degenerates, ctx); |
| postPipeline->append(SkRasterPipeline::apply_vector_mask, &ctx->fMask); |
| } |
| |
| return true; |
| } |
| |
| bool SkTwoPointConicalGradient::isRasterPipelineOnly() const { |
| #ifdef SK_SUPPORT_LEGACY_2PTCONICAL_GRADIENT |
| return false; |
| #else |
| return true; |
| #endif |
| } |