| /* |
| * Copyright 2006 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <algorithm> |
| #include "include/core/SkMallocPixelRef.h" |
| #include "include/private/SkFloatBits.h" |
| #include "include/private/SkHalf.h" |
| #include "src/core/SkColorSpacePriv.h" |
| #include "src/core/SkConvertPixels.h" |
| #include "src/core/SkReadBuffer.h" |
| #include "src/core/SkWriteBuffer.h" |
| #include "src/shaders/gradients/Sk4fLinearGradient.h" |
| #include "src/shaders/gradients/SkGradientShaderPriv.h" |
| #include "src/shaders/gradients/SkLinearGradient.h" |
| #include "src/shaders/gradients/SkRadialGradient.h" |
| #include "src/shaders/gradients/SkSweepGradient.h" |
| #include "src/shaders/gradients/SkTwoPointConicalGradient.h" |
| |
| enum GradientSerializationFlags { |
| // Bits 29:31 used for various boolean flags |
| kHasPosition_GSF = 0x80000000, |
| kHasLocalMatrix_GSF = 0x40000000, |
| kHasColorSpace_GSF = 0x20000000, |
| |
| // Bits 12:28 unused |
| |
| // Bits 8:11 for fTileMode |
| kTileModeShift_GSF = 8, |
| kTileModeMask_GSF = 0xF, |
| |
| // Bits 0:7 for fGradFlags (note that kForce4fContext_PrivateFlag is 0x80) |
| kGradFlagsShift_GSF = 0, |
| kGradFlagsMask_GSF = 0xFF, |
| }; |
| |
| void SkGradientShaderBase::Descriptor::flatten(SkWriteBuffer& buffer) const { |
| uint32_t flags = 0; |
| if (fPos) { |
| flags |= kHasPosition_GSF; |
| } |
| if (fLocalMatrix) { |
| flags |= kHasLocalMatrix_GSF; |
| } |
| sk_sp<SkData> colorSpaceData = fColorSpace ? fColorSpace->serialize() : nullptr; |
| if (colorSpaceData) { |
| flags |= kHasColorSpace_GSF; |
| } |
| SkASSERT(static_cast<uint32_t>(fTileMode) <= kTileModeMask_GSF); |
| flags |= ((unsigned)fTileMode << kTileModeShift_GSF); |
| SkASSERT(fGradFlags <= kGradFlagsMask_GSF); |
| flags |= (fGradFlags << kGradFlagsShift_GSF); |
| |
| buffer.writeUInt(flags); |
| |
| buffer.writeColor4fArray(fColors, fCount); |
| if (colorSpaceData) { |
| buffer.writeDataAsByteArray(colorSpaceData.get()); |
| } |
| if (fPos) { |
| buffer.writeScalarArray(fPos, fCount); |
| } |
| if (fLocalMatrix) { |
| buffer.writeMatrix(*fLocalMatrix); |
| } |
| } |
| |
| template <int N, typename T, bool MEM_MOVE> |
| static bool validate_array(SkReadBuffer& buffer, size_t count, SkSTArray<N, T, MEM_MOVE>* array) { |
| if (!buffer.validateCanReadN<T>(count)) { |
| return false; |
| } |
| |
| array->resize_back(count); |
| return true; |
| } |
| |
| bool SkGradientShaderBase::DescriptorScope::unflatten(SkReadBuffer& buffer) { |
| // New gradient format. Includes floating point color, color space, densely packed flags |
| uint32_t flags = buffer.readUInt(); |
| |
| fTileMode = (SkTileMode)((flags >> kTileModeShift_GSF) & kTileModeMask_GSF); |
| fGradFlags = (flags >> kGradFlagsShift_GSF) & kGradFlagsMask_GSF; |
| |
| fCount = buffer.getArrayCount(); |
| |
| if (!(validate_array(buffer, fCount, &fColorStorage) && |
| buffer.readColor4fArray(fColorStorage.begin(), fCount))) { |
| return false; |
| } |
| fColors = fColorStorage.begin(); |
| |
| if (SkToBool(flags & kHasColorSpace_GSF)) { |
| sk_sp<SkData> data = buffer.readByteArrayAsData(); |
| fColorSpace = data ? SkColorSpace::Deserialize(data->data(), data->size()) : nullptr; |
| } else { |
| fColorSpace = nullptr; |
| } |
| if (SkToBool(flags & kHasPosition_GSF)) { |
| if (!(validate_array(buffer, fCount, &fPosStorage) && |
| buffer.readScalarArray(fPosStorage.begin(), fCount))) { |
| return false; |
| } |
| fPos = fPosStorage.begin(); |
| } else { |
| fPos = nullptr; |
| } |
| if (SkToBool(flags & kHasLocalMatrix_GSF)) { |
| fLocalMatrix = &fLocalMatrixStorage; |
| buffer.readMatrix(&fLocalMatrixStorage); |
| } else { |
| fLocalMatrix = nullptr; |
| } |
| return buffer.isValid(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////////////////// |
| |
| SkGradientShaderBase::SkGradientShaderBase(const Descriptor& desc, const SkMatrix& ptsToUnit) |
| : INHERITED(desc.fLocalMatrix) |
| , fPtsToUnit(ptsToUnit) |
| , fColorSpace(desc.fColorSpace ? desc.fColorSpace : SkColorSpace::MakeSRGB()) |
| , fColorsAreOpaque(true) |
| { |
| fPtsToUnit.getType(); // Precache so reads are threadsafe. |
| SkASSERT(desc.fCount > 1); |
| |
| fGradFlags = static_cast<uint8_t>(desc.fGradFlags); |
| |
| SkASSERT((unsigned)desc.fTileMode < kSkTileModeCount); |
| fTileMode = desc.fTileMode; |
| |
| /* Note: we let the caller skip the first and/or last position. |
| i.e. pos[0] = 0.3, pos[1] = 0.7 |
| In these cases, we insert dummy entries to ensure that the final data |
| will be bracketed by [0, 1]. |
| i.e. our_pos[0] = 0, our_pos[1] = 0.3, our_pos[2] = 0.7, our_pos[3] = 1 |
| |
| Thus colorCount (the caller's value, and fColorCount (our value) may |
| differ by up to 2. In the above example: |
| colorCount = 2 |
| fColorCount = 4 |
| */ |
| fColorCount = desc.fCount; |
| // check if we need to add in dummy start and/or end position/colors |
| bool dummyFirst = false; |
| bool dummyLast = false; |
| if (desc.fPos) { |
| dummyFirst = desc.fPos[0] != 0; |
| dummyLast = desc.fPos[desc.fCount - 1] != SK_Scalar1; |
| fColorCount += dummyFirst + dummyLast; |
| } |
| |
| size_t storageSize = fColorCount * (sizeof(SkColor4f) + (desc.fPos ? sizeof(SkScalar) : 0)); |
| fOrigColors4f = reinterpret_cast<SkColor4f*>(fStorage.reset(storageSize)); |
| fOrigPos = desc.fPos ? reinterpret_cast<SkScalar*>(fOrigColors4f + fColorCount) |
| : nullptr; |
| |
| // Now copy over the colors, adding the dummies as needed |
| SkColor4f* origColors = fOrigColors4f; |
| if (dummyFirst) { |
| *origColors++ = desc.fColors[0]; |
| } |
| for (int i = 0; i < desc.fCount; ++i) { |
| origColors[i] = desc.fColors[i]; |
| fColorsAreOpaque = fColorsAreOpaque && (desc.fColors[i].fA == 1); |
| } |
| if (dummyLast) { |
| origColors += desc.fCount; |
| *origColors = desc.fColors[desc.fCount - 1]; |
| } |
| |
| if (desc.fPos) { |
| SkScalar prev = 0; |
| SkScalar* origPosPtr = fOrigPos; |
| *origPosPtr++ = prev; // force the first pos to 0 |
| |
| int startIndex = dummyFirst ? 0 : 1; |
| int count = desc.fCount + dummyLast; |
| |
| bool uniformStops = true; |
| const SkScalar uniformStep = desc.fPos[startIndex] - prev; |
| for (int i = startIndex; i < count; i++) { |
| // Pin the last value to 1.0, and make sure pos is monotonic. |
| auto curr = (i == desc.fCount) ? 1 : SkScalarPin(desc.fPos[i], prev, 1); |
| uniformStops &= SkScalarNearlyEqual(uniformStep, curr - prev); |
| |
| *origPosPtr++ = prev = curr; |
| } |
| |
| // If the stops are uniform, treat them as implicit. |
| if (uniformStops) { |
| fOrigPos = nullptr; |
| } |
| } |
| } |
| |
| SkGradientShaderBase::~SkGradientShaderBase() {} |
| |
| void SkGradientShaderBase::flatten(SkWriteBuffer& buffer) const { |
| Descriptor desc; |
| desc.fColors = fOrigColors4f; |
| desc.fColorSpace = fColorSpace; |
| desc.fPos = fOrigPos; |
| desc.fCount = fColorCount; |
| desc.fTileMode = fTileMode; |
| desc.fGradFlags = fGradFlags; |
| |
| const SkMatrix& m = this->getLocalMatrix(); |
| desc.fLocalMatrix = m.isIdentity() ? nullptr : &m; |
| desc.flatten(buffer); |
| } |
| |
| static void add_stop_color(SkRasterPipeline_GradientCtx* ctx, size_t stop, SkPMColor4f Fs, SkPMColor4f Bs) { |
| (ctx->fs[0])[stop] = Fs.fR; |
| (ctx->fs[1])[stop] = Fs.fG; |
| (ctx->fs[2])[stop] = Fs.fB; |
| (ctx->fs[3])[stop] = Fs.fA; |
| (ctx->bs[0])[stop] = Bs.fR; |
| (ctx->bs[1])[stop] = Bs.fG; |
| (ctx->bs[2])[stop] = Bs.fB; |
| (ctx->bs[3])[stop] = Bs.fA; |
| } |
| |
| static void add_const_color(SkRasterPipeline_GradientCtx* ctx, size_t stop, SkPMColor4f color) { |
| add_stop_color(ctx, stop, { 0, 0, 0, 0 }, color); |
| } |
| |
| // Calculate a factor F and a bias B so that color = F*t + B when t is in range of |
| // the stop. Assume that the distance between stops is 1/gapCount. |
| static void init_stop_evenly( |
| SkRasterPipeline_GradientCtx* ctx, float gapCount, size_t stop, SkPMColor4f c_l, SkPMColor4f c_r) { |
| // Clankium's GCC 4.9 targeting ARMv7 is barfing when we use Sk4f math here, so go scalar... |
| SkPMColor4f Fs = { |
| (c_r.fR - c_l.fR) * gapCount, |
| (c_r.fG - c_l.fG) * gapCount, |
| (c_r.fB - c_l.fB) * gapCount, |
| (c_r.fA - c_l.fA) * gapCount, |
| }; |
| SkPMColor4f Bs = { |
| c_l.fR - Fs.fR*(stop/gapCount), |
| c_l.fG - Fs.fG*(stop/gapCount), |
| c_l.fB - Fs.fB*(stop/gapCount), |
| c_l.fA - Fs.fA*(stop/gapCount), |
| }; |
| add_stop_color(ctx, stop, Fs, Bs); |
| } |
| |
| // For each stop we calculate a bias B and a scale factor F, such that |
| // for any t between stops n and n+1, the color we want is B[n] + F[n]*t. |
| static void init_stop_pos( |
| SkRasterPipeline_GradientCtx* ctx, size_t stop, float t_l, float t_r, SkPMColor4f c_l, SkPMColor4f c_r) { |
| // See note about Clankium's old compiler in init_stop_evenly(). |
| SkPMColor4f Fs = { |
| (c_r.fR - c_l.fR) / (t_r - t_l), |
| (c_r.fG - c_l.fG) / (t_r - t_l), |
| (c_r.fB - c_l.fB) / (t_r - t_l), |
| (c_r.fA - c_l.fA) / (t_r - t_l), |
| }; |
| SkPMColor4f Bs = { |
| c_l.fR - Fs.fR*t_l, |
| c_l.fG - Fs.fG*t_l, |
| c_l.fB - Fs.fB*t_l, |
| c_l.fA - Fs.fA*t_l, |
| }; |
| ctx->ts[stop] = t_l; |
| add_stop_color(ctx, stop, Fs, Bs); |
| } |
| |
| bool SkGradientShaderBase::onAppendStages(const SkStageRec& rec) const { |
| SkRasterPipeline* p = rec.fPipeline; |
| SkArenaAlloc* alloc = rec.fAlloc; |
| SkRasterPipeline_DecalTileCtx* decal_ctx = nullptr; |
| |
| SkMatrix matrix; |
| if (!this->computeTotalInverse(rec.fCTM, rec.fLocalM, &matrix)) { |
| return false; |
| } |
| matrix.postConcat(fPtsToUnit); |
| |
| SkRasterPipeline_<256> postPipeline; |
| |
| p->append(SkRasterPipeline::seed_shader); |
| p->append_matrix(alloc, matrix); |
| this->appendGradientStages(alloc, p, &postPipeline); |
| |
| switch(fTileMode) { |
| case SkTileMode::kMirror: p->append(SkRasterPipeline::mirror_x_1); break; |
| case SkTileMode::kRepeat: p->append(SkRasterPipeline::repeat_x_1); break; |
| case SkTileMode::kDecal: |
| decal_ctx = alloc->make<SkRasterPipeline_DecalTileCtx>(); |
| decal_ctx->limit_x = SkBits2Float(SkFloat2Bits(1.0f) + 1); |
| // reuse mask + limit_x stage, or create a custom decal_1 that just stores the mask |
| p->append(SkRasterPipeline::decal_x, decal_ctx); |
| // fall-through to clamp |
| case SkTileMode::kClamp: |
| if (!fOrigPos) { |
| // We clamp only when the stops are evenly spaced. |
| // If not, there may be hard stops, and clamping ruins hard stops at 0 and/or 1. |
| // In that case, we must make sure we're using the general "gradient" stage, |
| // which is the only stage that will correctly handle unclamped t. |
| p->append(SkRasterPipeline::clamp_x_1); |
| } |
| break; |
| } |
| |
| const bool premulGrad = fGradFlags & SkGradientShader::kInterpolateColorsInPremul_Flag; |
| |
| // Transform all of the colors to destination color space |
| SkColor4fXformer xformedColors(fOrigColors4f, fColorCount, fColorSpace.get(), rec.fDstCS); |
| |
| auto prepareColor = [premulGrad, &xformedColors](int i) { |
| SkColor4f c = xformedColors.fColors[i]; |
| return premulGrad ? c.premul() |
| : SkPMColor4f{ c.fR, c.fG, c.fB, c.fA }; |
| }; |
| |
| // The two-stop case with stops at 0 and 1. |
| if (fColorCount == 2 && fOrigPos == nullptr) { |
| const SkPMColor4f c_l = prepareColor(0), |
| c_r = prepareColor(1); |
| |
| // See F and B below. |
| auto ctx = alloc->make<SkRasterPipeline_EvenlySpaced2StopGradientCtx>(); |
| (Sk4f::Load(c_r.vec()) - Sk4f::Load(c_l.vec())).store(ctx->f); |
| ( Sk4f::Load(c_l.vec())).store(ctx->b); |
| ctx->interpolatedInPremul = premulGrad; |
| |
| p->append(SkRasterPipeline::evenly_spaced_2_stop_gradient, ctx); |
| } else { |
| auto* ctx = alloc->make<SkRasterPipeline_GradientCtx>(); |
| ctx->interpolatedInPremul = premulGrad; |
| |
| // Note: In order to handle clamps in search, the search assumes a stop conceptully placed |
| // at -inf. Therefore, the max number of stops is fColorCount+1. |
| for (int i = 0; i < 4; i++) { |
| // Allocate at least at for the AVX2 gather from a YMM register. |
| ctx->fs[i] = alloc->makeArray<float>(std::max(fColorCount+1, 8)); |
| ctx->bs[i] = alloc->makeArray<float>(std::max(fColorCount+1, 8)); |
| } |
| |
| if (fOrigPos == nullptr) { |
| // Handle evenly distributed stops. |
| |
| size_t stopCount = fColorCount; |
| float gapCount = stopCount - 1; |
| |
| SkPMColor4f c_l = prepareColor(0); |
| for (size_t i = 0; i < stopCount - 1; i++) { |
| SkPMColor4f c_r = prepareColor(i + 1); |
| init_stop_evenly(ctx, gapCount, i, c_l, c_r); |
| c_l = c_r; |
| } |
| add_const_color(ctx, stopCount - 1, c_l); |
| |
| ctx->stopCount = stopCount; |
| p->append(SkRasterPipeline::evenly_spaced_gradient, ctx); |
| } else { |
| // Handle arbitrary stops. |
| |
| ctx->ts = alloc->makeArray<float>(fColorCount+1); |
| |
| // Remove the dummy stops inserted by SkGradientShaderBase::SkGradientShaderBase |
| // because they are naturally handled by the search method. |
| int firstStop; |
| int lastStop; |
| if (fColorCount > 2) { |
| firstStop = fOrigColors4f[0] != fOrigColors4f[1] ? 0 : 1; |
| lastStop = fOrigColors4f[fColorCount - 2] != fOrigColors4f[fColorCount - 1] |
| ? fColorCount - 1 : fColorCount - 2; |
| } else { |
| firstStop = 0; |
| lastStop = 1; |
| } |
| |
| size_t stopCount = 0; |
| float t_l = fOrigPos[firstStop]; |
| SkPMColor4f c_l = prepareColor(firstStop); |
| add_const_color(ctx, stopCount++, c_l); |
| // N.B. lastStop is the index of the last stop, not one after. |
| for (int i = firstStop; i < lastStop; i++) { |
| float t_r = fOrigPos[i + 1]; |
| SkPMColor4f c_r = prepareColor(i + 1); |
| SkASSERT(t_l <= t_r); |
| if (t_l < t_r) { |
| init_stop_pos(ctx, stopCount, t_l, t_r, c_l, c_r); |
| stopCount += 1; |
| } |
| t_l = t_r; |
| c_l = c_r; |
| } |
| |
| ctx->ts[stopCount] = t_l; |
| add_const_color(ctx, stopCount++, c_l); |
| |
| ctx->stopCount = stopCount; |
| p->append(SkRasterPipeline::gradient, ctx); |
| } |
| } |
| |
| if (decal_ctx) { |
| p->append(SkRasterPipeline::check_decal_mask, decal_ctx); |
| } |
| |
| if (!premulGrad && !this->colorsAreOpaque()) { |
| p->append(SkRasterPipeline::premul); |
| } |
| |
| p->extend(postPipeline); |
| |
| return true; |
| } |
| |
| |
| bool SkGradientShaderBase::isOpaque() const { |
| return fColorsAreOpaque && (this->getTileMode() != SkTileMode::kDecal); |
| } |
| |
| static unsigned rounded_divide(unsigned numer, unsigned denom) { |
| return (numer + (denom >> 1)) / denom; |
| } |
| |
| bool SkGradientShaderBase::onAsLuminanceColor(SkColor* lum) const { |
| // we just compute an average color. |
| // possibly we could weight this based on the proportional width for each color |
| // assuming they are not evenly distributed in the fPos array. |
| int r = 0; |
| int g = 0; |
| int b = 0; |
| const int n = fColorCount; |
| // TODO: use linear colors? |
| for (int i = 0; i < n; ++i) { |
| SkColor c = this->getLegacyColor(i); |
| r += SkColorGetR(c); |
| g += SkColorGetG(c); |
| b += SkColorGetB(c); |
| } |
| *lum = SkColorSetRGB(rounded_divide(r, n), rounded_divide(g, n), rounded_divide(b, n)); |
| return true; |
| } |
| |
| SkColor4fXformer::SkColor4fXformer(const SkColor4f* colors, int colorCount, |
| SkColorSpace* src, SkColorSpace* dst) { |
| fColors = colors; |
| |
| if (dst && !SkColorSpace::Equals(src, dst)) { |
| fStorage.reset(colorCount); |
| |
| auto info = SkImageInfo::Make(colorCount,1, kRGBA_F32_SkColorType, kUnpremul_SkAlphaType); |
| |
| SkConvertPixels(info.makeColorSpace(sk_ref_sp(dst)), fStorage.begin(), info.minRowBytes(), |
| info.makeColorSpace(sk_ref_sp(src)), fColors , info.minRowBytes()); |
| |
| fColors = fStorage.begin(); |
| } |
| } |
| |
| void SkGradientShaderBase::commonAsAGradient(GradientInfo* info) const { |
| if (info) { |
| if (info->fColorCount >= fColorCount) { |
| if (info->fColors) { |
| for (int i = 0; i < fColorCount; ++i) { |
| info->fColors[i] = this->getLegacyColor(i); |
| } |
| } |
| if (info->fColorOffsets) { |
| for (int i = 0; i < fColorCount; ++i) { |
| info->fColorOffsets[i] = this->getPos(i); |
| } |
| } |
| } |
| info->fColorCount = fColorCount; |
| info->fTileMode = fTileMode; |
| info->fGradientFlags = fGradFlags; |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| // Return true if these parameters are valid/legal/safe to construct a gradient |
| // |
| static bool valid_grad(const SkColor4f colors[], const SkScalar pos[], int count, |
| SkTileMode tileMode) { |
| return nullptr != colors && count >= 1 && (unsigned)tileMode < kSkTileModeCount; |
| } |
| |
| static void desc_init(SkGradientShaderBase::Descriptor* desc, |
| const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace, |
| const SkScalar pos[], int colorCount, |
| SkTileMode mode, uint32_t flags, const SkMatrix* localMatrix) { |
| SkASSERT(colorCount > 1); |
| |
| desc->fColors = colors; |
| desc->fColorSpace = std::move(colorSpace); |
| desc->fPos = pos; |
| desc->fCount = colorCount; |
| desc->fTileMode = mode; |
| desc->fGradFlags = flags; |
| desc->fLocalMatrix = localMatrix; |
| } |
| |
| static SkColor4f average_gradient_color(const SkColor4f colors[], const SkScalar pos[], |
| int colorCount) { |
| // The gradient is a piecewise linear interpolation between colors. For a given interval, |
| // the integral between the two endpoints is 0.5 * (ci + cj) * (pj - pi), which provides that |
| // intervals average color. The overall average color is thus the sum of each piece. The thing |
| // to keep in mind is that the provided gradient definition may implicitly use p=0 and p=1. |
| Sk4f blend(0.0); |
| // Bake 1/(colorCount - 1) uniform stop difference into this scale factor |
| SkScalar wScale = pos ? 0.5 : 0.5 / (colorCount - 1); |
| for (int i = 0; i < colorCount - 1; ++i) { |
| // Calculate the average color for the interval between pos(i) and pos(i+1) |
| Sk4f c0 = Sk4f::Load(&colors[i]); |
| Sk4f c1 = Sk4f::Load(&colors[i + 1]); |
| // when pos == null, there are colorCount uniformly distributed stops, going from 0 to 1, |
| // so pos[i + 1] - pos[i] = 1/(colorCount-1) |
| SkScalar w = pos ? (pos[i + 1] - pos[i]) : SK_Scalar1; |
| blend += wScale * w * (c1 + c0); |
| } |
| |
| // Now account for any implicit intervals at the start or end of the stop definitions |
| if (pos) { |
| if (pos[0] > 0.0) { |
| // The first color is fixed between p = 0 to pos[0], so 0.5 * (ci + cj) * (pj - pi) |
| // becomes 0.5 * (c + c) * (pj - 0) = c * pj |
| Sk4f c = Sk4f::Load(&colors[0]); |
| blend += pos[0] * c; |
| } |
| if (pos[colorCount - 1] < SK_Scalar1) { |
| // The last color is fixed between pos[n-1] to p = 1, so 0.5 * (ci + cj) * (pj - pi) |
| // becomes 0.5 * (c + c) * (1 - pi) = c * (1 - pi) |
| Sk4f c = Sk4f::Load(&colors[colorCount - 1]); |
| blend += (1 - pos[colorCount - 1]) * c; |
| } |
| } |
| |
| SkColor4f avg; |
| blend.store(&avg); |
| return avg; |
| } |
| |
| // The default SkScalarNearlyZero threshold of .0024 is too big and causes regressions for svg |
| // gradients defined in the wild. |
| static constexpr SkScalar kDegenerateThreshold = SK_Scalar1 / (1 << 15); |
| |
| // Except for special circumstances of clamped gradients, every gradient shape--when degenerate-- |
| // can be mapped to the same fallbacks. The specific shape factories must account for special |
| // clamped conditions separately, this will always return the last color for clamped gradients. |
| static sk_sp<SkShader> make_degenerate_gradient(const SkColor4f colors[], const SkScalar pos[], |
| int colorCount, sk_sp<SkColorSpace> colorSpace, |
| SkTileMode mode) { |
| switch(mode) { |
| case SkTileMode::kDecal: |
| // normally this would reject the area outside of the interpolation region, so since |
| // inside region is empty when the radii are equal, the entire draw region is empty |
| return SkShaders::Empty(); |
| case SkTileMode::kRepeat: |
| case SkTileMode::kMirror: |
| // repeat and mirror are treated the same: the border colors are never visible, |
| // but approximate the final color as infinite repetitions of the colors, so |
| // it can be represented as the average color of the gradient. |
| return SkShaders::Color( |
| average_gradient_color(colors, pos, colorCount), std::move(colorSpace)); |
| case SkTileMode::kClamp: |
| // Depending on how the gradient shape degenerates, there may be a more specialized |
| // fallback representation for the factories to use, but this is a reasonable default. |
| return SkShaders::Color(colors[colorCount - 1], std::move(colorSpace)); |
| } |
| SkDEBUGFAIL("Should not be reached"); |
| return nullptr; |
| } |
| |
| // assumes colors is SkColor4f* and pos is SkScalar* |
| #define EXPAND_1_COLOR(count) \ |
| SkColor4f tmp[2]; \ |
| do { \ |
| if (1 == count) { \ |
| tmp[0] = tmp[1] = colors[0]; \ |
| colors = tmp; \ |
| pos = nullptr; \ |
| count = 2; \ |
| } \ |
| } while (0) |
| |
| struct ColorStopOptimizer { |
| ColorStopOptimizer(const SkColor4f* colors, const SkScalar* pos, int count, SkTileMode mode) |
| : fColors(colors) |
| , fPos(pos) |
| , fCount(count) { |
| |
| if (!pos || count != 3) { |
| return; |
| } |
| |
| if (SkScalarNearlyEqual(pos[0], 0.0f) && |
| SkScalarNearlyEqual(pos[1], 0.0f) && |
| SkScalarNearlyEqual(pos[2], 1.0f)) { |
| |
| if (SkTileMode::kRepeat == mode || SkTileMode::kMirror == mode || |
| colors[0] == colors[1]) { |
| |
| // Ignore the leftmost color/pos. |
| fColors += 1; |
| fPos += 1; |
| fCount = 2; |
| } |
| } else if (SkScalarNearlyEqual(pos[0], 0.0f) && |
| SkScalarNearlyEqual(pos[1], 1.0f) && |
| SkScalarNearlyEqual(pos[2], 1.0f)) { |
| |
| if (SkTileMode::kRepeat == mode || SkTileMode::kMirror == mode || |
| colors[1] == colors[2]) { |
| |
| // Ignore the rightmost color/pos. |
| fCount = 2; |
| } |
| } |
| } |
| |
| const SkColor4f* fColors; |
| const SkScalar* fPos; |
| int fCount; |
| }; |
| |
| struct ColorConverter { |
| ColorConverter(const SkColor* colors, int count) { |
| const float ONE_OVER_255 = 1.f / 255; |
| for (int i = 0; i < count; ++i) { |
| fColors4f.push_back({ |
| SkColorGetR(colors[i]) * ONE_OVER_255, |
| SkColorGetG(colors[i]) * ONE_OVER_255, |
| SkColorGetB(colors[i]) * ONE_OVER_255, |
| SkColorGetA(colors[i]) * ONE_OVER_255 }); |
| } |
| } |
| |
| SkSTArray<2, SkColor4f, true> fColors4f; |
| }; |
| |
| 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) { |
| ColorConverter converter(colors, colorCount); |
| return MakeLinear(pts, converter.fColors4f.begin(), nullptr, pos, colorCount, mode, flags, |
| localMatrix); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeLinear(const SkPoint pts[2], |
| const SkColor4f colors[], |
| sk_sp<SkColorSpace> colorSpace, |
| const SkScalar pos[], int colorCount, |
| SkTileMode mode, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| if (!pts || !SkScalarIsFinite((pts[1] - pts[0]).length())) { |
| return nullptr; |
| } |
| if (!valid_grad(colors, pos, colorCount, mode)) { |
| 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(), 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 make_degenerate_gradient(colors, pos, colorCount, std::move(colorSpace), mode); |
| } |
| |
| ColorStopOptimizer opt(colors, pos, colorCount, mode); |
| |
| SkGradientShaderBase::Descriptor desc; |
| desc_init(&desc, opt.fColors, std::move(colorSpace), opt.fPos, opt.fCount, mode, flags, |
| localMatrix); |
| return sk_make_sp<SkLinearGradient>(pts, desc); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeRadial(const SkPoint& center, SkScalar radius, |
| const SkColor colors[], |
| const SkScalar pos[], int colorCount, |
| SkTileMode mode, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| ColorConverter converter(colors, colorCount); |
| return MakeRadial(center, radius, converter.fColors4f.begin(), nullptr, pos, colorCount, mode, |
| flags, localMatrix); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeRadial(const SkPoint& center, SkScalar radius, |
| const SkColor4f colors[], |
| sk_sp<SkColorSpace> colorSpace, |
| const SkScalar pos[], int colorCount, |
| SkTileMode mode, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| if (radius < 0) { |
| return nullptr; |
| } |
| if (!valid_grad(colors, pos, colorCount, mode)) { |
| return nullptr; |
| } |
| if (1 == colorCount) { |
| return SkShaders::Color(colors[0], std::move(colorSpace)); |
| } |
| if (localMatrix && !localMatrix->invert(nullptr)) { |
| return nullptr; |
| } |
| |
| if (SkScalarNearlyZero(radius, kDegenerateThreshold)) { |
| // Degenerate gradient optimization, and no special logic needed for clamped radial gradient |
| return make_degenerate_gradient(colors, pos, colorCount, std::move(colorSpace), mode); |
| } |
| |
| ColorStopOptimizer opt(colors, pos, colorCount, mode); |
| |
| SkGradientShaderBase::Descriptor desc; |
| desc_init(&desc, opt.fColors, std::move(colorSpace), opt.fPos, opt.fCount, mode, flags, |
| localMatrix); |
| return sk_make_sp<SkRadialGradient>(center, radius, desc); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeTwoPointConical(const SkPoint& start, |
| SkScalar startRadius, |
| const SkPoint& end, |
| SkScalar endRadius, |
| const SkColor colors[], |
| const SkScalar pos[], |
| int colorCount, |
| SkTileMode mode, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| ColorConverter converter(colors, colorCount); |
| return MakeTwoPointConical(start, startRadius, end, endRadius, converter.fColors4f.begin(), |
| nullptr, pos, colorCount, mode, flags, localMatrix); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeTwoPointConical(const SkPoint& start, |
| SkScalar startRadius, |
| const SkPoint& end, |
| SkScalar endRadius, |
| const SkColor4f colors[], |
| sk_sp<SkColorSpace> colorSpace, |
| const SkScalar pos[], |
| int colorCount, |
| SkTileMode mode, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| if (startRadius < 0 || endRadius < 0) { |
| return nullptr; |
| } |
| if (!valid_grad(colors, pos, colorCount, mode)) { |
| return nullptr; |
| } |
| if (SkScalarNearlyZero((start - end).length(), kDegenerateThreshold)) { |
| // If the center positions are the same, then the gradient is the radial variant of a 2 pt |
| // conical gradient, an actual radial gradient (startRadius == 0), or it is fully degenerate |
| // (startRadius == endRadius). |
| if (SkScalarNearlyEqual(startRadius, endRadius, kDegenerateThreshold)) { |
| // Degenerate case, where the interpolation region area approaches zero. The proper |
| // behavior depends on the tile mode, which is consistent with the default degenerate |
| // gradient behavior, except when mode = clamp and the radii > 0. |
| if (mode == SkTileMode::kClamp && endRadius > kDegenerateThreshold) { |
| // The interpolation region becomes an infinitely thin ring at the radius, so the |
| // final gradient will be the first color repeated from p=0 to 1, and then a hard |
| // stop switching to the last color at p=1. |
| static constexpr SkScalar circlePos[3] = {0, 1, 1}; |
| SkColor4f reColors[3] = {colors[0], colors[0], colors[colorCount - 1]}; |
| return MakeRadial(start, endRadius, reColors, std::move(colorSpace), |
| circlePos, 3, mode, flags, localMatrix); |
| } else { |
| // Otherwise use the default degenerate case |
| return make_degenerate_gradient( |
| colors, pos, colorCount, std::move(colorSpace), mode); |
| } |
| } else if (SkScalarNearlyZero(startRadius, kDegenerateThreshold)) { |
| // We can treat this gradient as radial, which is faster. If we got here, we know |
| // that endRadius is not equal to 0, so this produces a meaningful gradient |
| return MakeRadial(start, endRadius, colors, std::move(colorSpace), pos, colorCount, |
| mode, flags, localMatrix); |
| } |
| // Else it's the 2pt conical radial variant with no degenerate radii, so fall through to the |
| // regular 2pt constructor. |
| } |
| |
| if (localMatrix && !localMatrix->invert(nullptr)) { |
| return nullptr; |
| } |
| EXPAND_1_COLOR(colorCount); |
| |
| ColorStopOptimizer opt(colors, pos, colorCount, mode); |
| |
| SkGradientShaderBase::Descriptor desc; |
| desc_init(&desc, opt.fColors, std::move(colorSpace), opt.fPos, opt.fCount, mode, flags, |
| localMatrix); |
| return SkTwoPointConicalGradient::Create(start, startRadius, end, endRadius, desc); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeSweep(SkScalar cx, SkScalar cy, |
| const SkColor colors[], |
| const SkScalar pos[], |
| int colorCount, |
| SkTileMode mode, |
| SkScalar startAngle, |
| SkScalar endAngle, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| ColorConverter converter(colors, colorCount); |
| return MakeSweep(cx, cy, converter.fColors4f.begin(), nullptr, pos, colorCount, |
| mode, startAngle, endAngle, flags, localMatrix); |
| } |
| |
| sk_sp<SkShader> SkGradientShader::MakeSweep(SkScalar cx, SkScalar cy, |
| const SkColor4f colors[], |
| sk_sp<SkColorSpace> colorSpace, |
| const SkScalar pos[], |
| int colorCount, |
| SkTileMode mode, |
| SkScalar startAngle, |
| SkScalar endAngle, |
| uint32_t flags, |
| const SkMatrix* localMatrix) { |
| if (!valid_grad(colors, pos, colorCount, mode)) { |
| return nullptr; |
| } |
| if (1 == colorCount) { |
| return SkShaders::Color(colors[0], std::move(colorSpace)); |
| } |
| if (!SkScalarIsFinite(startAngle) || !SkScalarIsFinite(endAngle) || startAngle > endAngle) { |
| return nullptr; |
| } |
| if (localMatrix && !localMatrix->invert(nullptr)) { |
| return nullptr; |
| } |
| |
| if (SkScalarNearlyEqual(startAngle, endAngle, kDegenerateThreshold)) { |
| // Degenerate gradient, which should follow default degenerate behavior unless it is |
| // clamped and the angle is greater than 0. |
| if (mode == SkTileMode::kClamp && endAngle > kDegenerateThreshold) { |
| // In this case, the first color is repeated from 0 to the angle, then a hardstop |
| // switches to the last color (all other colors are compressed to the infinitely thin |
| // interpolation region). |
| static constexpr SkScalar clampPos[3] = {0, 1, 1}; |
| SkColor4f reColors[3] = {colors[0], colors[0], colors[colorCount - 1]}; |
| return MakeSweep(cx, cy, reColors, std::move(colorSpace), clampPos, 3, mode, 0, |
| endAngle, flags, localMatrix); |
| } else { |
| return make_degenerate_gradient(colors, pos, colorCount, std::move(colorSpace), mode); |
| } |
| } |
| |
| if (startAngle <= 0 && endAngle >= 360) { |
| // If the t-range includes [0,1], then we can always use clamping (presumably faster). |
| mode = SkTileMode::kClamp; |
| } |
| |
| ColorStopOptimizer opt(colors, pos, colorCount, mode); |
| |
| SkGradientShaderBase::Descriptor desc; |
| desc_init(&desc, opt.fColors, std::move(colorSpace), opt.fPos, opt.fCount, mode, flags, |
| localMatrix); |
| |
| const SkScalar t0 = startAngle / 360, |
| t1 = endAngle / 360; |
| |
| return sk_make_sp<SkSweepGradient>(SkPoint::Make(cx, cy), t0, t1, desc); |
| } |
| |
| void SkGradientShader::RegisterFlattenables() { |
| SK_REGISTER_FLATTENABLE(SkLinearGradient); |
| SK_REGISTER_FLATTENABLE(SkRadialGradient); |
| SK_REGISTER_FLATTENABLE(SkSweepGradient); |
| SK_REGISTER_FLATTENABLE(SkTwoPointConicalGradient); |
| } |
