1 files changed, 421 insertions, 0 deletions

diff --git a/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
new file mode 100644
index 0000000000..4549527d51
--- /dev/null
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -0,0 +1,421 @@
+/*
+ * 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"
+
+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))));
+    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