The Tor Browser: gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp@b8a032363ba2 (annotated)

gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp@b8a032363ba2 (annotated)

gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * 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 "SkSweepGradient.h"
 SkSweepGradient::SkSweepGradient(SkScalar cx, SkScalar cy,
                                  const Descriptor& desc)
     : SkGradientShaderBase(desc)
     , fCenter(SkPoint::Make(cx, cy))
 {
     fPtsToUnit.setTranslate(-cx, -cy);
     // overwrite the tilemode to a canonical value (since sweep ignores it)
     fTileMode = SkShader::kClamp_TileMode;
 }
 SkShader::BitmapType SkSweepGradient::asABitmap(SkBitmap* bitmap,
     SkMatrix* matrix, SkShader::TileMode* xy) const {
     if (bitmap) {
         this->getGradientTableBitmap(bitmap);
     }
     if (matrix) {
         *matrix = fPtsToUnit;
     }
     if (xy) {
         xy[0] = fTileMode;
         xy[1] = kClamp_TileMode;
     }
     return kSweep_BitmapType;
 }
 SkShader::GradientType SkSweepGradient::asAGradient(GradientInfo* info) const {
     if (info) {
         commonAsAGradient(info);
         info->fPoint[0] = fCenter;
     }
     return kSweep_GradientType;
 }
 SkSweepGradient::SkSweepGradient(SkReadBuffer& buffer)
     : INHERITED(buffer),
       fCenter(buffer.readPoint()) {
 }
 void SkSweepGradient::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writePoint(fCenter);
 }
 //  returns angle in a circle [0..2PI) -> [0..255]
 static unsigned SkATan2_255(float y, float x) {
     //    static const float g255Over2PI = 255 / (2 * SK_ScalarPI);
     static const float g255Over2PI = 40.584510488433314f;
     float result = sk_float_atan2(y, x);
     if (result < 0) {
         result += 2 * SK_ScalarPI;
     }
     SkASSERT(result >= 0);
     // since our value is always >= 0, we can cast to int, which is faster than
     // calling floorf()
     int ir = (int)(result * g255Over2PI);
     SkASSERT(ir >= 0 && ir <= 255);
     return ir;
 }
 void SkSweepGradient::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
                                int count) {
     SkMatrix::MapXYProc proc = fDstToIndexProc;
     const SkMatrix&     matrix = fDstToIndex;
     const SkPMColor* SK_RESTRICT cache = this->getCache32();
     int                 toggle = init_dither_toggle(x, y);
     SkPoint             srcPt;
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
                      SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkScalar dx, fx = srcPt.fX;
         SkScalar dy, fy = srcPt.fY;
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed storage[2];
             (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
                                       &storage[0], &storage[1]);
             dx = SkFixedToScalar(storage[0]);
             dy = SkFixedToScalar(storage[1]);
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
             dx = matrix.getScaleX();
             dy = matrix.getSkewY();
         }
         for (; count > 0; --count) {
             *dstC++ = cache[toggle + SkATan2_255(fy, fx)];
             fx += dx;
             fy += dy;
             toggle = next_dither_toggle(toggle);
         }
     } else {  // perspective case
         for (int stop = x + count; x < stop; x++) {
             proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
                          SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
             *dstC++ = cache[toggle + SkATan2_255(srcPt.fY, srcPt.fX)];
             toggle = next_dither_toggle(toggle);
         }
     }
 }
 void SkSweepGradient::shadeSpan16(int x, int y, uint16_t* SK_RESTRICT dstC,
                                  int count) {
     SkMatrix::MapXYProc proc = fDstToIndexProc;
     const SkMatrix&     matrix = fDstToIndex;
     const uint16_t* SK_RESTRICT cache = this->getCache16();
     int                 toggle = init_dither_toggle16(x, y);
     SkPoint             srcPt;
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
                      SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkScalar dx, fx = srcPt.fX;
         SkScalar dy, fy = srcPt.fY;
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed storage[2];
             (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf,
                                       &storage[0], &storage[1]);
             dx = SkFixedToScalar(storage[0]);
             dy = SkFixedToScalar(storage[1]);
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
             dx = matrix.getScaleX();
             dy = matrix.getSkewY();
         }
         for (; count > 0; --count) {
             int index = SkATan2_255(fy, fx) >> (8 - kCache16Bits);
             *dstC++ = cache[toggle + index];
             toggle = next_dither_toggle16(toggle);
             fx += dx;
             fy += dy;
         }
     } else {  // perspective case
         for (int stop = x + count; x < stop; x++) {
             proc(matrix, SkIntToScalar(x) + SK_ScalarHalf,
                          SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
             int index = SkATan2_255(srcPt.fY, srcPt.fX);
             index >>= (8 - kCache16Bits);
             *dstC++ = cache[toggle + index];
             toggle = next_dither_toggle16(toggle);
         }
     }
 }
 /////////////////////////////////////////////////////////////////////
 #if SK_SUPPORT_GPU
 #include "GrTBackendEffectFactory.h"
 class GrGLSweepGradient : public GrGLGradientEffect {
 public:
     GrGLSweepGradient(const GrBackendEffectFactory& factory,
                       const GrDrawEffect&) : INHERITED (factory) { }
     virtual ~GrGLSweepGradient() { }
     virtual void emitCode(GrGLShaderBuilder*,
                           const GrDrawEffect&,
                           EffectKey,
                           const char* outputColor,
                           const char* inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
     static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
         return GenBaseGradientKey(drawEffect);
     }
 private:
     typedef GrGLGradientEffect INHERITED;
 };
 /////////////////////////////////////////////////////////////////////
 class GrSweepGradient : public GrGradientEffect {
 public:
     static GrEffectRef* Create(GrContext* ctx,
                                const SkSweepGradient& shader,
                                const SkMatrix& matrix) {
         AutoEffectUnref effect(SkNEW_ARGS(GrSweepGradient, (ctx, shader, matrix)));
         return CreateEffectRef(effect);
     }
     virtual ~GrSweepGradient() { }
     static const char* Name() { return "Sweep Gradient"; }
     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
         return GrTBackendEffectFactory<GrSweepGradient>::getInstance();
     }
     typedef GrGLSweepGradient GLEffect;
 private:
     GrSweepGradient(GrContext* ctx,
                     const SkSweepGradient& shader,
                     const SkMatrix& matrix)
     : INHERITED(ctx, shader, matrix, SkShader::kClamp_TileMode) { }
     GR_DECLARE_EFFECT_TEST;
     typedef GrGradientEffect INHERITED;
 };
 /////////////////////////////////////////////////////////////////////
 GR_DEFINE_EFFECT_TEST(GrSweepGradient);
 GrEffectRef* GrSweepGradient::TestCreate(SkRandom* random,
                                          GrContext* context,
                                          const GrDrawTargetCaps&,
                                          GrTexture**) {
     SkPoint center = {random->nextUScalar1(), random->nextUScalar1()};
     SkColor colors[kMaxRandomGradientColors];
     SkScalar stopsArray[kMaxRandomGradientColors];
     SkScalar* stops = stopsArray;
     SkShader::TileMode tmIgnored;
     int colorCount = RandomGradientParams(random, colors, &stops, &tmIgnored);
     SkAutoTUnref<SkShader> shader(SkGradientShader::CreateSweep(center.fX, center.fY,
                                                                 colors, stops, colorCount));
     SkPaint paint;
     return shader->asNewEffect(context, paint);
 }
 /////////////////////////////////////////////////////////////////////
 void GrGLSweepGradient::emitCode(GrGLShaderBuilder* builder,
                                  const GrDrawEffect&,
                                  EffectKey key,
                                  const char* outputColor,
                                  const char* inputColor,
                                  const TransformedCoordsArray& coords,
                                  const TextureSamplerArray& samplers) {
     this->emitUniforms(builder, key);
     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
     const GrGLContextInfo ctxInfo = builder->ctxInfo();
     SkString t;
     // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
     // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int
     // thus must us -1.0 * %s.x to work correctly
     if (kIntel_GrGLVendor != ctxInfo.vendor()){
         t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5",
                  coords2D.c_str(), coords2D.c_str());
     } else {
         t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5",
                  coords2D.c_str(), coords2D.c_str());
     }
     this->emitColor(builder, t.c_str(), key,
                           outputColor, inputColor, samplers);
 }
 /////////////////////////////////////////////////////////////////////
 GrEffectRef* SkSweepGradient::asNewEffect(GrContext* context, const SkPaint&) const {
     SkMatrix matrix;
     if (!this->getLocalMatrix().invert(&matrix)) {
         return NULL;
     }
     matrix.postConcat(fPtsToUnit);
     return GrSweepGradient::Create(context, *this, matrix);
 }
 #else
 GrEffectRef* SkSweepGradient::asNewEffect(GrContext*, const SkPaint&) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return NULL;
 }
 #endif
 #ifndef SK_IGNORE_TO_STRING
 void SkSweepGradient::toString(SkString* str) const {
     str->append("SkSweepGradient: (");
     str->append("center: (");
     str->appendScalar(fCenter.fX);
     str->append(", ");
     str->appendScalar(fCenter.fY);
     str->append(") ");
     this->INHERITED::toString(str);
     str->append(")");
 }
 #endif

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gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp@b8a032363ba2 (annotated)

gfx/skia/trunk/src/effects/gradients/SkSweepGradient.cpp