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

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

gfx/skia/trunk/src/effects/gradients/SkRadialGradient.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 "SkRadialGradient.h"
 #include "SkRadialGradient_Table.h"
 #define kSQRT_TABLE_BITS    11
 #define kSQRT_TABLE_SIZE    (1 << kSQRT_TABLE_BITS)
 #if 0
 #include <stdio.h>
 void SkRadialGradient_BuildTable() {
     // build it 0..127 x 0..127, so we use 2^15 - 1 in the numerator for our "fixed" table
     FILE* file = ::fopen("SkRadialGradient_Table.h", "w");
     SkASSERT(file);
     ::fprintf(file, "static const uint8_t gSqrt8Table[] = {\n");
     for (int i = 0; i < kSQRT_TABLE_SIZE; i++) {
         if ((i & 15) == 0) {
             ::fprintf(file, "\t");
         }
         uint8_t value = SkToU8(SkFixedSqrt(i * SK_Fixed1 / kSQRT_TABLE_SIZE) >> 8);
         ::fprintf(file, "0x%02X", value);
         if (i < kSQRT_TABLE_SIZE-1) {
             ::fprintf(file, ", ");
         }
         if ((i & 15) == 15) {
             ::fprintf(file, "\n");
         }
     }
     ::fprintf(file, "};\n");
     ::fclose(file);
 }
 #endif
 namespace {
 // GCC doesn't like using static functions as template arguments.  So force these to be non-static.
 inline SkFixed mirror_tileproc_nonstatic(SkFixed x) {
     return mirror_tileproc(x);
 }
 inline SkFixed repeat_tileproc_nonstatic(SkFixed x) {
     return repeat_tileproc(x);
 }
 void rad_to_unit_matrix(const SkPoint& center, SkScalar radius,
                                SkMatrix* matrix) {
     SkScalar    inv = SkScalarInvert(radius);
     matrix->setTranslate(-center.fX, -center.fY);
     matrix->postScale(inv, inv);
 }
 typedef void (* RadialShade16Proc)(SkScalar sfx, SkScalar sdx,
         SkScalar sfy, SkScalar sdy,
         uint16_t* dstC, const uint16_t* cache,
         int toggle, int count);
 void shadeSpan16_radial_clamp(SkScalar sfx, SkScalar sdx,
         SkScalar sfy, SkScalar sdy,
         uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
         int toggle, int count) {
     const uint8_t* SK_RESTRICT sqrt_table = gSqrt8Table;
     /* knock these down so we can pin against +- 0x7FFF, which is an
        immediate load, rather than 0xFFFF which is slower. This is a
        compromise, since it reduces our precision, but that appears
        to be visually OK. If we decide this is OK for all of our cases,
        we could (it seems) put this scale-down into fDstToIndex,
        to avoid having to do these extra shifts each time.
     */
     SkFixed fx = SkScalarToFixed(sfx) >> 1;
     SkFixed dx = SkScalarToFixed(sdx) >> 1;
     SkFixed fy = SkScalarToFixed(sfy) >> 1;
     SkFixed dy = SkScalarToFixed(sdy) >> 1;
     // might perform this check for the other modes,
     // but the win will be a smaller % of the total
     if (dy == 0) {
         fy = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
         fy *= fy;
         do {
             unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
             unsigned fi = (xx * xx + fy) >> (14 + 16 - kSQRT_TABLE_BITS);
             fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
             fx += dx;
             *dstC++ = cache[toggle +
                             (sqrt_table[fi] >> SkGradientShaderBase::kSqrt16Shift)];
             toggle = next_dither_toggle16(toggle);
         } while (--count != 0);
     } else {
         do {
             unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
             unsigned fi = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
             fi = (xx * xx + fi * fi) >> (14 + 16 - kSQRT_TABLE_BITS);
             fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
             fx += dx;
             fy += dy;
             *dstC++ = cache[toggle +
                             (sqrt_table[fi] >> SkGradientShaderBase::kSqrt16Shift)];
             toggle = next_dither_toggle16(toggle);
         } while (--count != 0);
     }
 }
 template <SkFixed (*TileProc)(SkFixed)>
 void shadeSpan16_radial(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                         uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
                         int toggle, int count) {
     do {
         const SkFixed dist = SkFloatToFixed(sk_float_sqrt(fx*fx + fy*fy));
         const unsigned fi = TileProc(dist);
         SkASSERT(fi <= 0xFFFF);
         *dstC++ = cache[toggle + (fi >> SkGradientShaderBase::kCache16Shift)];
         toggle = next_dither_toggle16(toggle);
         fx += dx;
         fy += dy;
     } while (--count != 0);
 }
 void shadeSpan16_radial_mirror(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                                uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
                                int toggle, int count) {
     shadeSpan16_radial<mirror_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, toggle, count);
 }
 void shadeSpan16_radial_repeat(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                                uint16_t* SK_RESTRICT dstC, const uint16_t* SK_RESTRICT cache,
                                int toggle, int count) {
     shadeSpan16_radial<repeat_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, toggle, count);
 }
 }  // namespace
 /////////////////////////////////////////////////////////////////////
 SkRadialGradient::SkRadialGradient(const SkPoint& center, SkScalar radius,
                                    const Descriptor& desc)
     : SkGradientShaderBase(desc),
       fCenter(center),
       fRadius(radius)
 {
     // make sure our table is insync with our current #define for kSQRT_TABLE_SIZE
     SkASSERT(sizeof(gSqrt8Table) == kSQRT_TABLE_SIZE);
     rad_to_unit_matrix(center, radius, &fPtsToUnit);
 }
 void SkRadialGradient::shadeSpan16(int x, int y, uint16_t* dstCParam,
                          int count) {
     SkASSERT(count > 0);
     uint16_t* SK_RESTRICT dstC = dstCParam;
     SkPoint             srcPt;
     SkMatrix::MapXYProc dstProc = fDstToIndexProc;
     TileProc            proc = fTileProc;
     const uint16_t* SK_RESTRICT cache = this->getCache16();
     int                 toggle = init_dither_toggle16(x, y);
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
                              SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkScalar sdx = fDstToIndex.getScaleX();
         SkScalar sdy = fDstToIndex.getSkewY();
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed storage[2];
             (void)fDstToIndex.fixedStepInX(SkIntToScalar(y),
                                            &storage[0], &storage[1]);
             sdx = SkFixedToScalar(storage[0]);
             sdy = SkFixedToScalar(storage[1]);
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
         }
         RadialShade16Proc shadeProc = shadeSpan16_radial_repeat;
         if (SkShader::kClamp_TileMode == fTileMode) {
             shadeProc = shadeSpan16_radial_clamp;
         } else if (SkShader::kMirror_TileMode == fTileMode) {
             shadeProc = shadeSpan16_radial_mirror;
         } else {
             SkASSERT(SkShader::kRepeat_TileMode == fTileMode);
         }
         (*shadeProc)(srcPt.fX, sdx, srcPt.fY, sdy, dstC,
                      cache, toggle, count);
     } else {    // perspective case
         SkScalar dstX = SkIntToScalar(x);
         SkScalar dstY = SkIntToScalar(y);
         do {
             dstProc(fDstToIndex, dstX, dstY, &srcPt);
             unsigned fi = proc(SkScalarToFixed(srcPt.length()));
             SkASSERT(fi <= 0xFFFF);
             int index = fi >> (16 - kCache16Bits);
             *dstC++ = cache[toggle + index];
             toggle = next_dither_toggle16(toggle);
             dstX += SK_Scalar1;
         } while (--count != 0);
     }
 }
 SkShader::BitmapType SkRadialGradient::asABitmap(SkBitmap* bitmap,
     SkMatrix* matrix, SkShader::TileMode* xy) const {
     if (bitmap) {
         this->getGradientTableBitmap(bitmap);
     }
     if (matrix) {
         matrix->setScale(SkIntToScalar(kCache32Count),
                          SkIntToScalar(kCache32Count));
         matrix->preConcat(fPtsToUnit);
     }
     if (xy) {
         xy[0] = fTileMode;
         xy[1] = kClamp_TileMode;
     }
     return kRadial_BitmapType;
 }
 SkShader::GradientType SkRadialGradient::asAGradient(GradientInfo* info) const {
     if (info) {
         commonAsAGradient(info);
         info->fPoint[0] = fCenter;
         info->fRadius[0] = fRadius;
     }
     return kRadial_GradientType;
 }
 SkRadialGradient::SkRadialGradient(SkReadBuffer& buffer)
     : INHERITED(buffer),
       fCenter(buffer.readPoint()),
       fRadius(buffer.readScalar()) {
 }
 void SkRadialGradient::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writePoint(fCenter);
     buffer.writeScalar(fRadius);
 }
 namespace {
 inline bool radial_completely_pinned(int fx, int dx, int fy, int dy) {
     // fast, overly-conservative test: checks unit square instead
     // of unit circle
     bool xClamped = (fx >= SK_FixedHalf && dx >= 0) ||
                     (fx <= -SK_FixedHalf && dx <= 0);
     bool yClamped = (fy >= SK_FixedHalf && dy >= 0) ||
                     (fy <= -SK_FixedHalf && dy <= 0);
     return xClamped || yClamped;
 }
 // Return true if (fx * fy) is always inside the unit circle
 // SkPin32 is expensive, but so are all the SkFixedMul in this test,
 // so it shouldn't be run if count is small.
 inline bool no_need_for_radial_pin(int fx, int dx,
                                           int fy, int dy, int count) {
     SkASSERT(count > 0);
     if (SkAbs32(fx) > 0x7FFF || SkAbs32(fy) > 0x7FFF) {
         return false;
     }
     if (fx*fx + fy*fy > 0x7FFF*0x7FFF) {
         return false;
     }
     fx += (count - 1) * dx;
     fy += (count - 1) * dy;
     if (SkAbs32(fx) > 0x7FFF || SkAbs32(fy) > 0x7FFF) {
         return false;
     }
     return fx*fx + fy*fy <= 0x7FFF*0x7FFF;
 }
 #define UNPINNED_RADIAL_STEP \
     fi = (fx * fx + fy * fy) >> (14 + 16 - kSQRT_TABLE_BITS); \
     *dstC++ = cache[toggle + \
                     (sqrt_table[fi] >> SkGradientShaderBase::kSqrt32Shift)]; \
     toggle = next_dither_toggle(toggle); \
     fx += dx; \
     fy += dy;
 typedef void (* RadialShadeProc)(SkScalar sfx, SkScalar sdx,
         SkScalar sfy, SkScalar sdy,
         SkPMColor* dstC, const SkPMColor* cache,
         int count, int toggle);
 // On Linux, this is faster with SkPMColor[] params than SkPMColor* SK_RESTRICT
 void shadeSpan_radial_clamp(SkScalar sfx, SkScalar sdx,
         SkScalar sfy, SkScalar sdy,
         SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
         int count, int toggle) {
     // Floating point seems to be slower than fixed point,
     // even when we have float hardware.
     const uint8_t* SK_RESTRICT sqrt_table = gSqrt8Table;
     SkFixed fx = SkScalarToFixed(sfx) >> 1;
     SkFixed dx = SkScalarToFixed(sdx) >> 1;
     SkFixed fy = SkScalarToFixed(sfy) >> 1;
     SkFixed dy = SkScalarToFixed(sdy) >> 1;
     if ((count > 4) && radial_completely_pinned(fx, dx, fy, dy)) {
         unsigned fi = SkGradientShaderBase::kCache32Count - 1;
         sk_memset32_dither(dstC,
             cache[toggle + fi],
             cache[next_dither_toggle(toggle) + fi],
             count);
     } else if ((count > 4) &&
                no_need_for_radial_pin(fx, dx, fy, dy, count)) {
         unsigned fi;
         // 4x unroll appears to be no faster than 2x unroll on Linux
         while (count > 1) {
             UNPINNED_RADIAL_STEP;
             UNPINNED_RADIAL_STEP;
             count -= 2;
         }
         if (count) {
             UNPINNED_RADIAL_STEP;
         }
     } else  {
         // Specializing for dy == 0 gains us 25% on Skia benchmarks
         if (dy == 0) {
             unsigned yy = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
             yy *= yy;
             do {
                 unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
                 unsigned fi = (xx * xx + yy) >> (14 + 16 - kSQRT_TABLE_BITS);
                 fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
                 *dstC++ = cache[toggle + (sqrt_table[fi] >>
                     SkGradientShaderBase::kSqrt32Shift)];
                 toggle = next_dither_toggle(toggle);
                 fx += dx;
             } while (--count != 0);
         } else {
             do {
                 unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1);
                 unsigned fi = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1);
                 fi = (xx * xx + fi * fi) >> (14 + 16 - kSQRT_TABLE_BITS);
                 fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS));
                 *dstC++ = cache[toggle + (sqrt_table[fi] >>
                     SkGradientShaderBase::kSqrt32Shift)];
                 toggle = next_dither_toggle(toggle);
                 fx += dx;
                 fy += dy;
             } while (--count != 0);
         }
     }
 }
 // Unrolling this loop doesn't seem to help (when float); we're stalling to
 // get the results of the sqrt (?), and don't have enough extra registers to
 // have many in flight.
 template <SkFixed (*TileProc)(SkFixed)>
 void shadeSpan_radial(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                       SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
                       int count, int toggle) {
     do {
         const SkFixed dist = SkFloatToFixed(sk_float_sqrt(fx*fx + fy*fy));
         const unsigned fi = TileProc(dist);
         SkASSERT(fi <= 0xFFFF);
         *dstC++ = cache[toggle + (fi >> SkGradientShaderBase::kCache32Shift)];
         toggle = next_dither_toggle(toggle);
         fx += dx;
         fy += dy;
     } while (--count != 0);
 }
 void shadeSpan_radial_mirror(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                              SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
                              int count, int toggle) {
     shadeSpan_radial<mirror_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, count, toggle);
 }
 void shadeSpan_radial_repeat(SkScalar fx, SkScalar dx, SkScalar fy, SkScalar dy,
                              SkPMColor* SK_RESTRICT dstC, const SkPMColor* SK_RESTRICT cache,
                              int count, int toggle) {
     shadeSpan_radial<repeat_tileproc_nonstatic>(fx, dx, fy, dy, dstC, cache, count, toggle);
 }
 }  // namespace
 void SkRadialGradient::shadeSpan(int x, int y,
                                 SkPMColor* SK_RESTRICT dstC, int count) {
     SkASSERT(count > 0);
     SkPoint             srcPt;
     SkMatrix::MapXYProc dstProc = fDstToIndexProc;
     TileProc            proc = fTileProc;
     const SkPMColor* SK_RESTRICT cache = this->getCache32();
     int toggle = init_dither_toggle(x, y);
     if (fDstToIndexClass != kPerspective_MatrixClass) {
         dstProc(fDstToIndex, SkIntToScalar(x) + SK_ScalarHalf,
                              SkIntToScalar(y) + SK_ScalarHalf, &srcPt);
         SkScalar sdx = fDstToIndex.getScaleX();
         SkScalar sdy = fDstToIndex.getSkewY();
         if (fDstToIndexClass == kFixedStepInX_MatrixClass) {
             SkFixed storage[2];
             (void)fDstToIndex.fixedStepInX(SkIntToScalar(y),
                                            &storage[0], &storage[1]);
             sdx = SkFixedToScalar(storage[0]);
             sdy = SkFixedToScalar(storage[1]);
         } else {
             SkASSERT(fDstToIndexClass == kLinear_MatrixClass);
         }
         RadialShadeProc shadeProc = shadeSpan_radial_repeat;
         if (SkShader::kClamp_TileMode == fTileMode) {
             shadeProc = shadeSpan_radial_clamp;
         } else if (SkShader::kMirror_TileMode == fTileMode) {
             shadeProc = shadeSpan_radial_mirror;
         } else {
             SkASSERT(SkShader::kRepeat_TileMode == fTileMode);
         }
         (*shadeProc)(srcPt.fX, sdx, srcPt.fY, sdy, dstC, cache, count, toggle);
     } else {    // perspective case
         SkScalar dstX = SkIntToScalar(x);
         SkScalar dstY = SkIntToScalar(y);
         do {
             dstProc(fDstToIndex, dstX, dstY, &srcPt);
             unsigned fi = proc(SkScalarToFixed(srcPt.length()));
             SkASSERT(fi <= 0xFFFF);
             *dstC++ = cache[fi >> SkGradientShaderBase::kCache32Shift];
             dstX += SK_Scalar1;
         } while (--count != 0);
     }
 }
 /////////////////////////////////////////////////////////////////////
 #if SK_SUPPORT_GPU
 #include "GrTBackendEffectFactory.h"
 class GrGLRadialGradient : public GrGLGradientEffect {
 public:
     GrGLRadialGradient(const GrBackendEffectFactory& factory,
                        const GrDrawEffect&) : INHERITED (factory) { }
     virtual ~GrGLRadialGradient() { }
     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 GrRadialGradient : public GrGradientEffect {
 public:
     static GrEffectRef* Create(GrContext* ctx,
                                const SkRadialGradient& shader,
                                const SkMatrix& matrix,
                                SkShader::TileMode tm) {
         AutoEffectUnref effect(SkNEW_ARGS(GrRadialGradient, (ctx, shader, matrix, tm)));
         return CreateEffectRef(effect);
     }
     virtual ~GrRadialGradient() { }
     static const char* Name() { return "Radial Gradient"; }
     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
         return GrTBackendEffectFactory<GrRadialGradient>::getInstance();
     }
     typedef GrGLRadialGradient GLEffect;
 private:
     GrRadialGradient(GrContext* ctx,
                      const SkRadialGradient& shader,
                      const SkMatrix& matrix,
                      SkShader::TileMode tm)
         : INHERITED(ctx, shader, matrix, tm) {
     }
     GR_DECLARE_EFFECT_TEST;
     typedef GrGradientEffect INHERITED;
 };
 /////////////////////////////////////////////////////////////////////
 GR_DEFINE_EFFECT_TEST(GrRadialGradient);
 GrEffectRef* GrRadialGradient::TestCreate(SkRandom* random,
                                           GrContext* context,
                                           const GrDrawTargetCaps&,
                                           GrTexture**) {
     SkPoint center = {random->nextUScalar1(), random->nextUScalar1()};
     SkScalar radius = random->nextUScalar1();
     SkColor colors[kMaxRandomGradientColors];
     SkScalar stopsArray[kMaxRandomGradientColors];
     SkScalar* stops = stopsArray;
     SkShader::TileMode tm;
     int colorCount = RandomGradientParams(random, colors, &stops, &tm);
     SkAutoTUnref<SkShader> shader(SkGradientShader::CreateRadial(center, radius,
                                                                  colors, stops, colorCount,
                                                                  tm));
     SkPaint paint;
     return shader->asNewEffect(context, paint);
 }
 /////////////////////////////////////////////////////////////////////
 void GrGLRadialGradient::emitCode(GrGLShaderBuilder* builder,
                                   const GrDrawEffect&,
                                   EffectKey key,
                                   const char* outputColor,
                                   const char* inputColor,
                                   const TransformedCoordsArray& coords,
                                   const TextureSamplerArray& samplers) {
     this->emitUniforms(builder, key);
     SkString t("length(");
     t.append(builder->ensureFSCoords2D(coords, 0));
     t.append(")");
     this->emitColor(builder, t.c_str(), key, outputColor, inputColor, samplers);
 }
 /////////////////////////////////////////////////////////////////////
 GrEffectRef* SkRadialGradient::asNewEffect(GrContext* context, const SkPaint&) const {
     SkASSERT(NULL != context);
     SkMatrix matrix;
     if (!this->getLocalMatrix().invert(&matrix)) {
         return NULL;
     }
     matrix.postConcat(fPtsToUnit);
     return GrRadialGradient::Create(context, *this, matrix, fTileMode);
 }
 #else
 GrEffectRef* SkRadialGradient::asNewEffect(GrContext*, const SkPaint&) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return NULL;
 }
 #endif
 #ifndef SK_IGNORE_TO_STRING
 void SkRadialGradient::toString(SkString* str) const {
     str->append("SkRadialGradient: (");
     str->append("center: (");
     str->appendScalar(fCenter.fX);
     str->append(", ");
     str->appendScalar(fCenter.fY);
     str->append(") radius: ");
     str->appendScalar(fRadius);
     str->append(" ");
     this->INHERITED::toString(str);
     str->append(")");
 }
 #endif

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

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