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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkRRectsGaussianEdgeMaskFilter.h"
#include "SkReadBuffer.h"
#include "SkRRect.h"
#include "SkWriteBuffer.h"
#if SK_SUPPORT_GPU
#include "GrFragmentProcessor.h"
#endif
/** \class SkRRectsGaussianEdgeMaskFilterImpl
* This mask filter applies a gaussian edge to the intersection of two round rects.
* The round rects must have the same radii at each corner and the x&y radii
* must also be equal.
*/
class SkRRectsGaussianEdgeMaskFilterImpl : public SkMaskFilter {
public:
SkRRectsGaussianEdgeMaskFilterImpl(const SkRRect& first, const SkRRect& second,
SkScalar radius)
: fFirst(first)
, fSecond(second)
, fRadius(radius) {
}
SkMask::Format getFormat() const override { return SkMask::kA8_Format; }
bool filterMask(SkMask* dst, const SkMask& src, const SkMatrix&,
SkIPoint* margin) const override;
#if SK_SUPPORT_GPU
bool asFragmentProcessor(GrFragmentProcessor**) const override;
#endif
SK_TO_STRING_OVERRIDE()
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkRRectsGaussianEdgeMaskFilterImpl)
protected:
void flatten(SkWriteBuffer&) const override;
private:
SkRRect fFirst;
SkRRect fSecond;
SkScalar fRadius;
friend class SkRRectsGaussianEdgeMaskFilter; // for serialization registration system
typedef SkMaskFilter INHERITED;
};
// x & y are in device space
static SkScalar compute_rrect_normalized_dist(const SkRRect& rr, const SkPoint& p, SkScalar rad) {
SkASSERT(rr.getType() == SkRRect::kOval_Type || rr.getType() == SkRRect::kRect_Type ||
rr.getType() == SkRRect::kSimple_Type);
SkASSERT(rad > 0.0f);
SkVector delta = { SkTAbs(p.fX - rr.rect().centerX()), SkTAbs(p.fY - rr.rect().centerY()) };
SkScalar halfW = 0.5f * rr.rect().width();
SkScalar halfH = 0.5f * rr.rect().height();
SkScalar invRad = 1.0f/rad;
const SkVector& radii = rr.getSimpleRadii();
SkASSERT(SkScalarNearlyEqual(radii.fX, radii.fY));
switch (rr.getType()) {
case SkRRect::kOval_Type: {
float scaledDist = delta.length() * invRad;
return SkTPin(halfW * invRad - scaledDist, 0.0f, 1.0f);
}
case SkRRect::kRect_Type: {
SkScalar xDist = (halfW - delta.fX) * invRad;
SkScalar yDist = (halfH - delta.fY) * invRad;
SkVector v = { 1.0f - SkTPin(xDist, 0.0f, 1.0f), 1.0f - SkTPin(yDist, 0.0f, 1.0f) };
return SkTPin(1.0f - v.length(), 0.0f, 1.0f);
}
case SkRRect::kSimple_Type: {
//----------------
// ice-cream-cone fractional distance computation
// When the blurRadius is larger than the corner radius we want to use it to
// compute the pointy end of the ice cream cone. If it smaller we just want to use
// the center of the corner's circle. When using the blurRadius the inset amount
// can't exceed the halfwidths of the RRect.
SkScalar insetDist = SkTMin(SkTMax(rad, radii.fX), SkTMin(halfW, halfH));
// "maxValue" is a correction term for if the blurRadius is larger than the
// size of the RRect. In that case we don't want to go all the way to black.
SkScalar maxValue = insetDist * invRad;
SkVector coneBottom = { halfW - insetDist, halfH - insetDist };
SkVector ptInConeSpace = delta - coneBottom;
SkVector cornerTop = { halfW - radii.fX - coneBottom.fX, halfH - coneBottom.fY };
SkVector cornerRight = { halfW - coneBottom.fX, halfH - radii.fY - coneBottom.fY };
SkScalar cross1 = ptInConeSpace.cross(cornerTop);
SkScalar cross2 = cornerRight.cross(ptInConeSpace);
bool inCone = cross1 > 0.0f && cross2 > 0.0f;
if (!inCone) {
SkScalar xDist = (halfW - delta.fX) * invRad;
SkScalar yDist = (halfH - delta.fY) * invRad;
return SkTPin(SkTMin(xDist, yDist), 0.0f, 1.0f); // perpendicular distance
}
SkVector cornerCenterInConeSpace = { insetDist - radii.fX, insetDist - radii.fY };
SkVector connectingVec = ptInConeSpace - cornerCenterInConeSpace;
float distToPtInConeSpace = SkPoint::Normalize(&ptInConeSpace);
// "a" (i.e., dot(ptInConeSpace, ptInConeSpace) should always be 1.0f since
// ptInConeSpace is now normalized
SkScalar b = 2.0f * ptInConeSpace.dot(connectingVec);
SkScalar c = connectingVec.dot(connectingVec) - radii.fX * radii.fY;
// lop off negative values that are outside the cone
SkScalar coneDist = SkTMax(0.0f, 0.5f * (-b + SkScalarSqrt(b*b - 4*c)));
// make the coneDist a fraction of how far it is from the edge to the cone's base
coneDist = (maxValue*coneDist) / (coneDist+distToPtInConeSpace);
return SkTPin(coneDist, 0.0f, 1.0f);
}
default:
return 0.0f;
}
}
bool SkRRectsGaussianEdgeMaskFilterImpl::filterMask(SkMask* dst, const SkMask& src,
const SkMatrix& matrix,
SkIPoint* margin) const {
if (src.fFormat != SkMask::kA8_Format) {
return false;
}
if (margin) {
margin->set(0, 0);
}
dst->fBounds = src.fBounds;
dst->fRowBytes = dst->fBounds.width();
dst->fFormat = SkMask::kA8_Format;
dst->fImage = nullptr;
if (src.fImage) {
size_t dstSize = dst->computeImageSize();
if (0 == dstSize) {
return false; // too big to allocate, abort
}
const uint8_t* srcPixels = src.fImage;
uint8_t* dstPixels = dst->fImage = SkMask::AllocImage(dstSize);
SkPoint basePt = { SkIntToScalar(src.fBounds.fLeft), SkIntToScalar(src.fBounds.fTop) };
for (int y = 0; y < dst->fBounds.height(); ++y) {
const uint8_t* srcRow = srcPixels + y * dst->fRowBytes;
uint8_t* dstRow = dstPixels + y*dst->fRowBytes;
for (int x = 0; x < dst->fBounds.width(); ++x) {
SkPoint curPt = { basePt.fX + x, basePt.fY + y };
SkVector vec;
vec.fX = 1.0f - compute_rrect_normalized_dist(fFirst, curPt, fRadius);
vec.fY = 1.0f - compute_rrect_normalized_dist(fSecond, curPt, fRadius);
SkScalar factor = SkTPin(vec.length(), 0.0f, 1.0f);
factor = exp(-factor * factor * 4.0f) - 0.018f;
SkASSERT(factor >= 0.0f && factor <= 1.0f);
dstRow[x] = (uint8_t) (factor * srcRow[x]);
}
}
}
return true;
}
////////////////////////////////////////////////////////////////////////////
#if SK_SUPPORT_GPU
#include "GrCoordTransform.h"
#include "GrFragmentProcessor.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLProgramDataManager.h"
#include "glsl/GrGLSLUniformHandler.h"
#include "SkGr.h"
class RRectsGaussianEdgeFP : public GrFragmentProcessor {
public:
enum Mode {
kCircle_Mode,
kRect_Mode,
kSimpleCircular_Mode,
};
RRectsGaussianEdgeFP(const SkRRect& first, const SkRRect& second, SkScalar radius)
: INHERITED(kCompatibleWithCoverageAsAlpha_OptimizationFlag)
, fFirst(first)
, fSecond(second)
, fRadius(radius) {
this->initClassID<RRectsGaussianEdgeFP>();
fFirstMode = ComputeMode(fFirst);
fSecondMode = ComputeMode(fSecond);
}
class GLSLRRectsGaussianEdgeFP : public GrGLSLFragmentProcessor {
public:
GLSLRRectsGaussianEdgeFP() { }
// This method emits code so that, for each shape, the distance from the edge is returned
// in 'outputName' clamped to 0..1 with positive distance being towards the center of the
// shape. The distance will have been normalized by the radius.
void emitModeCode(Mode mode,
GrGLSLFPFragmentBuilder* fragBuilder,
const char* posName,
const char* sizesName,
const char* radiiName,
const char* radName,
const char* outputName,
const char indices[2]) { // how to access the params for the 2 rrects
// Positive distance is towards the center of the circle.
// Map all the cases to the lower right quadrant.
fragBuilder->codeAppendf("vec2 delta = abs(sk_FragCoord.xy - %s.%s);",
posName, indices);
switch (mode) {
case kCircle_Mode:
// When a shadow circle gets large we can have some precision issues if
// we do "length(delta)/radius". The scaleDist temporary cuts the
// delta vector down a bit before invoking length.
fragBuilder->codeAppendf("float scaledDist = length(delta/%s);", radName);
fragBuilder->codeAppendf("%s = clamp((%s.%c/%s - scaledDist), 0.0, 1.0);",
outputName, sizesName, indices[0], radName);
break;
case kRect_Mode:
fragBuilder->codeAppendf(
"vec2 rectDist = vec2(1.0 - clamp((%s.%c - delta.x)/%s, 0.0, 1.0),"
"1.0 - clamp((%s.%c - delta.y)/%s, 0.0, 1.0));",
sizesName, indices[0], radName,
sizesName, indices[1], radName);
fragBuilder->codeAppendf("%s = clamp(1.0 - length(rectDist), 0.0, 1.0);",
outputName);
break;
case kSimpleCircular_Mode:
// For the circular round rect we combine 2 distances:
// the fractional position from the corner inset point to the corner's circle
// the minimum perpendicular distance to the bounding rectangle
// The first distance is used when the pixel is inside the ice-cream-cone-shaped
// portion of a corner. The second is used everywhere else.
// This is intended to approximate the interpolation pattern if we had
// tessellated this geometry into a RRect outside and a rect inside.
//----------------
// rect distance computation
fragBuilder->codeAppendf("float xDist = (%s.%c - delta.x) / %s;",
sizesName, indices[0], radName);
fragBuilder->codeAppendf("float yDist = (%s.%c - delta.y) / %s;",
sizesName, indices[1], radName);
fragBuilder->codeAppend("float rectDist = clamp(min(xDist, yDist), 0.0, 1.0);");
//----------------
// ice-cream-cone fractional distance computation
// When the blurRadius is larger than the corner radius we want to use it to
// compute the pointy end of the ice cream cone. If it smaller we just want to
// use the center of the corner's circle. When using the blurRadius the inset
// amount can't exceed the halfwidths of the RRect.
fragBuilder->codeAppendf("float insetDist = min(max(%s, %s.%c),"
"min(%s.%c, %s.%c));",
radName, radiiName, indices[0],
sizesName, indices[0], sizesName, indices[1]);
// "maxValue" is a correction term for if the blurRadius is larger than the
// size of the RRect. In that case we don't want to go all the way to black.
fragBuilder->codeAppendf("float maxValue = insetDist/%s;", radName);
fragBuilder->codeAppendf("vec2 coneBottom = vec2(%s.%c - insetDist,"
"%s.%c - insetDist);",
sizesName, indices[0], sizesName, indices[1]);
fragBuilder->codeAppendf("vec2 cornerTop = vec2(%s.%c - %s.%c, %s.%c) -"
"coneBottom;",
sizesName, indices[0], radiiName, indices[0],
sizesName, indices[1]);
fragBuilder->codeAppendf("vec2 cornerRight = vec2(%s.%c, %s.%c - %s.%c) -"
"coneBottom;",
sizesName, indices[0],
sizesName, indices[1], radiiName, indices[1]);
fragBuilder->codeAppend("vec2 ptInConeSpace = delta - coneBottom;");
fragBuilder->codeAppend("float distToPtInConeSpace = length(ptInConeSpace);");
fragBuilder->codeAppend("float cross1 = ptInConeSpace.x * cornerTop.y -"
"ptInConeSpace.y * cornerTop.x;");
fragBuilder->codeAppend("float cross2 = -ptInConeSpace.x * cornerRight.y + "
"ptInConeSpace.y * cornerRight.x;");
fragBuilder->codeAppend("float inCone = step(0.0, cross1) *"
"step(0.0, cross2);");
fragBuilder->codeAppendf("vec2 cornerCenterInConeSpace = vec2(insetDist -"
"%s.%c);",
radiiName, indices[0]);
fragBuilder->codeAppend("vec2 connectingVec = ptInConeSpace -"
"cornerCenterInConeSpace;");
fragBuilder->codeAppend("ptInConeSpace = normalize(ptInConeSpace);");
// "a" (i.e., dot(ptInConeSpace, ptInConeSpace) should always be 1.0f since
// ptInConeSpace is now normalized
fragBuilder->codeAppend("float b = 2.0 * dot(ptInConeSpace, connectingVec);");
fragBuilder->codeAppendf("float c = dot(connectingVec, connectingVec) - "
"%s.%c * %s.%c;",
radiiName, indices[0], radiiName, indices[0]);
fragBuilder->codeAppend("float fourAC = 4*c;");
// This max prevents sqrt(-1) when outside the cone
fragBuilder->codeAppend("float bSq = max(b*b, fourAC);");
// lop off negative values that are outside the cone
fragBuilder->codeAppend("float coneDist = "
"max(0.0, 0.5 * (-b + sqrt(bSq - fourAC)));");
// make the coneDist a fraction of how far it is from the edge to the
// cone's base
fragBuilder->codeAppend("coneDist = (maxValue*coneDist) /"
"(coneDist+distToPtInConeSpace);");
fragBuilder->codeAppend("coneDist = clamp(coneDist, 0.0, 1.0);");
//----------------
fragBuilder->codeAppendf("%s = mix(rectDist, coneDist, inCone);", outputName);
break;
}
}
void emitCode(EmitArgs& args) override {
const RRectsGaussianEdgeFP& fp = args.fFp.cast<RRectsGaussianEdgeFP>();
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
const char* positionsUniName = nullptr;
fPositionsUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec4f_GrSLType, kDefault_GrSLPrecision,
"Positions", &positionsUniName);
const char* sizesUniName = nullptr;
fSizesUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec4f_GrSLType, kDefault_GrSLPrecision,
"Sizes", &sizesUniName);
const char* radiiUniName = nullptr;
if (fp.fFirstMode == kSimpleCircular_Mode || fp.fSecondMode == kSimpleCircular_Mode) {
fRadiiUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec4f_GrSLType, kDefault_GrSLPrecision,
"Radii", &radiiUniName);
}
const char* radUniName = nullptr;
fRadiusUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kFloat_GrSLType, kDefault_GrSLPrecision,
"Radius", &radUniName);
fragBuilder->codeAppend("float firstDist;");
fragBuilder->codeAppend("{");
this->emitModeCode(fp.firstMode(), fragBuilder,
positionsUniName, sizesUniName, radiiUniName,
radUniName, "firstDist", "xy");
fragBuilder->codeAppend("}");
fragBuilder->codeAppend("float secondDist;");
fragBuilder->codeAppend("{");
this->emitModeCode(fp.secondMode(), fragBuilder,
positionsUniName, sizesUniName, radiiUniName,
radUniName, "secondDist", "zw");
fragBuilder->codeAppend("}");
fragBuilder->codeAppend("vec2 distVec = vec2(1.0 - firstDist, 1.0 - secondDist);");
// Finally use the distance to apply the Gaussian edge
fragBuilder->codeAppend("float factor = clamp(length(distVec), 0.0, 1.0);");
fragBuilder->codeAppend("factor = exp(-factor * factor * 4.0) - 0.018;");
fragBuilder->codeAppendf("%s = factor*%s;",
args.fOutputColor, args.fInputColor);
}
static void GenKey(const GrProcessor& proc, const GrShaderCaps&, GrProcessorKeyBuilder* b) {
const RRectsGaussianEdgeFP& fp = proc.cast<RRectsGaussianEdgeFP>();
b->add32(fp.firstMode() | (fp.secondMode() << 4));
}
protected:
void onSetData(const GrGLSLProgramDataManager& pdman,
const GrFragmentProcessor& proc) override {
const RRectsGaussianEdgeFP& edgeFP = proc.cast<RRectsGaussianEdgeFP>();
const SkRRect& first = edgeFP.first();
const SkRRect& second = edgeFP.second();
pdman.set4f(fPositionsUni,
first.getBounds().centerX(),
first.getBounds().centerY(),
second.getBounds().centerX(),
second.getBounds().centerY());
pdman.set4f(fSizesUni,
0.5f * first.rect().width(),
0.5f * first.rect().height(),
0.5f * second.rect().width(),
0.5f * second.rect().height());
if (edgeFP.firstMode() == kSimpleCircular_Mode ||
edgeFP.secondMode() == kSimpleCircular_Mode) {
// This is a bit of overkill since fX should equal fY for both round rects but it
// makes the shader code simpler.
pdman.set4f(fRadiiUni,
first.getSimpleRadii().fX, first.getSimpleRadii().fY,
second.getSimpleRadii().fX, second.getSimpleRadii().fY);
}
pdman.set1f(fRadiusUni, edgeFP.radius());
}
private:
// The centers of the two round rects (x1, y1, x2, y2)
GrGLSLProgramDataManager::UniformHandle fPositionsUni;
// The half widths and half heights of the two round rects (w1/2, h1/2, w2/2, h2/2)
// For circles we still upload both width & height to simplify things
GrGLSLProgramDataManager::UniformHandle fSizesUni;
// The corner radii of the two round rects (rx1, ry1, rx2, ry2)
// We upload both the x&y radii (although they are currently always the same) to make
// the indexing in the shader code simpler. In some future world we could also support
// non-circular corner round rects & ellipses.
GrGLSLProgramDataManager::UniformHandle fRadiiUni;
// The radius parameters (radius)
GrGLSLProgramDataManager::UniformHandle fRadiusUni;
typedef GrGLSLFragmentProcessor INHERITED;
};
void onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override {
GLSLRRectsGaussianEdgeFP::GenKey(*this, caps, b);
}
const char* name() const override { return "RRectsGaussianEdgeFP"; }
const SkRRect& first() const { return fFirst; }
Mode firstMode() const { return fFirstMode; }
const SkRRect& second() const { return fSecond; }
Mode secondMode() const { return fSecondMode; }
SkScalar radius() const { return fRadius; }
private:
static Mode ComputeMode(const SkRRect& rr) {
if (rr.isCircle()) {
return kCircle_Mode;
} else if (rr.isRect()) {
return kRect_Mode;
} else {
SkASSERT(rr.isSimpleCircular());
return kSimpleCircular_Mode;
}
}
GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
return new GLSLRRectsGaussianEdgeFP;
}
bool onIsEqual(const GrFragmentProcessor& proc) const override {
const RRectsGaussianEdgeFP& edgeFP = proc.cast<RRectsGaussianEdgeFP>();
return fFirst == edgeFP.fFirst &&
fSecond == edgeFP.fSecond &&
fRadius == edgeFP.fRadius;
}
SkRRect fFirst;
Mode fFirstMode;
SkRRect fSecond;
Mode fSecondMode;
SkScalar fRadius;
typedef GrFragmentProcessor INHERITED;
};
////////////////////////////////////////////////////////////////////////////
bool SkRRectsGaussianEdgeMaskFilterImpl::asFragmentProcessor(GrFragmentProcessor** fp) const {
if (fp) {
*fp = new RRectsGaussianEdgeFP(fFirst, fSecond, fRadius);
}
return true;
}
#endif
////////////////////////////////////////////////////////////////////////////
#ifndef SK_IGNORE_TO_STRING
void SkRRectsGaussianEdgeMaskFilterImpl::toString(SkString* str) const {
str->appendf("RRectsGaussianEdgeMaskFilter: ()");
}
#endif
sk_sp<SkFlattenable> SkRRectsGaussianEdgeMaskFilterImpl::CreateProc(SkReadBuffer& buf) {
SkRect rect1, rect2;
buf.readRect(&rect1);
SkScalar xRad1 = buf.readScalar();
SkScalar yRad1 = buf.readScalar();
buf.readRect(&rect2);
SkScalar xRad2 = buf.readScalar();
SkScalar yRad2 = buf.readScalar();
SkScalar radius = buf.readScalar();
return sk_make_sp<SkRRectsGaussianEdgeMaskFilterImpl>(SkRRect::MakeRectXY(rect1, xRad1, yRad1),
SkRRect::MakeRectXY(rect2, xRad2, yRad2),
radius);
}
void SkRRectsGaussianEdgeMaskFilterImpl::flatten(SkWriteBuffer& buf) const {
INHERITED::flatten(buf);
SkASSERT(fFirst.isRect() || fFirst.isCircle() || fFirst.isSimpleCircular());
buf.writeRect(fFirst.rect());
const SkVector& radii1 = fFirst.getSimpleRadii();
buf.writeScalar(radii1.fX);
buf.writeScalar(radii1.fY);
SkASSERT(fSecond.isRect() || fSecond.isCircle() || fSecond.isSimpleCircular());
buf.writeRect(fSecond.rect());
const SkVector& radii2 = fSecond.getSimpleRadii();
buf.writeScalar(radii2.fX);
buf.writeScalar(radii2.fY);
buf.writeScalar(fRadius);
}
///////////////////////////////////////////////////////////////////////////////
sk_sp<SkMaskFilter> SkRRectsGaussianEdgeMaskFilter::Make(const SkRRect& first,
const SkRRect& second,
SkScalar radius) {
if ((!first.isRect() && !first.isCircle() && !first.isSimpleCircular()) ||
(!second.isRect() && !second.isCircle() && !second.isSimpleCircular())) {
// we only deal with the shapes where the x & y radii are equal
// and the same for all four corners
return nullptr;
}
return sk_make_sp<SkRRectsGaussianEdgeMaskFilterImpl>(first, second, radius);
}
///////////////////////////////////////////////////////////////////////////////
SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkRRectsGaussianEdgeMaskFilter)
SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkRRectsGaussianEdgeMaskFilterImpl)
SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END
///////////////////////////////////////////////////////////////////////////////