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cobalt / cobalt / da45c04cd0b2a42259750905712e02601644c062 / . / third_party / skia_next / third_party / skia / src / core / SkBlurMF.cpp
blob: cbff40d8a8b2d3bb9c41190634085894b724dce3 [file] [log] [blame]
/*
* 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 "include/core/SkBitmap.h"
#include "include/core/SkMaskFilter.h"
#include "include/core/SkPathBuilder.h"
#include "include/core/SkRRect.h"
#include "include/core/SkStrokeRec.h"
#include "include/core/SkVertices.h"
#include "src/core/SkBlurMask.h"
#include "src/core/SkGpuBlurUtils.h"
#include "src/core/SkMaskFilterBase.h"
#include "src/core/SkMathPriv.h"
#include "src/core/SkMatrixProvider.h"
#include "src/core/SkRRectPriv.h"
#include "src/core/SkReadBuffer.h"
#include "src/core/SkStringUtils.h"
#include "src/core/SkWriteBuffer.h"
#if SK_SUPPORT_GPU
#include "include/gpu/GrRecordingContext.h"
#include "src/core/SkRuntimeEffectPriv.h"
#include "src/gpu/GrFragmentProcessor.h"
#include "src/gpu/GrRecordingContextPriv.h"
#include "src/gpu/GrResourceProvider.h"
#include "src/gpu/GrShaderCaps.h"
#include "src/gpu/GrStyle.h"
#include "src/gpu/GrTextureProxy.h"
#include "src/gpu/GrThreadSafeCache.h"
#include "src/gpu/SkGr.h"
#include "src/gpu/effects/GrMatrixEffect.h"
#include "src/gpu/effects/GrSkSLFP.h"
#include "src/gpu/effects/GrTextureEffect.h"
#include "src/gpu/geometry/GrStyledShape.h"
#include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
#include "src/gpu/glsl/GrGLSLProgramDataManager.h"
#include "src/gpu/glsl/GrGLSLUniformHandler.h"
#if SK_GPU_V1
#include "src/gpu/v1/SurfaceDrawContext_v1.h"
#endif // SK_GPU_V1
#endif // SK_SUPPORT_GPU
class SkBlurMaskFilterImpl : public SkMaskFilterBase {
public:
SkBlurMaskFilterImpl(SkScalar sigma, SkBlurStyle, bool respectCTM);
// overrides from SkMaskFilter
SkMask::Format getFormat() const override;
bool filterMask(SkMask* dst, const SkMask& src, const SkMatrix&,
SkIPoint* margin) const override;
#if SK_SUPPORT_GPU && SK_GPU_V1
bool canFilterMaskGPU(const GrStyledShape& shape,
const SkIRect& devSpaceShapeBounds,
const SkIRect& clipBounds,
const SkMatrix& ctm,
SkIRect* maskRect) const override;
bool directFilterMaskGPU(GrRecordingContext*,
skgpu::v1::SurfaceDrawContext*,
GrPaint&&,
const GrClip*,
const SkMatrix& viewMatrix,
const GrStyledShape&) const override;
GrSurfaceProxyView filterMaskGPU(GrRecordingContext*,
GrSurfaceProxyView srcView,
GrColorType srcColorType,
SkAlphaType srcAlphaType,
const SkMatrix& ctm,
const SkIRect& maskRect) const override;
#endif
void computeFastBounds(const SkRect&, SkRect*) const override;
bool asABlur(BlurRec*) const override;
protected:
FilterReturn filterRectsToNine(const SkRect[], int count, const SkMatrix&,
const SkIRect& clipBounds,
NinePatch*) const override;
FilterReturn filterRRectToNine(const SkRRect&, const SkMatrix&,
const SkIRect& clipBounds,
NinePatch*) const override;
bool filterRectMask(SkMask* dstM, const SkRect& r, const SkMatrix& matrix,
SkIPoint* margin, SkMask::CreateMode createMode) const;
bool filterRRectMask(SkMask* dstM, const SkRRect& r, const SkMatrix& matrix,
SkIPoint* margin, SkMask::CreateMode createMode) const;
bool ignoreXform() const { return !fRespectCTM; }
private:
SK_FLATTENABLE_HOOKS(SkBlurMaskFilterImpl)
// To avoid unseemly allocation requests (esp. for finite platforms like
// handset) we limit the radius so something manageable. (as opposed to
// a request like 10,000)
static const SkScalar kMAX_BLUR_SIGMA;
SkScalar fSigma;
SkBlurStyle fBlurStyle;
bool fRespectCTM;
SkBlurMaskFilterImpl(SkReadBuffer&);
void flatten(SkWriteBuffer&) const override;
SkScalar computeXformedSigma(const SkMatrix& ctm) const {
SkScalar xformedSigma = this->ignoreXform() ? fSigma : ctm.mapRadius(fSigma);
return std::min(xformedSigma, kMAX_BLUR_SIGMA);
}
friend class SkBlurMaskFilter;
using INHERITED = SkMaskFilter;
friend void sk_register_blur_maskfilter_createproc();
};
const SkScalar SkBlurMaskFilterImpl::kMAX_BLUR_SIGMA = SkIntToScalar(128);
///////////////////////////////////////////////////////////////////////////////
SkBlurMaskFilterImpl::SkBlurMaskFilterImpl(SkScalar sigma, SkBlurStyle style, bool respectCTM)
: fSigma(sigma)
, fBlurStyle(style)
, fRespectCTM(respectCTM) {
SkASSERT(fSigma > 0);
SkASSERT((unsigned)style <= kLastEnum_SkBlurStyle);
}
SkMask::Format SkBlurMaskFilterImpl::getFormat() const {
return SkMask::kA8_Format;
}
bool SkBlurMaskFilterImpl::asABlur(BlurRec* rec) const {
if (this->ignoreXform()) {
return false;
}
if (rec) {
rec->fSigma = fSigma;
rec->fStyle = fBlurStyle;
}
return true;
}
bool SkBlurMaskFilterImpl::filterMask(SkMask* dst, const SkMask& src,
const SkMatrix& matrix,
SkIPoint* margin) const {
SkScalar sigma = this->computeXformedSigma(matrix);
return SkBlurMask::BoxBlur(dst, src, sigma, fBlurStyle, margin);
}
bool SkBlurMaskFilterImpl::filterRectMask(SkMask* dst, const SkRect& r,
const SkMatrix& matrix,
SkIPoint* margin, SkMask::CreateMode createMode) const {
SkScalar sigma = computeXformedSigma(matrix);
return SkBlurMask::BlurRect(sigma, dst, r, fBlurStyle, margin, createMode);
}
bool SkBlurMaskFilterImpl::filterRRectMask(SkMask* dst, const SkRRect& r,
const SkMatrix& matrix,
SkIPoint* margin, SkMask::CreateMode createMode) const {
SkScalar sigma = computeXformedSigma(matrix);
return SkBlurMask::BlurRRect(sigma, dst, r, fBlurStyle, margin, createMode);
}
#include "include/core/SkCanvas.h"
static bool prepare_to_draw_into_mask(const SkRect& bounds, SkMask* mask) {
SkASSERT(mask != nullptr);
mask->fBounds = bounds.roundOut();
mask->fRowBytes = SkAlign4(mask->fBounds.width());
mask->fFormat = SkMask::kA8_Format;
const size_t size = mask->computeImageSize();
mask->fImage = SkMask::AllocImage(size, SkMask::kZeroInit_Alloc);
if (nullptr == mask->fImage) {
return false;
}
return true;
}
static bool draw_rrect_into_mask(const SkRRect rrect, SkMask* mask) {
if (!prepare_to_draw_into_mask(rrect.rect(), mask)) {
return false;
}
// FIXME: This code duplicates code in draw_rects_into_mask, below. Is there a
// clean way to share more code?
SkBitmap bitmap;
bitmap.installMaskPixels(*mask);
SkCanvas canvas(bitmap);
canvas.translate(-SkIntToScalar(mask->fBounds.left()),
-SkIntToScalar(mask->fBounds.top()));
SkPaint paint;
paint.setAntiAlias(true);
canvas.drawRRect(rrect, paint);
return true;
}
static bool draw_rects_into_mask(const SkRect rects[], int count, SkMask* mask) {
if (!prepare_to_draw_into_mask(rects[0], mask)) {
return false;
}
SkBitmap bitmap;
bitmap.installPixels(SkImageInfo::Make(mask->fBounds.width(),
mask->fBounds.height(),
kAlpha_8_SkColorType,
kPremul_SkAlphaType),
mask->fImage, mask->fRowBytes);
SkCanvas canvas(bitmap);
canvas.translate(-SkIntToScalar(mask->fBounds.left()),
-SkIntToScalar(mask->fBounds.top()));
SkPaint paint;
paint.setAntiAlias(true);
if (1 == count) {
canvas.drawRect(rects[0], paint);
} else {
// todo: do I need a fast way to do this?
SkPath path = SkPathBuilder().addRect(rects[0])
.addRect(rects[1])
.setFillType(SkPathFillType::kEvenOdd)
.detach();
canvas.drawPath(path, paint);
}
return true;
}
static bool rect_exceeds(const SkRect& r, SkScalar v) {
return r.fLeft < -v || r.fTop < -v || r.fRight > v || r.fBottom > v ||
r.width() > v || r.height() > v;
}
#include "src/core/SkMaskCache.h"
static SkCachedData* copy_mask_to_cacheddata(SkMask* mask) {
const size_t size = mask->computeTotalImageSize();
SkCachedData* data = SkResourceCache::NewCachedData(size);
if (data) {
memcpy(data->writable_data(), mask->fImage, size);
SkMask::FreeImage(mask->fImage);
mask->fImage = (uint8_t*)data->data();
}
return data;
}
static SkCachedData* find_cached_rrect(SkMask* mask, SkScalar sigma, SkBlurStyle style,
const SkRRect& rrect) {
return SkMaskCache::FindAndRef(sigma, style, rrect, mask);
}
static SkCachedData* add_cached_rrect(SkMask* mask, SkScalar sigma, SkBlurStyle style,
const SkRRect& rrect) {
SkCachedData* cache = copy_mask_to_cacheddata(mask);
if (cache) {
SkMaskCache::Add(sigma, style, rrect, *mask, cache);
}
return cache;
}
static SkCachedData* find_cached_rects(SkMask* mask, SkScalar sigma, SkBlurStyle style,
const SkRect rects[], int count) {
return SkMaskCache::FindAndRef(sigma, style, rects, count, mask);
}
static SkCachedData* add_cached_rects(SkMask* mask, SkScalar sigma, SkBlurStyle style,
const SkRect rects[], int count) {
SkCachedData* cache = copy_mask_to_cacheddata(mask);
if (cache) {
SkMaskCache::Add(sigma, style, rects, count, *mask, cache);
}
return cache;
}
static const bool c_analyticBlurRRect{true};
SkMaskFilterBase::FilterReturn
SkBlurMaskFilterImpl::filterRRectToNine(const SkRRect& rrect, const SkMatrix& matrix,
const SkIRect& clipBounds,
NinePatch* patch) const {
SkASSERT(patch != nullptr);
switch (rrect.getType()) {
case SkRRect::kEmpty_Type:
// Nothing to draw.
return kFalse_FilterReturn;
case SkRRect::kRect_Type:
// We should have caught this earlier.
SkASSERT(false);
[[fallthrough]];
case SkRRect::kOval_Type:
// The nine patch special case does not handle ovals, and we
// already have code for rectangles.
return kUnimplemented_FilterReturn;
// These three can take advantage of this fast path.
case SkRRect::kSimple_Type:
case SkRRect::kNinePatch_Type:
case SkRRect::kComplex_Type:
break;
}
// TODO: report correct metrics for innerstyle, where we do not grow the
// total bounds, but we do need an inset the size of our blur-radius
if (kInner_SkBlurStyle == fBlurStyle) {
return kUnimplemented_FilterReturn;
}
// TODO: take clipBounds into account to limit our coordinates up front
// for now, just skip too-large src rects (to take the old code path).
if (rect_exceeds(rrect.rect(), SkIntToScalar(32767))) {
return kUnimplemented_FilterReturn;
}
SkIPoint margin;
SkMask srcM, dstM;
srcM.fBounds = rrect.rect().roundOut();
srcM.fFormat = SkMask::kA8_Format;
srcM.fRowBytes = 0;
bool filterResult = false;
if (c_analyticBlurRRect) {
// special case for fast round rect blur
// don't actually do the blur the first time, just compute the correct size
filterResult = this->filterRRectMask(&dstM, rrect, matrix, &margin,
SkMask::kJustComputeBounds_CreateMode);
}
if (!filterResult) {
filterResult = this->filterMask(&dstM, srcM, matrix, &margin);
}
if (!filterResult) {
return kFalse_FilterReturn;
}
// Now figure out the appropriate width and height of the smaller round rectangle
// to stretch. It will take into account the larger radius per side as well as double
// the margin, to account for inner and outer blur.
const SkVector& UL = rrect.radii(SkRRect::kUpperLeft_Corner);
const SkVector& UR = rrect.radii(SkRRect::kUpperRight_Corner);
const SkVector& LR = rrect.radii(SkRRect::kLowerRight_Corner);
const SkVector& LL = rrect.radii(SkRRect::kLowerLeft_Corner);
const SkScalar leftUnstretched = std::max(UL.fX, LL.fX) + SkIntToScalar(2 * margin.fX);
const SkScalar rightUnstretched = std::max(UR.fX, LR.fX) + SkIntToScalar(2 * margin.fX);
// Extra space in the middle to ensure an unchanging piece for stretching. Use 3 to cover
// any fractional space on either side plus 1 for the part to stretch.
const SkScalar stretchSize = SkIntToScalar(3);
const SkScalar totalSmallWidth = leftUnstretched + rightUnstretched + stretchSize;
if (totalSmallWidth >= rrect.rect().width()) {
// There is no valid piece to stretch.
return kUnimplemented_FilterReturn;
}
const SkScalar topUnstretched = std::max(UL.fY, UR.fY) + SkIntToScalar(2 * margin.fY);
const SkScalar bottomUnstretched = std::max(LL.fY, LR.fY) + SkIntToScalar(2 * margin.fY);
const SkScalar totalSmallHeight = topUnstretched + bottomUnstretched + stretchSize;
if (totalSmallHeight >= rrect.rect().height()) {
// There is no valid piece to stretch.
return kUnimplemented_FilterReturn;
}
SkRect smallR = SkRect::MakeWH(totalSmallWidth, totalSmallHeight);
SkRRect smallRR;
SkVector radii[4];
radii[SkRRect::kUpperLeft_Corner] = UL;
radii[SkRRect::kUpperRight_Corner] = UR;
radii[SkRRect::kLowerRight_Corner] = LR;
radii[SkRRect::kLowerLeft_Corner] = LL;
smallRR.setRectRadii(smallR, radii);
const SkScalar sigma = this->computeXformedSigma(matrix);
SkCachedData* cache = find_cached_rrect(&patch->fMask, sigma, fBlurStyle, smallRR);
if (!cache) {
bool analyticBlurWorked = false;
if (c_analyticBlurRRect) {
analyticBlurWorked =
this->filterRRectMask(&patch->fMask, smallRR, matrix, &margin,
SkMask::kComputeBoundsAndRenderImage_CreateMode);
}
if (!analyticBlurWorked) {
if (!draw_rrect_into_mask(smallRR, &srcM)) {
return kFalse_FilterReturn;
}
SkAutoMaskFreeImage amf(srcM.fImage);
if (!this->filterMask(&patch->fMask, srcM, matrix, &margin)) {
return kFalse_FilterReturn;
}
}
cache = add_cached_rrect(&patch->fMask, sigma, fBlurStyle, smallRR);
}
patch->fMask.fBounds.offsetTo(0, 0);
patch->fOuterRect = dstM.fBounds;
patch->fCenter.fX = SkScalarCeilToInt(leftUnstretched) + 1;
patch->fCenter.fY = SkScalarCeilToInt(topUnstretched) + 1;
SkASSERT(nullptr == patch->fCache);
patch->fCache = cache; // transfer ownership to patch
return kTrue_FilterReturn;
}
// Use the faster analytic blur approach for ninepatch rects
static const bool c_analyticBlurNinepatch{true};
SkMaskFilterBase::FilterReturn
SkBlurMaskFilterImpl::filterRectsToNine(const SkRect rects[], int count,
const SkMatrix& matrix,
const SkIRect& clipBounds,
NinePatch* patch) const {
if (count < 1 || count > 2) {
return kUnimplemented_FilterReturn;
}
// TODO: report correct metrics for innerstyle, where we do not grow the
// total bounds, but we do need an inset the size of our blur-radius
if (kInner_SkBlurStyle == fBlurStyle || kOuter_SkBlurStyle == fBlurStyle) {
return kUnimplemented_FilterReturn;
}
// TODO: take clipBounds into account to limit our coordinates up front
// for now, just skip too-large src rects (to take the old code path).
if (rect_exceeds(rects[0], SkIntToScalar(32767))) {
return kUnimplemented_FilterReturn;
}
SkIPoint margin;
SkMask srcM, dstM;
srcM.fBounds = rects[0].roundOut();
srcM.fFormat = SkMask::kA8_Format;
srcM.fRowBytes = 0;
bool filterResult = false;
if (count == 1 && c_analyticBlurNinepatch) {
// special case for fast rect blur
// don't actually do the blur the first time, just compute the correct size
filterResult = this->filterRectMask(&dstM, rects[0], matrix, &margin,
SkMask::kJustComputeBounds_CreateMode);
} else {
filterResult = this->filterMask(&dstM, srcM, matrix, &margin);
}
if (!filterResult) {
return kFalse_FilterReturn;
}
/*
* smallR is the smallest version of 'rect' that will still guarantee that
* we get the same blur results on all edges, plus 1 center row/col that is
* representative of the extendible/stretchable edges of the ninepatch.
* Since our actual edge may be fractional we inset 1 more to be sure we
* don't miss any interior blur.
* x is an added pixel of blur, and { and } are the (fractional) edge
* pixels from the original rect.
*
* x x { x x .... x x } x x
*
* Thus, in this case, we inset by a total of 5 (on each side) beginning
* with our outer-rect (dstM.fBounds)
*/
SkRect smallR[2];
SkIPoint center;
// +2 is from +1 for each edge (to account for possible fractional edges
int smallW = dstM.fBounds.width() - srcM.fBounds.width() + 2;
int smallH = dstM.fBounds.height() - srcM.fBounds.height() + 2;
SkIRect innerIR;
if (1 == count) {
innerIR = srcM.fBounds;
center.set(smallW, smallH);
} else {
SkASSERT(2 == count);
rects[1].roundIn(&innerIR);
center.set(smallW + (innerIR.left() - srcM.fBounds.left()),
smallH + (innerIR.top() - srcM.fBounds.top()));
}
// +1 so we get a clean, stretchable, center row/col
smallW += 1;
smallH += 1;
// we want the inset amounts to be integral, so we don't change any
// fractional phase on the fRight or fBottom of our smallR.
const SkScalar dx = SkIntToScalar(innerIR.width() - smallW);
const SkScalar dy = SkIntToScalar(innerIR.height() - smallH);
if (dx < 0 || dy < 0) {
// we're too small, relative to our blur, to break into nine-patch,
// so we ask to have our normal filterMask() be called.
return kUnimplemented_FilterReturn;
}
smallR[0].setLTRB(rects[0].left(), rects[0].top(),
rects[0].right() - dx, rects[0].bottom() - dy);
if (smallR[0].width() < 2 || smallR[0].height() < 2) {
return kUnimplemented_FilterReturn;
}
if (2 == count) {
smallR[1].setLTRB(rects[1].left(), rects[1].top(),
rects[1].right() - dx, rects[1].bottom() - dy);
SkASSERT(!smallR[1].isEmpty());
}
const SkScalar sigma = this->computeXformedSigma(matrix);
SkCachedData* cache = find_cached_rects(&patch->fMask, sigma, fBlurStyle, smallR, count);
if (!cache) {
if (count > 1 || !c_analyticBlurNinepatch) {
if (!draw_rects_into_mask(smallR, count, &srcM)) {
return kFalse_FilterReturn;
}
SkAutoMaskFreeImage amf(srcM.fImage);
if (!this->filterMask(&patch->fMask, srcM, matrix, &margin)) {
return kFalse_FilterReturn;
}
} else {
if (!this->filterRectMask(&patch->fMask, smallR[0], matrix, &margin,
SkMask::kComputeBoundsAndRenderImage_CreateMode)) {
return kFalse_FilterReturn;
}
}
cache = add_cached_rects(&patch->fMask, sigma, fBlurStyle, smallR, count);
}
patch->fMask.fBounds.offsetTo(0, 0);
patch->fOuterRect = dstM.fBounds;
patch->fCenter = center;
SkASSERT(nullptr == patch->fCache);
patch->fCache = cache; // transfer ownership to patch
return kTrue_FilterReturn;
}
void SkBlurMaskFilterImpl::computeFastBounds(const SkRect& src,
SkRect* dst) const {
// TODO: if we're doing kInner blur, should we return a different outset?
// i.e. pad == 0 ?
SkScalar pad = 3.0f * fSigma;
dst->setLTRB(src.fLeft - pad, src.fTop - pad,
src.fRight + pad, src.fBottom + pad);
}
sk_sp<SkFlattenable> SkBlurMaskFilterImpl::CreateProc(SkReadBuffer& buffer) {
const SkScalar sigma = buffer.readScalar();
SkBlurStyle style = buffer.read32LE(kLastEnum_SkBlurStyle);
uint32_t flags = buffer.read32LE(0x3); // historically we only recorded 2 bits
bool respectCTM = !(flags & 1); // historically we stored ignoreCTM in low bit
return SkMaskFilter::MakeBlur((SkBlurStyle)style, sigma, respectCTM);
}
void SkBlurMaskFilterImpl::flatten(SkWriteBuffer& buffer) const {
buffer.writeScalar(fSigma);
buffer.writeUInt(fBlurStyle);
buffer.writeUInt(!fRespectCTM); // historically we recorded ignoreCTM
}
#if SK_SUPPORT_GPU && SK_GPU_V1
///////////////////////////////////////////////////////////////////////////////
// Circle Blur
///////////////////////////////////////////////////////////////////////////////
// Computes an unnormalized half kernel (right side). Returns the summation of all the half
// kernel values.
static float make_unnormalized_half_kernel(float* halfKernel, int halfKernelSize, float sigma) {
const float invSigma = 1.f / sigma;
const float b = -0.5f * invSigma * invSigma;
float tot = 0.0f;
// Compute half kernel values at half pixel steps out from the center.
float t = 0.5f;
for (int i = 0; i < halfKernelSize; ++i) {
float value = expf(t * t * b);
tot += value;
halfKernel[i] = value;
t += 1.f;
}
return tot;
}
// Create a Gaussian half-kernel (right side) and a summed area table given a sigma and number
// of discrete steps. The half kernel is normalized to sum to 0.5.
static void make_half_kernel_and_summed_table(float* halfKernel,
float* summedHalfKernel,
int halfKernelSize,
float sigma) {
// The half kernel should sum to 0.5 not 1.0.
const float tot = 2.f * make_unnormalized_half_kernel(halfKernel, halfKernelSize, sigma);
float sum = 0.f;
for (int i = 0; i < halfKernelSize; ++i) {
halfKernel[i] /= tot;
sum += halfKernel[i];
summedHalfKernel[i] = sum;
}
}
// Applies the 1D half kernel vertically at points along the x axis to a circle centered at the
// origin with radius circleR.
void apply_kernel_in_y(float* results,
int numSteps,
float firstX,
float circleR,
int halfKernelSize,
const float* summedHalfKernelTable) {
float x = firstX;
for (int i = 0; i < numSteps; ++i, x += 1.f) {
if (x < -circleR || x > circleR) {
results[i] = 0;
continue;
}
float y = sqrtf(circleR * circleR - x * x);
// In the column at x we exit the circle at +y and -y
// The summed table entry j is actually reflects an offset of j + 0.5.
y -= 0.5f;
int yInt = SkScalarFloorToInt(y);
SkASSERT(yInt >= -1);
if (y < 0) {
results[i] = (y + 0.5f) * summedHalfKernelTable[0];
} else if (yInt >= halfKernelSize - 1) {
results[i] = 0.5f;
} else {
float yFrac = y - yInt;
results[i] = (1.f - yFrac) * summedHalfKernelTable[yInt] +
yFrac * summedHalfKernelTable[yInt + 1];
}
}
}
// Apply a Gaussian at point (evalX, 0) to a circle centered at the origin with radius circleR.
// This relies on having a half kernel computed for the Gaussian and a table of applications of
// the half kernel in y to columns at (evalX - halfKernel, evalX - halfKernel + 1, ..., evalX +
// halfKernel) passed in as yKernelEvaluations.
static uint8_t eval_at(float evalX,
float circleR,
const float* halfKernel,
int halfKernelSize,
const float* yKernelEvaluations) {
float acc = 0;
float x = evalX - halfKernelSize;
for (int i = 0; i < halfKernelSize; ++i, x += 1.f) {
if (x < -circleR || x > circleR) {
continue;
}
float verticalEval = yKernelEvaluations[i];
acc += verticalEval * halfKernel[halfKernelSize - i - 1];
}
for (int i = 0; i < halfKernelSize; ++i, x += 1.f) {
if (x < -circleR || x > circleR) {
continue;
}
float verticalEval = yKernelEvaluations[i + halfKernelSize];
acc += verticalEval * halfKernel[i];
}
// Since we applied a half kernel in y we multiply acc by 2 (the circle is symmetric about
// the x axis).
return SkUnitScalarClampToByte(2.f * acc);
}
// This function creates a profile of a blurred circle. It does this by computing a kernel for
// half the Gaussian and a matching summed area table. The summed area table is used to compute
// an array of vertical applications of the half kernel to the circle along the x axis. The
// table of y evaluations has 2 * k + n entries where k is the size of the half kernel and n is
// the size of the profile being computed. Then for each of the n profile entries we walk out k
// steps in each horizontal direction multiplying the corresponding y evaluation by the half
// kernel entry and sum these values to compute the profile entry.
static void create_circle_profile(uint8_t* weights,
float sigma,
float circleR,
int profileTextureWidth) {
const int numSteps = profileTextureWidth;
// The full kernel is 6 sigmas wide.
int halfKernelSize = SkScalarCeilToInt(6.0f * sigma);
// round up to next multiple of 2 and then divide by 2
halfKernelSize = ((halfKernelSize + 1) & ~1) >> 1;
// Number of x steps at which to apply kernel in y to cover all the profile samples in x.
int numYSteps = numSteps + 2 * halfKernelSize;
SkAutoTArray<float> bulkAlloc(halfKernelSize + halfKernelSize + numYSteps);
float* halfKernel = bulkAlloc.get();
float* summedKernel = bulkAlloc.get() + halfKernelSize;
float* yEvals = bulkAlloc.get() + 2 * halfKernelSize;
make_half_kernel_and_summed_table(halfKernel, summedKernel, halfKernelSize, sigma);
float firstX = -halfKernelSize + 0.5f;
apply_kernel_in_y(yEvals, numYSteps, firstX, circleR, halfKernelSize, summedKernel);
for (int i = 0; i < numSteps - 1; ++i) {
float evalX = i + 0.5f;
weights[i] = eval_at(evalX, circleR, halfKernel, halfKernelSize, yEvals + i);
}
// Ensure the tail of the Gaussian goes to zero.
weights[numSteps - 1] = 0;
}
static void create_half_plane_profile(uint8_t* profile, int profileWidth) {
SkASSERT(!(profileWidth & 0x1));
// The full kernel is 6 sigmas wide.
float sigma = profileWidth / 6.f;
int halfKernelSize = profileWidth / 2;
SkAutoTArray<float> halfKernel(halfKernelSize);
// The half kernel should sum to 0.5.
const float tot = 2.f * make_unnormalized_half_kernel(halfKernel.get(), halfKernelSize, sigma);
float sum = 0.f;
// Populate the profile from the right edge to the middle.
for (int i = 0; i < halfKernelSize; ++i) {
halfKernel[halfKernelSize - i - 1] /= tot;
sum += halfKernel[halfKernelSize - i - 1];
profile[profileWidth - i - 1] = SkUnitScalarClampToByte(sum);
}
// Populate the profile from the middle to the left edge (by flipping the half kernel and
// continuing the summation).
for (int i = 0; i < halfKernelSize; ++i) {
sum += halfKernel[i];
profile[halfKernelSize - i - 1] = SkUnitScalarClampToByte(sum);
}
// Ensure tail goes to 0.
profile[profileWidth - 1] = 0;
}
static std::unique_ptr<GrFragmentProcessor> create_profile_effect(GrRecordingContext* rContext,
const SkRect& circle,
float sigma,
float* solidRadius,
float* textureRadius) {
float circleR = circle.width() / 2.0f;
if (!sk_float_isfinite(circleR) || circleR < SK_ScalarNearlyZero) {
return nullptr;
}
auto threadSafeCache = rContext->priv().threadSafeCache();
// Profile textures are cached by the ratio of sigma to circle radius and by the size of the
// profile texture (binned by powers of 2).
SkScalar sigmaToCircleRRatio = sigma / circleR;
// When sigma is really small this becomes a equivalent to convolving a Gaussian with a
// half-plane. Similarly, in the extreme high ratio cases circle becomes a point WRT to the
// Guassian and the profile texture is a just a Gaussian evaluation. However, we haven't yet
// implemented this latter optimization.
sigmaToCircleRRatio = std::min(sigmaToCircleRRatio, 8.f);
SkFixed sigmaToCircleRRatioFixed;
static const SkScalar kHalfPlaneThreshold = 0.1f;
bool useHalfPlaneApprox = false;
if (sigmaToCircleRRatio <= kHalfPlaneThreshold) {
useHalfPlaneApprox = true;
sigmaToCircleRRatioFixed = 0;
*solidRadius = circleR - 3 * sigma;
*textureRadius = 6 * sigma;
} else {
// Convert to fixed point for the key.
sigmaToCircleRRatioFixed = SkScalarToFixed(sigmaToCircleRRatio);
// We shave off some bits to reduce the number of unique entries. We could probably
// shave off more than we do.
sigmaToCircleRRatioFixed &= ~0xff;
sigmaToCircleRRatio = SkFixedToScalar(sigmaToCircleRRatioFixed);
sigma = circleR * sigmaToCircleRRatio;
*solidRadius = 0;
*textureRadius = circleR + 3 * sigma;
}
static constexpr int kProfileTextureWidth = 512;
// This would be kProfileTextureWidth/textureRadius if it weren't for the fact that we do
// the calculation of the profile coord in a coord space that has already been scaled by
// 1 / textureRadius. This is done to avoid overflow in length().
SkMatrix texM = SkMatrix::Scale(kProfileTextureWidth, 1.f);
static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
GrUniqueKey key;
GrUniqueKey::Builder builder(&key, kDomain, 1, "1-D Circular Blur");
builder[0] = sigmaToCircleRRatioFixed;
builder.finish();
GrSurfaceProxyView profileView = threadSafeCache->find(key);
if (profileView) {
SkASSERT(profileView.asTextureProxy());
SkASSERT(profileView.origin() == kTopLeft_GrSurfaceOrigin);
return GrTextureEffect::Make(std::move(profileView), kPremul_SkAlphaType, texM);
}
SkBitmap bm;
if (!bm.tryAllocPixels(SkImageInfo::MakeA8(kProfileTextureWidth, 1))) {
return nullptr;
}
if (useHalfPlaneApprox) {
create_half_plane_profile(bm.getAddr8(0, 0), kProfileTextureWidth);
} else {
// Rescale params to the size of the texture we're creating.
SkScalar scale = kProfileTextureWidth / *textureRadius;
create_circle_profile(
bm.getAddr8(0, 0), sigma * scale, circleR * scale, kProfileTextureWidth);
}
bm.setImmutable();
profileView = std::get<0>(GrMakeUncachedBitmapProxyView(rContext, bm));
if (!profileView) {
return nullptr;
}
profileView = threadSafeCache->add(key, profileView);
return GrTextureEffect::Make(std::move(profileView), kPremul_SkAlphaType, texM);
}
static std::unique_ptr<GrFragmentProcessor> make_circle_blur(GrRecordingContext* context,
const SkRect& circle,
float sigma) {
if (SkGpuBlurUtils::IsEffectivelyZeroSigma(sigma)) {
return nullptr;
}
float solidRadius;
float textureRadius;
std::unique_ptr<GrFragmentProcessor> profile =
create_profile_effect(context, circle, sigma, &solidRadius, &textureRadius);
if (!profile) {
return nullptr;
}
static auto effect = SkMakeRuntimeEffect(SkRuntimeEffect::MakeForShader, R"(
uniform shader blurProfile;
uniform half4 circleData;
half4 main(float2 xy, half4 inColor) {
// We just want to compute "(length(vec) - circleData.z + 0.5) * circleData.w" but need
// to rearrange to avoid passing large values to length() that would overflow.
half2 vec = half2((sk_FragCoord.xy - circleData.xy) * circleData.w);
half dist = length(vec) + (0.5 - circleData.z) * circleData.w;
return inColor * blurProfile.eval(half2(dist, 0.5)).a;
}
)");
SkV4 circleData = {circle.centerX(), circle.centerY(), solidRadius, 1.f / textureRadius};
return GrSkSLFP::Make(effect, "CircleBlur", /*inputFP=*/nullptr,
GrSkSLFP::OptFlags::kCompatibleWithCoverageAsAlpha,
"blurProfile", GrSkSLFP::IgnoreOptFlags(std::move(profile)),
"circleData", circleData);
}
///////////////////////////////////////////////////////////////////////////////
// Rect Blur
///////////////////////////////////////////////////////////////////////////////
static std::unique_ptr<GrFragmentProcessor> make_rect_integral_fp(GrRecordingContext* rContext,
float sixSigma) {
SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(sixSigma / 6.f));
auto threadSafeCache = rContext->priv().threadSafeCache();
int width = SkGpuBlurUtils::CreateIntegralTable(sixSigma, nullptr);
static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
GrUniqueKey key;
GrUniqueKey::Builder builder(&key, kDomain, 1, "Rect Blur Mask");
builder[0] = width;
builder.finish();
SkMatrix m = SkMatrix::Scale(width / sixSigma, 1.f);
GrSurfaceProxyView view = threadSafeCache->find(key);
if (view) {
SkASSERT(view.origin() == kTopLeft_GrSurfaceOrigin);
return GrTextureEffect::Make(
std::move(view), kPremul_SkAlphaType, m, GrSamplerState::Filter::kLinear);
}
SkBitmap bitmap;
if (!SkGpuBlurUtils::CreateIntegralTable(sixSigma, &bitmap)) {
return {};
}
view = std::get<0>(GrMakeUncachedBitmapProxyView(rContext, bitmap));
if (!view) {
return {};
}
view = threadSafeCache->add(key, view);
SkASSERT(view.origin() == kTopLeft_GrSurfaceOrigin);
return GrTextureEffect::Make(
std::move(view), kPremul_SkAlphaType, m, GrSamplerState::Filter::kLinear);
}
static std::unique_ptr<GrFragmentProcessor> make_rect_blur(GrRecordingContext* context,
const GrShaderCaps& caps,
const SkRect& srcRect,
const SkMatrix& viewMatrix,
float transformedSigma) {
SkASSERT(viewMatrix.preservesRightAngles());
SkASSERT(srcRect.isSorted());
if (SkGpuBlurUtils::IsEffectivelyZeroSigma(transformedSigma)) {
// No need to blur the rect
return nullptr;
}
SkMatrix invM;
SkRect rect;
if (viewMatrix.rectStaysRect()) {
invM = SkMatrix::I();
// We can do everything in device space when the src rect projects to a rect in device space
SkAssertResult(viewMatrix.mapRect(&rect, srcRect));
} else {
// The view matrix may scale, perhaps anisotropically. But we want to apply our device space
// "transformedSigma" to the delta of frag coord from the rect edges. Factor out the scaling
// to define a space that is purely rotation/translation from device space (and scale from
// src space) We'll meet in the middle: pre-scale the src rect to be in this space and then
// apply the inverse of the rotation/translation portion to the frag coord.
SkMatrix m;
SkSize scale;
if (!viewMatrix.decomposeScale(&scale, &m)) {
return nullptr;
}
if (!m.invert(&invM)) {
return nullptr;
}
rect = {srcRect.left() * scale.width(),
srcRect.top() * scale.height(),
srcRect.right() * scale.width(),
srcRect.bottom() * scale.height()};
}
if (!caps.floatIs32Bits()) {
// We promote the math that gets us into the Gaussian space to full float when the rect
// coords are large. If we don't have full float then fail. We could probably clip the rect
// to an outset device bounds instead.
if (SkScalarAbs(rect.fLeft) > 16000.f || SkScalarAbs(rect.fTop) > 16000.f ||
SkScalarAbs(rect.fRight) > 16000.f || SkScalarAbs(rect.fBottom) > 16000.f) {
return nullptr;
}
}
const float sixSigma = 6 * transformedSigma;
std::unique_ptr<GrFragmentProcessor> integral = make_rect_integral_fp(context, sixSigma);
if (!integral) {
return nullptr;
}
// In the fast variant we think of the midpoint of the integral texture as aligning with the
// closest rect edge both in x and y. To simplify texture coord calculation we inset the rect so
// that the edge of the inset rect corresponds to t = 0 in the texture. It actually simplifies
// things a bit in the !isFast case, too.
float threeSigma = sixSigma / 2;
SkRect insetRect = {rect.left() + threeSigma,
rect.top() + threeSigma,
rect.right() - threeSigma,
rect.bottom() - threeSigma};
// In our fast variant we find the nearest horizontal and vertical edges and for each do a
// lookup in the integral texture for each and multiply them. When the rect is less than 6 sigma
// wide then things aren't so simple and we have to consider both the left and right edge of the
// rectangle (and similar in y).
bool isFast = insetRect.isSorted();
static auto effect = SkMakeRuntimeEffect(SkRuntimeEffect::MakeForShader, R"(
// Effect that is a LUT for integral of normal distribution. The value at x:[0,6*sigma] is
// the integral from -inf to (3*sigma - x). I.e. x is mapped from [0, 6*sigma] to
// [3*sigma to -3*sigma]. The flip saves a reversal in the shader.
uniform shader integral;
uniform float4 rect;
uniform int isFast; // specialized
half4 main(float2 pos, half4 inColor) {
half xCoverage, yCoverage;
if (bool(isFast)) {
// Get the smaller of the signed distance from the frag coord to the left and right
// edges and similar for y.
// The integral texture goes "backwards" (from 3*sigma to -3*sigma), So, the below
// computations align the left edge of the integral texture with the inset rect's
// edge extending outward 6 * sigma from the inset rect.
half2 xy = max(half2(rect.LT - pos), half2(pos - rect.RB));
xCoverage = integral.eval(half2(xy.x, 0.5)).a;
yCoverage = integral.eval(half2(xy.y, 0.5)).a;
} else {
// We just consider just the x direction here. In practice we compute x and y
// separately and multiply them together.
// We define our coord system so that the point at which we're evaluating a kernel
// defined by the normal distribution (K) at 0. In this coord system let L be left
// edge and R be the right edge of the rectangle.
// We can calculate C by integrating K with the half infinite ranges outside the
// L to R range and subtracting from 1:
// C = 1 - <integral of K from from -inf to L> - <integral of K from R to inf>
// K is symmetric about x=0 so:
// C = 1 - <integral of K from from -inf to L> - <integral of K from -inf to -R>
// The integral texture goes "backwards" (from 3*sigma to -3*sigma) which is
// factored in to the below calculations.
// Also, our rect uniform was pre-inset by 3 sigma from the actual rect being
// blurred, also factored in.
half4 rect = half4(half2(rect.LT - pos), half2(pos - rect.RB));
xCoverage = 1 - integral.eval(half2(rect.L, 0.5)).a
- integral.eval(half2(rect.R, 0.5)).a;
yCoverage = 1 - integral.eval(half2(rect.T, 0.5)).a
- integral.eval(half2(rect.B, 0.5)).a;
}
return inColor * xCoverage * yCoverage;
}
)");
std::unique_ptr<GrFragmentProcessor> fp =
GrSkSLFP::Make(effect, "RectBlur", /*inputFP=*/nullptr,
GrSkSLFP::OptFlags::kCompatibleWithCoverageAsAlpha,
"integral", GrSkSLFP::IgnoreOptFlags(std::move(integral)),
"rect", insetRect,
"isFast", GrSkSLFP::Specialize<int>(isFast));
if (!invM.isIdentity()) {
fp = GrMatrixEffect::Make(invM, std::move(fp));
}
return GrFragmentProcessor::DeviceSpace(std::move(fp));
}
///////////////////////////////////////////////////////////////////////////////
// RRect Blur
///////////////////////////////////////////////////////////////////////////////
static constexpr auto kBlurredRRectMaskOrigin = kTopLeft_GrSurfaceOrigin;
static void make_blurred_rrect_key(GrUniqueKey* key,
const SkRRect& rrectToDraw,
float xformedSigma) {
SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
GrUniqueKey::Builder builder(key, kDomain, 9, "RoundRect Blur Mask");
builder[0] = SkScalarCeilToInt(xformedSigma - 1 / 6.0f);
int index = 1;
// TODO: this is overkill for _simple_ circular rrects
for (auto c : {SkRRect::kUpperLeft_Corner,
SkRRect::kUpperRight_Corner,
SkRRect::kLowerRight_Corner,
SkRRect::kLowerLeft_Corner}) {
SkASSERT(SkScalarIsInt(rrectToDraw.radii(c).fX) && SkScalarIsInt(rrectToDraw.radii(c).fY));
builder[index++] = SkScalarCeilToInt(rrectToDraw.radii(c).fX);
builder[index++] = SkScalarCeilToInt(rrectToDraw.radii(c).fY);
}
builder.finish();
}
static bool fillin_view_on_gpu(GrDirectContext* dContext,
const GrSurfaceProxyView& lazyView,
sk_sp<GrThreadSafeCache::Trampoline> trampoline,
const SkRRect& rrectToDraw,
const SkISize& dimensions,
float xformedSigma) {
#if SK_GPU_V1
SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
// We cache blur masks. Use default surface props here so we can use the same cached mask
// regardless of the final dst surface.
SkSurfaceProps defaultSurfaceProps;
std::unique_ptr<skgpu::v1::SurfaceDrawContext> sdc =
skgpu::v1::SurfaceDrawContext::MakeWithFallback(dContext,
GrColorType::kAlpha_8,
nullptr,
SkBackingFit::kExact,
dimensions,
defaultSurfaceProps,
1,
GrMipmapped::kNo,
GrProtected::kNo,
kBlurredRRectMaskOrigin);
if (!sdc) {
return false;
}
GrPaint paint;
sdc->clear(SK_PMColor4fTRANSPARENT);
sdc->drawRRect(nullptr,
std::move(paint),
GrAA::kYes,
SkMatrix::I(),
rrectToDraw,
GrStyle::SimpleFill());
GrSurfaceProxyView srcView = sdc->readSurfaceView();
SkASSERT(srcView.asTextureProxy());
auto rtc2 = SkGpuBlurUtils::GaussianBlur(dContext,
std::move(srcView),
sdc->colorInfo().colorType(),
sdc->colorInfo().alphaType(),
nullptr,
SkIRect::MakeSize(dimensions),
SkIRect::MakeSize(dimensions),
xformedSigma,
xformedSigma,
SkTileMode::kClamp,
SkBackingFit::kExact);
if (!rtc2 || !rtc2->readSurfaceView()) {
return false;
}
auto view = rtc2->readSurfaceView();
SkASSERT(view.swizzle() == lazyView.swizzle());
SkASSERT(view.origin() == lazyView.origin());
trampoline->fProxy = view.asTextureProxyRef();
return true;
#else
return false;
#endif
}
// Evaluate the vertical blur at the specified 'y' value given the location of the top of the
// rrect.
static uint8_t eval_V(float top, int y, const uint8_t* integral, int integralSize, float sixSigma) {
if (top < 0) {
return 0; // an empty column
}
float fT = (top - y - 0.5f) * (integralSize / sixSigma);
if (fT < 0) {
return 255;
} else if (fT >= integralSize - 1) {
return 0;
}
int lower = (int)fT;
float frac = fT - lower;
SkASSERT(lower + 1 < integralSize);
return integral[lower] * (1.0f - frac) + integral[lower + 1] * frac;
}
// Apply a gaussian 'kernel' horizontally at the specified 'x', 'y' location.
static uint8_t eval_H(int x,
int y,
const std::vector<float>& topVec,
const float* kernel,
int kernelSize,
const uint8_t* integral,
int integralSize,
float sixSigma) {
SkASSERT(0 <= x && x < (int)topVec.size());
SkASSERT(kernelSize % 2);
float accum = 0.0f;
int xSampleLoc = x - (kernelSize / 2);
for (int i = 0; i < kernelSize; ++i, ++xSampleLoc) {
if (xSampleLoc < 0 || xSampleLoc >= (int)topVec.size()) {
continue;
}
accum += kernel[i] * eval_V(topVec[xSampleLoc], y, integral, integralSize, sixSigma);
}
return accum + 0.5f;
}
// Create a cpu-side blurred-rrect mask that is close to the version the gpu would've produced.
// The match needs to be close bc the cpu- and gpu-generated version must be interchangeable.
static GrSurfaceProxyView create_mask_on_cpu(GrRecordingContext* rContext,
const SkRRect& rrectToDraw,
const SkISize& dimensions,
float xformedSigma) {
SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
int radius = SkGpuBlurUtils::SigmaRadius(xformedSigma);
int kernelSize = 2 * radius + 1;
SkASSERT(kernelSize % 2);
SkASSERT(dimensions.width() % 2);
SkASSERT(dimensions.height() % 2);
SkVector radii = rrectToDraw.getSimpleRadii();
SkASSERT(SkScalarNearlyEqual(radii.fX, radii.fY));
const int halfWidthPlus1 = (dimensions.width() / 2) + 1;
const int halfHeightPlus1 = (dimensions.height() / 2) + 1;
std::unique_ptr<float[]> kernel(new float[kernelSize]);
SkGpuBlurUtils::Compute1DGaussianKernel(kernel.get(), xformedSigma, radius);
SkBitmap integral;
if (!SkGpuBlurUtils::CreateIntegralTable(6 * xformedSigma, &integral)) {
return {};
}
SkBitmap result;
if (!result.tryAllocPixels(SkImageInfo::MakeA8(dimensions.width(), dimensions.height()))) {
return {};
}
std::vector<float> topVec;
topVec.reserve(dimensions.width());
for (int x = 0; x < dimensions.width(); ++x) {
if (x < rrectToDraw.rect().fLeft || x > rrectToDraw.rect().fRight) {
topVec.push_back(-1);
} else {
if (x + 0.5f < rrectToDraw.rect().fLeft + radii.fX) { // in the circular section
float xDist = rrectToDraw.rect().fLeft + radii.fX - x - 0.5f;
float h = sqrtf(radii.fX * radii.fX - xDist * xDist);
SkASSERT(0 <= h && h < radii.fY);
topVec.push_back(rrectToDraw.rect().fTop + radii.fX - h + 3 * xformedSigma);
} else {
topVec.push_back(rrectToDraw.rect().fTop + 3 * xformedSigma);
}
}
}
for (int y = 0; y < halfHeightPlus1; ++y) {
uint8_t* scanline = result.getAddr8(0, y);
for (int x = 0; x < halfWidthPlus1; ++x) {
scanline[x] = eval_H(x,
y,
topVec,
kernel.get(),
kernelSize,
integral.getAddr8(0, 0),
integral.width(),
6 * xformedSigma);
scanline[dimensions.width() - x - 1] = scanline[x];
}
memcpy(result.getAddr8(0, dimensions.height() - y - 1), scanline, result.rowBytes());
}
result.setImmutable();
auto view = std::get<0>(GrMakeUncachedBitmapProxyView(rContext, result));
if (!view) {
return {};
}
SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
return view;
}
static std::unique_ptr<GrFragmentProcessor> find_or_create_rrect_blur_mask_fp(
GrRecordingContext* rContext,
const SkRRect& rrectToDraw,
const SkISize& dimensions,
float xformedSigma) {
SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
GrUniqueKey key;
make_blurred_rrect_key(&key, rrectToDraw, xformedSigma);
auto threadSafeCache = rContext->priv().threadSafeCache();
// It seems like we could omit this matrix and modify the shader code to not normalize
// the coords used to sample the texture effect. However, the "proxyDims" value in the
// shader is not always the actual the proxy dimensions. This is because 'dimensions' here
// was computed using integer corner radii as determined in
// SkComputeBlurredRRectParams whereas the shader code uses the float radius to compute
// 'proxyDims'. Why it draws correctly with these unequal values is a mystery for the ages.
auto m = SkMatrix::Scale(dimensions.width(), dimensions.height());
GrSurfaceProxyView view;
if (GrDirectContext* dContext = rContext->asDirectContext()) {
// The gpu thread gets priority over the recording threads. If the gpu thread is first,
// it crams a lazy proxy into the cache and then fills it in later.
#ifndef SKIA_STRUCTURED_BINDINGS_BACKPORT
auto [lazyView, trampoline] = GrThreadSafeCache::CreateLazyView(dContext,
GrColorType::kAlpha_8,
dimensions,
kBlurredRRectMaskOrigin,
SkBackingFit::kExact);
#else
STRUCTURED_BINDING_2(lazyView, trampoline, GrThreadSafeCache::CreateLazyView(dContext,
GrColorType::kAlpha_8,
dimensions,
kBlurredRRectMaskOrigin,
SkBackingFit::kExact));
#endif
if (!lazyView) {
return nullptr;
}
view = threadSafeCache->findOrAdd(key, lazyView);
if (view != lazyView) {
SkASSERT(view.asTextureProxy());
SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
return GrTextureEffect::Make(std::move(view), kPremul_SkAlphaType, m);
}
if (!fillin_view_on_gpu(dContext,
lazyView,
std::move(trampoline),
rrectToDraw,
dimensions,
xformedSigma)) {
// In this case something has gone disastrously wrong so set up to drop the draw
// that needed this resource and reduce future pollution of the cache.
threadSafeCache->remove(key);
return nullptr;
}
} else {
view = threadSafeCache->find(key);
if (view) {
SkASSERT(view.asTextureProxy());
SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
return GrTextureEffect::Make(std::move(view), kPremul_SkAlphaType, m);
}
view = create_mask_on_cpu(rContext, rrectToDraw, dimensions, xformedSigma);
if (!view) {
return nullptr;
}
view = threadSafeCache->add(key, view);
}
SkASSERT(view.asTextureProxy());
SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
return GrTextureEffect::Make(std::move(view), kPremul_SkAlphaType, m);
}
static std::unique_ptr<GrFragmentProcessor> make_rrect_blur(GrRecordingContext* context,
float sigma,
float xformedSigma,
const SkRRect& srcRRect,
const SkRRect& devRRect) {
// Should've been caught up-stream
#ifdef SK_DEBUG
SkASSERTF(!SkRRectPriv::IsCircle(devRRect),
"Unexpected circle. %d\n\t%s\n\t%s",
SkRRectPriv::IsCircle(srcRRect),
srcRRect.dumpToString(true).c_str(),
devRRect.dumpToString(true).c_str());
SkASSERTF(!devRRect.isRect(),
"Unexpected rect. %d\n\t%s\n\t%s",
srcRRect.isRect(),
srcRRect.dumpToString(true).c_str(),
devRRect.dumpToString(true).c_str());
#endif
// TODO: loosen this up
if (!SkRRectPriv::IsSimpleCircular(devRRect)) {
return nullptr;
}
if (SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma)) {
return nullptr;
}
// Make sure we can successfully ninepatch this rrect -- the blur sigma has to be sufficiently
// small relative to both the size of the corner radius and the width (and height) of the rrect.
SkRRect rrectToDraw;
SkISize dimensions;
SkScalar ignored[SkGpuBlurUtils::kBlurRRectMaxDivisions];
bool ninePatchable = SkGpuBlurUtils::ComputeBlurredRRectParams(srcRRect,
devRRect,
sigma,
xformedSigma,
&rrectToDraw,
&dimensions,
ignored,
ignored,
ignored,
ignored);
if (!ninePatchable) {
return nullptr;
}
std::unique_ptr<GrFragmentProcessor> maskFP =
find_or_create_rrect_blur_mask_fp(context, rrectToDraw, dimensions, xformedSigma);
if (!maskFP) {
return nullptr;
}
static auto effect = SkMakeRuntimeEffect(SkRuntimeEffect::MakeForShader, R"(
uniform shader ninePatchFP;
uniform half cornerRadius;
uniform float4 proxyRect;
uniform half blurRadius;
half4 main(float2 xy, half4 inColor) {
// Warp the fragment position to the appropriate part of the 9-patch blur texture by
// snipping out the middle section of the proxy rect.
float2 translatedFragPosFloat = sk_FragCoord.xy - proxyRect.LT;
float2 proxyCenter = (proxyRect.RB - proxyRect.LT) * 0.5;
half edgeSize = 2.0 * blurRadius + cornerRadius + 0.5;
// Position the fragment so that (0, 0) marks the center of the proxy rectangle.
// Negative coordinates are on the left/top side and positive numbers are on the
// right/bottom.
translatedFragPosFloat -= proxyCenter;
// Temporarily strip off the fragment's sign. x/y are now strictly increasing as we
// move away from the center.
half2 fragDirection = half2(sign(translatedFragPosFloat));
translatedFragPosFloat = abs(translatedFragPosFloat);
// Our goal is to snip out the "middle section" of the proxy rect (everything but the
// edge). We've repositioned our fragment position so that (0, 0) is the centerpoint
// and x/y are always positive, so we can subtract here and interpret negative results
// as being within the middle section.
half2 translatedFragPosHalf = half2(translatedFragPosFloat - (proxyCenter - edgeSize));
// Remove the middle section by clamping to zero.
translatedFragPosHalf = max(translatedFragPosHalf, 0);
// Reapply the fragment's sign, so that negative coordinates once again mean left/top
// side and positive means bottom/right side.
translatedFragPosHalf *= fragDirection;
// Offset the fragment so that (0, 0) marks the upper-left again, instead of the center
// point.
translatedFragPosHalf += half2(edgeSize);
half2 proxyDims = half2(2.0 * edgeSize);
half2 texCoord = translatedFragPosHalf / proxyDims;
return inColor * ninePatchFP.eval(texCoord).a;
}
)");
float cornerRadius = SkRRectPriv::GetSimpleRadii(devRRect).fX;
float blurRadius = 3.f * SkScalarCeilToScalar(xformedSigma - 1 / 6.0f);
SkRect proxyRect = devRRect.getBounds().makeOutset(blurRadius, blurRadius);
return GrSkSLFP::Make(effect, "RRectBlur", /*inputFP=*/nullptr,
GrSkSLFP::OptFlags::kCompatibleWithCoverageAsAlpha,
"ninePatchFP", GrSkSLFP::IgnoreOptFlags(std::move(maskFP)),
"cornerRadius", cornerRadius,
"proxyRect", proxyRect,
"blurRadius", blurRadius);
}
///////////////////////////////////////////////////////////////////////////////
bool SkBlurMaskFilterImpl::directFilterMaskGPU(GrRecordingContext* context,
skgpu::v1::SurfaceDrawContext* sdc,
GrPaint&& paint,
const GrClip* clip,
const SkMatrix& viewMatrix,
const GrStyledShape& shape) const {
SkASSERT(sdc);
if (fBlurStyle != kNormal_SkBlurStyle) {
return false;
}
// TODO: we could handle blurred stroked circles
if (!shape.style().isSimpleFill()) {
return false;
}
SkScalar xformedSigma = this->computeXformedSigma(viewMatrix);
if (SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma)) {
sdc->drawShape(clip, std::move(paint), GrAA::kYes, viewMatrix, GrStyledShape(shape));
return true;
}
SkRRect srcRRect;
bool inverted;
if (!shape.asRRect(&srcRRect, nullptr, nullptr, &inverted) || inverted) {
return false;
}
std::unique_ptr<GrFragmentProcessor> fp;
SkRRect devRRect;
bool devRRectIsValid = srcRRect.transform(viewMatrix, &devRRect);
bool devRRectIsCircle = devRRectIsValid && SkRRectPriv::IsCircle(devRRect);
bool canBeRect = srcRRect.isRect() && viewMatrix.preservesRightAngles();
bool canBeCircle = (SkRRectPriv::IsCircle(srcRRect) && viewMatrix.isSimilarity()) ||
devRRectIsCircle;
if (canBeRect || canBeCircle) {
if (canBeRect) {
fp = make_rect_blur(context, *context->priv().caps()->shaderCaps(),
srcRRect.rect(), viewMatrix, xformedSigma);
} else {
SkRect devBounds;
if (devRRectIsCircle) {
devBounds = devRRect.getBounds();
} else {
SkPoint center = {srcRRect.getBounds().centerX(), srcRRect.getBounds().centerY()};
viewMatrix.mapPoints(&center, 1);
SkScalar radius = viewMatrix.mapVector(0, srcRRect.width()/2.f).length();
devBounds = {center.x() - radius,
center.y() - radius,
center.x() + radius,
center.y() + radius};
}
fp = make_circle_blur(context, devBounds, xformedSigma);
}
if (!fp) {
return false;
}
paint.setCoverageFragmentProcessor(std::move(fp));
SkRect srcProxyRect = srcRRect.rect();
// Determine how much to outset the src rect to ensure we hit pixels within three sigma.
SkScalar outsetX = 3.0f*xformedSigma;
SkScalar outsetY = 3.0f*xformedSigma;
if (viewMatrix.isScaleTranslate()) {
outsetX /= SkScalarAbs(viewMatrix.getScaleX());
outsetY /= SkScalarAbs(viewMatrix.getScaleY());
} else {
SkSize scale;
if (!viewMatrix.decomposeScale(&scale, nullptr)) {
return false;
}
outsetX /= scale.width();
outsetY /= scale.height();
}
srcProxyRect.outset(outsetX, outsetY);
sdc->drawRect(clip, std::move(paint), GrAA::kNo, viewMatrix, srcProxyRect);
return true;
}
if (!viewMatrix.isScaleTranslate()) {
return false;
}
if (!devRRectIsValid || !SkRRectPriv::AllCornersCircular(devRRect)) {
return false;
}
fp = make_rrect_blur(context, fSigma, xformedSigma, srcRRect, devRRect);
if (!fp) {
return false;
}
if (!this->ignoreXform()) {
SkRect srcProxyRect = srcRRect.rect();
srcProxyRect.outset(3.0f*fSigma, 3.0f*fSigma);
paint.setCoverageFragmentProcessor(std::move(fp));
sdc->drawRect(clip, std::move(paint), GrAA::kNo, viewMatrix, srcProxyRect);
} else {
SkMatrix inverse;
if (!viewMatrix.invert(&inverse)) {
return false;
}
SkIRect proxyBounds;
float extra=3.f*SkScalarCeilToScalar(xformedSigma-1/6.0f);
devRRect.rect().makeOutset(extra, extra).roundOut(&proxyBounds);
paint.setCoverageFragmentProcessor(std::move(fp));
sdc->fillPixelsWithLocalMatrix(clip, std::move(paint), proxyBounds, inverse);
}
return true;
}
bool SkBlurMaskFilterImpl::canFilterMaskGPU(const GrStyledShape& shape,
const SkIRect& devSpaceShapeBounds,
const SkIRect& clipBounds,
const SkMatrix& ctm,
SkIRect* maskRect) const {
SkScalar xformedSigma = this->computeXformedSigma(ctm);
if (SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma)) {
*maskRect = devSpaceShapeBounds;
return maskRect->intersect(clipBounds);
}
if (maskRect) {
float sigma3 = 3 * SkScalarToFloat(xformedSigma);
// Outset srcRect and clipRect by 3 * sigma, to compute affected blur area.
SkIRect clipRect = clipBounds.makeOutset(sigma3, sigma3);
SkIRect srcRect = devSpaceShapeBounds.makeOutset(sigma3, sigma3);
if (!srcRect.intersect(clipRect)) {
srcRect.setEmpty();
}
*maskRect = srcRect;
}
// We prefer to blur paths with small blur radii on the CPU.
static const SkScalar kMIN_GPU_BLUR_SIZE = SkIntToScalar(64);
static const SkScalar kMIN_GPU_BLUR_SIGMA = SkIntToScalar(32);
if (devSpaceShapeBounds.width() <= kMIN_GPU_BLUR_SIZE &&
devSpaceShapeBounds.height() <= kMIN_GPU_BLUR_SIZE &&
xformedSigma <= kMIN_GPU_BLUR_SIGMA) {
return false;
}
return true;
}
GrSurfaceProxyView SkBlurMaskFilterImpl::filterMaskGPU(GrRecordingContext* context,
GrSurfaceProxyView srcView,
GrColorType srcColorType,
SkAlphaType srcAlphaType,
const SkMatrix& ctm,
const SkIRect& maskRect) const {
// 'maskRect' isn't snapped to the UL corner but the mask in 'src' is.
const SkIRect clipRect = SkIRect::MakeWH(maskRect.width(), maskRect.height());
SkScalar xformedSigma = this->computeXformedSigma(ctm);
// If we're doing a normal blur, we can clobber the pathTexture in the
// gaussianBlur. Otherwise, we need to save it for later compositing.
bool isNormalBlur = (kNormal_SkBlurStyle == fBlurStyle);
auto srcBounds = SkIRect::MakeSize(srcView.proxy()->dimensions());
auto surfaceDrawContext = SkGpuBlurUtils::GaussianBlur(context,
srcView,
srcColorType,
srcAlphaType,
nullptr,
clipRect,
srcBounds,
xformedSigma,
xformedSigma,
SkTileMode::kClamp);
if (!surfaceDrawContext || !surfaceDrawContext->asTextureProxy()) {
return {};
}
if (!isNormalBlur) {
GrPaint paint;
// Blend pathTexture over blurTexture.
paint.setCoverageFragmentProcessor(GrTextureEffect::Make(std::move(srcView), srcAlphaType));
if (kInner_SkBlurStyle == fBlurStyle) {
// inner: dst = dst * src
paint.setCoverageSetOpXPFactory(SkRegion::kIntersect_Op);
} else if (kSolid_SkBlurStyle == fBlurStyle) {
// solid: dst = src + dst - src * dst
// = src + (1 - src) * dst
paint.setCoverageSetOpXPFactory(SkRegion::kUnion_Op);
} else if (kOuter_SkBlurStyle == fBlurStyle) {
// outer: dst = dst * (1 - src)
// = 0 * src + (1 - src) * dst
paint.setCoverageSetOpXPFactory(SkRegion::kDifference_Op);
} else {
paint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);
}
surfaceDrawContext->fillPixelsWithLocalMatrix(nullptr, std::move(paint), clipRect,
SkMatrix::I());
}
return surfaceDrawContext->readSurfaceView();
}
#endif // SK_SUPPORT_GPU && SK_GPU_V1
void sk_register_blur_maskfilter_createproc() { SK_REGISTER_FLATTENABLE(SkBlurMaskFilterImpl); }
sk_sp<SkMaskFilter> SkMaskFilter::MakeBlur(SkBlurStyle style, SkScalar sigma, bool respectCTM) {
if (SkScalarIsFinite(sigma) && sigma > 0) {
return sk_sp<SkMaskFilter>(new SkBlurMaskFilterImpl(sigma, style, respectCTM));
}
return nullptr;
}