/*
|
* Copyright 2011 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 "SkBlurImageFilter.h"
|
|
#include <algorithm>
|
|
#include "SkArenaAlloc.h"
|
#include "SkAutoPixmapStorage.h"
|
#include "SkBitmap.h"
|
#include "SkColorData.h"
|
#include "SkColorSpaceXformer.h"
|
#include "SkImageFilterPriv.h"
|
#include "SkTFitsIn.h"
|
#include "SkGpuBlurUtils.h"
|
#include "SkNx.h"
|
#include "SkOpts.h"
|
#include "SkReadBuffer.h"
|
#include "SkSpecialImage.h"
|
#include "SkWriteBuffer.h"
|
|
#if SK_SUPPORT_GPU
|
#include "GrContext.h"
|
#include "GrTextureProxy.h"
|
#include "SkGr.h"
|
#endif
|
|
static constexpr double kPi = 3.14159265358979323846264338327950288;
|
|
class SkBlurImageFilterImpl final : public SkImageFilter {
|
public:
|
SkBlurImageFilterImpl(SkScalar sigmaX,
|
SkScalar sigmaY,
|
sk_sp<SkImageFilter> input,
|
const CropRect* cropRect,
|
SkBlurImageFilter::TileMode tileMode);
|
|
SkRect computeFastBounds(const SkRect&) const override;
|
|
protected:
|
void flatten(SkWriteBuffer&) const override;
|
sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
|
SkIPoint* offset) const override;
|
sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
|
SkIRect onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
|
MapDirection, const SkIRect* inputRect) const override;
|
|
private:
|
SK_FLATTENABLE_HOOKS(SkBlurImageFilterImpl)
|
|
typedef SkImageFilter INHERITED;
|
friend class SkImageFilter;
|
|
#if SK_SUPPORT_GPU
|
sk_sp<SkSpecialImage> gpuFilter(
|
SkSpecialImage *source, SkVector sigma, const sk_sp<SkSpecialImage> &input,
|
SkIRect inputBounds, SkIRect dstBounds, SkIPoint inputOffset,
|
const OutputProperties& outProps, SkIPoint* offset) const;
|
#endif
|
|
SkSize fSigma;
|
SkBlurImageFilter::TileMode fTileMode;
|
};
|
|
void SkImageFilter::RegisterFlattenables() { SK_REGISTER_FLATTENABLE(SkBlurImageFilterImpl); }
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
sk_sp<SkImageFilter> SkBlurImageFilter::Make(SkScalar sigmaX, SkScalar sigmaY,
|
sk_sp<SkImageFilter> input,
|
const SkImageFilter::CropRect* cropRect,
|
TileMode tileMode) {
|
if (sigmaX < SK_ScalarNearlyZero && sigmaY < SK_ScalarNearlyZero && !cropRect) {
|
return input;
|
}
|
return sk_sp<SkImageFilter>(
|
new SkBlurImageFilterImpl(sigmaX, sigmaY, input, cropRect, tileMode));
|
}
|
|
// This rather arbitrary-looking value results in a maximum box blur kernel size
|
// of 1000 pixels on the raster path, which matches the WebKit and Firefox
|
// implementations. Since the GPU path does not compute a box blur, putting
|
// the limit on sigma ensures consistent behaviour between the GPU and
|
// raster paths.
|
#define MAX_SIGMA SkIntToScalar(532)
|
|
static SkVector map_sigma(const SkSize& localSigma, const SkMatrix& ctm) {
|
SkVector sigma = SkVector::Make(localSigma.width(), localSigma.height());
|
ctm.mapVectors(&sigma, 1);
|
sigma.fX = SkMinScalar(SkScalarAbs(sigma.fX), MAX_SIGMA);
|
sigma.fY = SkMinScalar(SkScalarAbs(sigma.fY), MAX_SIGMA);
|
return sigma;
|
}
|
|
SkBlurImageFilterImpl::SkBlurImageFilterImpl(SkScalar sigmaX,
|
SkScalar sigmaY,
|
sk_sp<SkImageFilter> input,
|
const CropRect* cropRect,
|
SkBlurImageFilter::TileMode tileMode)
|
: INHERITED(&input, 1, cropRect), fSigma{sigmaX, sigmaY}, fTileMode(tileMode) {}
|
|
sk_sp<SkFlattenable> SkBlurImageFilterImpl::CreateProc(SkReadBuffer& buffer) {
|
SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
|
SkScalar sigmaX = buffer.readScalar();
|
SkScalar sigmaY = buffer.readScalar();
|
SkBlurImageFilter::TileMode tileMode;
|
if (buffer.isVersionLT(SkReadBuffer::kTileModeInBlurImageFilter_Version)) {
|
tileMode = SkBlurImageFilter::kClampToBlack_TileMode;
|
} else {
|
tileMode = buffer.read32LE(SkBlurImageFilter::kLast_TileMode);
|
}
|
|
static_assert(SkBlurImageFilter::kLast_TileMode == 2, "CreateProc");
|
|
return SkBlurImageFilter::Make(
|
sigmaX, sigmaY, common.getInput(0), &common.cropRect(), tileMode);
|
}
|
|
void SkBlurImageFilterImpl::flatten(SkWriteBuffer& buffer) const {
|
this->INHERITED::flatten(buffer);
|
buffer.writeScalar(fSigma.fWidth);
|
buffer.writeScalar(fSigma.fHeight);
|
|
static_assert(SkBlurImageFilter::kLast_TileMode == 2, "flatten");
|
SkASSERT(fTileMode <= SkBlurImageFilter::kLast_TileMode);
|
|
buffer.writeInt(static_cast<int>(fTileMode));
|
}
|
|
#if SK_SUPPORT_GPU
|
static GrTextureDomain::Mode to_texture_domain_mode(SkBlurImageFilter::TileMode tileMode) {
|
switch (tileMode) {
|
case SkBlurImageFilter::TileMode::kClamp_TileMode:
|
return GrTextureDomain::kClamp_Mode;
|
case SkBlurImageFilter::TileMode::kClampToBlack_TileMode:
|
return GrTextureDomain::kDecal_Mode;
|
case SkBlurImageFilter::TileMode::kRepeat_TileMode:
|
return GrTextureDomain::kRepeat_Mode;
|
default:
|
SK_ABORT("Unsupported tile mode.");
|
return GrTextureDomain::kDecal_Mode;
|
}
|
}
|
#endif
|
|
// This is defined by the SVG spec:
|
// https://drafts.fxtf.org/filter-effects/#feGaussianBlurElement
|
static int calculate_window(double sigma) {
|
// NB 136 is the largest sigma that will not cause a buffer full of 255 mask values to overflow
|
// using the Gauss filter. It also limits the size of buffers used hold intermediate values.
|
// Explanation of maximums:
|
// sum0 = window * 255
|
// sum1 = window * sum0 -> window * window * 255
|
// sum2 = window * sum1 -> window * window * window * 255 -> window^3 * 255
|
//
|
// The value window^3 * 255 must fit in a uint32_t. So,
|
// window^3 < 2^32. window = 255.
|
//
|
// window = floor(sigma * 3 * sqrt(2 * kPi) / 4 + 0.5)
|
// For window <= 255, the largest value for sigma is 136.
|
sigma = SkTPin(sigma, 0.0, 136.0);
|
auto possibleWindow = static_cast<int>(floor(sigma * 3 * sqrt(2 * kPi) / 4 + 0.5));
|
return std::max(1, possibleWindow);
|
}
|
|
// Calculating the border is tricky. The border is the distance in pixels between the first dst
|
// pixel and the first src pixel (or the last src pixel and the last dst pixel).
|
// I will go through the odd case which is simpler, and then through the even case. Given a
|
// stack of filters seven wide for the odd case of three passes.
|
//
|
// S
|
// aaaAaaa
|
// bbbBbbb
|
// cccCccc
|
// D
|
//
|
// The furthest changed pixel is when the filters are in the following configuration.
|
//
|
// S
|
// aaaAaaa
|
// bbbBbbb
|
// cccCccc
|
// D
|
//
|
// The A pixel is calculated using the value S, the B uses A, and the C uses B, and
|
// finally D is C. So, with a window size of seven the border is nine. In the odd case, the
|
// border is 3*((window - 1)/2).
|
//
|
// For even cases the filter stack is more complicated. The spec specifies two passes
|
// of even filters and a final pass of odd filters. A stack for a width of six looks like
|
// this.
|
//
|
// S
|
// aaaAaa
|
// bbBbbb
|
// cccCccc
|
// D
|
//
|
// The furthest pixel looks like this.
|
//
|
// S
|
// aaaAaa
|
// bbBbbb
|
// cccCccc
|
// D
|
//
|
// For a window of six, the border value is eight. In the even case the border is 3 *
|
// (window/2) - 1.
|
static int calculate_border(int window) {
|
return (window & 1) == 1 ? 3 * ((window - 1) / 2) : 3 * (window / 2) - 1;
|
}
|
|
static int calculate_buffer(int window) {
|
int bufferSize = window - 1;
|
return (window & 1) == 1 ? 3 * bufferSize : 3 * bufferSize + 1;
|
}
|
|
// blur_one_direction implements the common three pass box filter approximation of Gaussian blur,
|
// but combines all three passes into a single pass. This approach is facilitated by three circular
|
// buffers the width of the window which track values for trailing edges of each of the three
|
// passes. This allows the algorithm to use more precision in the calculation because the values
|
// are not rounded each pass. And this implementation also avoids a trap that's easy to fall
|
// into resulting in blending in too many zeroes near the edge.
|
//
|
// In general, a window sum has the form:
|
// sum_n+1 = sum_n + leading_edge - trailing_edge.
|
// If instead we do the subtraction at the end of the previous iteration, we can just
|
// calculate the sums instead of having to do the subtractions too.
|
//
|
// In previous iteration:
|
// sum_n+1 = sum_n - trailing_edge.
|
//
|
// In this iteration:
|
// sum_n+1 = sum_n + leading_edge.
|
//
|
// Now we can stack all three sums and do them at once. Sum0 gets its leading edge from the
|
// actual data. Sum1's leading edge is just Sum0, and Sum2's leading edge is Sum1. So, doing the
|
// three passes at the same time has the form:
|
//
|
// sum0_n+1 = sum0_n + leading edge
|
// sum1_n+1 = sum1_n + sum0_n+1
|
// sum2_n+1 = sum2_n + sum1_n+1
|
//
|
// sum2_n+1 / window^3 is the new value of the destination pixel.
|
//
|
// Reduce the sums by the trailing edges which were stored in the circular buffers,
|
// for the next go around. This is the case for odd sized windows, even windows the the third
|
// circular buffer is one larger then the first two circular buffers.
|
//
|
// sum2_n+2 = sum2_n+1 - buffer2[i];
|
// buffer2[i] = sum1;
|
// sum1_n+2 = sum1_n+1 - buffer1[i];
|
// buffer1[i] = sum0;
|
// sum0_n+2 = sum0_n+1 - buffer0[i];
|
// buffer0[i] = leading edge
|
//
|
// This is all encapsulated in the processValue function below.
|
//
|
using Pass0And1 = Sk4u[2];
|
// The would be dLeft parameter is assumed to be 0.
|
static void blur_one_direction(Sk4u* buffer, int window,
|
int srcLeft, int srcRight, int dstRight,
|
const uint32_t* src, int srcXStride, int srcYStride, int srcH,
|
uint32_t* dst, int dstXStride, int dstYStride) {
|
|
// The circular buffers are one less than the window.
|
auto pass0Count = window - 1,
|
pass1Count = window - 1,
|
pass2Count = (window & 1) == 1 ? window - 1 : window;
|
|
Pass0And1* buffer01Start = (Pass0And1*)buffer;
|
Sk4u* buffer2Start = buffer + pass0Count + pass1Count;
|
Pass0And1* buffer01End = (Pass0And1*)buffer2Start;
|
Sk4u* buffer2End = buffer2Start + pass2Count;
|
|
// If the window is odd then the divisor is just window ^ 3 otherwise,
|
// it is window * window * (window + 1) = window ^ 3 + window ^ 2;
|
auto window2 = window * window;
|
auto window3 = window2 * window;
|
auto divisor = (window & 1) == 1 ? window3 : window3 + window2;
|
|
// NB the sums in the blur code use the following technique to avoid
|
// adding 1/2 to round the divide.
|
//
|
// Sum/d + 1/2 == (Sum + h) / d
|
// Sum + d(1/2) == Sum + h
|
// h == (1/2)d
|
//
|
// But the d/2 it self should be rounded.
|
// h == d/2 + 1/2 == (d + 1) / 2
|
//
|
// weight = 1 / d * 2 ^ 32
|
auto weight = static_cast<uint32_t>(round(1.0 / divisor * (1ull << 32)));
|
auto half = static_cast<uint32_t>((divisor + 1) / 2);
|
|
auto border = calculate_border(window);
|
|
// Calculate the start and end of the source pixels with respect to the destination start.
|
auto srcStart = srcLeft - border,
|
srcEnd = srcRight - border,
|
dstEnd = dstRight;
|
|
for (auto y = 0; y < srcH; y++) {
|
auto buffer01Cursor = buffer01Start;
|
auto buffer2Cursor = buffer2Start;
|
|
Sk4u sum0{0u};
|
Sk4u sum1{0u};
|
Sk4u sum2{half};
|
|
sk_bzero(buffer01Start, (buffer2End - (Sk4u *) (buffer01Start)) * sizeof(*buffer2Start));
|
|
// Given an expanded input pixel, move the window ahead using the leadingEdge value.
|
auto processValue = [&](const Sk4u& leadingEdge) -> Sk4u {
|
sum0 += leadingEdge;
|
sum1 += sum0;
|
sum2 += sum1;
|
|
Sk4u value = sum2.mulHi(weight);
|
|
sum2 -= *buffer2Cursor;
|
*buffer2Cursor = sum1;
|
buffer2Cursor = (buffer2Cursor + 1) < buffer2End ? buffer2Cursor + 1 : buffer2Start;
|
|
sum1 -= (*buffer01Cursor)[1];
|
(*buffer01Cursor)[1] = sum0;
|
sum0 -= (*buffer01Cursor)[0];
|
(*buffer01Cursor)[0] = leadingEdge;
|
buffer01Cursor =
|
(buffer01Cursor + 1) < buffer01End ? buffer01Cursor + 1 : buffer01Start;
|
|
return value;
|
};
|
|
auto srcIdx = srcStart;
|
auto dstIdx = 0;
|
const uint32_t* srcCursor = src;
|
uint32_t* dstCursor = dst;
|
|
// The destination pixels are not effected by the src pixels,
|
// change to zero as per the spec.
|
// https://drafts.fxtf.org/filter-effects/#FilterPrimitivesOverviewIntro
|
while (dstIdx < srcIdx) {
|
*dstCursor = 0;
|
dstCursor += dstXStride;
|
SK_PREFETCH(dstCursor);
|
dstIdx++;
|
}
|
|
// The edge of the source is before the edge of the destination. Calculate the sums for
|
// the pixels before the start of the destination.
|
while (dstIdx > srcIdx) {
|
Sk4u leadingEdge = srcIdx < srcEnd ? SkNx_cast<uint32_t>(Sk4b::Load(srcCursor)) : 0;
|
(void) processValue(leadingEdge);
|
srcCursor += srcXStride;
|
srcIdx++;
|
}
|
|
// The dstIdx and srcIdx are in sync now; the code just uses the dstIdx for both now.
|
// Consume the source generating pixels to dst.
|
auto loopEnd = std::min(dstEnd, srcEnd);
|
while (dstIdx < loopEnd) {
|
Sk4u leadingEdge = SkNx_cast<uint32_t>(Sk4b::Load(srcCursor));
|
SkNx_cast<uint8_t>(processValue(leadingEdge)).store(dstCursor);
|
srcCursor += srcXStride;
|
dstCursor += dstXStride;
|
SK_PREFETCH(dstCursor);
|
dstIdx++;
|
}
|
|
// The leading edge is beyond the end of the source. Assume that the pixels
|
// are now 0x0000 until the end of the destination.
|
loopEnd = dstEnd;
|
while (dstIdx < loopEnd) {
|
SkNx_cast<uint8_t>(processValue(0u)).store(dstCursor);
|
dstCursor += dstXStride;
|
SK_PREFETCH(dstCursor);
|
dstIdx++;
|
}
|
|
src += srcYStride;
|
dst += dstYStride;
|
}
|
}
|
|
static sk_sp<SkSpecialImage> copy_image_with_bounds(
|
SkSpecialImage *source, const sk_sp<SkSpecialImage> &input,
|
SkIRect srcBounds, SkIRect dstBounds) {
|
SkBitmap inputBM;
|
if (!input->getROPixels(&inputBM)) {
|
return nullptr;
|
}
|
|
if (inputBM.colorType() != kN32_SkColorType) {
|
return nullptr;
|
}
|
|
SkBitmap src;
|
inputBM.extractSubset(&src, srcBounds);
|
|
// Make everything relative to the destination bounds.
|
srcBounds.offset(-dstBounds.x(), -dstBounds.y());
|
dstBounds.offset(-dstBounds.x(), -dstBounds.y());
|
|
auto srcW = srcBounds.width(),
|
dstW = dstBounds.width(),
|
dstH = dstBounds.height();
|
|
SkImageInfo dstInfo = SkImageInfo::Make(dstW, dstH, inputBM.colorType(), inputBM.alphaType());
|
|
SkBitmap dst;
|
if (!dst.tryAllocPixels(dstInfo)) {
|
return nullptr;
|
}
|
|
// There is no blurring to do, but we still need to copy the source while accounting for the
|
// dstBounds. Remember that the src was intersected with the dst.
|
int y = 0;
|
size_t dstWBytes = dstW * sizeof(uint32_t);
|
for (;y < srcBounds.top(); y++) {
|
sk_bzero(dst.getAddr32(0, y), dstWBytes);
|
}
|
|
for (;y < srcBounds.bottom(); y++) {
|
int x = 0;
|
uint32_t* dstPtr = dst.getAddr32(0, y);
|
for (;x < srcBounds.left(); x++) {
|
*dstPtr++ = 0;
|
}
|
|
memcpy(dstPtr, src.getAddr32(x - srcBounds.left(), y - srcBounds.top()),
|
srcW * sizeof(uint32_t));
|
|
dstPtr += srcW;
|
x += srcW;
|
|
for (;x < dstBounds.right(); x++) {
|
*dstPtr++ = 0;
|
}
|
}
|
|
for (;y < dstBounds.bottom(); y++) {
|
sk_bzero(dst.getAddr32(0, y), dstWBytes);
|
}
|
|
return SkSpecialImage::MakeFromRaster(SkIRect::MakeWH(dstBounds.width(),
|
dstBounds.height()),
|
dst, &source->props());
|
}
|
|
// TODO: Implement CPU backend for different fTileMode.
|
static sk_sp<SkSpecialImage> cpu_blur(
|
SkVector sigma,
|
SkSpecialImage *source, const sk_sp<SkSpecialImage> &input,
|
SkIRect srcBounds, SkIRect dstBounds) {
|
auto windowW = calculate_window(sigma.x()),
|
windowH = calculate_window(sigma.y());
|
|
if (windowW <= 1 && windowH <= 1) {
|
return copy_image_with_bounds(source, input, srcBounds, dstBounds);
|
}
|
|
SkBitmap inputBM;
|
|
if (!input->getROPixels(&inputBM)) {
|
return nullptr;
|
}
|
|
if (inputBM.colorType() != kN32_SkColorType) {
|
return nullptr;
|
}
|
|
SkBitmap src;
|
inputBM.extractSubset(&src, srcBounds);
|
|
// Make everything relative to the destination bounds.
|
srcBounds.offset(-dstBounds.x(), -dstBounds.y());
|
dstBounds.offset(-dstBounds.x(), -dstBounds.y());
|
|
auto srcW = srcBounds.width(),
|
srcH = srcBounds.height(),
|
dstW = dstBounds.width(),
|
dstH = dstBounds.height();
|
|
SkImageInfo dstInfo = SkImageInfo::Make(dstW, dstH, inputBM.colorType(), inputBM.alphaType());
|
|
SkBitmap dst;
|
if (!dst.tryAllocPixels(dstInfo)) {
|
return nullptr;
|
}
|
|
auto bufferSizeW = calculate_buffer(windowW),
|
bufferSizeH = calculate_buffer(windowH);
|
|
// The amount 1024 is enough for buffers up to 10 sigma. The tmp bitmap will be
|
// allocated on the heap.
|
SkSTArenaAlloc<1024> alloc;
|
Sk4u* buffer = alloc.makeArrayDefault<Sk4u>(std::max(bufferSizeW, bufferSizeH));
|
|
// Basic Plan: The three cases to handle
|
// * Horizontal and Vertical - blur horizontally while copying values from the source to
|
// the destination. Then, do an in-place vertical blur.
|
// * Horizontal only - blur horizontally copying values from the source to the destination.
|
// * Vertical only - blur vertically copying values from the source to the destination.
|
|
// Default to vertical only blur case. If a horizontal blur is needed, then these values
|
// will be adjusted while doing the horizontal blur.
|
auto intermediateSrc = static_cast<uint32_t *>(src.getPixels());
|
auto intermediateRowBytesAsPixels = src.rowBytesAsPixels();
|
auto intermediateWidth = srcW;
|
|
// Because the border is calculated before the fork of the GPU/CPU path. The border is
|
// the maximum of the two rendering methods. In the case where sigma is zero, then the
|
// src and dst left values are the same. If sigma is small resulting in a window size of
|
// 1, then border calculations add some pixels which will always be zero. Inset the
|
// destination by those zero pixels. This case is very rare.
|
auto intermediateDst = dst.getAddr32(srcBounds.left(), 0);
|
|
// The following code is executed very rarely, I have never seen it in a real web
|
// page. If sigma is small but not zero then shared GPU/CPU border calculation
|
// code adds extra pixels for the border. Just clear everything to clear those pixels.
|
// This solution is overkill, but very simple.
|
if (windowW == 1 || windowH == 1) {
|
dst.eraseColor(0);
|
}
|
|
if (windowW > 1) {
|
// Make int64 to avoid overflow in multiplication below.
|
int64_t shift = srcBounds.top() - dstBounds.top();
|
|
// For the horizontal blur, starts part way down in anticipation of the vertical blur.
|
// For a vertical sigma of zero shift should be zero. But, for small sigma,
|
// shift may be > 0 but the vertical window could be 1.
|
intermediateSrc = static_cast<uint32_t *>(dst.getPixels())
|
+ (shift > 0 ? shift * dst.rowBytesAsPixels() : 0);
|
intermediateRowBytesAsPixels = dst.rowBytesAsPixels();
|
intermediateWidth = dstW;
|
intermediateDst = static_cast<uint32_t *>(dst.getPixels());
|
|
blur_one_direction(
|
buffer, windowW,
|
srcBounds.left(), srcBounds.right(), dstBounds.right(),
|
static_cast<uint32_t *>(src.getPixels()), 1, src.rowBytesAsPixels(), srcH,
|
intermediateSrc, 1, intermediateRowBytesAsPixels);
|
}
|
|
if (windowH > 1) {
|
blur_one_direction(
|
buffer, windowH,
|
srcBounds.top(), srcBounds.bottom(), dstBounds.bottom(),
|
intermediateSrc, intermediateRowBytesAsPixels, 1, intermediateWidth,
|
intermediateDst, dst.rowBytesAsPixels(), 1);
|
}
|
|
return SkSpecialImage::MakeFromRaster(SkIRect::MakeWH(dstBounds.width(),
|
dstBounds.height()),
|
dst, &source->props());
|
}
|
|
sk_sp<SkSpecialImage> SkBlurImageFilterImpl::onFilterImage(SkSpecialImage* source,
|
const Context& ctx,
|
SkIPoint* offset) const {
|
SkIPoint inputOffset = SkIPoint::Make(0, 0);
|
|
sk_sp<SkSpecialImage> input(this->filterInput(0, source, ctx, &inputOffset));
|
if (!input) {
|
return nullptr;
|
}
|
|
SkIRect inputBounds = SkIRect::MakeXYWH(inputOffset.fX, inputOffset.fY,
|
input->width(), input->height());
|
|
// Calculate the destination bounds.
|
SkIRect dstBounds;
|
if (!this->applyCropRect(this->mapContext(ctx), inputBounds, &dstBounds)) {
|
return nullptr;
|
}
|
if (!inputBounds.intersect(dstBounds)) {
|
return nullptr;
|
}
|
|
// Save the offset in preparation to make all rectangles relative to the inputOffset.
|
SkIPoint resultOffset = SkIPoint::Make(dstBounds.fLeft, dstBounds.fTop);
|
|
// Make all bounds relative to the inputOffset.
|
inputBounds.offset(-inputOffset);
|
dstBounds.offset(-inputOffset);
|
|
const SkVector sigma = map_sigma(fSigma, ctx.ctm());
|
if (sigma.x() < 0 || sigma.y() < 0) {
|
return nullptr;
|
}
|
|
sk_sp<SkSpecialImage> result;
|
#if SK_SUPPORT_GPU
|
if (source->isTextureBacked()) {
|
// Ensure the input is in the destination's gamut. This saves us from having to do the
|
// xform during the filter itself.
|
input = ImageToColorSpace(input.get(), ctx.outputProperties());
|
|
result = this->gpuFilter(source, sigma, input, inputBounds, dstBounds, inputOffset,
|
ctx.outputProperties(), &resultOffset);
|
} else
|
#endif
|
{
|
result = cpu_blur(sigma, source, input, inputBounds, dstBounds);
|
}
|
|
// Return the resultOffset if the blur succeeded.
|
if (result != nullptr) {
|
*offset = resultOffset;
|
}
|
return result;
|
}
|
|
#if SK_SUPPORT_GPU
|
sk_sp<SkSpecialImage> SkBlurImageFilterImpl::gpuFilter(
|
SkSpecialImage *source, SkVector sigma, const sk_sp<SkSpecialImage> &input,
|
SkIRect inputBounds, SkIRect dstBounds, SkIPoint inputOffset,
|
const OutputProperties& outProps, SkIPoint* offset) const
|
{
|
if (0 == sigma.x() && 0 == sigma.y()) {
|
offset->fX = inputBounds.x() + inputOffset.fX;
|
offset->fY = inputBounds.y() + inputOffset.fY;
|
return input->makeSubset(inputBounds);
|
}
|
|
GrContext* context = source->getContext();
|
|
sk_sp<GrTextureProxy> inputTexture(input->asTextureProxyRef(context));
|
if (!inputTexture) {
|
return nullptr;
|
}
|
|
// Typically, we would create the RTC with the output's color space (from ctx), but we
|
// always blur in the PixelConfig of the *input*. Those might not be compatible (if they
|
// have different transfer functions). We've already guaranteed that those color spaces
|
// have the same gamut, so in this case, we do everything in the input's color space.
|
// ...
|
// Unless the output is legacy. In that case, the input could be almost anything (if we're
|
// using SkColorSpaceXformCanvas), but we can't make a corresponding RTC. We don't care to,
|
// either, we want to do our blending (and blurring) without any color correction, so pass
|
// nullptr here, causing us to operate entirely in the input's color space, with no decoding.
|
// Then, when we create the output image later, we tag it with the input's color space, so
|
// it will be tagged correctly, regardless of how we created the intermediate RTCs.
|
sk_sp<GrRenderTargetContext> renderTargetContext(SkGpuBlurUtils::GaussianBlur(
|
context,
|
std::move(inputTexture),
|
outProps.colorSpace() ? sk_ref_sp(input->getColorSpace()) : nullptr,
|
dstBounds,
|
inputBounds,
|
sigma.x(),
|
sigma.y(),
|
to_texture_domain_mode(fTileMode),
|
input->alphaType()));
|
if (!renderTargetContext) {
|
return nullptr;
|
}
|
|
return SkSpecialImage::MakeDeferredFromGpu(
|
context,
|
SkIRect::MakeWH(dstBounds.width(), dstBounds.height()),
|
kNeedNewImageUniqueID_SpecialImage,
|
renderTargetContext->asTextureProxyRef(),
|
sk_ref_sp(input->getColorSpace()),
|
&source->props());
|
}
|
#endif
|
|
sk_sp<SkImageFilter> SkBlurImageFilterImpl::onMakeColorSpace(SkColorSpaceXformer* xformer)
|
const {
|
SkASSERT(1 == this->countInputs());
|
|
auto input = xformer->apply(this->getInput(0));
|
if (this->getInput(0) != input.get()) {
|
return SkBlurImageFilter::Make(fSigma.width(), fSigma.height(), std::move(input),
|
this->getCropRectIfSet(), fTileMode);
|
}
|
return this->refMe();
|
}
|
|
SkRect SkBlurImageFilterImpl::computeFastBounds(const SkRect& src) const {
|
SkRect bounds = this->getInput(0) ? this->getInput(0)->computeFastBounds(src) : src;
|
bounds.outset(fSigma.width() * 3, fSigma.height() * 3);
|
return bounds;
|
}
|
|
SkIRect SkBlurImageFilterImpl::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
|
MapDirection, const SkIRect* inputRect) const {
|
SkVector sigma = map_sigma(fSigma, ctm);
|
return src.makeOutset(SkScalarCeilToInt(sigma.x() * 3), SkScalarCeilToInt(sigma.y() * 3));
|
}
|
