/*
* 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 "SkBitmap.h"
#include "SkBlurImageFilter.h"
#include "SkColorPriv.h"
#include "SkDevice.h"
#include "SkGpuBlurUtils.h"
#include "SkOpts.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
#if SK_SUPPORT_GPU
#include "GrContext.h"
#include "SkGr.h"
#endif
// 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;
}
SkBlurImageFilter::SkBlurImageFilter(SkScalar sigmaX,
SkScalar sigmaY,
SkImageFilter* input,
const CropRect* cropRect)
: INHERITED(1, &input, cropRect), fSigma(SkSize::Make(sigmaX, sigmaY)) {
}
SkFlattenable* SkBlurImageFilter::CreateProc(SkReadBuffer& buffer) {
SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
SkScalar sigmaX = buffer.readScalar();
SkScalar sigmaY = buffer.readScalar();
return Create(sigmaX, sigmaY, common.getInput(0), &common.cropRect());
}
void SkBlurImageFilter::flatten(SkWriteBuffer& buffer) const {
this->INHERITED::flatten(buffer);
buffer.writeScalar(fSigma.fWidth);
buffer.writeScalar(fSigma.fHeight);
}
static void getBox3Params(SkScalar s, int *kernelSize, int* kernelSize3, int *lowOffset,
int *highOffset)
{
float pi = SkScalarToFloat(SK_ScalarPI);
int d = static_cast<int>(floorf(SkScalarToFloat(s) * 3.0f * sqrtf(2.0f * pi) / 4.0f + 0.5f));
*kernelSize = d;
if (d % 2 == 1) {
*lowOffset = *highOffset = (d - 1) / 2;
*kernelSize3 = d;
} else {
*highOffset = d / 2;
*lowOffset = *highOffset - 1;
*kernelSize3 = d + 1;
}
}
bool SkBlurImageFilter::onFilterImageDeprecated(Proxy* proxy,
const SkBitmap& source, const Context& ctx,
SkBitmap* dst, SkIPoint* offset) const {
SkBitmap src = source;
SkIPoint srcOffset = SkIPoint::Make(0, 0);
if (!this->filterInputDeprecated(0, proxy, source, ctx, &src, &srcOffset)) {
return false;
}
if (src.colorType() != kN32_SkColorType) {
return false;
}
SkIRect srcBounds = src.bounds();
srcBounds.offset(srcOffset);
SkIRect dstBounds;
if (!this->applyCropRect(this->mapContext(ctx), srcBounds, &dstBounds)) {
return false;
}
if (!srcBounds.intersect(dstBounds)) {
return false;
}
SkVector sigma = map_sigma(fSigma, ctx.ctm());
int kernelSizeX, kernelSizeX3, lowOffsetX, highOffsetX;
int kernelSizeY, kernelSizeY3, lowOffsetY, highOffsetY;
getBox3Params(sigma.x(), &kernelSizeX, &kernelSizeX3, &lowOffsetX, &highOffsetX);
getBox3Params(sigma.y(), &kernelSizeY, &kernelSizeY3, &lowOffsetY, &highOffsetY);
if (kernelSizeX < 0 || kernelSizeY < 0) {
return false;
}
if (kernelSizeX == 0 && kernelSizeY == 0) {
src.extractSubset(dst, srcBounds);
offset->fX = srcBounds.x();
offset->fY = srcBounds.y();
return true;
}
SkAutoLockPixels alp(src);
if (!src.getPixels()) {
return false;
}
SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(dstBounds.width(), dstBounds.height()));
if (!device) {
return false;
}
*dst = device->accessBitmap(false);
SkAutoLockPixels alp_dst(*dst);
SkAutoTUnref<SkBaseDevice> tempDevice(proxy->createDevice(dst->width(), dst->height()));
if (!tempDevice) {
return false;
}
SkBitmap temp = tempDevice->accessBitmap(false);
SkAutoLockPixels alpTemp(temp);
offset->fX = dstBounds.fLeft;
offset->fY = dstBounds.fTop;
SkPMColor* t = temp.getAddr32(0, 0);
SkPMColor* d = dst->getAddr32(0, 0);
int w = dstBounds.width(), h = dstBounds.height();
const SkPMColor* s = src.getAddr32(srcBounds.x() - srcOffset.x(), srcBounds.y() - srcOffset.y());
srcBounds.offset(-dstBounds.x(), -dstBounds.y());
dstBounds.offset(-dstBounds.x(), -dstBounds.y());
SkIRect srcBoundsT = SkIRect::MakeLTRB(srcBounds.top(), srcBounds.left(), srcBounds.bottom(), srcBounds.right());
SkIRect dstBoundsT = SkIRect::MakeWH(dstBounds.height(), dstBounds.width());
int sw = src.rowBytesAsPixels();
/**
*
* In order to make memory accesses cache-friendly, we reorder the passes to
* use contiguous memory reads wherever possible.
*
* For example, the 6 passes of the X-and-Y blur case are rewritten as
* follows. Instead of 3 passes in X and 3 passes in Y, we perform
* 2 passes in X, 1 pass in X transposed to Y on write, 2 passes in X,
* then 1 pass in X transposed to Y on write.
*
* +----+ +----+ +----+ +---+ +---+ +---+ +----+
* + AB + ----> | AB | ----> | AB | -----> | A | ----> | A | ----> | A | -----> | AB |
* +----+ blurX +----+ blurX +----+ blurXY | B | blurX | B | blurX | B | blurXY +----+
* +---+ +---+ +---+
*
* In this way, two of the y-blurs become x-blurs applied to transposed
* images, and all memory reads are contiguous.
*/
if (kernelSizeX > 0 && kernelSizeY > 0) {
SkOpts::box_blur_xx(s, sw, srcBounds, t, kernelSizeX, lowOffsetX, highOffsetX, w, h);
SkOpts::box_blur_xx(t, w, dstBounds, d, kernelSizeX, highOffsetX, lowOffsetX, w, h);
SkOpts::box_blur_xy(d, w, dstBounds, t, kernelSizeX3, highOffsetX, highOffsetX, w, h);
SkOpts::box_blur_xx(t, h, dstBoundsT, d, kernelSizeY, lowOffsetY, highOffsetY, h, w);
SkOpts::box_blur_xx(d, h, dstBoundsT, t, kernelSizeY, highOffsetY, lowOffsetY, h, w);
SkOpts::box_blur_xy(t, h, dstBoundsT, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
} else if (kernelSizeX > 0) {
SkOpts::box_blur_xx(s, sw, srcBounds, d, kernelSizeX, lowOffsetX, highOffsetX, w, h);
SkOpts::box_blur_xx(d, w, dstBounds, t, kernelSizeX, highOffsetX, lowOffsetX, w, h);
SkOpts::box_blur_xx(t, w, dstBounds, d, kernelSizeX3, highOffsetX, highOffsetX, w, h);
} else if (kernelSizeY > 0) {
SkOpts::box_blur_yx(s, sw, srcBoundsT, d, kernelSizeY, lowOffsetY, highOffsetY, h, w);
SkOpts::box_blur_xx(d, h, dstBoundsT, t, kernelSizeY, highOffsetY, lowOffsetY, h, w);
SkOpts::box_blur_xy(t, h, dstBoundsT, d, kernelSizeY3, highOffsetY, highOffsetY, h, w);
}
return true;
}
void SkBlurImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
if (this->getInput(0)) {
this->getInput(0)->computeFastBounds(src, dst);
} else {
*dst = src;
}
dst->outset(SkScalarMul(fSigma.width(), SkIntToScalar(3)),
SkScalarMul(fSigma.height(), SkIntToScalar(3)));
}
void SkBlurImageFilter::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
SkIRect* dst, MapDirection) const {
*dst = src;
SkVector sigma = map_sigma(fSigma, ctm);
dst->outset(SkScalarCeilToInt(SkScalarMul(sigma.x(), SkIntToScalar(3))),
SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
}
bool SkBlurImageFilter::filterImageGPUDeprecated(Proxy* proxy, const SkBitmap& src,
const Context& ctx,
SkBitmap* result, SkIPoint* offset) const {
#if SK_SUPPORT_GPU
SkBitmap input = src;
SkIPoint srcOffset = SkIPoint::Make(0, 0);
if (!this->filterInputGPUDeprecated(0, proxy, src, ctx, &input, &srcOffset)) {
return false;
}
SkIRect srcBounds = input.bounds();
srcBounds.offset(srcOffset);
SkIRect dstBounds;
if (!this->applyCropRect(this->mapContext(ctx), srcBounds, &dstBounds)) {
return false;
}
if (!srcBounds.intersect(dstBounds)) {
return false;
}
SkVector sigma = map_sigma(fSigma, ctx.ctm());
if (sigma.x() == 0 && sigma.y() == 0) {
input.extractSubset(result, srcBounds);
offset->fX = srcBounds.x();
offset->fY = srcBounds.y();
return true;
}
offset->fX = dstBounds.fLeft;
offset->fY = dstBounds.fTop;
srcBounds.offset(-srcOffset);
dstBounds.offset(-srcOffset);
SkRect srcBoundsF(SkRect::Make(srcBounds));
GrTexture* inputTexture = input.getTexture();
SkAutoTUnref<GrTexture> tex(SkGpuBlurUtils::GaussianBlur(inputTexture->getContext(),
inputTexture,
false,
SkRect::Make(dstBounds),
&srcBoundsF,
sigma.x(),
sigma.y()));
if (!tex) {
return false;
}
GrWrapTextureInBitmap(tex, dstBounds.width(), dstBounds.height(), false, result);
return true;
#else
SkDEBUGFAIL("Should not call in GPU-less build");
return false;
#endif
}
#ifndef SK_IGNORE_TO_STRING
void SkBlurImageFilter::toString(SkString* str) const {
str->appendf("SkBlurImageFilter: (");
str->appendf("sigma: (%f, %f) input (", fSigma.fWidth, fSigma.fHeight);
if (this->getInput(0)) {
this->getInput(0)->toString(str);
}
str->append("))");
}
#endif