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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkGpuBlurUtils.h"
#include "SkRect.h"
#if SK_SUPPORT_GPU
#include "effects/GrConvolutionEffect.h"
#include "effects/GrTextureDomainEffect.h"
#include "GrContext.h"
#endif
namespace SkGpuBlurUtils {
#if SK_SUPPORT_GPU
#define MAX_BLUR_SIGMA 4.0f
static void scale_rect(SkRect* rect, float xScale, float yScale) {
rect->fLeft = SkScalarMul(rect->fLeft, SkFloatToScalar(xScale));
rect->fTop = SkScalarMul(rect->fTop, SkFloatToScalar(yScale));
rect->fRight = SkScalarMul(rect->fRight, SkFloatToScalar(xScale));
rect->fBottom = SkScalarMul(rect->fBottom, SkFloatToScalar(yScale));
}
static float adjust_sigma(float sigma, int *scaleFactor, int *radius) {
*scaleFactor = 1;
while (sigma > MAX_BLUR_SIGMA) {
*scaleFactor *= 2;
sigma *= 0.5f;
}
*radius = static_cast<int>(ceilf(sigma * 3.0f));
GrAssert(*radius <= GrConvolutionEffect::kMaxKernelRadius);
return sigma;
}
static void convolve_gaussian(GrContext* context,
GrTexture* texture,
const SkRect& srcRect,
const SkRect& dstRect,
bool cropToSrcRect,
float sigma,
int radius,
Gr1DKernelEffect::Direction direction) {
GrPaint paint;
paint.reset();
float bounds[2] = { 0.0f, 1.0f };
if (cropToSrcRect) {
if (direction == Gr1DKernelEffect::kX_Direction) {
bounds[0] = SkScalarToFloat(srcRect.left()) / texture->width();
bounds[1] = SkScalarToFloat(srcRect.right()) / texture->width();
} else {
bounds[0] = SkScalarToFloat(srcRect.top()) / texture->height();
bounds[1] = SkScalarToFloat(srcRect.bottom()) / texture->height();
}
}
SkAutoTUnref<GrEffectRef> conv(GrConvolutionEffect::CreateGaussian(texture,
direction,
radius,
sigma,
cropToSrcRect,
bounds));
paint.addColorEffect(conv);
context->drawRectToRect(paint, dstRect, srcRect);
}
GrTexture* GaussianBlur(GrContext* context,
GrTexture* srcTexture,
bool canClobberSrc,
const SkRect& rect,
bool cropToRect,
float sigmaX,
float sigmaY) {
GrAssert(NULL != context);
GrContext::AutoRenderTarget art(context);
GrContext::AutoMatrix am;
am.setIdentity(context);
SkIRect clearRect;
int scaleFactorX, radiusX;
int scaleFactorY, radiusY;
sigmaX = adjust_sigma(sigmaX, &scaleFactorX, &radiusX);
sigmaY = adjust_sigma(sigmaY, &scaleFactorY, &radiusY);
SkRect srcRect(rect);
scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
srcRect.roundOut();
scale_rect(&srcRect, static_cast<float>(scaleFactorX),
static_cast<float>(scaleFactorY));
GrContext::AutoClip acs(context, SkRect::MakeWH(srcRect.width(), srcRect.height()));
GrAssert(kBGRA_8888_GrPixelConfig == srcTexture->config() ||
kRGBA_8888_GrPixelConfig == srcTexture->config() ||
kAlpha_8_GrPixelConfig == srcTexture->config());
GrTextureDesc desc;
desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
desc.fWidth = SkScalarFloorToInt(srcRect.width());
desc.fHeight = SkScalarFloorToInt(srcRect.height());
desc.fConfig = srcTexture->config();
GrAutoScratchTexture temp1, temp2;
GrTexture* dstTexture = temp1.set(context, desc);
GrTexture* tempTexture = canClobberSrc ? srcTexture : temp2.set(context, desc);
if (NULL == dstTexture || NULL == tempTexture) {
return NULL;
}
for (int i = 1; i < scaleFactorX || i < scaleFactorY; i *= 2) {
GrPaint paint;
SkMatrix matrix;
matrix.setIDiv(srcTexture->width(), srcTexture->height());
context->setRenderTarget(dstTexture->asRenderTarget());
SkRect dstRect(srcRect);
if (cropToRect && i == 1) {
dstRect.offset(-dstRect.fLeft, -dstRect.fTop);
SkRect domain;
matrix.mapRect(&domain, rect);
domain.inset(i < scaleFactorX ? SK_ScalarHalf / srcTexture->width() : 0.0f,
i < scaleFactorY ? SK_ScalarHalf / srcTexture->height() : 0.0f);
SkAutoTUnref<GrEffectRef> effect(GrTextureDomainEffect::Create(
srcTexture,
matrix,
domain,
GrTextureDomainEffect::kDecal_WrapMode,
GrTextureParams::kBilerp_FilterMode));
paint.addColorEffect(effect);
} else {
GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
paint.addColorTextureEffect(srcTexture, matrix, params);
}
scale_rect(&dstRect, i < scaleFactorX ? 0.5f : 1.0f,
i < scaleFactorY ? 0.5f : 1.0f);
context->drawRectToRect(paint, dstRect, srcRect);
srcRect = dstRect;
srcTexture = dstTexture;
SkTSwap(dstTexture, tempTexture);
}
SkIRect srcIRect;
srcRect.roundOut(&srcIRect);
if (sigmaX > 0.0f) {
if (scaleFactorX > 1) {
// Clear out a radius to the right of the srcRect to prevent the
// X convolution from reading garbage.
clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
radiusX, srcIRect.height());
context->clear(&clearRect, 0x0);
}
context->setRenderTarget(dstTexture->asRenderTarget());
SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
convolve_gaussian(context, srcTexture, srcRect, dstRect, cropToRect,
sigmaX, radiusX, Gr1DKernelEffect::kX_Direction);
srcTexture = dstTexture;
srcRect = dstRect;
SkTSwap(dstTexture, tempTexture);
}
if (sigmaY > 0.0f) {
if (scaleFactorY > 1 || sigmaX > 0.0f) {
// Clear out a radius below the srcRect to prevent the Y
// convolution from reading garbage.
clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
srcIRect.width(), radiusY);
context->clear(&clearRect, 0x0);
}
context->setRenderTarget(dstTexture->asRenderTarget());
SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
convolve_gaussian(context, srcTexture, srcRect, dstRect, cropToRect,
sigmaY, radiusY, Gr1DKernelEffect::kY_Direction);
srcTexture = dstTexture;
srcRect = dstRect;
SkTSwap(dstTexture, tempTexture);
}
if (scaleFactorX > 1 || scaleFactorY > 1) {
// Clear one pixel to the right and below, to accommodate bilinear
// upsampling.
clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
srcIRect.width() + 1, 1);
context->clear(&clearRect, 0x0);
clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
1, srcIRect.height());
context->clear(&clearRect, 0x0);
SkMatrix matrix;
matrix.setIDiv(srcTexture->width(), srcTexture->height());
context->setRenderTarget(dstTexture->asRenderTarget());
GrPaint paint;
// FIXME: this should be mitchell, not bilinear.
GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
paint.addColorTextureEffect(srcTexture, matrix, params);
SkRect dstRect(srcRect);
scale_rect(&dstRect, (float) scaleFactorX, (float) scaleFactorY);
context->drawRectToRect(paint, dstRect, srcRect);
srcRect = dstRect;
srcTexture = dstTexture;
SkTSwap(dstTexture, tempTexture);
}
if (srcTexture == temp1.texture()) {
return temp1.detach();
} else if (srcTexture == temp2.texture()) {
return temp2.detach();
} else {
srcTexture->ref();
return srcTexture;
}
}
#endif
}
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