sk_sp<GrDrawContext> GaussianBlur(GrContext* context,
GrTexture* origSrc,
sk_sp<SkColorSpace> colorSpace,
const SkIRect& dstBounds,
const SkIRect* srcBounds,
float sigmaX,
float sigmaY,
SkBackingFit fit) {
SkASSERT(context);
SkIRect clearRect;
int scaleFactorX, radiusX;
int scaleFactorY, radiusY;
int maxTextureSize = context->caps()->maxTextureSize();
sigmaX = adjust_sigma(sigmaX, maxTextureSize, &scaleFactorX, &radiusX);
sigmaY = adjust_sigma(sigmaY, maxTextureSize, &scaleFactorY, &radiusY);
SkASSERT(sigmaX || sigmaY);
SkIPoint srcOffset = SkIPoint::Make(-dstBounds.x(), -dstBounds.y());
SkIRect localDstBounds = SkIRect::MakeWH(dstBounds.width(), dstBounds.height());
SkIRect localSrcBounds;
SkIRect srcRect;
if (srcBounds) {
srcRect = localSrcBounds = *srcBounds;
srcRect.offset(srcOffset);
srcBounds = &localSrcBounds;
} else {
srcRect = localDstBounds;
}
scale_irect_roundout(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
scale_irect(&srcRect, scaleFactorX, scaleFactorY);
// setup new clip
GrFixedClip clip(localDstBounds);
sk_sp<GrTexture> srcTexture(sk_ref_sp(origSrc));
SkASSERT(kBGRA_8888_GrPixelConfig == srcTexture->config() ||
kRGBA_8888_GrPixelConfig == srcTexture->config() ||
kSRGBA_8888_GrPixelConfig == srcTexture->config() ||
kSBGRA_8888_GrPixelConfig == srcTexture->config() ||
kRGBA_half_GrPixelConfig == srcTexture->config() ||
kAlpha_8_GrPixelConfig == srcTexture->config());
const int width = dstBounds.width();
const int height = dstBounds.height();
const GrPixelConfig config = srcTexture->config();
sk_sp<GrDrawContext> dstDrawContext(context->makeDrawContext(fit,
width, height, config, colorSpace,
0, kDefault_GrSurfaceOrigin));
if (!dstDrawContext) {
return nullptr;
}
// For really small blurs (certainly no wider than 5x5 on desktop gpus) it is faster to just
// launch a single non separable kernel vs two launches
if (sigmaX > 0.0f && sigmaY > 0.0f &&
(2 * radiusX + 1) * (2 * radiusY + 1) <= MAX_KERNEL_SIZE) {
// We shouldn't be scaling because this is a small size blur
SkASSERT((1 == scaleFactorX) && (1 == scaleFactorY));
convolve_gaussian_2d(dstDrawContext.get(), clip, localDstBounds, srcOffset,
srcTexture.get(), radiusX, radiusY, sigmaX, sigmaY, srcBounds);
return dstDrawContext;
}
sk_sp<GrDrawContext> tmpDrawContext(context->makeDrawContext(fit,
width, height, config, colorSpace,
0, kDefault_GrSurfaceOrigin));
if (!tmpDrawContext) {
return nullptr;
}
sk_sp<GrDrawContext> srcDrawContext;
SkASSERT(SkIsPow2(scaleFactorX) && SkIsPow2(scaleFactorY));
for (int i = 1; i < scaleFactorX || i < scaleFactorY; i *= 2) {
GrPaint paint;
paint.setGammaCorrect(dstDrawContext->isGammaCorrect());
SkMatrix matrix;
matrix.setIDiv(srcTexture->width(), srcTexture->height());
SkIRect dstRect(srcRect);
if (srcBounds && i == 1) {
SkRect domain;
matrix.mapRect(&domain, SkRect::Make(*srcBounds));
domain.inset((i < scaleFactorX) ? SK_ScalarHalf / srcTexture->width() : 0.0f,
(i < scaleFactorY) ? SK_ScalarHalf / srcTexture->height() : 0.0f);
sk_sp<GrFragmentProcessor> fp(GrTextureDomainEffect::Make(
srcTexture.get(),
nullptr,
matrix,
domain,
GrTextureDomain::kDecal_Mode,
GrTextureParams::kBilerp_FilterMode));
paint.addColorFragmentProcessor(std::move(fp));
srcRect.offset(-srcOffset);
srcOffset.set(0, 0);
} else {
GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
paint.addColorTextureProcessor(srcTexture.get(), nullptr, matrix, params);
}
paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
shrink_irect_by_2(&dstRect, i < scaleFactorX, i < scaleFactorY);
dstDrawContext->fillRectToRect(clip, paint, SkMatrix::I(),
SkRect::Make(dstRect), SkRect::Make(srcRect));
srcDrawContext = dstDrawContext;
srcRect = dstRect;
srcTexture = srcDrawContext->asTexture();
dstDrawContext.swap(tmpDrawContext);
localSrcBounds = srcRect;
}
srcRect = localDstBounds;
scale_irect_roundout(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
if (sigmaX > 0.0f) {
if (scaleFactorX > 1) {
SkASSERT(srcDrawContext);
// Clear out a radius to the right of the srcRect to prevent the
// X convolution from reading garbage.
clearRect = SkIRect::MakeXYWH(srcRect.fRight, srcRect.fTop,
radiusX, srcRect.height());
srcDrawContext->clear(&clearRect, 0x0, false);
}
convolve_gaussian(dstDrawContext.get(), clip, srcRect,
srcTexture.get(), Gr1DKernelEffect::kX_Direction, radiusX, sigmaX,
srcBounds, srcOffset);
srcDrawContext = dstDrawContext;
srcTexture = srcDrawContext->asTexture();
srcRect.offsetTo(0, 0);
dstDrawContext.swap(tmpDrawContext);
localSrcBounds = srcRect;
srcOffset.set(0, 0);
}
if (sigmaY > 0.0f) {
if (scaleFactorY > 1 || sigmaX > 0.0f) {
SkASSERT(srcDrawContext);
// Clear out a radius below the srcRect to prevent the Y
// convolution from reading garbage.
clearRect = SkIRect::MakeXYWH(srcRect.fLeft, srcRect.fBottom,
srcRect.width(), radiusY);
srcDrawContext->clear(&clearRect, 0x0, false);
}
convolve_gaussian(dstDrawContext.get(), clip, srcRect,
srcTexture.get(), Gr1DKernelEffect::kY_Direction, radiusY, sigmaY,
srcBounds, srcOffset);
srcDrawContext = dstDrawContext;
srcRect.offsetTo(0, 0);
dstDrawContext.swap(tmpDrawContext);
}
SkASSERT(srcDrawContext);
srcTexture = nullptr; // we don't use this from here on out
if (scaleFactorX > 1 || scaleFactorY > 1) {
// Clear one pixel to the right and below, to accommodate bilinear upsampling.
clearRect = SkIRect::MakeXYWH(srcRect.fLeft, srcRect.fBottom, srcRect.width() + 1, 1);
srcDrawContext->clear(&clearRect, 0x0, false);
clearRect = SkIRect::MakeXYWH(srcRect.fRight, srcRect.fTop, 1, srcRect.height());
srcDrawContext->clear(&clearRect, 0x0, false);
SkMatrix matrix;
matrix.setIDiv(srcDrawContext->width(), srcDrawContext->height());
GrPaint paint;
paint.setGammaCorrect(dstDrawContext->isGammaCorrect());
// FIXME: this should be mitchell, not bilinear.
GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
sk_sp<GrTexture> tex(srcDrawContext->asTexture());
paint.addColorTextureProcessor(tex.get(), nullptr, matrix, params);
paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
SkIRect dstRect(srcRect);
scale_irect(&dstRect, scaleFactorX, scaleFactorY);
dstDrawContext->fillRectToRect(clip, paint, SkMatrix::I(),
SkRect::Make(dstRect), SkRect::Make(srcRect));
srcDrawContext = dstDrawContext;
srcRect = dstRect;
dstDrawContext.swap(tmpDrawContext);
}
return srcDrawContext;
}
