コード例 #1
0
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;
}
コード例 #2
0
GrTexture* GaussianBlur(GrContext* context,
                        GrTexture* srcTexture,
                        bool canClobberSrc,
                        const SkRect& rect,
                        bool cropToRect,
                        float sigmaX,
                        float sigmaY) {
    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);

    SkRect srcRect(rect);
    scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
    srcRect.roundOut(&srcRect);
    scale_rect(&srcRect, static_cast<float>(scaleFactorX),
                         static_cast<float>(scaleFactorY));

    // setup new clip
    GrClip clip(SkRect::MakeWH(srcRect.width(), srcRect.height()));

    SkASSERT(kBGRA_8888_GrPixelConfig == srcTexture->config() ||
             kRGBA_8888_GrPixelConfig == srcTexture->config() ||
             kAlpha_8_GrPixelConfig == srcTexture->config());

    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = SkScalarFloorToInt(srcRect.width());
    desc.fHeight = SkScalarFloorToInt(srcRect.height());
    desc.fConfig = srcTexture->config();

    GrTexture* dstTexture;
    GrTexture* tempTexture;
    SkAutoTUnref<GrTexture> temp1, temp2;

    temp1.reset(context->textureProvider()->refScratchTexture(
        desc, GrTextureProvider::kApprox_ScratchTexMatch));
    dstTexture = temp1.get();
    if (canClobberSrc) {
        tempTexture = srcTexture;
    } else {
        temp2.reset(context->textureProvider()->refScratchTexture(
            desc, GrTextureProvider::kApprox_ScratchTexMatch));
        tempTexture = temp2.get();
    }

    if (NULL == dstTexture || NULL == tempTexture) {
        return NULL;
    }

    GrDrawContext* drawContext = context->drawContext();
    if (!drawContext) {
        return NULL;
    }

    for (int i = 1; i < scaleFactorX || i < scaleFactorY; i *= 2) {
        GrPaint paint;
        SkMatrix matrix;
        matrix.setIDiv(srcTexture->width(), srcTexture->height());
        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<GrFragmentProcessor> fp(   GrTextureDomainEffect::Create(
                paint.getProcessorDataManager(),
                srcTexture,
                matrix,
                domain,
                GrTextureDomain::kDecal_Mode,
                GrTextureParams::kBilerp_FilterMode));
            paint.addColorProcessor(fp);
        } else {
            GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
            paint.addColorTextureProcessor(srcTexture, matrix, params);
        }
        scale_rect(&dstRect, i < scaleFactorX ? 0.5f : 1.0f,
                             i < scaleFactorY ? 0.5f : 1.0f);
        drawContext->drawNonAARectToRect(dstTexture->asRenderTarget(), clip, paint, SkMatrix::I(),
                                         dstRect, srcRect);
        srcRect = dstRect;
        srcTexture = dstTexture;
        SkTSwap(dstTexture, tempTexture);
    }

    const SkIRect srcIRect = srcRect.roundOut();

    // 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 &&
            (2 * radiusX + 1) * (2 * radiusY + 1) <= MAX_KERNEL_SIZE) {
        // We shouldn't be scaling because this is a small size blur
        SkASSERT((scaleFactorX == scaleFactorY) == 1);
        SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
        convolve_gaussian_2d(drawContext, dstTexture->asRenderTarget(), clip, srcRect, dstRect,
                             srcTexture, radiusX, radiusY, sigmaX, sigmaY, cropToRect, srcIRect);
        srcTexture = dstTexture;
        srcRect = dstRect;
        SkTSwap(dstTexture, tempTexture);

    } else {
        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());
                drawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
            }
            SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
            convolve_gaussian(drawContext, dstTexture->asRenderTarget(), clip, srcRect, dstRect,
                              srcTexture, Gr1DKernelEffect::kX_Direction, radiusX, sigmaX,
                              cropToRect);
            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);
                drawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
            }

            SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
            convolve_gaussian(drawContext, dstTexture->asRenderTarget(), clip, srcRect,
                              dstRect, srcTexture, Gr1DKernelEffect::kY_Direction, radiusY, sigmaY,
                              cropToRect);
            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);
        drawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
        clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
                                      1, srcIRect.height());
        drawContext->clear(srcTexture->asRenderTarget(), &clearRect, 0x0, false);
        SkMatrix matrix;
        matrix.setIDiv(srcTexture->width(), srcTexture->height());

        GrPaint paint;
        // FIXME:  this should be mitchell, not bilinear.
        GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
        paint.addColorTextureProcessor(srcTexture, matrix, params);

        SkRect dstRect(srcRect);
        scale_rect(&dstRect, (float) scaleFactorX, (float) scaleFactorY);
        drawContext->drawNonAARectToRect(dstTexture->asRenderTarget(), clip, paint,
                                         SkMatrix::I(), dstRect, srcRect);
        srcRect = dstRect;
        srcTexture = dstTexture;
        SkTSwap(dstTexture, tempTexture);
    }
    return SkRef(srcTexture);
}
コード例 #3
0
ファイル: SkGpuBlurUtils.cpp プロジェクト: keinvo/skia
GrTexture* GaussianBlur(GrContext* context,
                        GrTexture* srcTexture,
                        bool canClobberSrc,
                        const SkRect& dstBounds,
                        const SkRect* srcBounds,
                        float sigmaX,
                        float sigmaY,
                        GrTextureProvider::SizeConstraint constraint) {
    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);

    SkPoint srcOffset = SkPoint::Make(-dstBounds.x(), -dstBounds.y());
    SkRect localDstBounds = SkRect::MakeWH(dstBounds.width(), dstBounds.height());
    SkRect localSrcBounds;
    SkRect srcRect;
    if (srcBounds) {
        srcRect = localSrcBounds = *srcBounds;
        srcRect.offset(srcOffset);
        srcBounds = &localSrcBounds;
    } else {
        srcRect = localDstBounds;
    }

    scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
    srcRect.roundOut(&srcRect);
    scale_rect(&srcRect, static_cast<float>(scaleFactorX),
                         static_cast<float>(scaleFactorY));

    // setup new clip
    GrClip clip(localDstBounds);

    SkASSERT(kBGRA_8888_GrPixelConfig == srcTexture->config() ||
             kRGBA_8888_GrPixelConfig == srcTexture->config() ||
             kAlpha_8_GrPixelConfig == srcTexture->config());

    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = SkScalarFloorToInt(dstBounds.width());
    desc.fHeight = SkScalarFloorToInt(dstBounds.height());
    desc.fConfig = srcTexture->config();

    GrTexture* dstTexture;
    GrTexture* tempTexture;
    SkAutoTUnref<GrTexture> temp1, temp2;

    temp1.reset(context->textureProvider()->createTexture(desc, constraint));
    dstTexture = temp1.get();
    if (canClobberSrc) {
        tempTexture = srcTexture;
    } else {
        temp2.reset(context->textureProvider()->createTexture(desc, constraint));
        tempTexture = temp2.get();
    }

    if (nullptr == dstTexture || nullptr == tempTexture) {
        return nullptr;
    }

    SkAutoTUnref<GrDrawContext> srcDrawContext;

    for (int i = 1; i < scaleFactorX || i < scaleFactorY; i *= 2) {
        GrPaint paint;
        SkMatrix matrix;
        matrix.setIDiv(srcTexture->width(), srcTexture->height());
        SkRect dstRect(srcRect);
        if (srcBounds && i == 1) {
            SkRect domain;
            matrix.mapRect(&domain, *srcBounds);
            domain.inset((i < scaleFactorX) ? SK_ScalarHalf / srcTexture->width() : 0.0f,
                         (i < scaleFactorY) ? SK_ScalarHalf / srcTexture->height() : 0.0f);
            SkAutoTUnref<const GrFragmentProcessor> fp(GrTextureDomainEffect::Create(
                srcTexture,
                matrix,
                domain,
                GrTextureDomain::kDecal_Mode,
                GrTextureParams::kBilerp_FilterMode));
            paint.addColorFragmentProcessor(fp);
            srcRect.offset(-srcOffset);
            srcOffset.set(0, 0);
        } else {
            GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
            paint.addColorTextureProcessor(srcTexture, matrix, params);
        }
        paint.setPorterDuffXPFactory(SkXfermode::kSrc_Mode);
        scale_rect(&dstRect, i < scaleFactorX ? 0.5f : 1.0f,
                             i < scaleFactorY ? 0.5f : 1.0f);

        SkAutoTUnref<GrDrawContext> dstDrawContext(
                                             context->drawContext(dstTexture->asRenderTarget()));
        if (!dstDrawContext) {
            return nullptr;
        }
        dstDrawContext->fillRectToRect(clip, paint, SkMatrix::I(), dstRect, srcRect);

        srcDrawContext.swap(dstDrawContext);
        srcRect = dstRect;
        srcTexture = dstTexture;
        SkTSwap(dstTexture, tempTexture);
        localSrcBounds = srcRect;
    }

    // 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
    srcRect = localDstBounds;
    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));

        SkAutoTUnref<GrDrawContext> dstDrawContext(
                                             context->drawContext(dstTexture->asRenderTarget()));
        if (!dstDrawContext) {
            return nullptr;
        }
        convolve_gaussian_2d(dstDrawContext, clip, srcRect, srcOffset,
                             srcTexture, radiusX, radiusY, sigmaX, sigmaY, srcBounds);

        srcDrawContext.swap(dstDrawContext);
        srcRect.offsetTo(0, 0);
        srcTexture = dstTexture;
        SkTSwap(dstTexture, tempTexture);

    } else {
        scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
        srcRect.roundOut(&srcRect);
        const SkIRect srcIRect = srcRect.roundOut();
        if (sigmaX > 0.0f) {
            if (scaleFactorX > 1) {
                // TODO: if we pass in the source draw context we don't need this here
                if (!srcDrawContext) {
                    srcDrawContext.reset(context->drawContext(srcTexture->asRenderTarget()));
                    if (!srcDrawContext) {
                        return nullptr;
                    }        
                }

                // 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());
                srcDrawContext->clear(&clearRect, 0x0, false);
            }

            SkAutoTUnref<GrDrawContext> dstDrawContext(
                                             context->drawContext(dstTexture->asRenderTarget()));
            if (!dstDrawContext) {
                return nullptr;
            }
            convolve_gaussian(dstDrawContext, clip, srcRect,
                              srcTexture, Gr1DKernelEffect::kX_Direction, radiusX, sigmaX,
                              srcBounds, srcOffset);
            srcDrawContext.swap(dstDrawContext);
            srcTexture = dstTexture;
            srcRect.offsetTo(0, 0);
            SkTSwap(dstTexture, tempTexture);
            localSrcBounds = srcRect;
            srcOffset.set(0, 0);
        }

        if (sigmaY > 0.0f) {
            if (scaleFactorY > 1 || sigmaX > 0.0f) {
                // TODO: if we pass in the source draw context we don't need this here
                if (!srcDrawContext) {
                    srcDrawContext.reset(context->drawContext(srcTexture->asRenderTarget()));
                    if (!srcDrawContext) {
                        return nullptr;
                    }        
                }

                // 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);
                srcDrawContext->clear(&clearRect, 0x0, false);
            }

            SkAutoTUnref<GrDrawContext> dstDrawContext(
                                               context->drawContext(dstTexture->asRenderTarget()));
            if (!dstDrawContext) {
                return nullptr;
            }
            convolve_gaussian(dstDrawContext, clip, srcRect,
                              srcTexture, Gr1DKernelEffect::kY_Direction, radiusY, sigmaY,
                              srcBounds, srcOffset);

            srcDrawContext.swap(dstDrawContext);
            srcTexture = dstTexture;
            srcRect.offsetTo(0, 0);
            SkTSwap(dstTexture, tempTexture);
        }
    }
    const SkIRect srcIRect = srcRect.roundOut();

    if (scaleFactorX > 1 || scaleFactorY > 1) {
        SkASSERT(srcDrawContext);

        // Clear one pixel to the right and below, to accommodate bilinear
        // upsampling.
        clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
                                      srcIRect.width() + 1, 1);
        srcDrawContext->clear(&clearRect, 0x0, false);
        clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
                                      1, srcIRect.height());
        srcDrawContext->clear(&clearRect, 0x0, false);
        SkMatrix matrix;
        matrix.setIDiv(srcTexture->width(), srcTexture->height());

        GrPaint paint;
        // FIXME:  this should be mitchell, not bilinear.
        GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kBilerp_FilterMode);
        paint.addColorTextureProcessor(srcTexture, matrix, params);
        paint.setPorterDuffXPFactory(SkXfermode::kSrc_Mode);

        SkRect dstRect(srcRect);
        scale_rect(&dstRect, (float) scaleFactorX, (float) scaleFactorY);

        SkAutoTUnref<GrDrawContext> dstDrawContext(
                                context->drawContext(dstTexture->asRenderTarget()));
        if (!dstDrawContext) {
            return nullptr;
        }
        dstDrawContext->fillRectToRect(clip, paint, SkMatrix::I(), dstRect, srcRect);

        srcDrawContext.swap(dstDrawContext);
        srcRect = dstRect;
        srcTexture = dstTexture;
        SkTSwap(dstTexture, tempTexture);
    }

    return SkRef(srcTexture);
}