src/effects/SkBlurMaskFilter.cpp

/*
 * Copyright 2006 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 "SkBlurMaskFilter.h"
#include "SkBlurMask.h"
#include "SkGpuBlurUtils.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
#include "SkMaskFilter.h"
#include "SkRRect.h"
#include "SkStringUtils.h"
#include "SkStrokeRec.h"

#if SK_SUPPORT_GPU
#include "GrCircleBlurFragmentProcessor.h"
#include "GrContext.h"
#include "GrRenderTargetContext.h"
#include "GrTexture.h"
#include "GrFragmentProcessor.h"
#include "GrInvariantOutput.h"
#include "GrShaderCaps.h"
#include "GrStyle.h"
#include "GrTextureProxy.h"
#include "effects/GrSimpleTextureEffect.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLProgramDataManager.h"
#include "glsl/GrGLSLUniformHandler.h"
#endif

SkScalar SkBlurMaskFilter::ConvertRadiusToSigma(SkScalar radius) {
    return SkBlurMask::ConvertRadiusToSigma(radius);
}

class SkBlurMaskFilterImpl : public SkMaskFilter {
public:
    SkBlurMaskFilterImpl(SkScalar sigma, SkBlurStyle, const SkRect& occluder, uint32_t flags);

    // overrides from SkMaskFilter
    SkMask::Format getFormat() const override;
    bool filterMask(SkMask* dst, const SkMask& src, const SkMatrix&,
                    SkIPoint* margin) const override;

#if SK_SUPPORT_GPU
    bool canFilterMaskGPU(const SkRRect& devRRect,
                          const SkIRect& clipBounds,
                          const SkMatrix& ctm,
                          SkRect* maskRect) const override;
    bool directFilterMaskGPU(GrTextureProvider* texProvider,
                             GrRenderTargetContext* renderTargetContext,
                             GrPaint&&,
                             const GrClip&,
                             const SkMatrix& viewMatrix,
                             const SkStrokeRec& strokeRec,
                             const SkPath& path) const override;
    bool directFilterRRectMaskGPU(GrContext*,
                                  GrRenderTargetContext* renderTargetContext,
                                  GrPaint&&,
                                  const GrClip&,
                                  const SkMatrix& viewMatrix,
                                  const SkStrokeRec& strokeRec,
                                  const SkRRect& rrect,
                                  const SkRRect& devRRect) const override;
    sk_sp<GrTextureProxy> filterMaskGPU(GrContext*,
                                        sk_sp<GrTextureProxy> srcProxy,
                                        const SkMatrix& ctm,
                                        const SkIRect& maskRect) const override;
#endif

    void computeFastBounds(const SkRect&, SkRect*) const override;
    bool asABlur(BlurRec*) const override;

    SK_TO_STRING_OVERRIDE()
    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBlurMaskFilterImpl)

protected:
    FilterReturn filterRectsToNine(const SkRect[], int count, const SkMatrix&,
                                   const SkIRect& clipBounds,
                                   NinePatch*) const override;

    FilterReturn filterRRectToNine(const SkRRect&, const SkMatrix&,
                                   const SkIRect& clipBounds,
                                   NinePatch*) const override;

    bool filterRectMask(SkMask* dstM, const SkRect& r, const SkMatrix& matrix,
                        SkIPoint* margin, SkMask::CreateMode createMode) const;
    bool filterRRectMask(SkMask* dstM, const SkRRect& r, const SkMatrix& matrix,
                        SkIPoint* margin, SkMask::CreateMode createMode) const;

    bool ignoreXform() const {
        return SkToBool(fBlurFlags & SkBlurMaskFilter::kIgnoreTransform_BlurFlag);
    }

private:
    // To avoid unseemly allocation requests (esp. for finite platforms like
    // handset) we limit the radius so something manageable. (as opposed to
    // a request like 10,000)
    static const SkScalar kMAX_BLUR_SIGMA;

    SkScalar    fSigma;
    SkBlurStyle fBlurStyle;
    SkRect      fOccluder;
    uint32_t    fBlurFlags;

    SkBlurQuality getQuality() const {
        return (fBlurFlags & SkBlurMaskFilter::kHighQuality_BlurFlag) ?
                kHigh_SkBlurQuality : kLow_SkBlurQuality;
    }

    SkBlurMaskFilterImpl(SkReadBuffer&);
    void flatten(SkWriteBuffer&) const override;

    SkScalar computeXformedSigma(const SkMatrix& ctm) const {
        SkScalar xformedSigma = this->ignoreXform() ? fSigma : ctm.mapRadius(fSigma);
        return SkMinScalar(xformedSigma, kMAX_BLUR_SIGMA);
    }

    friend class SkBlurMaskFilter;

    typedef SkMaskFilter INHERITED;
};

const SkScalar SkBlurMaskFilterImpl::kMAX_BLUR_SIGMA = SkIntToScalar(128);

sk_sp<SkMaskFilter> SkBlurMaskFilter::Make(SkBlurStyle style, SkScalar sigma,
                                           const SkRect& occluder, uint32_t flags) {
    SkASSERT(!(flags & ~SkBlurMaskFilter::kAll_BlurFlag));
    SkASSERT(style <= kLastEnum_SkBlurStyle);

    if (!SkScalarIsFinite(sigma) || sigma <= 0) {
        return nullptr;
    }

    return sk_sp<SkMaskFilter>(new SkBlurMaskFilterImpl(sigma, style, occluder, flags));
}

// linearly interpolate between y1 & y3 to match x2's position between x1 & x3
static SkScalar interp(SkScalar x1, SkScalar x2, SkScalar x3, SkScalar y1, SkScalar y3) {
    SkASSERT(x1 <= x2 && x2 <= x3);
    SkASSERT(y1 <= y3);

    SkScalar t = (x2 - x1) / (x3 - x1);
    return y1 + t * (y3 - y1);
}

// Insert 'lower' and 'higher' into 'array1' and insert a new value at each matching insertion
// point in 'array2' that linearly interpolates between the existing values.
// Return a bit mask which contains a copy of 'inputMask' for all the cells between the two
// insertion points.
static uint32_t insert_into_arrays(SkScalar* array1, SkScalar* array2,
                                   SkScalar lower, SkScalar higher,
                                   int* num, uint32_t inputMask, int maskSize) {
    SkASSERT(lower < higher);
    SkASSERT(lower >= array1[0] && higher <= array1[*num-1]);

    int32_t skipMask = 0x0;
    int i;
    for (i = 0; i < *num; ++i) {
        if (lower >= array1[i] && lower < array1[i+1]) {
            if (!SkScalarNearlyEqual(lower, array1[i])) {
                memmove(&array1[i+2], &array1[i+1], (*num-i-1)*sizeof(SkScalar));
                array1[i+1] = lower;
                memmove(&array2[i+2], &array2[i+1], (*num-i-1)*sizeof(SkScalar));
                array2[i+1] = interp(array1[i], lower, array1[i+2], array2[i], array2[i+2]);
                i++;
                (*num)++;
            }
            break;
        }
    }
    for ( ; i < *num; ++i) {
        skipMask |= inputMask << (i*maskSize);
        if (higher > array1[i] && higher <= array1[i+1]) {
            if (!SkScalarNearlyEqual(higher, array1[i+1])) {
                memmove(&array1[i+2], &array1[i+1], (*num-i-1)*sizeof(SkScalar));
                array1[i+1] = higher;
                memmove(&array2[i+2], &array2[i+1], (*num-i-1)*sizeof(SkScalar));
                array2[i+1] = interp(array1[i], higher, array1[i+2], array2[i], array2[i+2]);
                (*num)++;
            }
            break;
        }
    }

    return skipMask;
}

bool SkBlurMaskFilter::ComputeBlurredRRectParams(const SkRRect& srcRRect, const SkRRect& devRRect,
                                                 const SkRect& occluder,
                                                 SkScalar sigma, SkScalar xformedSigma,
                                                 SkRRect* rrectToDraw,
                                                 SkISize* widthHeight,
                                                 SkScalar rectXs[kMaxDivisions],
                                                 SkScalar rectYs[kMaxDivisions],
                                                 SkScalar texXs[kMaxDivisions],
                                                 SkScalar texYs[kMaxDivisions],
                                                 int* numXs, int* numYs, uint32_t* skipMask) {
    unsigned int devBlurRadius = 3*SkScalarCeilToInt(xformedSigma-1/6.0f);
    SkScalar srcBlurRadius = 3.0f * sigma;

    const SkRect& devOrig = devRRect.getBounds();
    const SkVector& devRadiiUL = devRRect.radii(SkRRect::kUpperLeft_Corner);
    const SkVector& devRadiiUR = devRRect.radii(SkRRect::kUpperRight_Corner);
    const SkVector& devRadiiLR = devRRect.radii(SkRRect::kLowerRight_Corner);
    const SkVector& devRadiiLL = devRRect.radii(SkRRect::kLowerLeft_Corner);

    const int devLeft  = SkScalarCeilToInt(SkTMax<SkScalar>(devRadiiUL.fX, devRadiiLL.fX));
    const int devTop   = SkScalarCeilToInt(SkTMax<SkScalar>(devRadiiUL.fY, devRadiiUR.fY));
    const int devRight = SkScalarCeilToInt(SkTMax<SkScalar>(devRadiiUR.fX, devRadiiLR.fX));
    const int devBot   = SkScalarCeilToInt(SkTMax<SkScalar>(devRadiiLL.fY, devRadiiLR.fY));

    // This is a conservative check for nine-patchability
    if (devOrig.fLeft + devLeft + devBlurRadius >= devOrig.fRight  - devRight - devBlurRadius ||
        devOrig.fTop  + devTop  + devBlurRadius >= devOrig.fBottom - devBot   - devBlurRadius) {
        return false;
    }

    const SkVector& srcRadiiUL = srcRRect.radii(SkRRect::kUpperLeft_Corner);
    const SkVector& srcRadiiUR = srcRRect.radii(SkRRect::kUpperRight_Corner);
    const SkVector& srcRadiiLR = srcRRect.radii(SkRRect::kLowerRight_Corner);
    const SkVector& srcRadiiLL = srcRRect.radii(SkRRect::kLowerLeft_Corner);

    const SkScalar srcLeft  = SkTMax<SkScalar>(srcRadiiUL.fX, srcRadiiLL.fX);
    const SkScalar srcTop   = SkTMax<SkScalar>(srcRadiiUL.fY, srcRadiiUR.fY);
    const SkScalar srcRight = SkTMax<SkScalar>(srcRadiiUR.fX, srcRadiiLR.fX);
    const SkScalar srcBot   = SkTMax<SkScalar>(srcRadiiLL.fY, srcRadiiLR.fY);

    int newRRWidth = 2*devBlurRadius + devLeft + devRight + 1;
    int newRRHeight = 2*devBlurRadius + devTop + devBot + 1;
    widthHeight->fWidth = newRRWidth + 2 * devBlurRadius;
    widthHeight->fHeight = newRRHeight + 2 * devBlurRadius;

    const SkRect srcProxyRect = srcRRect.getBounds().makeOutset(srcBlurRadius, srcBlurRadius);

    rectXs[0] = srcProxyRect.fLeft;
    rectXs[1] = srcProxyRect.fLeft + 2*srcBlurRadius + srcLeft;
    rectXs[2] = srcProxyRect.fRight - 2*srcBlurRadius - srcRight;
    rectXs[3] = srcProxyRect.fRight;

    rectYs[0] = srcProxyRect.fTop;
    rectYs[1] = srcProxyRect.fTop + 2*srcBlurRadius + srcTop;
    rectYs[2] = srcProxyRect.fBottom - 2*srcBlurRadius - srcBot;
    rectYs[3] = srcProxyRect.fBottom;

    texXs[0] = 0.0f;
    texXs[1] = 2.0f*devBlurRadius + devLeft;
    texXs[2] = 2.0f*devBlurRadius + devLeft + 1;
    texXs[3] = SkIntToScalar(widthHeight->fWidth);

    texYs[0] = 0.0f;
    texYs[1] = 2.0f*devBlurRadius + devTop;
    texYs[2] = 2.0f*devBlurRadius + devTop + 1;
    texYs[3] = SkIntToScalar(widthHeight->fHeight);

    SkRect temp = occluder;

    *numXs = 4;
    *numYs = 4;
    *skipMask = 0;
    if (!temp.isEmpty() && (srcProxyRect.contains(temp) || temp.intersect(srcProxyRect))) {
        *skipMask = insert_into_arrays(rectXs, texXs, temp.fLeft, temp.fRight, numXs, 0x1, 1);
        *skipMask = insert_into_arrays(rectYs, texYs, temp.fTop, temp.fBottom,
                                       numYs, *skipMask, *numXs-1);
    }

    const SkRect newRect = SkRect::MakeXYWH(SkIntToScalar(devBlurRadius),
                                            SkIntToScalar(devBlurRadius),
                                            SkIntToScalar(newRRWidth),
                                            SkIntToScalar(newRRHeight));
    SkVector newRadii[4];
    newRadii[0] = { SkScalarCeilToScalar(devRadiiUL.fX), SkScalarCeilToScalar(devRadiiUL.fY) };
    newRadii[1] = { SkScalarCeilToScalar(devRadiiUR.fX), SkScalarCeilToScalar(devRadiiUR.fY) };
    newRadii[2] = { SkScalarCeilToScalar(devRadiiLR.fX), SkScalarCeilToScalar(devRadiiLR.fY) };
    newRadii[3] = { SkScalarCeilToScalar(devRadiiLL.fX), SkScalarCeilToScalar(devRadiiLL.fY) };

    rrectToDraw->setRectRadii(newRect, newRadii);
    return true;
}

///////////////////////////////////////////////////////////////////////////////

SkBlurMaskFilterImpl::SkBlurMaskFilterImpl(SkScalar sigma, SkBlurStyle style,
                                           const SkRect& occluder, uint32_t flags)
    : fSigma(sigma)
    , fBlurStyle(style)
    , fOccluder(occluder)
    , fBlurFlags(flags) {
    SkASSERT(fSigma > 0);
    SkASSERT((unsigned)style <= kLastEnum_SkBlurStyle);
    SkASSERT(flags <= SkBlurMaskFilter::kAll_BlurFlag);
}

SkMask::Format SkBlurMaskFilterImpl::getFormat() const {
    return SkMask::kA8_Format;
}

bool SkBlurMaskFilterImpl::asABlur(BlurRec* rec) const {
    if (this->ignoreXform()) {
        return false;
    }

    if (rec) {
        rec->fSigma = fSigma;
        rec->fStyle = fBlurStyle;
        rec->fQuality = this->getQuality();
    }
    return true;
}

bool SkBlurMaskFilterImpl::filterMask(SkMask* dst, const SkMask& src,
                                      const SkMatrix& matrix,
                                      SkIPoint* margin) const {
    SkScalar sigma = this->computeXformedSigma(matrix);
    return SkBlurMask::BoxBlur(dst, src, sigma, fBlurStyle, this->getQuality(), margin);
}

bool SkBlurMaskFilterImpl::filterRectMask(SkMask* dst, const SkRect& r,
                                          const SkMatrix& matrix,
                                          SkIPoint* margin, SkMask::CreateMode createMode) const {
    SkScalar sigma = computeXformedSigma(matrix);

    return SkBlurMask::BlurRect(sigma, dst, r, fBlurStyle, margin, createMode);
}

bool SkBlurMaskFilterImpl::filterRRectMask(SkMask* dst, const SkRRect& r,
                                          const SkMatrix& matrix,
                                          SkIPoint* margin, SkMask::CreateMode createMode) const {
    SkScalar sigma = computeXformedSigma(matrix);

    return SkBlurMask::BlurRRect(sigma, dst, r, fBlurStyle, margin, createMode);
}

#include "SkCanvas.h"

static bool prepare_to_draw_into_mask(const SkRect& bounds, SkMask* mask) {
    SkASSERT(mask != nullptr);

    mask->fBounds = bounds.roundOut();
    mask->fRowBytes = SkAlign4(mask->fBounds.width());
    mask->fFormat = SkMask::kA8_Format;
    const size_t size = mask->computeImageSize();
    mask->fImage = SkMask::AllocImage(size);
    if (nullptr == mask->fImage) {
        return false;
    }

    // FIXME: use sk_calloc in AllocImage?
    sk_bzero(mask->fImage, size);
    return true;
}

static bool draw_rrect_into_mask(const SkRRect rrect, SkMask* mask) {
    if (!prepare_to_draw_into_mask(rrect.rect(), mask)) {
        return false;
    }

    // FIXME: This code duplicates code in draw_rects_into_mask, below. Is there a
    // clean way to share more code?
    SkBitmap bitmap;
    bitmap.installMaskPixels(*mask);

    SkCanvas canvas(bitmap);
    canvas.translate(-SkIntToScalar(mask->fBounds.left()),
                     -SkIntToScalar(mask->fBounds.top()));

    SkPaint paint;
    paint.setAntiAlias(true);
    canvas.drawRRect(rrect, paint);
    return true;
}

static bool draw_rects_into_mask(const SkRect rects[], int count, SkMask* mask) {
    if (!prepare_to_draw_into_mask(rects[0], mask)) {
        return false;
    }

    SkBitmap bitmap;
    bitmap.installPixels(SkImageInfo::Make(mask->fBounds.width(),
                                           mask->fBounds.height(),
                                           kAlpha_8_SkColorType,
                                           kPremul_SkAlphaType),
                         mask->fImage, mask->fRowBytes);

    SkCanvas canvas(bitmap);
    canvas.translate(-SkIntToScalar(mask->fBounds.left()),
                     -SkIntToScalar(mask->fBounds.top()));

    SkPaint paint;
    paint.setAntiAlias(true);

    if (1 == count) {
        canvas.drawRect(rects[0], paint);
    } else {
        // todo: do I need a fast way to do this?
        SkPath path;
        path.addRect(rects[0]);
        path.addRect(rects[1]);
        path.setFillType(SkPath::kEvenOdd_FillType);
        canvas.drawPath(path, paint);
    }
    return true;
}

static bool rect_exceeds(const SkRect& r, SkScalar v) {
    return r.fLeft < -v || r.fTop < -v || r.fRight > v || r.fBottom > v ||
           r.width() > v || r.height() > v;
}

#include "SkMaskCache.h"

static SkCachedData* copy_mask_to_cacheddata(SkMask* mask) {
    const size_t size = mask->computeTotalImageSize();
    SkCachedData* data = SkResourceCache::NewCachedData(size);
    if (data) {
        memcpy(data->writable_data(), mask->fImage, size);
        SkMask::FreeImage(mask->fImage);
        mask->fImage = (uint8_t*)data->data();
    }
    return data;
}

static SkCachedData* find_cached_rrect(SkMask* mask, SkScalar sigma, SkBlurStyle style,
                                       SkBlurQuality quality, const SkRRect& rrect) {
    return SkMaskCache::FindAndRef(sigma, style, quality, rrect, mask);
}

static SkCachedData* add_cached_rrect(SkMask* mask, SkScalar sigma, SkBlurStyle style,
                                      SkBlurQuality quality, const SkRRect& rrect) {
    SkCachedData* cache = copy_mask_to_cacheddata(mask);
    if (cache) {
        SkMaskCache::Add(sigma, style, quality, rrect, *mask, cache);
    }
    return cache;
}

static SkCachedData* find_cached_rects(SkMask* mask, SkScalar sigma, SkBlurStyle style,
                                       SkBlurQuality quality, const SkRect rects[], int count) {
    return SkMaskCache::FindAndRef(sigma, style, quality, rects, count, mask);
}

static SkCachedData* add_cached_rects(SkMask* mask, SkScalar sigma, SkBlurStyle style,
                                      SkBlurQuality quality, const SkRect rects[], int count) {
    SkCachedData* cache = copy_mask_to_cacheddata(mask);
    if (cache) {
        SkMaskCache::Add(sigma, style, quality, rects, count, *mask, cache);
    }
    return cache;
}

#ifdef SK_IGNORE_FAST_RRECT_BLUR
  // Use the faster analytic blur approach for ninepatch round rects
  static const bool c_analyticBlurRRect{false};
#else
  static const bool c_analyticBlurRRect{true};
#endif

SkMaskFilter::FilterReturn
SkBlurMaskFilterImpl::filterRRectToNine(const SkRRect& rrect, const SkMatrix& matrix,
                                        const SkIRect& clipBounds,
                                        NinePatch* patch) const {
    SkASSERT(patch != nullptr);
    switch (rrect.getType()) {
        case SkRRect::kEmpty_Type:
            // Nothing to draw.
            return kFalse_FilterReturn;

        case SkRRect::kRect_Type:
            // We should have caught this earlier.
            SkASSERT(false);
            // Fall through.
        case SkRRect::kOval_Type:
            // The nine patch special case does not handle ovals, and we
            // already have code for rectangles.
            return kUnimplemented_FilterReturn;

        // These three can take advantage of this fast path.
        case SkRRect::kSimple_Type:
        case SkRRect::kNinePatch_Type:
        case SkRRect::kComplex_Type:
            break;
    }

    // TODO: report correct metrics for innerstyle, where we do not grow the
    // total bounds, but we do need an inset the size of our blur-radius
    if (kInner_SkBlurStyle == fBlurStyle) {
        return kUnimplemented_FilterReturn;
    }

    // TODO: take clipBounds into account to limit our coordinates up front
    // for now, just skip too-large src rects (to take the old code path).
    if (rect_exceeds(rrect.rect(), SkIntToScalar(32767))) {
        return kUnimplemented_FilterReturn;
    }

    SkIPoint margin;
    SkMask  srcM, dstM;
    srcM.fBounds = rrect.rect().roundOut();
    srcM.fFormat = SkMask::kA8_Format;
    srcM.fRowBytes = 0;

    bool filterResult = false;
    if (c_analyticBlurRRect) {
        // special case for fast round rect blur
        // don't actually do the blur the first time, just compute the correct size
        filterResult = this->filterRRectMask(&dstM, rrect, matrix, &margin,
                                            SkMask::kJustComputeBounds_CreateMode);
    }

    if (!filterResult) {
        filterResult = this->filterMask(&dstM, srcM, matrix, &margin);
    }

    if (!filterResult) {
        return kFalse_FilterReturn;
    }

    // Now figure out the appropriate width and height of the smaller round rectangle
    // to stretch. It will take into account the larger radius per side as well as double
    // the margin, to account for inner and outer blur.
    const SkVector& UL = rrect.radii(SkRRect::kUpperLeft_Corner);
    const SkVector& UR = rrect.radii(SkRRect::kUpperRight_Corner);
    const SkVector& LR = rrect.radii(SkRRect::kLowerRight_Corner);
    const SkVector& LL = rrect.radii(SkRRect::kLowerLeft_Corner);

    const SkScalar leftUnstretched = SkTMax(UL.fX, LL.fX) + SkIntToScalar(2 * margin.fX);
    const SkScalar rightUnstretched = SkTMax(UR.fX, LR.fX) + SkIntToScalar(2 * margin.fX);

    // Extra space in the middle to ensure an unchanging piece for stretching. Use 3 to cover
    // any fractional space on either side plus 1 for the part to stretch.
    const SkScalar stretchSize = SkIntToScalar(3);

    const SkScalar totalSmallWidth = leftUnstretched + rightUnstretched + stretchSize;
    if (totalSmallWidth >= rrect.rect().width()) {
        // There is no valid piece to stretch.
        return kUnimplemented_FilterReturn;
    }

    const SkScalar topUnstretched = SkTMax(UL.fY, UR.fY) + SkIntToScalar(2 * margin.fY);
    const SkScalar bottomUnstretched = SkTMax(LL.fY, LR.fY) + SkIntToScalar(2 * margin.fY);

    const SkScalar totalSmallHeight = topUnstretched + bottomUnstretched + stretchSize;
    if (totalSmallHeight >= rrect.rect().height()) {
        // There is no valid piece to stretch.
        return kUnimplemented_FilterReturn;
    }

    SkRect smallR = SkRect::MakeWH(totalSmallWidth, totalSmallHeight);

    SkRRect smallRR;
    SkVector radii[4];
    radii[SkRRect::kUpperLeft_Corner] = UL;
    radii[SkRRect::kUpperRight_Corner] = UR;
    radii[SkRRect::kLowerRight_Corner] = LR;
    radii[SkRRect::kLowerLeft_Corner] = LL;
    smallRR.setRectRadii(smallR, radii);

    const SkScalar sigma = this->computeXformedSigma(matrix);
    SkCachedData* cache = find_cached_rrect(&patch->fMask, sigma, fBlurStyle,
                                            this->getQuality(), smallRR);
    if (!cache) {
        bool analyticBlurWorked = false;
        if (c_analyticBlurRRect) {
            analyticBlurWorked =
                this->filterRRectMask(&patch->fMask, smallRR, matrix, &margin,
                                      SkMask::kComputeBoundsAndRenderImage_CreateMode);
        }

        if (!analyticBlurWorked) {
            if (!draw_rrect_into_mask(smallRR, &srcM)) {
                return kFalse_FilterReturn;
            }

            SkAutoMaskFreeImage amf(srcM.fImage);

            if (!this->filterMask(&patch->fMask, srcM, matrix, &margin)) {
                return kFalse_FilterReturn;
            }
        }
        cache = add_cached_rrect(&patch->fMask, sigma, fBlurStyle, this->getQuality(), smallRR);
    }

    patch->fMask.fBounds.offsetTo(0, 0);
    patch->fOuterRect = dstM.fBounds;
    patch->fCenter.fX = SkScalarCeilToInt(leftUnstretched) + 1;
    patch->fCenter.fY = SkScalarCeilToInt(topUnstretched) + 1;
    SkASSERT(nullptr == patch->fCache);
    patch->fCache = cache;  // transfer ownership to patch
    return kTrue_FilterReturn;
}

// Use the faster analytic blur approach for ninepatch rects
static const bool c_analyticBlurNinepatch{true};

SkMaskFilter::FilterReturn
SkBlurMaskFilterImpl::filterRectsToNine(const SkRect rects[], int count,
                                        const SkMatrix& matrix,
                                        const SkIRect& clipBounds,
                                        NinePatch* patch) const {
    if (count < 1 || count > 2) {
        return kUnimplemented_FilterReturn;
    }

    // TODO: report correct metrics for innerstyle, where we do not grow the
    // total bounds, but we do need an inset the size of our blur-radius
    if (kInner_SkBlurStyle == fBlurStyle || kOuter_SkBlurStyle == fBlurStyle) {
        return kUnimplemented_FilterReturn;
    }

    // TODO: take clipBounds into account to limit our coordinates up front
    // for now, just skip too-large src rects (to take the old code path).
    if (rect_exceeds(rects[0], SkIntToScalar(32767))) {
        return kUnimplemented_FilterReturn;
    }

    SkIPoint margin;
    SkMask  srcM, dstM;
    srcM.fBounds = rects[0].roundOut();
    srcM.fFormat = SkMask::kA8_Format;
    srcM.fRowBytes = 0;

    bool filterResult = false;
    if (count == 1 && c_analyticBlurNinepatch) {
        // special case for fast rect blur
        // don't actually do the blur the first time, just compute the correct size
        filterResult = this->filterRectMask(&dstM, rects[0], matrix, &margin,
                                            SkMask::kJustComputeBounds_CreateMode);
    } else {
        filterResult = this->filterMask(&dstM, srcM, matrix, &margin);
    }

    if (!filterResult) {
        return kFalse_FilterReturn;
    }

    /*
     *  smallR is the smallest version of 'rect' that will still guarantee that
     *  we get the same blur results on all edges, plus 1 center row/col that is
     *  representative of the extendible/stretchable edges of the ninepatch.
     *  Since our actual edge may be fractional we inset 1 more to be sure we
     *  don't miss any interior blur.
     *  x is an added pixel of blur, and { and } are the (fractional) edge
     *  pixels from the original rect.
     *
     *   x x { x x .... x x } x x
     *
     *  Thus, in this case, we inset by a total of 5 (on each side) beginning
     *  with our outer-rect (dstM.fBounds)
     */
    SkRect smallR[2];
    SkIPoint center;

    // +2 is from +1 for each edge (to account for possible fractional edges
    int smallW = dstM.fBounds.width() - srcM.fBounds.width() + 2;
    int smallH = dstM.fBounds.height() - srcM.fBounds.height() + 2;
    SkIRect innerIR;

    if (1 == count) {
        innerIR = srcM.fBounds;
        center.set(smallW, smallH);
    } else {
        SkASSERT(2 == count);
        rects[1].roundIn(&innerIR);
        center.set(smallW + (innerIR.left() - srcM.fBounds.left()),
                   smallH + (innerIR.top() - srcM.fBounds.top()));
    }

    // +1 so we get a clean, stretchable, center row/col
    smallW += 1;
    smallH += 1;

    // we want the inset amounts to be integral, so we don't change any
    // fractional phase on the fRight or fBottom of our smallR.
    const SkScalar dx = SkIntToScalar(innerIR.width() - smallW);
    const SkScalar dy = SkIntToScalar(innerIR.height() - smallH);
    if (dx < 0 || dy < 0) {
        // we're too small, relative to our blur, to break into nine-patch,
        // so we ask to have our normal filterMask() be called.
        return kUnimplemented_FilterReturn;
    }

    smallR[0].set(rects[0].left(), rects[0].top(), rects[0].right() - dx, rects[0].bottom() - dy);
    if (smallR[0].width() < 2 || smallR[0].height() < 2) {
        return kUnimplemented_FilterReturn;
    }
    if (2 == count) {
        smallR[1].set(rects[1].left(), rects[1].top(),
                      rects[1].right() - dx, rects[1].bottom() - dy);
        SkASSERT(!smallR[1].isEmpty());
    }

    const SkScalar sigma = this->computeXformedSigma(matrix);
    SkCachedData* cache = find_cached_rects(&patch->fMask, sigma, fBlurStyle,
                                            this->getQuality(), smallR, count);
    if (!cache) {
        if (count > 1 || !c_analyticBlurNinepatch) {
            if (!draw_rects_into_mask(smallR, count, &srcM)) {
                return kFalse_FilterReturn;
            }

            SkAutoMaskFreeImage amf(srcM.fImage);

            if (!this->filterMask(&patch->fMask, srcM, matrix, &margin)) {
                return kFalse_FilterReturn;
            }
        } else {
            if (!this->filterRectMask(&patch->fMask, smallR[0], matrix, &margin,
                                      SkMask::kComputeBoundsAndRenderImage_CreateMode)) {
                return kFalse_FilterReturn;
            }
        }
        cache = add_cached_rects(&patch->fMask, sigma, fBlurStyle, this->getQuality(), smallR, count);
    }
    patch->fMask.fBounds.offsetTo(0, 0);
    patch->fOuterRect = dstM.fBounds;
    patch->fCenter = center;
    SkASSERT(nullptr == patch->fCache);
    patch->fCache = cache;  // transfer ownership to patch
    return kTrue_FilterReturn;
}

void SkBlurMaskFilterImpl::computeFastBounds(const SkRect& src,
                                             SkRect* dst) const {
    SkScalar pad = 3.0f * fSigma;

    dst->set(src.fLeft  - pad, src.fTop    - pad,
             src.fRight + pad, src.fBottom + pad);
}

sk_sp<SkFlattenable> SkBlurMaskFilterImpl::CreateProc(SkReadBuffer& buffer) {
    const SkScalar sigma = buffer.readScalar();
    const unsigned style = buffer.readUInt();
    unsigned flags = buffer.readUInt();

    buffer.validate(style <= kLastEnum_SkBlurStyle);
    buffer.validate(!(flags & ~SkBlurMaskFilter::kAll_BlurFlag));

    flags &= SkBlurMaskFilter::kAll_BlurFlag;

    SkRect occluder;
    if (buffer.isVersionLT(SkReadBuffer::kBlurMaskFilterWritesOccluder)) {
        occluder.setEmpty();
    } else {
        buffer.readRect(&occluder);
    }

    if (style <= kLastEnum_SkBlurStyle) {
        return SkBlurMaskFilter::Make((SkBlurStyle)style, sigma, occluder, flags);
    }
    return nullptr;
}

void SkBlurMaskFilterImpl::flatten(SkWriteBuffer& buffer) const {
    buffer.writeScalar(fSigma);
    buffer.writeUInt(fBlurStyle);
    buffer.writeUInt(fBlurFlags);
    buffer.writeRect(fOccluder);
}


#if SK_SUPPORT_GPU

class GrGLRectBlurEffect;

class GrRectBlurEffect : public GrFragmentProcessor {
public:
    ~GrRectBlurEffect() override { }

    const char* name() const override { return "RectBlur"; }

    static sk_sp<GrFragmentProcessor> Make(GrTextureProvider *textureProvider,
                                           const SkRect& rect, float sigma) {
        int doubleProfileSize = SkScalarCeilToInt(12*sigma);

        if (doubleProfileSize >= rect.width() || doubleProfileSize >= rect.height()) {
            // if the blur sigma is too large so the gaussian overlaps the whole
            // rect in either direction, fall back to CPU path for now.
            return nullptr;
        }

        sk_sp<GrTexture> blurProfile(CreateBlurProfileTexture(textureProvider, sigma));
        if (!blurProfile) {
           return nullptr;
        }
        // in OpenGL ES, mediump floats have a minimum range of 2^14. If we have coordinates bigger
        // than that, the shader math will end up with infinities and result in the blur effect not
        // working correctly. To avoid this, we switch into highp when the coordinates are too big.
        // As 2^14 is the minimum range but the actual range can be bigger, we might end up
        // switching to highp sooner than strictly necessary, but most devices that have a bigger
        // range for mediump also have mediump being exactly the same as highp (e.g. all non-OpenGL
        // ES devices), and thus incur no additional penalty for the switch.
        static const SkScalar kMAX_BLUR_COORD = SkIntToScalar(16000);
        GrSLPrecision precision;
        if (SkScalarAbs(rect.top()) > kMAX_BLUR_COORD ||
            SkScalarAbs(rect.left()) > kMAX_BLUR_COORD ||
            SkScalarAbs(rect.bottom()) > kMAX_BLUR_COORD ||
            SkScalarAbs(rect.right()) > kMAX_BLUR_COORD ||
            SkScalarAbs(rect.width()) > kMAX_BLUR_COORD ||
            SkScalarAbs(rect.height()) > kMAX_BLUR_COORD) {
            precision = kHigh_GrSLPrecision;
        } else {
            precision = kDefault_GrSLPrecision;
        }

        return sk_sp<GrFragmentProcessor>(
                new GrRectBlurEffect(rect, sigma, blurProfile.get(), precision));
    }

    const SkRect& getRect() const { return fRect; }
    float getSigma() const { return fSigma; }
    GrSLPrecision precision() const { return fPrecision; }

private:
    GrRectBlurEffect(const SkRect& rect, float sigma, GrTexture *blurProfile,
                     GrSLPrecision fPrecision);

    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;

    void onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override;

    bool onIsEqual(const GrFragmentProcessor&) const override;

    void onComputeInvariantOutput(GrInvariantOutput* inout) const override;

    static GrTexture* CreateBlurProfileTexture(GrTextureProvider*, float sigma);

    SkRect          fRect;
    float           fSigma;
    TextureSampler  fBlurProfileSampler;
    GrSLPrecision   fPrecision;

    GR_DECLARE_FRAGMENT_PROCESSOR_TEST;

    typedef GrFragmentProcessor INHERITED;
};

class GrGLRectBlurEffect : public GrGLSLFragmentProcessor {
public:
    void emitCode(EmitArgs&) override;

    static void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder* b);

protected:
    void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;

private:
    typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;

    UniformHandle       fProxyRectUniform;
    UniformHandle       fProfileSizeUniform;

    typedef GrGLSLFragmentProcessor INHERITED;
};

void OutputRectBlurProfileLookup(GrGLSLFPFragmentBuilder* fragBuilder,
                                 GrGLSLFragmentProcessor::SamplerHandle sampler,
                                 const char *output,
                                 const char *profileSize, const char *loc,
                                 const char *blurred_width,
                                 const char *sharp_width) {
    fragBuilder->codeAppendf("float %s;", output);
    fragBuilder->codeAppendf("{");
    fragBuilder->codeAppendf("float coord = ((abs(%s - 0.5 * %s) - 0.5 * %s)) / %s;",
                           loc, blurred_width, sharp_width, profileSize);
    fragBuilder->codeAppendf("%s = ", output);
    fragBuilder->appendTextureLookup(sampler, "vec2(coord,0.5)");
    fragBuilder->codeAppend(".a;");
    fragBuilder->codeAppendf("}");
}


void GrGLRectBlurEffect::GenKey(const GrProcessor& proc, const GrShaderCaps&,
                                GrProcessorKeyBuilder* b) {
    const GrRectBlurEffect& rbe = proc.cast<GrRectBlurEffect>();

    b->add32(rbe.precision());
}


void GrGLRectBlurEffect::emitCode(EmitArgs& args) {
    const GrRectBlurEffect& rbe = args.fFp.cast<GrRectBlurEffect>();

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;

    const char *rectName;
    const char *profileSizeName;

    SkString precisionString;
    if (args.fShaderCaps->usesPrecisionModifiers()) {
        precisionString.printf("%s ", GrGLSLPrecisionString(rbe.precision()));
    }
    fProxyRectUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                   kVec4f_GrSLType,
                                                   rbe.precision(),
                                                   "proxyRect",
                                                   &rectName);
    fProfileSizeUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                     kFloat_GrSLType,
                                                     kDefault_GrSLPrecision,
                                                     "profileSize",
                                                     &profileSizeName);

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;

    if (args.fInputColor) {
        fragBuilder->codeAppendf("vec4 src=%s;", args.fInputColor);
    } else {
        fragBuilder->codeAppendf("vec4 src=vec4(1);");
    }

    fragBuilder->codeAppendf("%s vec2 translatedPos = sk_FragCoord.xy - %s.xy;",
                             precisionString.c_str(), rectName);
    fragBuilder->codeAppendf("%s float width = %s.z - %s.x;", precisionString.c_str(), rectName,
                             rectName);
    fragBuilder->codeAppendf("%s float height = %s.w - %s.y;", precisionString.c_str(), rectName,
                             rectName);

    fragBuilder->codeAppendf("%s vec2 smallDims = vec2(width - %s, height - %s);",
                             precisionString.c_str(), profileSizeName, profileSizeName);
    fragBuilder->codeAppendf("%s float center = 2.0 * floor(%s/2.0 + .25) - 1.0;",
                             precisionString.c_str(), profileSizeName);
    fragBuilder->codeAppendf("%s vec2 wh = smallDims - vec2(center,center);",
                             precisionString.c_str());

    OutputRectBlurProfileLookup(fragBuilder, args.fTexSamplers[0], "horiz_lookup", profileSizeName,
                                "translatedPos.x", "width", "wh.x");
    OutputRectBlurProfileLookup(fragBuilder, args.fTexSamplers[0], "vert_lookup", profileSizeName,
                                "translatedPos.y", "height", "wh.y");

    fragBuilder->codeAppendf("float final = horiz_lookup * vert_lookup;");
    fragBuilder->codeAppendf("%s = src * final;", args.fOutputColor);
}

void GrGLRectBlurEffect::onSetData(const GrGLSLProgramDataManager& pdman,
                                   const GrProcessor& proc) {
    const GrRectBlurEffect& rbe = proc.cast<GrRectBlurEffect>();
    SkRect rect = rbe.getRect();

    pdman.set4f(fProxyRectUniform, rect.fLeft, rect.fTop, rect.fRight, rect.fBottom);
    pdman.set1f(fProfileSizeUniform, SkScalarCeilToScalar(6*rbe.getSigma()));
}

GrTexture* GrRectBlurEffect::CreateBlurProfileTexture(GrTextureProvider* textureProvider,
                                                      float sigma) {
    GrSurfaceDesc texDesc;

    unsigned int profileSize = SkScalarCeilToInt(6*sigma);

    texDesc.fWidth = profileSize;
    texDesc.fHeight = 1;
    texDesc.fConfig = kAlpha_8_GrPixelConfig;
    texDesc.fIsMipMapped = false;

    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
    GrUniqueKey key;
    GrUniqueKey::Builder builder(&key, kDomain, 1);
    builder[0] = profileSize;
    builder.finish();

    GrTexture *blurProfile = textureProvider->findAndRefTextureByUniqueKey(key);

    if (!blurProfile) {
        std::unique_ptr<uint8_t[]> profile(SkBlurMask::ComputeBlurProfile(sigma));

        blurProfile = textureProvider->createTexture(texDesc, SkBudgeted::kYes, profile.get(), 0);
        if (blurProfile) {
            textureProvider->assignUniqueKeyToTexture(key, blurProfile);
        }
    }

    return blurProfile;
}

GrRectBlurEffect::GrRectBlurEffect(const SkRect& rect, float sigma, GrTexture *blurProfile,
                                   GrSLPrecision precision)
    : fRect(rect)
    , fSigma(sigma)
    , fBlurProfileSampler(blurProfile)
    , fPrecision(precision) {
    this->initClassID<GrRectBlurEffect>();
    this->addTextureSampler(&fBlurProfileSampler);
}

void GrRectBlurEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
                                             GrProcessorKeyBuilder* b) const {
    GrGLRectBlurEffect::GenKey(*this, caps, b);
}

GrGLSLFragmentProcessor* GrRectBlurEffect::onCreateGLSLInstance() const {
    return new GrGLRectBlurEffect;
}

bool GrRectBlurEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
    const GrRectBlurEffect& s = sBase.cast<GrRectBlurEffect>();
    return this->getSigma() == s.getSigma() && this->getRect() == s.getRect();
}

void GrRectBlurEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
    inout->mulByUnknownSingleComponent();
}

GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrRectBlurEffect);

sk_sp<GrFragmentProcessor> GrRectBlurEffect::TestCreate(GrProcessorTestData* d) {
    float sigma = d->fRandom->nextRangeF(3,8);
    float width = d->fRandom->nextRangeF(200,300);
    float height = d->fRandom->nextRangeF(200,300);
    return GrRectBlurEffect::Make(d->fContext->textureProvider(), SkRect::MakeWH(width, height),
                                  sigma);
}

bool SkBlurMaskFilterImpl::directFilterMaskGPU(GrTextureProvider* texProvider,
                                               GrRenderTargetContext* renderTargetContext,
                                               GrPaint&& paint,
                                               const GrClip& clip,
                                               const SkMatrix& viewMatrix,
                                               const SkStrokeRec& strokeRec,
                                               const SkPath& path) const {
    SkASSERT(renderTargetContext);

    if (fBlurStyle != kNormal_SkBlurStyle) {
        return false;
    }

    // TODO: we could handle blurred stroked circles
    if (!strokeRec.isFillStyle()) {
        return false;
    }

    SkScalar xformedSigma = this->computeXformedSigma(viewMatrix);

    sk_sp<GrFragmentProcessor> fp;

    SkRect rect;
    if (path.isRect(&rect)) {
        SkScalar pad = 3.0f * xformedSigma;
        rect.outset(pad, pad);

        fp = GrRectBlurEffect::Make(texProvider, rect, xformedSigma);
    } else if (path.isOval(&rect) && SkScalarNearlyEqual(rect.width(), rect.height())) {
        fp = GrCircleBlurFragmentProcessor::Make(texProvider, rect, xformedSigma);

        // expand the rect for the coverage geometry
        int pad = SkScalarCeilToInt(6*xformedSigma)/2;
        rect.outset(SkIntToScalar(pad), SkIntToScalar(pad));
    } else {
        return false;
    }

    if (!fp) {
        return false;
    }

    SkMatrix inverse;
    if (!viewMatrix.invert(&inverse)) {
        return false;
    }

    paint.addCoverageFragmentProcessor(std::move(fp));
    renderTargetContext->fillRectWithLocalMatrix(clip, std::move(paint), GrAA::kNo, SkMatrix::I(),
                                                 rect, inverse);
    return true;
}

//////////////////////////////////////////////////////////////////////////////

class GrRRectBlurEffect : public GrFragmentProcessor {
public:

    static sk_sp<GrFragmentProcessor> Make(GrContext*,
                                           float sigma, float xformedSigma,
                                           const SkRRect& srcRRect, const SkRRect& devRRect);

    virtual ~GrRRectBlurEffect() {}
    const char* name() const override { return "GrRRectBlur"; }

    const SkRRect& getRRect() const { return fRRect; }
    float getSigma() const { return fSigma; }

private:
    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;

    GrRRectBlurEffect(float sigma, const SkRRect&, GrTexture* profileTexture);

    virtual void onGetGLSLProcessorKey(const GrShaderCaps& caps,
                                       GrProcessorKeyBuilder* b) const override;

    bool onIsEqual(const GrFragmentProcessor& other) const override;

    void onComputeInvariantOutput(GrInvariantOutput* inout) const override;

    SkRRect             fRRect;
    float               fSigma;
    TextureSampler      fNinePatchSampler;

    GR_DECLARE_FRAGMENT_PROCESSOR_TEST;

    typedef GrFragmentProcessor INHERITED;
};

static sk_sp<GrTexture> find_or_create_rrect_blur_mask(GrContext* context,
                                                       const SkRRect& rrectToDraw,
                                                       const SkISize& size,
                                                       float xformedSigma) {
    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
    GrUniqueKey key;
    GrUniqueKey::Builder builder(&key, kDomain, 9);
    builder[0] = SkScalarCeilToInt(xformedSigma-1/6.0f);

    int index = 1;
    for (auto c : { SkRRect::kUpperLeft_Corner,  SkRRect::kUpperRight_Corner,
                    SkRRect::kLowerRight_Corner, SkRRect::kLowerLeft_Corner }) {
        SkASSERT(SkScalarIsInt(rrectToDraw.radii(c).fX) && SkScalarIsInt(rrectToDraw.radii(c).fY));
        builder[index++] = SkScalarCeilToInt(rrectToDraw.radii(c).fX);
        builder[index++] = SkScalarCeilToInt(rrectToDraw.radii(c).fY);
    }
    builder.finish();

    sk_sp<GrTexture> mask(context->textureProvider()->findAndRefTextureByUniqueKey(key));
    if (!mask) {
        // TODO: this could be approx but the texture coords will need to be updated
        sk_sp<GrRenderTargetContext> rtc(context->makeDeferredRenderTargetContextWithFallback(
            SkBackingFit::kExact, size.fWidth, size.fHeight, kAlpha_8_GrPixelConfig, nullptr));
        if (!rtc) {
            return nullptr;
        }

        GrPaint paint;

        rtc->clear(nullptr, 0x0, true);
        rtc->drawRRect(GrNoClip(), std::move(paint), GrAA::kYes, SkMatrix::I(), rrectToDraw,
                       GrStyle::SimpleFill());

        sk_sp<GrTexture> srcTexture(rtc->asTexture());
        if (!srcTexture) {
            return nullptr;
        }
        sk_sp<GrRenderTargetContext> rtc2(SkGpuBlurUtils::GaussianBlur(context,
                                                                       srcTexture.get(),
                                                                       nullptr,
                                                                       SkIRect::MakeWH(
                                                                                    size.fWidth,
                                                                                    size.fHeight),
                                                                       nullptr,
                                                                       xformedSigma, xformedSigma,
                                                                       SkBackingFit::kExact));
        if (!rtc2) {
            return nullptr;
        }

        mask = rtc2->asTexture();
        if (!mask) {
            return nullptr;
        }
        context->textureProvider()->assignUniqueKeyToTexture(key, mask.get());
    }

    return mask;
}

sk_sp<GrFragmentProcessor> GrRRectBlurEffect::Make(GrContext* context,
                                                   float sigma, float xformedSigma,
                                                   const SkRRect& srcRRect, const SkRRect& devRRect) {
    SkASSERT(!devRRect.isCircle() && !devRRect.isRect()); // Should've been caught up-stream

    // TODO: loosen this up
    if (!devRRect.isSimpleCircular()) {
        return nullptr;
    }

    // Make sure we can successfully ninepatch this rrect -- the blur sigma has to be
    // sufficiently small relative to both the size of the corner radius and the
    // width (and height) of the rrect.
    SkRRect rrectToDraw;
    SkISize size;
    SkScalar ignored[SkBlurMaskFilter::kMaxDivisions];
    int ignoredSize;
    uint32_t ignored32;

    bool ninePatchable = SkBlurMaskFilter::ComputeBlurredRRectParams(srcRRect, devRRect,
                                                                     SkRect::MakeEmpty(),
                                                                     sigma, xformedSigma,
                                                                     &rrectToDraw, &size,
                                                                     ignored, ignored,
                                                                     ignored, ignored,
                                                                     &ignoredSize, &ignoredSize,
                                                                     &ignored32);
    if (!ninePatchable) {
        return nullptr;
    }

    sk_sp<GrTexture> mask(find_or_create_rrect_blur_mask(context, rrectToDraw, size, xformedSigma));
    if (!mask) {
        return nullptr;
    }

    return sk_sp<GrFragmentProcessor>(new GrRRectBlurEffect(xformedSigma,
                                                            devRRect,
                                                            mask.get()));
}

void GrRRectBlurEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
    inout->mulByUnknownSingleComponent();
}

GrRRectBlurEffect::GrRRectBlurEffect(float sigma, const SkRRect& rrect, GrTexture *ninePatchTexture)
    : fRRect(rrect),
      fSigma(sigma),
      fNinePatchSampler(ninePatchTexture) {
    this->initClassID<GrRRectBlurEffect>();
    this->addTextureSampler(&fNinePatchSampler);
}

bool GrRRectBlurEffect::onIsEqual(const GrFragmentProcessor& other) const {
    const GrRRectBlurEffect& rrbe = other.cast<GrRRectBlurEffect>();
    return fRRect.getSimpleRadii().fX == rrbe.fRRect.getSimpleRadii().fX &&
           fSigma == rrbe.fSigma &&
           fRRect.rect() == rrbe.fRRect.rect();
}

//////////////////////////////////////////////////////////////////////////////

GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrRRectBlurEffect);

sk_sp<GrFragmentProcessor> GrRRectBlurEffect::TestCreate(GrProcessorTestData* d) {
    SkScalar w = d->fRandom->nextRangeScalar(100.f, 1000.f);
    SkScalar h = d->fRandom->nextRangeScalar(100.f, 1000.f);
    SkScalar r = d->fRandom->nextRangeF(1.f, 9.f);
    SkScalar sigma = d->fRandom->nextRangeF(1.f,10.f);
    SkRRect rrect;
    rrect.setRectXY(SkRect::MakeWH(w, h), r, r);
    return GrRRectBlurEffect::Make(d->fContext, sigma, sigma, rrect, rrect);
}

//////////////////////////////////////////////////////////////////////////////

class GrGLRRectBlurEffect : public GrGLSLFragmentProcessor {
public:
    void emitCode(EmitArgs&) override;

protected:
    void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;

private:
    GrGLSLProgramDataManager::UniformHandle fProxyRectUniform;
    GrGLSLProgramDataManager::UniformHandle fCornerRadiusUniform;
    GrGLSLProgramDataManager::UniformHandle fBlurRadiusUniform;
    typedef GrGLSLFragmentProcessor INHERITED;
};

void GrGLRRectBlurEffect::emitCode(EmitArgs& args) {
    const char *rectName;
    const char *cornerRadiusName;
    const char *blurRadiusName;

    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    // The proxy rect has left, top, right, and bottom edges correspond to
    // components x, y, z, and w, respectively.

    fProxyRectUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                   kVec4f_GrSLType,
                                                   kDefault_GrSLPrecision,
                                                   "proxyRect",
                                                   &rectName);
    fCornerRadiusUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                      kFloat_GrSLType,
                                                      kDefault_GrSLPrecision,
                                                      "cornerRadius",
                                                      &cornerRadiusName);
    fBlurRadiusUniform = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                                    kFloat_GrSLType,
                                                    kDefault_GrSLPrecision,
                                                    "blurRadius",
                                                    &blurRadiusName);

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;

    // warp the fragment position to the appropriate part of the 9patch blur texture

    fragBuilder->codeAppendf("vec2 rectCenter = (%s.xy + %s.zw)/2.0;", rectName, rectName);
    fragBuilder->codeAppendf("vec2 translatedFragPos = sk_FragCoord.xy - %s.xy;", rectName);
    fragBuilder->codeAppendf("float threshold = %s + 2.0*%s;", cornerRadiusName, blurRadiusName);
    fragBuilder->codeAppendf("vec2 middle = %s.zw - %s.xy - 2.0*threshold;", rectName, rectName);

    fragBuilder->codeAppendf(
           "if (translatedFragPos.x >= threshold && translatedFragPos.x < (middle.x+threshold)) {");
    fragBuilder->codeAppendf("translatedFragPos.x = threshold;\n");
    fragBuilder->codeAppendf("} else if (translatedFragPos.x >= (middle.x + threshold)) {");
    fragBuilder->codeAppendf("translatedFragPos.x -= middle.x - 1.0;");
    fragBuilder->codeAppendf("}");

    fragBuilder->codeAppendf(
            "if (translatedFragPos.y > threshold && translatedFragPos.y < (middle.y+threshold)) {");
    fragBuilder->codeAppendf("translatedFragPos.y = threshold;");
    fragBuilder->codeAppendf("} else if (translatedFragPos.y >= (middle.y + threshold)) {");
    fragBuilder->codeAppendf("translatedFragPos.y -= middle.y - 1.0;");
    fragBuilder->codeAppendf("}");

    fragBuilder->codeAppendf("vec2 proxyDims = vec2(2.0*threshold+1.0);");
    fragBuilder->codeAppendf("vec2 texCoord = translatedFragPos / proxyDims;");

    fragBuilder->codeAppendf("%s = ", args.fOutputColor);
    fragBuilder->appendTextureLookupAndModulate(args.fInputColor, args.fTexSamplers[0], "texCoord");
    fragBuilder->codeAppend(";");
}

void GrGLRRectBlurEffect::onSetData(const GrGLSLProgramDataManager& pdman,
                                    const GrProcessor& proc) {
    const GrRRectBlurEffect& brre = proc.cast<GrRRectBlurEffect>();
    const SkRRect& rrect = brre.getRRect();

    float blurRadius = 3.f*SkScalarCeilToScalar(brre.getSigma()-1/6.0f);
    pdman.set1f(fBlurRadiusUniform, blurRadius);

    SkRect rect = rrect.getBounds();
    rect.outset(blurRadius, blurRadius);
    pdman.set4f(fProxyRectUniform, rect.fLeft, rect.fTop, rect.fRight, rect.fBottom);

    SkScalar radius = 0;
    SkASSERT(rrect.isSimpleCircular() || rrect.isRect());
    radius = rrect.getSimpleRadii().fX;
    pdman.set1f(fCornerRadiusUniform, radius);
}

void GrRRectBlurEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
                                              GrProcessorKeyBuilder* b) const {
    GrGLRRectBlurEffect::GenKey(*this, caps, b);
}

GrGLSLFragmentProcessor* GrRRectBlurEffect::onCreateGLSLInstance() const {
    return new GrGLRRectBlurEffect;
}

bool SkBlurMaskFilterImpl::directFilterRRectMaskGPU(GrContext* context,
                                                    GrRenderTargetContext* renderTargetContext,
                                                    GrPaint&& paint,
                                                    const GrClip& clip,
                                                    const SkMatrix& viewMatrix,
                                                    const SkStrokeRec& strokeRec,
                                                    const SkRRect& srcRRect,
                                                    const SkRRect& devRRect) const {
    SkASSERT(renderTargetContext);

    if (fBlurStyle != kNormal_SkBlurStyle) {
        return false;
    }

    if (!strokeRec.isFillStyle()) {
        return false;
    }

    SkScalar xformedSigma = this->computeXformedSigma(viewMatrix);

    if (devRRect.isRect() || devRRect.isCircle()) {
        if (this->ignoreXform()) {
            return false;
        }

        sk_sp<GrFragmentProcessor> fp;
        if (devRRect.isRect()) {
            SkScalar pad = 3.0f * xformedSigma;
            const SkRect dstCoverageRect = devRRect.rect().makeOutset(pad, pad);

            fp = GrRectBlurEffect::Make(context->textureProvider(), dstCoverageRect, xformedSigma);
        } else {
            fp = GrCircleBlurFragmentProcessor::Make(context->textureProvider(),
                                                     devRRect.rect(),
                                                     xformedSigma);
        }

        if (!fp) {
            return false;
        }

        paint.addCoverageFragmentProcessor(std::move(fp));

        SkRect srcProxyRect = srcRRect.rect();
        srcProxyRect.outset(3.0f*fSigma, 3.0f*fSigma);

        renderTargetContext->drawRect(clip, std::move(paint), GrAA::kNo, viewMatrix, srcProxyRect);
        return true;
    }

    sk_sp<GrFragmentProcessor> fp(GrRRectBlurEffect::Make(context, fSigma, xformedSigma,
                                                          srcRRect, devRRect));
    if (!fp) {
        return false;
    }

    if (!this->ignoreXform()) {
        SkRect srcProxyRect = srcRRect.rect();
        srcProxyRect.outset(3.0f*fSigma, 3.0f*fSigma);

        SkPoint points[8];
        uint16_t indices[24];
        int numPoints, numIndices;

        SkRect temp = fOccluder;

        if (!temp.isEmpty() && (srcProxyRect.contains(temp) || temp.intersect(srcProxyRect))) {
            srcProxyRect.toQuad(points);
            temp.toQuad(&points[4]);
            numPoints = 8;

            static const uint16_t ringI[24] = { 0, 1, 5, 5, 4, 0,
                                                1, 2, 6, 6, 5, 1,
                                                2, 3, 7, 7, 6, 2,
                                                3, 0, 4, 4, 7, 3 };
            memcpy(indices, ringI, sizeof(ringI));
            numIndices = 24;
        } else {
            // full rect case
            srcProxyRect.toQuad(points);
            numPoints = 4;

            static const uint16_t fullI[6] = { 0, 1, 2, 0, 2, 3 };
            memcpy(indices, fullI, sizeof(fullI));
            numIndices = 6;
        }

        paint.addCoverageFragmentProcessor(std::move(fp));
        renderTargetContext->drawVertices(clip, std::move(paint), viewMatrix,
                                          kTriangles_GrPrimitiveType, numPoints, points, nullptr,
                                          nullptr, indices, numIndices);

    } else {
        SkMatrix inverse;
        if (!viewMatrix.invert(&inverse)) {
            return false;
        }

        float extra=3.f*SkScalarCeilToScalar(xformedSigma-1/6.0f);
        SkRect proxyRect = devRRect.rect();
        proxyRect.outset(extra, extra);

        paint.addCoverageFragmentProcessor(std::move(fp));
        renderTargetContext->fillRectWithLocalMatrix(clip, std::move(paint), GrAA::kNo,
                                                     SkMatrix::I(), proxyRect, inverse);
    }

    return true;
}

bool SkBlurMaskFilterImpl::canFilterMaskGPU(const SkRRect& devRRect,
                                            const SkIRect& clipBounds,
                                            const SkMatrix& ctm,
                                            SkRect* maskRect) const {
    SkScalar xformedSigma = this->computeXformedSigma(ctm);
    if (xformedSigma <= 0) {
        return false;
    }

    // We always do circles and simple circular rrects on the GPU
    if (!devRRect.isCircle() && !devRRect.isSimpleCircular()) {
        static const SkScalar kMIN_GPU_BLUR_SIZE  = SkIntToScalar(64);
        static const SkScalar kMIN_GPU_BLUR_SIGMA = SkIntToScalar(32);

        if (devRRect.width() <= kMIN_GPU_BLUR_SIZE &&
            devRRect.height() <= kMIN_GPU_BLUR_SIZE &&
            xformedSigma <= kMIN_GPU_BLUR_SIGMA) {
            // We prefer to blur small rects with small radii on the CPU.
            return false;
        }
    }

    if (nullptr == maskRect) {
        // don't need to compute maskRect
        return true;
    }

    float sigma3 = 3 * SkScalarToFloat(xformedSigma);

    SkRect clipRect = SkRect::Make(clipBounds);
    SkRect srcRect(devRRect.rect());

    // Outset srcRect and clipRect by 3 * sigma, to compute affected blur area.
    srcRect.outset(sigma3, sigma3);
    clipRect.outset(sigma3, sigma3);
    if (!srcRect.intersect(clipRect)) {
        srcRect.setEmpty();
    }
    *maskRect = srcRect;
    return true;
}

sk_sp<GrTextureProxy> SkBlurMaskFilterImpl::filterMaskGPU(GrContext* context,
                                                          sk_sp<GrTextureProxy> srcProxy,
                                                          const SkMatrix& ctm,
                                                          const SkIRect& maskRect) const {
    // 'maskRect' isn't snapped to the UL corner but the mask in 'src' is.
    const SkIRect clipRect = SkIRect::MakeWH(maskRect.width(), maskRect.height());

    SkScalar xformedSigma = this->computeXformedSigma(ctm);
    SkASSERT(xformedSigma > 0);

    // TODO: defer this further (i.e., push the proxy into GaussianBlur)
    GrTexture* src = srcProxy->instantiate(context->textureProvider());
    if (!src) {
        return nullptr;
    }

    // If we're doing a normal blur, we can clobber the pathTexture in the
    // gaussianBlur.  Otherwise, we need to save it for later compositing.
    bool isNormalBlur = (kNormal_SkBlurStyle == fBlurStyle);
    sk_sp<GrRenderTargetContext> renderTargetContext(SkGpuBlurUtils::GaussianBlur(context, src,
                                                                                  nullptr, clipRect,
                                                                                  nullptr,
                                                                                  xformedSigma,
                                                                                  xformedSigma));
    if (!renderTargetContext) {
        return nullptr;
    }

    if (!isNormalBlur) {
        GrPaint paint;
        // Blend pathTexture over blurTexture.
        paint.addCoverageFragmentProcessor(
                                        GrSimpleTextureEffect::Make(src, nullptr, SkMatrix::I()));
        if (kInner_SkBlurStyle == fBlurStyle) {
            // inner:  dst = dst * src
            paint.setCoverageSetOpXPFactory(SkRegion::kIntersect_Op);
        } else if (kSolid_SkBlurStyle == fBlurStyle) {
            // solid:  dst = src + dst - src * dst
            //             = src + (1 - src) * dst
            paint.setCoverageSetOpXPFactory(SkRegion::kUnion_Op);
        } else if (kOuter_SkBlurStyle == fBlurStyle) {
            // outer:  dst = dst * (1 - src)
            //             = 0 * src + (1 - src) * dst
            paint.setCoverageSetOpXPFactory(SkRegion::kDifference_Op);
        } else {
            paint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);
        }

        renderTargetContext->drawRect(GrNoClip(), std::move(paint), GrAA::kNo, SkMatrix::I(),
                                      SkRect::Make(clipRect));
    }

    return sk_ref_sp(renderTargetContext->asDeferredTexture());
}

#endif // SK_SUPPORT_GPU


#ifndef SK_IGNORE_TO_STRING
void SkBlurMaskFilterImpl::toString(SkString* str) const {
    str->append("SkBlurMaskFilterImpl: (");

    str->append("sigma: ");
    str->appendScalar(fSigma);
    str->append(" ");

    static const char* gStyleName[kLastEnum_SkBlurStyle + 1] = {
        "normal", "solid", "outer", "inner"
    };

    str->appendf("style: %s ", gStyleName[fBlurStyle]);
    str->append("flags: (");
    if (fBlurFlags) {
        bool needSeparator = false;
        SkAddFlagToString(str, this->ignoreXform(), "IgnoreXform", &needSeparator);
        SkAddFlagToString(str,
                          SkToBool(fBlurFlags & SkBlurMaskFilter::kHighQuality_BlurFlag),
                          "HighQuality", &needSeparator);
    } else {
        str->append("None");
    }
    str->append("))");
}
#endif

SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkBlurMaskFilter)
    SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkBlurMaskFilterImpl)
SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END