xref: /third_party/skia/src/core/SkBlurMF.cpp (revision cb93a386)
1/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "include/core/SkBitmap.h"
9#include "include/core/SkMaskFilter.h"
10#include "include/core/SkPathBuilder.h"
11#include "include/core/SkRRect.h"
12#include "include/core/SkStrokeRec.h"
13#include "include/core/SkVertices.h"
14#include "src/core/SkBlurMask.h"
15#include "src/core/SkGpuBlurUtils.h"
16#include "src/core/SkMaskFilterBase.h"
17#include "src/core/SkMathPriv.h"
18#include "src/core/SkMatrixProvider.h"
19#include "src/core/SkRRectPriv.h"
20#include "src/core/SkReadBuffer.h"
21#include "src/core/SkStringUtils.h"
22#include "src/core/SkSDFFilter.h"
23#include "src/core/SkWriteBuffer.h"
24
25#if SK_SUPPORT_GPU
26#include "include/gpu/GrRecordingContext.h"
27#include "src/core/SkRuntimeEffectPriv.h"
28#include "src/gpu/GrFragmentProcessor.h"
29#include "src/gpu/GrRecordingContextPriv.h"
30#include "src/gpu/GrResourceProvider.h"
31#include "src/gpu/GrShaderCaps.h"
32#include "src/gpu/GrStyle.h"
33#include "src/gpu/GrTextureProxy.h"
34#include "src/gpu/GrThreadSafeCache.h"
35#include "src/gpu/SkGr.h"
36#include "src/gpu/effects/GrMatrixEffect.h"
37#include "src/gpu/effects/GrSkSLFP.h"
38#include "src/gpu/effects/GrTextureEffect.h"
39#include "src/gpu/geometry/GrStyledShape.h"
40#include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
41#include "src/gpu/glsl/GrGLSLProgramDataManager.h"
42#include "src/gpu/glsl/GrGLSLUniformHandler.h"
43#if SK_GPU_V1
44#include "src/gpu/v1/SurfaceDrawContext_v1.h"
45#endif // SK_GPU_V1
46#endif // SK_SUPPORT_GPU
47
48class SkBlurMaskFilterImpl : public SkMaskFilterBase {
49public:
50    SkBlurMaskFilterImpl(SkScalar sigma, SkBlurStyle, bool respectCTM);
51
52    // overrides from SkMaskFilter
53    SkMask::Format getFormat() const override;
54    bool filterMask(SkMask* dst, const SkMask& src, const SkMatrix&,
55                    SkIPoint* margin) const override;
56
57#if SK_SUPPORT_GPU && SK_GPU_V1
58    bool canFilterMaskGPU(const GrStyledShape& shape,
59                          const SkIRect& devSpaceShapeBounds,
60                          const SkIRect& clipBounds,
61                          const SkMatrix& ctm,
62                          SkIRect* maskRect,
63                          const bool canUseSDFBlur = false) const override;
64    bool directFilterMaskGPU(GrRecordingContext*,
65                             skgpu::v1::SurfaceDrawContext*,
66                             GrPaint&&,
67                             const GrClip*,
68                             const SkMatrix& viewMatrix,
69                             const GrStyledShape&) const override;
70    GrSurfaceProxyView filterMaskGPU(GrRecordingContext*,
71                                     GrSurfaceProxyView srcView,
72                                     GrColorType srcColorType,
73                                     SkAlphaType srcAlphaType,
74                                     const SkMatrix& ctm,
75                                     const SkIRect& maskRect) const override;
76
77    float getNoxFormedSigma3() const override;
78
79    GrSurfaceProxyView filterMaskGPUNoxFormed(GrRecordingContext*, GrSurfaceProxyView srcView,
80        GrColorType srcColorType, SkAlphaType srcAlphaType, const SkMatrix& viewMatrix, const SkIRect& maskRect,
81        const SkRRect& srcRRect) const override;
82#endif
83
84    void computeFastBounds(const SkRect&, SkRect*) const override;
85    bool asABlur(BlurRec*) const override;
86
87
88protected:
89    FilterReturn filterRectsToNine(const SkRect[], int count, const SkMatrix&,
90                                   const SkIRect& clipBounds,
91                                   NinePatch*) const override;
92
93    FilterReturn filterRRectToNine(const SkRRect&, const SkMatrix&,
94                                   const SkIRect& clipBounds,
95                                   NinePatch*) const override;
96
97    bool filterRectMask(SkMask* dstM, const SkRect& r, const SkMatrix& matrix,
98                        SkIPoint* margin, SkMask::CreateMode createMode) const;
99    bool filterRRectMask(SkMask* dstM, const SkRRect& r, const SkMatrix& matrix,
100                        SkIPoint* margin, SkMask::CreateMode createMode) const;
101
102    bool ignoreXform() const { return !fRespectCTM; }
103
104private:
105    SK_FLATTENABLE_HOOKS(SkBlurMaskFilterImpl)
106    // To avoid unseemly allocation requests (esp. for finite platforms like
107    // handset) we limit the radius so something manageable. (as opposed to
108    // a request like 10,000)
109    static const SkScalar kMAX_BLUR_SIGMA;
110
111    SkScalar    fSigma;
112    SkBlurStyle fBlurStyle;
113    bool        fRespectCTM;
114
115    SkBlurMaskFilterImpl(SkReadBuffer&);
116    void flatten(SkWriteBuffer&) const override;
117
118    SkScalar computeXformedSigma(const SkMatrix& ctm) const {
119        SkScalar xformedSigma = this->ignoreXform() ? fSigma : ctm.mapRadius(fSigma);
120        return std::min(xformedSigma, kMAX_BLUR_SIGMA);
121    }
122
123    friend class SkBlurMaskFilter;
124
125    using INHERITED = SkMaskFilter;
126    friend void sk_register_blur_maskfilter_createproc();
127};
128
129const SkScalar SkBlurMaskFilterImpl::kMAX_BLUR_SIGMA = SkIntToScalar(128);
130
131///////////////////////////////////////////////////////////////////////////////
132
133SkBlurMaskFilterImpl::SkBlurMaskFilterImpl(SkScalar sigma, SkBlurStyle style, bool respectCTM)
134    : fSigma(sigma)
135    , fBlurStyle(style)
136    , fRespectCTM(respectCTM) {
137    SkASSERT(fSigma > 0);
138    SkASSERT((unsigned)style <= kLastEnum_SkBlurStyle);
139}
140
141SkMask::Format SkBlurMaskFilterImpl::getFormat() const {
142    return SkMask::kA8_Format;
143}
144
145bool SkBlurMaskFilterImpl::asABlur(BlurRec* rec) const {
146    if (this->ignoreXform()) {
147        return false;
148    }
149
150    if (rec) {
151        rec->fSigma = fSigma;
152        rec->fStyle = fBlurStyle;
153    }
154    return true;
155}
156
157bool SkBlurMaskFilterImpl::filterMask(SkMask* dst, const SkMask& src,
158                                      const SkMatrix& matrix,
159                                      SkIPoint* margin) const {
160    SkScalar sigma = this->computeXformedSigma(matrix);
161    return SkBlurMask::BoxBlur(dst, src, sigma, fBlurStyle, margin);
162}
163
164bool SkBlurMaskFilterImpl::filterRectMask(SkMask* dst, const SkRect& r,
165                                          const SkMatrix& matrix,
166                                          SkIPoint* margin, SkMask::CreateMode createMode) const {
167    SkScalar sigma = computeXformedSigma(matrix);
168
169    return SkBlurMask::BlurRect(sigma, dst, r, fBlurStyle, margin, createMode);
170}
171
172bool SkBlurMaskFilterImpl::filterRRectMask(SkMask* dst, const SkRRect& r,
173                                          const SkMatrix& matrix,
174                                          SkIPoint* margin, SkMask::CreateMode createMode) const {
175    SkScalar sigma = computeXformedSigma(matrix);
176
177    return SkBlurMask::BlurRRect(sigma, dst, r, fBlurStyle, margin, createMode);
178}
179
180#include "include/core/SkCanvas.h"
181
182static bool prepare_to_draw_into_mask(const SkRect& bounds, SkMask* mask) {
183    SkASSERT(mask != nullptr);
184
185    mask->fBounds = bounds.roundOut();
186    mask->fRowBytes = SkAlign4(mask->fBounds.width());
187    mask->fFormat = SkMask::kA8_Format;
188    const size_t size = mask->computeImageSize();
189    mask->fImage = SkMask::AllocImage(size, SkMask::kZeroInit_Alloc);
190    if (nullptr == mask->fImage) {
191        return false;
192    }
193    return true;
194}
195
196static bool draw_rrect_into_mask(const SkRRect rrect, SkMask* mask) {
197    if (!prepare_to_draw_into_mask(rrect.rect(), mask)) {
198        return false;
199    }
200
201    // FIXME: This code duplicates code in draw_rects_into_mask, below. Is there a
202    // clean way to share more code?
203    SkBitmap bitmap;
204    bitmap.installMaskPixels(*mask);
205
206    SkCanvas canvas(bitmap);
207    canvas.translate(-SkIntToScalar(mask->fBounds.left()),
208                     -SkIntToScalar(mask->fBounds.top()));
209
210    SkPaint paint;
211    paint.setAntiAlias(true);
212    canvas.drawRRect(rrect, paint);
213    return true;
214}
215
216static bool draw_rects_into_mask(const SkRect rects[], int count, SkMask* mask) {
217    if (!prepare_to_draw_into_mask(rects[0], mask)) {
218        return false;
219    }
220
221    SkBitmap bitmap;
222    bitmap.installPixels(SkImageInfo::Make(mask->fBounds.width(),
223                                           mask->fBounds.height(),
224                                           kAlpha_8_SkColorType,
225                                           kPremul_SkAlphaType),
226                         mask->fImage, mask->fRowBytes);
227
228    SkCanvas canvas(bitmap);
229    canvas.translate(-SkIntToScalar(mask->fBounds.left()),
230                     -SkIntToScalar(mask->fBounds.top()));
231
232    SkPaint paint;
233    paint.setAntiAlias(true);
234
235    if (1 == count) {
236        canvas.drawRect(rects[0], paint);
237    } else {
238        // todo: do I need a fast way to do this?
239        SkPath path = SkPathBuilder().addRect(rects[0])
240                                     .addRect(rects[1])
241                                     .setFillType(SkPathFillType::kEvenOdd)
242                                     .detach();
243        canvas.drawPath(path, paint);
244    }
245    return true;
246}
247
248static bool rect_exceeds(const SkRect& r, SkScalar v) {
249    return r.fLeft < -v || r.fTop < -v || r.fRight > v || r.fBottom > v ||
250           r.width() > v || r.height() > v;
251}
252
253#include "src/core/SkMaskCache.h"
254
255static SkCachedData* copy_mask_to_cacheddata(SkMask* mask) {
256    const size_t size = mask->computeTotalImageSize();
257    SkCachedData* data = SkResourceCache::NewCachedData(size);
258    if (data) {
259        memcpy(data->writable_data(), mask->fImage, size);
260        SkMask::FreeImage(mask->fImage);
261        mask->fImage = (uint8_t*)data->data();
262    }
263    return data;
264}
265
266static SkCachedData* find_cached_rrect(SkMask* mask, SkScalar sigma, SkBlurStyle style,
267                                       const SkRRect& rrect) {
268    return SkMaskCache::FindAndRef(sigma, style, rrect, mask);
269}
270
271static SkCachedData* add_cached_rrect(SkMask* mask, SkScalar sigma, SkBlurStyle style,
272                                      const SkRRect& rrect) {
273    SkCachedData* cache = copy_mask_to_cacheddata(mask);
274    if (cache) {
275        SkMaskCache::Add(sigma, style, rrect, *mask, cache);
276    }
277    return cache;
278}
279
280static SkCachedData* find_cached_rects(SkMask* mask, SkScalar sigma, SkBlurStyle style,
281                                       const SkRect rects[], int count) {
282    return SkMaskCache::FindAndRef(sigma, style, rects, count, mask);
283}
284
285static SkCachedData* add_cached_rects(SkMask* mask, SkScalar sigma, SkBlurStyle style,
286                                      const SkRect rects[], int count) {
287    SkCachedData* cache = copy_mask_to_cacheddata(mask);
288    if (cache) {
289        SkMaskCache::Add(sigma, style, rects, count, *mask, cache);
290    }
291    return cache;
292}
293
294static const bool c_analyticBlurRRect{true};
295
296SkMaskFilterBase::FilterReturn
297SkBlurMaskFilterImpl::filterRRectToNine(const SkRRect& rrect, const SkMatrix& matrix,
298                                        const SkIRect& clipBounds,
299                                        NinePatch* patch) const {
300    SkASSERT(patch != nullptr);
301    switch (rrect.getType()) {
302        case SkRRect::kEmpty_Type:
303            // Nothing to draw.
304            return kFalse_FilterReturn;
305
306        case SkRRect::kRect_Type:
307            // We should have caught this earlier.
308            SkASSERT(false);
309            [[fallthrough]];
310        case SkRRect::kOval_Type:
311            // The nine patch special case does not handle ovals, and we
312            // already have code for rectangles.
313            return kUnimplemented_FilterReturn;
314
315        // These three can take advantage of this fast path.
316        case SkRRect::kSimple_Type:
317        case SkRRect::kNinePatch_Type:
318        case SkRRect::kComplex_Type:
319            break;
320    }
321
322    // TODO: report correct metrics for innerstyle, where we do not grow the
323    // total bounds, but we do need an inset the size of our blur-radius
324    if (kInner_SkBlurStyle == fBlurStyle) {
325        return kUnimplemented_FilterReturn;
326    }
327
328    // TODO: take clipBounds into account to limit our coordinates up front
329    // for now, just skip too-large src rects (to take the old code path).
330    if (rect_exceeds(rrect.rect(), SkIntToScalar(32767))) {
331        return kUnimplemented_FilterReturn;
332    }
333
334    SkIPoint margin;
335    SkMask  srcM, dstM;
336    srcM.fBounds = rrect.rect().roundOut();
337    srcM.fFormat = SkMask::kA8_Format;
338    srcM.fRowBytes = 0;
339
340    bool filterResult = false;
341    if (c_analyticBlurRRect) {
342        // special case for fast round rect blur
343        // don't actually do the blur the first time, just compute the correct size
344        filterResult = this->filterRRectMask(&dstM, rrect, matrix, &margin,
345                                            SkMask::kJustComputeBounds_CreateMode);
346    }
347
348    if (!filterResult) {
349        filterResult = this->filterMask(&dstM, srcM, matrix, &margin);
350    }
351
352    if (!filterResult) {
353        return kFalse_FilterReturn;
354    }
355
356    // Now figure out the appropriate width and height of the smaller round rectangle
357    // to stretch. It will take into account the larger radius per side as well as double
358    // the margin, to account for inner and outer blur.
359    const SkVector& UL = rrect.radii(SkRRect::kUpperLeft_Corner);
360    const SkVector& UR = rrect.radii(SkRRect::kUpperRight_Corner);
361    const SkVector& LR = rrect.radii(SkRRect::kLowerRight_Corner);
362    const SkVector& LL = rrect.radii(SkRRect::kLowerLeft_Corner);
363
364    const SkScalar leftUnstretched = std::max(UL.fX, LL.fX) + SkIntToScalar(2 * margin.fX);
365    const SkScalar rightUnstretched = std::max(UR.fX, LR.fX) + SkIntToScalar(2 * margin.fX);
366
367    // Extra space in the middle to ensure an unchanging piece for stretching. Use 3 to cover
368    // any fractional space on either side plus 1 for the part to stretch.
369    const SkScalar stretchSize = SkIntToScalar(3);
370
371    const SkScalar totalSmallWidth = leftUnstretched + rightUnstretched + stretchSize;
372    if (totalSmallWidth >= rrect.rect().width()) {
373        // There is no valid piece to stretch.
374        return kUnimplemented_FilterReturn;
375    }
376
377    const SkScalar topUnstretched = std::max(UL.fY, UR.fY) + SkIntToScalar(2 * margin.fY);
378    const SkScalar bottomUnstretched = std::max(LL.fY, LR.fY) + SkIntToScalar(2 * margin.fY);
379
380    const SkScalar totalSmallHeight = topUnstretched + bottomUnstretched + stretchSize;
381    if (totalSmallHeight >= rrect.rect().height()) {
382        // There is no valid piece to stretch.
383        return kUnimplemented_FilterReturn;
384    }
385
386    SkRect smallR = SkRect::MakeWH(totalSmallWidth, totalSmallHeight);
387
388    SkRRect smallRR;
389    SkVector radii[4];
390    radii[SkRRect::kUpperLeft_Corner] = UL;
391    radii[SkRRect::kUpperRight_Corner] = UR;
392    radii[SkRRect::kLowerRight_Corner] = LR;
393    radii[SkRRect::kLowerLeft_Corner] = LL;
394    smallRR.setRectRadii(smallR, radii);
395
396    const SkScalar sigma = this->computeXformedSigma(matrix);
397    SkCachedData* cache = find_cached_rrect(&patch->fMask, sigma, fBlurStyle, smallRR);
398    if (!cache) {
399        bool analyticBlurWorked = false;
400        if (c_analyticBlurRRect) {
401            analyticBlurWorked =
402                this->filterRRectMask(&patch->fMask, smallRR, matrix, &margin,
403                                      SkMask::kComputeBoundsAndRenderImage_CreateMode);
404        }
405
406        if (!analyticBlurWorked) {
407            if (!draw_rrect_into_mask(smallRR, &srcM)) {
408                return kFalse_FilterReturn;
409            }
410
411            SkAutoMaskFreeImage amf(srcM.fImage);
412
413            if (!this->filterMask(&patch->fMask, srcM, matrix, &margin)) {
414                return kFalse_FilterReturn;
415            }
416        }
417        cache = add_cached_rrect(&patch->fMask, sigma, fBlurStyle, smallRR);
418    }
419
420    patch->fMask.fBounds.offsetTo(0, 0);
421    patch->fOuterRect = dstM.fBounds;
422    patch->fCenter.fX = SkScalarCeilToInt(leftUnstretched) + 1;
423    patch->fCenter.fY = SkScalarCeilToInt(topUnstretched) + 1;
424    SkASSERT(nullptr == patch->fCache);
425    patch->fCache = cache;  // transfer ownership to patch
426    return kTrue_FilterReturn;
427}
428
429// Use the faster analytic blur approach for ninepatch rects
430static const bool c_analyticBlurNinepatch{true};
431
432SkMaskFilterBase::FilterReturn
433SkBlurMaskFilterImpl::filterRectsToNine(const SkRect rects[], int count,
434                                        const SkMatrix& matrix,
435                                        const SkIRect& clipBounds,
436                                        NinePatch* patch) const {
437    if (count < 1 || count > 2) {
438        return kUnimplemented_FilterReturn;
439    }
440
441    // TODO: report correct metrics for innerstyle, where we do not grow the
442    // total bounds, but we do need an inset the size of our blur-radius
443    if (kInner_SkBlurStyle == fBlurStyle || kOuter_SkBlurStyle == fBlurStyle) {
444        return kUnimplemented_FilterReturn;
445    }
446
447    // TODO: take clipBounds into account to limit our coordinates up front
448    // for now, just skip too-large src rects (to take the old code path).
449    if (rect_exceeds(rects[0], SkIntToScalar(32767))) {
450        return kUnimplemented_FilterReturn;
451    }
452
453    SkIPoint margin;
454    SkMask  srcM, dstM;
455    srcM.fBounds = rects[0].roundOut();
456    srcM.fFormat = SkMask::kA8_Format;
457    srcM.fRowBytes = 0;
458
459    bool filterResult = false;
460    if (count == 1 && c_analyticBlurNinepatch) {
461        // special case for fast rect blur
462        // don't actually do the blur the first time, just compute the correct size
463        filterResult = this->filterRectMask(&dstM, rects[0], matrix, &margin,
464                                            SkMask::kJustComputeBounds_CreateMode);
465    } else {
466        filterResult = this->filterMask(&dstM, srcM, matrix, &margin);
467    }
468
469    if (!filterResult) {
470        return kFalse_FilterReturn;
471    }
472
473    /*
474     *  smallR is the smallest version of 'rect' that will still guarantee that
475     *  we get the same blur results on all edges, plus 1 center row/col that is
476     *  representative of the extendible/stretchable edges of the ninepatch.
477     *  Since our actual edge may be fractional we inset 1 more to be sure we
478     *  don't miss any interior blur.
479     *  x is an added pixel of blur, and { and } are the (fractional) edge
480     *  pixels from the original rect.
481     *
482     *   x x { x x .... x x } x x
483     *
484     *  Thus, in this case, we inset by a total of 5 (on each side) beginning
485     *  with our outer-rect (dstM.fBounds)
486     */
487    SkRect smallR[2];
488    SkIPoint center;
489
490    // +2 is from +1 for each edge (to account for possible fractional edges
491    int smallW = dstM.fBounds.width() - srcM.fBounds.width() + 2;
492    int smallH = dstM.fBounds.height() - srcM.fBounds.height() + 2;
493    SkIRect innerIR;
494
495    if (1 == count) {
496        innerIR = srcM.fBounds;
497        center.set(smallW, smallH);
498    } else {
499        SkASSERT(2 == count);
500        rects[1].roundIn(&innerIR);
501        center.set(smallW + (innerIR.left() - srcM.fBounds.left()),
502                   smallH + (innerIR.top() - srcM.fBounds.top()));
503    }
504
505    // +1 so we get a clean, stretchable, center row/col
506    smallW += 1;
507    smallH += 1;
508
509    // we want the inset amounts to be integral, so we don't change any
510    // fractional phase on the fRight or fBottom of our smallR.
511    const SkScalar dx = SkIntToScalar(innerIR.width() - smallW);
512    const SkScalar dy = SkIntToScalar(innerIR.height() - smallH);
513    if (dx < 0 || dy < 0) {
514        // we're too small, relative to our blur, to break into nine-patch,
515        // so we ask to have our normal filterMask() be called.
516        return kUnimplemented_FilterReturn;
517    }
518
519    smallR[0].setLTRB(rects[0].left(),       rects[0].top(),
520                      rects[0].right() - dx, rects[0].bottom() - dy);
521    if (smallR[0].width() < 2 || smallR[0].height() < 2) {
522        return kUnimplemented_FilterReturn;
523    }
524    if (2 == count) {
525        smallR[1].setLTRB(rects[1].left(), rects[1].top(),
526                          rects[1].right() - dx, rects[1].bottom() - dy);
527        SkASSERT(!smallR[1].isEmpty());
528    }
529
530    const SkScalar sigma = this->computeXformedSigma(matrix);
531    SkCachedData* cache = find_cached_rects(&patch->fMask, sigma, fBlurStyle, smallR, count);
532    if (!cache) {
533        if (count > 1 || !c_analyticBlurNinepatch) {
534            if (!draw_rects_into_mask(smallR, count, &srcM)) {
535                return kFalse_FilterReturn;
536            }
537
538            SkAutoMaskFreeImage amf(srcM.fImage);
539
540            if (!this->filterMask(&patch->fMask, srcM, matrix, &margin)) {
541                return kFalse_FilterReturn;
542            }
543        } else {
544            if (!this->filterRectMask(&patch->fMask, smallR[0], matrix, &margin,
545                                      SkMask::kComputeBoundsAndRenderImage_CreateMode)) {
546                return kFalse_FilterReturn;
547            }
548        }
549        cache = add_cached_rects(&patch->fMask, sigma, fBlurStyle, smallR, count);
550    }
551    patch->fMask.fBounds.offsetTo(0, 0);
552    patch->fOuterRect = dstM.fBounds;
553    patch->fCenter = center;
554    SkASSERT(nullptr == patch->fCache);
555    patch->fCache = cache;  // transfer ownership to patch
556    return kTrue_FilterReturn;
557}
558
559void SkBlurMaskFilterImpl::computeFastBounds(const SkRect& src,
560                                             SkRect* dst) const {
561    // TODO: if we're doing kInner blur, should we return a different outset?
562    //       i.e. pad == 0 ?
563
564    SkScalar pad = 3.0f * fSigma;
565
566    dst->setLTRB(src.fLeft  - pad, src.fTop    - pad,
567                 src.fRight + pad, src.fBottom + pad);
568}
569
570sk_sp<SkFlattenable> SkBlurMaskFilterImpl::CreateProc(SkReadBuffer& buffer) {
571    const SkScalar sigma = buffer.readScalar();
572    SkBlurStyle style = buffer.read32LE(kLastEnum_SkBlurStyle);
573
574    uint32_t flags = buffer.read32LE(0x3);  // historically we only recorded 2 bits
575    bool respectCTM = !(flags & 1); // historically we stored ignoreCTM in low bit
576
577    return SkMaskFilter::MakeBlur((SkBlurStyle)style, sigma, respectCTM);
578}
579
580void SkBlurMaskFilterImpl::flatten(SkWriteBuffer& buffer) const {
581    buffer.writeScalar(fSigma);
582    buffer.writeUInt(fBlurStyle);
583    buffer.writeUInt(!fRespectCTM); // historically we recorded ignoreCTM
584}
585
586
587#if SK_SUPPORT_GPU && SK_GPU_V1
588
589///////////////////////////////////////////////////////////////////////////////
590//  Circle Blur
591///////////////////////////////////////////////////////////////////////////////
592
593// Computes an unnormalized half kernel (right side). Returns the summation of all the half
594// kernel values.
595static float make_unnormalized_half_kernel(float* halfKernel, int halfKernelSize, float sigma) {
596    const float invSigma = 1.f / sigma;
597    const float b = -0.5f * invSigma * invSigma;
598    float tot = 0.0f;
599    // Compute half kernel values at half pixel steps out from the center.
600    float t = 0.5f;
601    for (int i = 0; i < halfKernelSize; ++i) {
602        float value = expf(t * t * b);
603        tot += value;
604        halfKernel[i] = value;
605        t += 1.f;
606    }
607    return tot;
608}
609
610// Create a Gaussian half-kernel (right side) and a summed area table given a sigma and number
611// of discrete steps. The half kernel is normalized to sum to 0.5.
612static void make_half_kernel_and_summed_table(float* halfKernel,
613                                              float* summedHalfKernel,
614                                              int halfKernelSize,
615                                              float sigma) {
616    // The half kernel should sum to 0.5 not 1.0.
617    const float tot = 2.f * make_unnormalized_half_kernel(halfKernel, halfKernelSize, sigma);
618    float sum = 0.f;
619    for (int i = 0; i < halfKernelSize; ++i) {
620        halfKernel[i] /= tot;
621        sum += halfKernel[i];
622        summedHalfKernel[i] = sum;
623    }
624}
625
626// Applies the 1D half kernel vertically at points along the x axis to a circle centered at the
627// origin with radius circleR.
628void apply_kernel_in_y(float* results,
629                       int numSteps,
630                       float firstX,
631                       float circleR,
632                       int halfKernelSize,
633                       const float* summedHalfKernelTable) {
634    float x = firstX;
635    for (int i = 0; i < numSteps; ++i, x += 1.f) {
636        if (x < -circleR || x > circleR) {
637            results[i] = 0;
638            continue;
639        }
640        float y = sqrtf(circleR * circleR - x * x);
641        // In the column at x we exit the circle at +y and -y
642        // The summed table entry j is actually reflects an offset of j + 0.5.
643        y -= 0.5f;
644        int yInt = SkScalarFloorToInt(y);
645        SkASSERT(yInt >= -1);
646        if (y < 0) {
647            results[i] = (y + 0.5f) * summedHalfKernelTable[0];
648        } else if (yInt >= halfKernelSize - 1) {
649            results[i] = 0.5f;
650        } else {
651            float yFrac = y - yInt;
652            results[i] = (1.f - yFrac) * summedHalfKernelTable[yInt] +
653                         yFrac * summedHalfKernelTable[yInt + 1];
654        }
655    }
656}
657
658// Apply a Gaussian at point (evalX, 0) to a circle centered at the origin with radius circleR.
659// This relies on having a half kernel computed for the Gaussian and a table of applications of
660// the half kernel in y to columns at (evalX - halfKernel, evalX - halfKernel + 1, ..., evalX +
661// halfKernel) passed in as yKernelEvaluations.
662static uint8_t eval_at(float evalX,
663                       float circleR,
664                       const float* halfKernel,
665                       int halfKernelSize,
666                       const float* yKernelEvaluations) {
667    float acc = 0;
668
669    float x = evalX - halfKernelSize;
670    for (int i = 0; i < halfKernelSize; ++i, x += 1.f) {
671        if (x < -circleR || x > circleR) {
672            continue;
673        }
674        float verticalEval = yKernelEvaluations[i];
675        acc += verticalEval * halfKernel[halfKernelSize - i - 1];
676    }
677    for (int i = 0; i < halfKernelSize; ++i, x += 1.f) {
678        if (x < -circleR || x > circleR) {
679            continue;
680        }
681        float verticalEval = yKernelEvaluations[i + halfKernelSize];
682        acc += verticalEval * halfKernel[i];
683    }
684    // Since we applied a half kernel in y we multiply acc by 2 (the circle is symmetric about
685    // the x axis).
686    return SkUnitScalarClampToByte(2.f * acc);
687}
688
689// This function creates a profile of a blurred circle. It does this by computing a kernel for
690// half the Gaussian and a matching summed area table. The summed area table is used to compute
691// an array of vertical applications of the half kernel to the circle along the x axis. The
692// table of y evaluations has 2 * k + n entries where k is the size of the half kernel and n is
693// the size of the profile being computed. Then for each of the n profile entries we walk out k
694// steps in each horizontal direction multiplying the corresponding y evaluation by the half
695// kernel entry and sum these values to compute the profile entry.
696static void create_circle_profile(uint8_t* weights,
697                                  float sigma,
698                                  float circleR,
699                                  int profileTextureWidth) {
700    const int numSteps = profileTextureWidth;
701
702    // The full kernel is 6 sigmas wide.
703    int halfKernelSize = SkScalarCeilToInt(6.0f * sigma);
704    // round up to next multiple of 2 and then divide by 2
705    halfKernelSize = ((halfKernelSize + 1) & ~1) >> 1;
706
707    // Number of x steps at which to apply kernel in y to cover all the profile samples in x.
708    int numYSteps = numSteps + 2 * halfKernelSize;
709
710    SkAutoTArray<float> bulkAlloc(halfKernelSize + halfKernelSize + numYSteps);
711    float* halfKernel = bulkAlloc.get();
712    float* summedKernel = bulkAlloc.get() + halfKernelSize;
713    float* yEvals = bulkAlloc.get() + 2 * halfKernelSize;
714    make_half_kernel_and_summed_table(halfKernel, summedKernel, halfKernelSize, sigma);
715
716    float firstX = -halfKernelSize + 0.5f;
717    apply_kernel_in_y(yEvals, numYSteps, firstX, circleR, halfKernelSize, summedKernel);
718
719    for (int i = 0; i < numSteps - 1; ++i) {
720        float evalX = i + 0.5f;
721        weights[i] = eval_at(evalX, circleR, halfKernel, halfKernelSize, yEvals + i);
722    }
723    // Ensure the tail of the Gaussian goes to zero.
724    weights[numSteps - 1] = 0;
725}
726
727static void create_half_plane_profile(uint8_t* profile, int profileWidth) {
728    SkASSERT(!(profileWidth & 0x1));
729    // The full kernel is 6 sigmas wide.
730    float sigma = profileWidth / 6.f;
731    int halfKernelSize = profileWidth / 2;
732
733    SkAutoTArray<float> halfKernel(halfKernelSize);
734
735    // The half kernel should sum to 0.5.
736    const float tot = 2.f * make_unnormalized_half_kernel(halfKernel.get(), halfKernelSize, sigma);
737    float sum = 0.f;
738    // Populate the profile from the right edge to the middle.
739    for (int i = 0; i < halfKernelSize; ++i) {
740        halfKernel[halfKernelSize - i - 1] /= tot;
741        sum += halfKernel[halfKernelSize - i - 1];
742        profile[profileWidth - i - 1] = SkUnitScalarClampToByte(sum);
743    }
744    // Populate the profile from the middle to the left edge (by flipping the half kernel and
745    // continuing the summation).
746    for (int i = 0; i < halfKernelSize; ++i) {
747        sum += halfKernel[i];
748        profile[halfKernelSize - i - 1] = SkUnitScalarClampToByte(sum);
749    }
750    // Ensure tail goes to 0.
751    profile[profileWidth - 1] = 0;
752}
753
754static std::unique_ptr<GrFragmentProcessor> create_profile_effect(GrRecordingContext* rContext,
755                                                                  const SkRect& circle,
756                                                                  float sigma,
757                                                                  float* solidRadius,
758                                                                  float* textureRadius) {
759    float circleR = circle.width() / 2.0f;
760    if (!sk_float_isfinite(circleR) || circleR < SK_ScalarNearlyZero) {
761        return nullptr;
762    }
763
764    auto threadSafeCache = rContext->priv().threadSafeCache();
765
766    // Profile textures are cached by the ratio of sigma to circle radius and by the size of the
767    // profile texture (binned by powers of 2).
768    SkScalar sigmaToCircleRRatio = sigma / circleR;
769    // When sigma is really small this becomes a equivalent to convolving a Gaussian with a
770    // half-plane. Similarly, in the extreme high ratio cases circle becomes a point WRT to the
771    // Guassian and the profile texture is a just a Gaussian evaluation. However, we haven't yet
772    // implemented this latter optimization.
773    sigmaToCircleRRatio = std::min(sigmaToCircleRRatio, 8.f);
774    SkFixed sigmaToCircleRRatioFixed;
775    static const SkScalar kHalfPlaneThreshold = 0.1f;
776    bool useHalfPlaneApprox = false;
777    if (sigmaToCircleRRatio <= kHalfPlaneThreshold) {
778        useHalfPlaneApprox = true;
779        sigmaToCircleRRatioFixed = 0;
780        *solidRadius = circleR - 3 * sigma;
781        *textureRadius = 6 * sigma;
782    } else {
783        // Convert to fixed point for the key.
784        sigmaToCircleRRatioFixed = SkScalarToFixed(sigmaToCircleRRatio);
785        // We shave off some bits to reduce the number of unique entries. We could probably
786        // shave off more than we do.
787        sigmaToCircleRRatioFixed &= ~0xff;
788        sigmaToCircleRRatio = SkFixedToScalar(sigmaToCircleRRatioFixed);
789        sigma = circleR * sigmaToCircleRRatio;
790        *solidRadius = 0;
791        *textureRadius = circleR + 3 * sigma;
792    }
793
794    static constexpr int kProfileTextureWidth = 512;
795    // This would be kProfileTextureWidth/textureRadius if it weren't for the fact that we do
796    // the calculation of the profile coord in a coord space that has already been scaled by
797    // 1 / textureRadius. This is done to avoid overflow in length().
798    SkMatrix texM = SkMatrix::Scale(kProfileTextureWidth, 1.f);
799
800    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
801    GrUniqueKey key;
802    GrUniqueKey::Builder builder(&key, kDomain, 1, "1-D Circular Blur");
803    builder[0] = sigmaToCircleRRatioFixed;
804    builder.finish();
805
806    GrSurfaceProxyView profileView = threadSafeCache->find(key);
807    if (profileView) {
808        SkASSERT(profileView.asTextureProxy());
809        SkASSERT(profileView.origin() == kTopLeft_GrSurfaceOrigin);
810        return GrTextureEffect::Make(std::move(profileView), kPremul_SkAlphaType, texM);
811    }
812
813    SkBitmap bm;
814    if (!bm.tryAllocPixels(SkImageInfo::MakeA8(kProfileTextureWidth, 1))) {
815        return nullptr;
816    }
817
818    if (useHalfPlaneApprox) {
819        create_half_plane_profile(bm.getAddr8(0, 0), kProfileTextureWidth);
820    } else {
821        // Rescale params to the size of the texture we're creating.
822        SkScalar scale = kProfileTextureWidth / *textureRadius;
823        create_circle_profile(
824                bm.getAddr8(0, 0), sigma * scale, circleR * scale, kProfileTextureWidth);
825    }
826    bm.setImmutable();
827
828    profileView = std::get<0>(GrMakeUncachedBitmapProxyView(rContext, bm));
829    if (!profileView) {
830        return nullptr;
831    }
832
833    profileView = threadSafeCache->add(key, profileView);
834    return GrTextureEffect::Make(std::move(profileView), kPremul_SkAlphaType, texM);
835}
836
837static std::unique_ptr<GrFragmentProcessor> make_circle_blur(GrRecordingContext* context,
838                                                             const SkRect& circle,
839                                                             float sigma) {
840    if (SkGpuBlurUtils::IsEffectivelyZeroSigma(sigma)) {
841        return nullptr;
842    }
843
844    float solidRadius;
845    float textureRadius;
846    std::unique_ptr<GrFragmentProcessor> profile =
847            create_profile_effect(context, circle, sigma, &solidRadius, &textureRadius);
848    if (!profile) {
849        return nullptr;
850    }
851
852    static auto effect = SkMakeRuntimeEffect(SkRuntimeEffect::MakeForShader, R"(
853        uniform shader blurProfile;
854        uniform float4 circleData;
855
856        half4 main(float2 xy, half4 inColor) {
857            // We just want to compute "(length(vec) - circleData.z + 0.5) * circleData.w" but need
858            // to rearrange to avoid passing large values to length() that would overflow.
859            half4 halfCircleData = circleData;
860            half2 vec = (sk_FragCoord.xy - halfCircleData.xy) * circleData.w;
861            half dist = length(vec) + (0.5 - halfCircleData.z) * halfCircleData.w;
862            return inColor * blurProfile.eval(half2(dist, 0.5)).a;
863        }
864    )");
865
866    SkV4 circleData = {circle.centerX(), circle.centerY(), solidRadius, 1.f / textureRadius};
867    return GrSkSLFP::Make(effect, "CircleBlur", /*inputFP=*/nullptr,
868                          GrSkSLFP::OptFlags::kCompatibleWithCoverageAsAlpha,
869                          "blurProfile", GrSkSLFP::IgnoreOptFlags(std::move(profile)),
870                          "circleData", circleData);
871}
872
873///////////////////////////////////////////////////////////////////////////////
874//  Rect Blur
875///////////////////////////////////////////////////////////////////////////////
876
877static std::unique_ptr<GrFragmentProcessor> make_rect_integral_fp(GrRecordingContext* rContext,
878                                                                  float sixSigma) {
879    SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(sixSigma / 6.f));
880    auto threadSafeCache = rContext->priv().threadSafeCache();
881
882    int width = SkGpuBlurUtils::CreateIntegralTable(sixSigma, nullptr);
883
884    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
885    GrUniqueKey key;
886    GrUniqueKey::Builder builder(&key, kDomain, 1, "Rect Blur Mask");
887    builder[0] = width;
888    builder.finish();
889
890    SkMatrix m = SkMatrix::Scale(width / sixSigma, 1.f);
891
892    GrSurfaceProxyView view = threadSafeCache->find(key);
893
894    if (view) {
895        SkASSERT(view.origin() == kTopLeft_GrSurfaceOrigin);
896        return GrTextureEffect::Make(
897                std::move(view), kPremul_SkAlphaType, m, GrSamplerState::Filter::kLinear);
898    }
899
900    SkBitmap bitmap;
901    if (!SkGpuBlurUtils::CreateIntegralTable(sixSigma, &bitmap)) {
902        return {};
903    }
904
905    view = std::get<0>(GrMakeUncachedBitmapProxyView(rContext, bitmap));
906    if (!view) {
907        return {};
908    }
909
910    view = threadSafeCache->add(key, view);
911
912    SkASSERT(view.origin() == kTopLeft_GrSurfaceOrigin);
913    return GrTextureEffect::Make(
914            std::move(view), kPremul_SkAlphaType, m, GrSamplerState::Filter::kLinear);
915}
916
917static std::unique_ptr<GrFragmentProcessor> make_rect_blur(GrRecordingContext* context,
918                                                           const GrShaderCaps& caps,
919                                                           const SkRect& srcRect,
920                                                           const SkMatrix& viewMatrix,
921                                                           float transformedSigma) {
922    SkASSERT(viewMatrix.preservesRightAngles());
923    SkASSERT(srcRect.isSorted());
924
925    if (SkGpuBlurUtils::IsEffectivelyZeroSigma(transformedSigma)) {
926        // No need to blur the rect
927        return nullptr;
928    }
929
930    SkMatrix invM;
931    SkRect rect;
932    if (viewMatrix.rectStaysRect()) {
933        invM = SkMatrix::I();
934        // We can do everything in device space when the src rect projects to a rect in device space
935        SkAssertResult(viewMatrix.mapRect(&rect, srcRect));
936    } else {
937        // The view matrix may scale, perhaps anisotropically. But we want to apply our device space
938        // "transformedSigma" to the delta of frag coord from the rect edges. Factor out the scaling
939        // to define a space that is purely rotation/translation from device space (and scale from
940        // src space) We'll meet in the middle: pre-scale the src rect to be in this space and then
941        // apply the inverse of the rotation/translation portion to the frag coord.
942        SkMatrix m;
943        SkSize scale;
944        if (!viewMatrix.decomposeScale(&scale, &m)) {
945            return nullptr;
946        }
947        if (!m.invert(&invM)) {
948            return nullptr;
949        }
950        rect = {srcRect.left() * scale.width(),
951                srcRect.top() * scale.height(),
952                srcRect.right() * scale.width(),
953                srcRect.bottom() * scale.height()};
954    }
955
956    if (!caps.floatIs32Bits()) {
957        // We promote the math that gets us into the Gaussian space to full float when the rect
958        // coords are large. If we don't have full float then fail. We could probably clip the rect
959        // to an outset device bounds instead.
960        if (SkScalarAbs(rect.fLeft) > 16000.f || SkScalarAbs(rect.fTop) > 16000.f ||
961            SkScalarAbs(rect.fRight) > 16000.f || SkScalarAbs(rect.fBottom) > 16000.f) {
962            return nullptr;
963        }
964    }
965
966    const float sixSigma = 6 * transformedSigma;
967    std::unique_ptr<GrFragmentProcessor> integral = make_rect_integral_fp(context, sixSigma);
968    if (!integral) {
969        return nullptr;
970    }
971
972    // In the fast variant we think of the midpoint of the integral texture as aligning with the
973    // closest rect edge both in x and y. To simplify texture coord calculation we inset the rect so
974    // that the edge of the inset rect corresponds to t = 0 in the texture. It actually simplifies
975    // things a bit in the !isFast case, too.
976    float threeSigma = sixSigma / 2;
977    SkRect insetRect = {rect.left() + threeSigma,
978                        rect.top() + threeSigma,
979                        rect.right() - threeSigma,
980                        rect.bottom() - threeSigma};
981
982    // In our fast variant we find the nearest horizontal and vertical edges and for each do a
983    // lookup in the integral texture for each and multiply them. When the rect is less than 6 sigma
984    // wide then things aren't so simple and we have to consider both the left and right edge of the
985    // rectangle (and similar in y).
986    bool isFast = insetRect.isSorted();
987
988    static auto effect = SkMakeRuntimeEffect(SkRuntimeEffect::MakeForShader, R"(
989        // Effect that is a LUT for integral of normal distribution. The value at x:[0,6*sigma] is
990        // the integral from -inf to (3*sigma - x). I.e. x is mapped from [0, 6*sigma] to
991        // [3*sigma to -3*sigma]. The flip saves a reversal in the shader.
992        uniform shader integral;
993
994        uniform float4 rect;
995        uniform int isFast;  // specialized
996
997        half4 main(float2 pos, half4 inColor) {
998            half xCoverage, yCoverage;
999            if (bool(isFast)) {
1000                // Get the smaller of the signed distance from the frag coord to the left and right
1001                // edges and similar for y.
1002                // The integral texture goes "backwards" (from 3*sigma to -3*sigma), So, the below
1003                // computations align the left edge of the integral texture with the inset rect's
1004                // edge extending outward 6 * sigma from the inset rect.
1005                half2 xy = max(half2(rect.LT - pos), half2(pos - rect.RB));
1006                xCoverage = integral.eval(half2(xy.x, 0.5)).a;
1007                yCoverage = integral.eval(half2(xy.y, 0.5)).a;
1008            } else {
1009                // We just consider just the x direction here. In practice we compute x and y
1010                // separately and multiply them together.
1011                // We define our coord system so that the point at which we're evaluating a kernel
1012                // defined by the normal distribution (K) at 0. In this coord system let L be left
1013                // edge and R be the right edge of the rectangle.
1014                // We can calculate C by integrating K with the half infinite ranges outside the
1015                // L to R range and subtracting from 1:
1016                //   C = 1 - <integral of K from from -inf to  L> - <integral of K from R to inf>
1017                // K is symmetric about x=0 so:
1018                //   C = 1 - <integral of K from from -inf to  L> - <integral of K from -inf to -R>
1019
1020                // The integral texture goes "backwards" (from 3*sigma to -3*sigma) which is
1021                // factored in to the below calculations.
1022                // Also, our rect uniform was pre-inset by 3 sigma from the actual rect being
1023                // blurred, also factored in.
1024                half4 rect = half4(half2(rect.LT - pos), half2(pos - rect.RB));
1025                xCoverage = 1 - integral.eval(half2(rect.L, 0.5)).a
1026                              - integral.eval(half2(rect.R, 0.5)).a;
1027                yCoverage = 1 - integral.eval(half2(rect.T, 0.5)).a
1028                              - integral.eval(half2(rect.B, 0.5)).a;
1029            }
1030            return inColor * xCoverage * yCoverage;
1031        }
1032    )");
1033
1034    std::unique_ptr<GrFragmentProcessor> fp =
1035            GrSkSLFP::Make(effect, "RectBlur", /*inputFP=*/nullptr,
1036                           GrSkSLFP::OptFlags::kCompatibleWithCoverageAsAlpha,
1037                           "integral", GrSkSLFP::IgnoreOptFlags(std::move(integral)),
1038                           "rect", insetRect,
1039                           "isFast", GrSkSLFP::Specialize<int>(isFast));
1040    if (!invM.isIdentity()) {
1041        fp = GrMatrixEffect::Make(invM, std::move(fp));
1042    }
1043    return GrFragmentProcessor::DeviceSpace(std::move(fp));
1044}
1045
1046///////////////////////////////////////////////////////////////////////////////
1047//  RRect Blur
1048///////////////////////////////////////////////////////////////////////////////
1049
1050static constexpr auto kBlurredRRectMaskOrigin = kTopLeft_GrSurfaceOrigin;
1051
1052static void make_blurred_rrect_key(GrUniqueKey* key,
1053                                   const SkRRect& rrectToDraw,
1054                                   float xformedSigma) {
1055    SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
1056    static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
1057
1058    GrUniqueKey::Builder builder(key, kDomain, 9, "RoundRect Blur Mask");
1059    builder[0] = SkScalarCeilToInt(xformedSigma - 1 / 6.0f);
1060
1061    int index = 1;
1062    // TODO: this is overkill for _simple_ circular rrects
1063    for (auto c : {SkRRect::kUpperLeft_Corner,
1064                   SkRRect::kUpperRight_Corner,
1065                   SkRRect::kLowerRight_Corner,
1066                   SkRRect::kLowerLeft_Corner}) {
1067        SkASSERT(SkScalarIsInt(rrectToDraw.radii(c).fX) && SkScalarIsInt(rrectToDraw.radii(c).fY));
1068        builder[index++] = SkScalarCeilToInt(rrectToDraw.radii(c).fX);
1069        builder[index++] = SkScalarCeilToInt(rrectToDraw.radii(c).fY);
1070    }
1071    builder.finish();
1072}
1073
1074static bool fillin_view_on_gpu(GrDirectContext* dContext,
1075                               const GrSurfaceProxyView& lazyView,
1076                               sk_sp<GrThreadSafeCache::Trampoline> trampoline,
1077                               const SkRRect& rrectToDraw,
1078                               const SkISize& dimensions,
1079                               float xformedSigma) {
1080#if SK_GPU_V1
1081    SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
1082
1083    // We cache blur masks. Use default surface props here so we can use the same cached mask
1084    // regardless of the final dst surface.
1085    SkSurfaceProps defaultSurfaceProps;
1086
1087    std::unique_ptr<skgpu::v1::SurfaceDrawContext> sdc =
1088            skgpu::v1::SurfaceDrawContext::MakeWithFallback(dContext,
1089                                                            GrColorType::kAlpha_8,
1090                                                            nullptr,
1091                                                            SkBackingFit::kExact,
1092                                                            dimensions,
1093                                                            defaultSurfaceProps,
1094                                                            1,
1095                                                            GrMipmapped::kNo,
1096                                                            GrProtected::kNo,
1097                                                            kBlurredRRectMaskOrigin);
1098    if (!sdc) {
1099        return false;
1100    }
1101
1102    GrPaint paint;
1103
1104    sdc->clear(SK_PMColor4fTRANSPARENT);
1105    sdc->drawRRect(nullptr,
1106                   std::move(paint),
1107                   GrAA::kYes,
1108                   SkMatrix::I(),
1109                   rrectToDraw,
1110                   GrStyle::SimpleFill());
1111
1112    GrSurfaceProxyView srcView = sdc->readSurfaceView();
1113    SkASSERT(srcView.asTextureProxy());
1114    auto rtc2 = SkGpuBlurUtils::GaussianBlur(dContext,
1115                                             std::move(srcView),
1116                                             sdc->colorInfo().colorType(),
1117                                             sdc->colorInfo().alphaType(),
1118                                             nullptr,
1119                                             SkIRect::MakeSize(dimensions),
1120                                             SkIRect::MakeSize(dimensions),
1121                                             xformedSigma,
1122                                             xformedSigma,
1123                                             SkTileMode::kClamp,
1124                                             SkBackingFit::kExact);
1125    if (!rtc2 || !rtc2->readSurfaceView()) {
1126        return false;
1127    }
1128
1129    auto view = rtc2->readSurfaceView();
1130    SkASSERT(view.swizzle() == lazyView.swizzle());
1131    SkASSERT(view.origin() == lazyView.origin());
1132    trampoline->fProxy = view.asTextureProxyRef();
1133
1134    return true;
1135#else
1136    return false;
1137#endif
1138}
1139
1140// Evaluate the vertical blur at the specified 'y' value given the location of the top of the
1141// rrect.
1142static uint8_t eval_V(float top, int y, const uint8_t* integral, int integralSize, float sixSigma) {
1143    if (top < 0) {
1144        return 0;  // an empty column
1145    }
1146
1147    float fT = (top - y - 0.5f) * (integralSize / sixSigma);
1148    if (fT < 0) {
1149        return 255;
1150    } else if (fT >= integralSize - 1) {
1151        return 0;
1152    }
1153
1154    int lower = (int)fT;
1155    float frac = fT - lower;
1156
1157    SkASSERT(lower + 1 < integralSize);
1158
1159    return integral[lower] * (1.0f - frac) + integral[lower + 1] * frac;
1160}
1161
1162// Apply a gaussian 'kernel' horizontally at the specified 'x', 'y' location.
1163static uint8_t eval_H(int x,
1164                      int y,
1165                      const std::vector<float>& topVec,
1166                      const float* kernel,
1167                      int kernelSize,
1168                      const uint8_t* integral,
1169                      int integralSize,
1170                      float sixSigma) {
1171    SkASSERT(0 <= x && x < (int)topVec.size());
1172    SkASSERT(kernelSize % 2);
1173
1174    float accum = 0.0f;
1175
1176    int xSampleLoc = x - (kernelSize / 2);
1177    for (int i = 0; i < kernelSize; ++i, ++xSampleLoc) {
1178        if (xSampleLoc < 0 || xSampleLoc >= (int)topVec.size()) {
1179            continue;
1180        }
1181
1182        accum += kernel[i] * eval_V(topVec[xSampleLoc], y, integral, integralSize, sixSigma);
1183    }
1184
1185    return accum + 0.5f;
1186}
1187
1188// Create a cpu-side blurred-rrect mask that is close to the version the gpu would've produced.
1189// The match needs to be close bc the cpu- and gpu-generated version must be interchangeable.
1190static GrSurfaceProxyView create_mask_on_cpu(GrRecordingContext* rContext,
1191                                             const SkRRect& rrectToDraw,
1192                                             const SkISize& dimensions,
1193                                             float xformedSigma) {
1194    SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
1195    int radius = SkGpuBlurUtils::SigmaRadius(xformedSigma);
1196    int kernelSize = 2 * radius + 1;
1197
1198    SkASSERT(kernelSize % 2);
1199    SkASSERT(dimensions.width() % 2);
1200    SkASSERT(dimensions.height() % 2);
1201
1202    SkVector radii = rrectToDraw.getSimpleRadii();
1203    SkASSERT(SkScalarNearlyEqual(radii.fX, radii.fY));
1204
1205    const int halfWidthPlus1 = (dimensions.width() / 2) + 1;
1206    const int halfHeightPlus1 = (dimensions.height() / 2) + 1;
1207
1208    std::unique_ptr<float[]> kernel(new float[kernelSize]);
1209
1210    SkGpuBlurUtils::Compute1DGaussianKernel(kernel.get(), xformedSigma, radius);
1211
1212    SkBitmap integral;
1213    if (!SkGpuBlurUtils::CreateIntegralTable(6 * xformedSigma, &integral)) {
1214        return {};
1215    }
1216
1217    SkBitmap result;
1218    if (!result.tryAllocPixels(SkImageInfo::MakeA8(dimensions.width(), dimensions.height()))) {
1219        return {};
1220    }
1221
1222    std::vector<float> topVec;
1223    topVec.reserve(dimensions.width());
1224    for (int x = 0; x < dimensions.width(); ++x) {
1225        if (x < rrectToDraw.rect().fLeft || x > rrectToDraw.rect().fRight) {
1226            topVec.push_back(-1);
1227        } else {
1228            if (x + 0.5f < rrectToDraw.rect().fLeft + radii.fX) {  // in the circular section
1229                float xDist = rrectToDraw.rect().fLeft + radii.fX - x - 0.5f;
1230                float h = sqrtf(radii.fX * radii.fX - xDist * xDist);
1231                SkASSERT(0 <= h && h < radii.fY);
1232                topVec.push_back(rrectToDraw.rect().fTop + radii.fX - h + 3 * xformedSigma);
1233            } else {
1234                topVec.push_back(rrectToDraw.rect().fTop + 3 * xformedSigma);
1235            }
1236        }
1237    }
1238
1239    for (int y = 0; y < halfHeightPlus1; ++y) {
1240        uint8_t* scanline = result.getAddr8(0, y);
1241
1242        for (int x = 0; x < halfWidthPlus1; ++x) {
1243            scanline[x] = eval_H(x,
1244                                 y,
1245                                 topVec,
1246                                 kernel.get(),
1247                                 kernelSize,
1248                                 integral.getAddr8(0, 0),
1249                                 integral.width(),
1250                                 6 * xformedSigma);
1251            scanline[dimensions.width() - x - 1] = scanline[x];
1252        }
1253
1254        memcpy(result.getAddr8(0, dimensions.height() - y - 1), scanline, result.rowBytes());
1255    }
1256
1257    result.setImmutable();
1258
1259    auto view = std::get<0>(GrMakeUncachedBitmapProxyView(rContext, result));
1260    if (!view) {
1261        return {};
1262    }
1263
1264    SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
1265    return view;
1266}
1267
1268static std::unique_ptr<GrFragmentProcessor> find_or_create_rrect_blur_mask_fp(
1269        GrRecordingContext* rContext,
1270        const SkRRect& rrectToDraw,
1271        const SkISize& dimensions,
1272        float xformedSigma) {
1273    SkASSERT(!SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma));
1274    GrUniqueKey key;
1275    make_blurred_rrect_key(&key, rrectToDraw, xformedSigma);
1276
1277    auto threadSafeCache = rContext->priv().threadSafeCache();
1278
1279    // It seems like we could omit this matrix and modify the shader code to not normalize
1280    // the coords used to sample the texture effect. However, the "proxyDims" value in the
1281    // shader is not always the actual the proxy dimensions. This is because 'dimensions' here
1282    // was computed using integer corner radii as determined in
1283    // SkComputeBlurredRRectParams whereas the shader code uses the float radius to compute
1284    // 'proxyDims'. Why it draws correctly with these unequal values is a mystery for the ages.
1285    auto m = SkMatrix::Scale(dimensions.width(), dimensions.height());
1286
1287    GrSurfaceProxyView view;
1288
1289    if (GrDirectContext* dContext = rContext->asDirectContext()) {
1290        // The gpu thread gets priority over the recording threads. If the gpu thread is first,
1291        // it crams a lazy proxy into the cache and then fills it in later.
1292        auto [lazyView, trampoline] = GrThreadSafeCache::CreateLazyView(dContext,
1293                                                                        GrColorType::kAlpha_8,
1294                                                                        dimensions,
1295                                                                        kBlurredRRectMaskOrigin,
1296                                                                        SkBackingFit::kExact);
1297        if (!lazyView) {
1298            return nullptr;
1299        }
1300
1301        view = threadSafeCache->findOrAdd(key, lazyView);
1302        if (view != lazyView) {
1303            SkASSERT(view.asTextureProxy());
1304            SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
1305            return GrTextureEffect::Make(std::move(view), kPremul_SkAlphaType, m);
1306        }
1307
1308        if (!fillin_view_on_gpu(dContext,
1309                                lazyView,
1310                                std::move(trampoline),
1311                                rrectToDraw,
1312                                dimensions,
1313                                xformedSigma)) {
1314            // In this case something has gone disastrously wrong so set up to drop the draw
1315            // that needed this resource and reduce future pollution of the cache.
1316            threadSafeCache->remove(key);
1317            return nullptr;
1318        }
1319    } else {
1320        view = threadSafeCache->find(key);
1321        if (view) {
1322            SkASSERT(view.asTextureProxy());
1323            SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
1324            return GrTextureEffect::Make(std::move(view), kPremul_SkAlphaType, m);
1325        }
1326
1327        view = create_mask_on_cpu(rContext, rrectToDraw, dimensions, xformedSigma);
1328        if (!view) {
1329            return nullptr;
1330        }
1331
1332        view = threadSafeCache->add(key, view);
1333    }
1334
1335    SkASSERT(view.asTextureProxy());
1336    SkASSERT(view.origin() == kBlurredRRectMaskOrigin);
1337    return GrTextureEffect::Make(std::move(view), kPremul_SkAlphaType, m);
1338}
1339
1340static std::unique_ptr<GrFragmentProcessor> make_rrect_blur(GrRecordingContext* context,
1341                                                            float sigma,
1342                                                            float xformedSigma,
1343                                                            const SkRRect& srcRRect,
1344                                                            const SkRRect& devRRect) {
1345    // Should've been caught up-stream
1346#ifdef SK_DEBUG
1347    SkASSERTF(!SkRRectPriv::IsCircle(devRRect),
1348              "Unexpected circle. %d\n\t%s\n\t%s",
1349              SkRRectPriv::IsCircle(srcRRect),
1350              srcRRect.dumpToString(true).c_str(),
1351              devRRect.dumpToString(true).c_str());
1352    SkASSERTF(!devRRect.isRect(),
1353              "Unexpected rect. %d\n\t%s\n\t%s",
1354              srcRRect.isRect(),
1355              srcRRect.dumpToString(true).c_str(),
1356              devRRect.dumpToString(true).c_str());
1357#endif
1358
1359    // TODO: loosen this up
1360    if (!SkRRectPriv::IsSimpleCircular(devRRect)) {
1361        return nullptr;
1362    }
1363
1364    if (SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma)) {
1365        return nullptr;
1366    }
1367
1368    // Make sure we can successfully ninepatch this rrect -- the blur sigma has to be sufficiently
1369    // small relative to both the size of the corner radius and the width (and height) of the rrect.
1370    SkRRect rrectToDraw;
1371    SkISize dimensions;
1372    SkScalar ignored[SkGpuBlurUtils::kBlurRRectMaxDivisions];
1373
1374    bool ninePatchable = SkGpuBlurUtils::ComputeBlurredRRectParams(srcRRect,
1375                                                                   devRRect,
1376                                                                   sigma,
1377                                                                   xformedSigma,
1378                                                                   &rrectToDraw,
1379                                                                   &dimensions,
1380                                                                   ignored,
1381                                                                   ignored,
1382                                                                   ignored,
1383                                                                   ignored);
1384    if (!ninePatchable) {
1385        return nullptr;
1386    }
1387
1388    std::unique_ptr<GrFragmentProcessor> maskFP =
1389            find_or_create_rrect_blur_mask_fp(context, rrectToDraw, dimensions, xformedSigma);
1390    if (!maskFP) {
1391        return nullptr;
1392    }
1393
1394    static auto effect = SkMakeRuntimeEffect(SkRuntimeEffect::MakeForShader, R"(
1395        uniform shader ninePatchFP;
1396
1397        uniform half cornerRadius;
1398        uniform float4 proxyRect;
1399        uniform half blurRadius;
1400
1401        half4 main(float2 xy, half4 inColor) {
1402            // Warp the fragment position to the appropriate part of the 9-patch blur texture by
1403            // snipping out the middle section of the proxy rect.
1404            float2 translatedFragPosFloat = sk_FragCoord.xy - proxyRect.LT;
1405            float2 proxyCenter = (proxyRect.RB - proxyRect.LT) * 0.5;
1406            half edgeSize = 2.0 * blurRadius + cornerRadius + 0.5;
1407
1408            // Position the fragment so that (0, 0) marks the center of the proxy rectangle.
1409            // Negative coordinates are on the left/top side and positive numbers are on the
1410            // right/bottom.
1411            translatedFragPosFloat -= proxyCenter;
1412
1413            // Temporarily strip off the fragment's sign. x/y are now strictly increasing as we
1414            // move away from the center.
1415            half2 fragDirection = half2(sign(translatedFragPosFloat));
1416            translatedFragPosFloat = abs(translatedFragPosFloat);
1417
1418            // Our goal is to snip out the "middle section" of the proxy rect (everything but the
1419            // edge). We've repositioned our fragment position so that (0, 0) is the centerpoint
1420            // and x/y are always positive, so we can subtract here and interpret negative results
1421            // as being within the middle section.
1422            half2 translatedFragPosHalf = half2(translatedFragPosFloat - (proxyCenter - edgeSize));
1423
1424            // Remove the middle section by clamping to zero.
1425            translatedFragPosHalf = max(translatedFragPosHalf, 0);
1426
1427            // Reapply the fragment's sign, so that negative coordinates once again mean left/top
1428            // side and positive means bottom/right side.
1429            translatedFragPosHalf *= fragDirection;
1430
1431            // Offset the fragment so that (0, 0) marks the upper-left again, instead of the center
1432            // point.
1433            translatedFragPosHalf += half2(edgeSize);
1434
1435            half2 proxyDims = half2(2.0 * edgeSize);
1436            half2 texCoord = translatedFragPosHalf / proxyDims;
1437
1438            return inColor * ninePatchFP.eval(texCoord).a;
1439        }
1440    )");
1441
1442    float cornerRadius = SkRRectPriv::GetSimpleRadii(devRRect).fX;
1443    float blurRadius = 3.f * SkScalarCeilToScalar(xformedSigma - 1 / 6.0f);
1444    SkRect proxyRect = devRRect.getBounds().makeOutset(blurRadius, blurRadius);
1445
1446    return GrSkSLFP::Make(effect, "RRectBlur", /*inputFP=*/nullptr,
1447                          GrSkSLFP::OptFlags::kCompatibleWithCoverageAsAlpha,
1448                          "ninePatchFP", GrSkSLFP::IgnoreOptFlags(std::move(maskFP)),
1449                          "cornerRadius", cornerRadius,
1450                          "proxyRect", proxyRect,
1451                          "blurRadius", blurRadius);
1452}
1453
1454///////////////////////////////////////////////////////////////////////////////
1455
1456bool SkBlurMaskFilterImpl::directFilterMaskGPU(GrRecordingContext* context,
1457                                               skgpu::v1::SurfaceDrawContext* sdc,
1458                                               GrPaint&& paint,
1459                                               const GrClip* clip,
1460                                               const SkMatrix& viewMatrix,
1461                                               const GrStyledShape& shape) const {
1462    SkASSERT(sdc);
1463
1464    if (fBlurStyle != kNormal_SkBlurStyle) {
1465        return false;
1466    }
1467
1468    // TODO: we could handle blurred stroked circles
1469    if (!shape.style().isSimpleFill()) {
1470        return false;
1471    }
1472
1473    SkScalar xformedSigma = this->computeXformedSigma(viewMatrix);
1474    if (SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma)) {
1475        sdc->drawShape(clip, std::move(paint), GrAA::kYes, viewMatrix, GrStyledShape(shape));
1476        return true;
1477    }
1478
1479    SkRRect srcRRect;
1480    bool inverted;
1481    if (!shape.asRRect(&srcRRect, nullptr, nullptr, &inverted) || inverted) {
1482        return false;
1483    }
1484
1485    std::unique_ptr<GrFragmentProcessor> fp;
1486
1487    SkRRect devRRect;
1488    bool devRRectIsValid = srcRRect.transform(viewMatrix, &devRRect);
1489
1490    bool devRRectIsCircle = devRRectIsValid && SkRRectPriv::IsCircle(devRRect);
1491
1492    bool canBeRect = srcRRect.isRect() && viewMatrix.preservesRightAngles();
1493    bool canBeCircle = (SkRRectPriv::IsCircle(srcRRect) && viewMatrix.isSimilarity()) ||
1494                       devRRectIsCircle;
1495
1496    if (canBeRect || canBeCircle) {
1497        if (canBeRect) {
1498            fp = make_rect_blur(context, *context->priv().caps()->shaderCaps(),
1499                                srcRRect.rect(), viewMatrix, xformedSigma);
1500        } else {
1501            SkRect devBounds;
1502            if (devRRectIsCircle) {
1503                devBounds = devRRect.getBounds();
1504            } else {
1505                SkPoint center = {srcRRect.getBounds().centerX(), srcRRect.getBounds().centerY()};
1506                viewMatrix.mapPoints(&center, 1);
1507                SkScalar radius = viewMatrix.mapVector(0, srcRRect.width()/2.f).length();
1508                devBounds = {center.x() - radius,
1509                             center.y() - radius,
1510                             center.x() + radius,
1511                             center.y() + radius};
1512            }
1513            fp = make_circle_blur(context, devBounds, xformedSigma);
1514        }
1515
1516        if (!fp) {
1517            return false;
1518        }
1519
1520        SkRect srcProxyRect = srcRRect.rect();
1521        // Determine how much to outset the src rect to ensure we hit pixels within three sigma.
1522        SkScalar outsetX = 3.0f*xformedSigma;
1523        SkScalar outsetY = 3.0f*xformedSigma;
1524        if (viewMatrix.isScaleTranslate()) {
1525            outsetX /= SkScalarAbs(viewMatrix.getScaleX());
1526            outsetY /= SkScalarAbs(viewMatrix.getScaleY());
1527        } else {
1528            SkSize scale;
1529            if (!viewMatrix.decomposeScale(&scale, nullptr)) {
1530                return false;
1531            }
1532            outsetX /= scale.width();
1533            outsetY /= scale.height();
1534        }
1535        srcProxyRect.outset(outsetX, outsetY);
1536
1537        paint.setCoverageFragmentProcessor(std::move(fp));
1538        sdc->drawRect(clip, std::move(paint), GrAA::kNo, viewMatrix, srcProxyRect);
1539        return true;
1540    }
1541    if (!viewMatrix.isScaleTranslate()) {
1542        return false;
1543    }
1544    if (!devRRectIsValid || !SkRRectPriv::AllCornersCircular(devRRect)) {
1545        return false;
1546    }
1547
1548    fp = make_rrect_blur(context, fSigma, xformedSigma, srcRRect, devRRect);
1549    if (!fp) {
1550        return false;
1551    }
1552
1553    if (!this->ignoreXform()) {
1554        SkRect srcProxyRect = srcRRect.rect();
1555        srcProxyRect.outset(3.0f*fSigma, 3.0f*fSigma);
1556        paint.setCoverageFragmentProcessor(std::move(fp));
1557        sdc->drawRect(clip, std::move(paint), GrAA::kNo, viewMatrix, srcProxyRect);
1558    } else {
1559        SkMatrix inverse;
1560        if (!viewMatrix.invert(&inverse)) {
1561            return false;
1562        }
1563
1564        SkIRect proxyBounds;
1565        float extra=3.f*SkScalarCeilToScalar(xformedSigma-1/6.0f);
1566        devRRect.rect().makeOutset(extra, extra).roundOut(&proxyBounds);
1567
1568        paint.setCoverageFragmentProcessor(std::move(fp));
1569        sdc->fillPixelsWithLocalMatrix(clip, std::move(paint), proxyBounds, inverse);
1570    }
1571
1572    return true;
1573}
1574
1575bool SkBlurMaskFilterImpl::canFilterMaskGPU(const GrStyledShape& shape,
1576                                            const SkIRect& devSpaceShapeBounds,
1577                                            const SkIRect& clipBounds,
1578                                            const SkMatrix& ctm,
1579                                            SkIRect* maskRect,
1580                                            const bool canUseSDFBlur) const {
1581    SkScalar xformedSigma = this->computeXformedSigma(ctm);
1582    if (SkGpuBlurUtils::IsEffectivelyZeroSigma(xformedSigma)) {
1583        *maskRect = devSpaceShapeBounds;
1584        return maskRect->intersect(clipBounds);
1585    }
1586
1587    if (maskRect) {
1588        float sigma3 = 3 * SkScalarToFloat(xformedSigma);
1589
1590        // Outset srcRect and clipRect by 3 * sigma, to compute affected blur area.
1591        SkIRect clipRect = clipBounds.makeOutset(sigma3, sigma3);
1592        SkIRect srcRect = devSpaceShapeBounds.makeOutset(sigma3, sigma3);
1593
1594        if (!canUseSDFBlur && !srcRect.intersect(clipRect)) {
1595            srcRect.setEmpty();
1596        }
1597        SkRRect srcRRect;
1598        bool inverted;
1599        if (canUseSDFBlur && shape.asRRect(&srcRRect, nullptr, nullptr, &inverted)) {
1600            SkScalar sx = ctm.getScaleX();
1601            SkScalar sy = ctm.getScaleY();
1602            float noxFormedSigma3 = this->getNoxFormedSigma3();
1603            int sigmaX = noxFormedSigma3 * sx;
1604            int sigmaY = noxFormedSigma3 * sy;
1605            srcRect = devSpaceShapeBounds.makeOutset(sigmaX, sigmaY);
1606            srcRect = SkIRect::MakeXYWH(srcRect.fLeft, srcRect.fTop,
1607                srcRect.width() + srcRRect.rect().fLeft * sx,
1608                srcRect.height() + srcRRect.rect().fTop * sy);
1609        }
1610        *maskRect = srcRect;
1611    }
1612
1613    // We prefer to blur paths with small blur radii on the CPU.
1614    static const SkScalar kMIN_GPU_BLUR_SIZE  = SkIntToScalar(64);
1615    static const SkScalar kMIN_GPU_BLUR_SIGMA = SkIntToScalar(32);
1616
1617    if (devSpaceShapeBounds.width() <= kMIN_GPU_BLUR_SIZE &&
1618        devSpaceShapeBounds.height() <= kMIN_GPU_BLUR_SIZE &&
1619        xformedSigma <= kMIN_GPU_BLUR_SIGMA) {
1620        return false;
1621    }
1622
1623    return true;
1624}
1625
1626GrSurfaceProxyView SkBlurMaskFilterImpl::filterMaskGPU(GrRecordingContext* context,
1627                                                       GrSurfaceProxyView srcView,
1628                                                       GrColorType srcColorType,
1629                                                       SkAlphaType srcAlphaType,
1630                                                       const SkMatrix& ctm,
1631                                                       const SkIRect& maskRect) const {
1632    // 'maskRect' isn't snapped to the UL corner but the mask in 'src' is.
1633    const SkIRect clipRect = SkIRect::MakeWH(maskRect.width(), maskRect.height());
1634
1635    SkScalar xformedSigma = this->computeXformedSigma(ctm);
1636
1637    // If we're doing a normal blur, we can clobber the pathTexture in the
1638    // gaussianBlur.  Otherwise, we need to save it for later compositing.
1639    bool isNormalBlur = (kNormal_SkBlurStyle == fBlurStyle);
1640    auto srcBounds = SkIRect::MakeSize(srcView.proxy()->dimensions());
1641    auto surfaceDrawContext = SkGpuBlurUtils::GaussianBlur(context,
1642                                                            srcView,
1643                                                            srcColorType,
1644                                                            srcAlphaType,
1645                                                            nullptr,
1646                                                            clipRect,
1647                                                            srcBounds,
1648                                                            xformedSigma,
1649                                                            xformedSigma,
1650                                                            SkTileMode::kClamp);
1651    if (!surfaceDrawContext || !surfaceDrawContext->asTextureProxy()) {
1652        return {};
1653    }
1654
1655    if (!isNormalBlur) {
1656        GrPaint paint;
1657        // Blend pathTexture over blurTexture.
1658        paint.setCoverageFragmentProcessor(GrTextureEffect::Make(std::move(srcView), srcAlphaType));
1659        if (kInner_SkBlurStyle == fBlurStyle) {
1660            // inner:  dst = dst * src
1661            paint.setCoverageSetOpXPFactory(SkRegion::kIntersect_Op);
1662        } else if (kSolid_SkBlurStyle == fBlurStyle) {
1663            // solid:  dst = src + dst - src * dst
1664            //             = src + (1 - src) * dst
1665            paint.setCoverageSetOpXPFactory(SkRegion::kUnion_Op);
1666        } else if (kOuter_SkBlurStyle == fBlurStyle) {
1667            // outer:  dst = dst * (1 - src)
1668            //             = 0 * src + (1 - src) * dst
1669            paint.setCoverageSetOpXPFactory(SkRegion::kDifference_Op);
1670        } else {
1671            paint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);
1672        }
1673
1674        surfaceDrawContext->fillPixelsWithLocalMatrix(nullptr, std::move(paint), clipRect,
1675                                                      SkMatrix::I());
1676    }
1677
1678    return surfaceDrawContext->readSurfaceView();
1679}
1680
1681float SkBlurMaskFilterImpl::getNoxFormedSigma3() const
1682{
1683    constexpr float kSigma_Factor = 3.f;
1684    return kSigma_Factor * fSigma;
1685}
1686
1687GrSurfaceProxyView SkBlurMaskFilterImpl::filterMaskGPUNoxFormed(GrRecordingContext* context,
1688    GrSurfaceProxyView srcView, GrColorType srcColorType, SkAlphaType srcAlphaType, const SkMatrix& viewMatrix,
1689    const SkIRect& maskRect, const SkRRect& srcRRect) const
1690{
1691    const SkIRect clipRect = SkIRect::MakeWH(maskRect.width(), maskRect.height());
1692
1693    float noxFormedSigma = this->getNoxFormedSigma3();
1694
1695    bool isNormalBlur = (kNormal_SkBlurStyle == fBlurStyle);
1696    if (!isNormalBlur) {
1697        return {};
1698    }
1699    auto srcBounds = SkIRect::MakeSize(srcView.proxy()->dimensions());
1700    auto surfaceDrawContext = SDFBlur::SDFBlur(context, srcView, srcColorType, srcAlphaType, nullptr,
1701        clipRect, srcBounds, noxFormedSigma, SkTileMode::kClamp, viewMatrix, srcRRect);
1702    if (!surfaceDrawContext || !surfaceDrawContext->asTextureProxy()) {
1703        return {};
1704    }
1705
1706    return surfaceDrawContext->readSurfaceView();
1707}
1708
1709#endif // SK_SUPPORT_GPU && SK_GPU_V1
1710
1711void sk_register_blur_maskfilter_createproc() { SK_REGISTER_FLATTENABLE(SkBlurMaskFilterImpl); }
1712
1713sk_sp<SkMaskFilter> SkMaskFilter::MakeBlur(SkBlurStyle style, SkScalar sigma, bool respectCTM) {
1714    if (SkScalarIsFinite(sigma) && sigma > 0) {
1715        return sk_sp<SkMaskFilter>(new SkBlurMaskFilterImpl(sigma, style, respectCTM));
1716    }
1717    return nullptr;
1718}
1719