Fast path for blurred round rects -- blur a small 9patch rect on the CPU

src/effects/SkBlurMaskFilter.cpp

Index: src/effects/SkBlurMaskFilter.cpp
diff --git a/src/effects/SkBlurMaskFilter.cpp b/src/effects/SkBlurMaskFilter.cpp
index ff98daf048181bec780ebfd6df271fc53b807c0e..ab137d446d74f8201023e40ea1765f464d167442 100644
--- a/src/effects/SkBlurMaskFilter.cpp
+++ b/src/effects/SkBlurMaskFilter.cpp
@@ -25,6 +25,7 @@
 #include "effects/GrSimpleTextureEffect.h"
 #include "GrTBackendEffectFactory.h"
 #include "SkGrPixelRef.h"
+#include "SkDraw.h"
 #endif
 
 class SkBlurMaskFilterImpl : public SkMaskFilter {
@@ -260,9 +261,9 @@ static bool rect_exceeds(const SkRect& r, SkScalar v) {
 }
 
 #ifdef SK_IGNORE_FAST_RRECT_BLUR
-SK_CONF_DECLARE( bool, c_analyticBlurRRect, "mask.filter.blur.analyticRRect", false, "Use the faster analytic blur approach for ninepatch rects" );
+SK_CONF_DECLARE( bool, c_analyticBlurRRect, "mask.filter.blur.analytibrrect", false, "Use the faster analytic blur approach for ninepatch rects" );

[bsalomon, 2014/04/23 19:50:30]

analytibrrect?

 #else
-SK_CONF_DECLARE( bool, c_analyticBlurRRect, "mask.filter.blur.analyticRRect", true, "Use the faster analytic blur approach for ninepatch round rects" );
+SK_CONF_DECLARE( bool, c_analyticBlurRRect, "mask.filter.blur.analytibrrect", true, "Use the faster analytic blur approach for ninepatch round rects" );
 #endif
 
 SkMaskFilter::FilterReturn
@@ -819,11 +820,287 @@ bool SkBlurMaskFilterImpl::directFilterMaskGPU(GrContext* context,
     return true;
 }
 
+class GrGLRRectBlurEffect;
+
+class GrRRectBlurEffect : public GrEffect {
+public:
+
+    // The flags are used to indicate which corners are circluar (unflagged corners are assumed to

[bsalomon, 2014/04/23 19:50:30]

Delete comment?

[humper, 2014/04/23 20:11:49]

Done.

+    // be square).
+    static GrEffectRef* Create(GrContext* context, float sigma, const SkRRect&);
+
+    virtual ~GrRRectBlurEffect() {};
+    static const char* Name() { return "GrRRectBlur"; }
+
+    const SkRRect& getRRect() const { return fRRect; }
+    float getSigma() const { return fSigma; }
+
+    typedef GrGLRRectBlurEffect GLEffect;
+
+    virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
+
+    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
+
+private:
+    GrRRectBlurEffect(float sigma, const SkRRect&, GrTexture* profileTexture);
+
+    virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE;
+
+    SkRRect             fRRect;
+    float               fSigma;
+    GrTextureAccess     fNinePatchAccess;
+
+    GR_DECLARE_EFFECT_TEST;
+
+    typedef GrEffect INHERITED;
+};
+
+
+GrEffectRef* GrRRectBlurEffect::Create(GrContext* context, float sigma, const SkRRect& rrect) {
+    if (!rrect.isSimpleCircular()) {
+        SkDebugf( "not simple circular\n" );
+        return NULL;
+    }
+
+    // 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.
+
+    unsigned int blurRadius = 3*SkScalarCeilToInt(sigma-1/6.0f);
+    unsigned int cornerRadius = SkScalarCeilToInt(rrect.getSimpleRadii().x());
+    if (cornerRadius + blurRadius > rrect.width()/2 ||
+        cornerRadius + blurRadius > rrect.height()/2) {
+        return NULL;
+    }
+
+    static const GrCacheID::Domain gRRectBlurDomain = GrCacheID::GenerateDomain();
+    GrCacheID::Key key;
+    memset(&key, 0, sizeof(key));
+    key.fData32[0] = blurRadius;
+    key.fData32[1] = cornerRadius;
+    GrCacheID blurRRectNinePatchID(gRRectBlurDomain, key);
+
+    GrTextureParams params;
+    params.setFilterMode(GrTextureParams::kBilerp_FilterMode);
+
+    unsigned int smallRectSide = 2*(blurRadius + cornerRadius) + 1;
+    unsigned int texSide = smallRectSide + 2*blurRadius;
+    GrTextureDesc texDesc;
+    texDesc.fWidth = texSide;
+    texDesc.fHeight = texSide;
+    texDesc.fConfig = kAlpha_8_GrPixelConfig;
+
+    GrTexture *blurNinePatchTexture = context->findAndRefTexture(texDesc, blurRRectNinePatchID, &params);
+
+    if (NULL == blurNinePatchTexture) {
+        SkMask mask;
+
+        mask.fBounds = SkIRect::MakeWH(smallRectSide, smallRectSide);
+        mask.fFormat = SkMask::kA8_Format;
+        mask.fRowBytes = mask.fBounds.width();
+        mask.fImage = SkMask::AllocImage(mask.computeTotalImageSize());
+        SkAutoMaskFreeImage amfi(mask.fImage);
+
+        memset(mask.fImage, 0, mask.computeTotalImageSize());
+
+        SkRect smallRect;
+        smallRect.setWH( smallRectSide,smallRectSide );

[bsalomon, 2014/04/23 19:50:30]

smallRect.setWH(smallRectSide, smallRectSide); // whitespace change

[humper, 2014/04/23 20:11:49]

Done.

+
+        SkRRect smallRRect;
+        smallRRect.setRectXY(smallRect, cornerRadius, cornerRadius);
+
+        SkPath path;
+        path.addRRect( smallRRect );
+
+        SkDraw::DrawToMask(path, &mask.fBounds, NULL, NULL, &mask, SkMask::kJustRenderImage_CreateMode, SkPaint::kFill_Style);
+
+        SkMask blurred_mask;
+        SkBlurMask::BoxBlur(&blurred_mask, mask, sigma, SkBlurMask::kNormal_Style, SkBlurMask::kHigh_Quality, NULL, true );
+
+        blurNinePatchTexture = context->createTexture(&params, texDesc, blurRRectNinePatchID, blurred_mask.fImage, 0);
+    }
+
+    if (NULL == blurNinePatchTexture) {
+        return NULL;
+    }
+
+    return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrRRectBlurEffect,
+                                                      (sigma, rrect, blurNinePatchTexture))));
+}
+
+void GrRRectBlurEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
+    *validFlags = 0;
+}
+
+const GrBackendEffectFactory& GrRRectBlurEffect::getFactory() const {
+    return GrTBackendEffectFactory<GrRRectBlurEffect>::getInstance();
+}
+
+GrRRectBlurEffect::GrRRectBlurEffect(float sigma, const SkRRect& rrect, GrTexture *ninePatchTexture)
+    : fRRect(rrect),
+      fSigma(sigma),
+      fNinePatchAccess(ninePatchTexture) {
+    this->addTextureAccess(&fNinePatchAccess);
+    this->setWillReadFragmentPosition();
+}
+
+bool GrRRectBlurEffect::onIsEqual(const GrEffect& other) const {
+    const GrRRectBlurEffect& rrbe = CastEffect<GrRRectBlurEffect>(other);
+    return fRRect == rrbe.fRRect && fSigma == rrbe.fSigma;

[bsalomon, 2014/04/23 19:50:30]

maybe it doesn't really matter much, but it seems like the rrects don't need to
be the same, just the radius. Maybe comparing the texture is better since it is
keyed off both the radii?

[humper, 2014/04/23 20:11:49]

This was a bug -- changed to just look at the corner radius.  The texture might
not be computed yet, I think.

+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+GR_DEFINE_EFFECT_TEST(GrRRectBlurEffect);
+
+GrEffectRef* GrRRectBlurEffect::TestCreate(SkRandom* random,
+                                     GrContext* context,
+                                     const GrDrawTargetCaps& caps,
+                                     GrTexture*[]) {
+    SkScalar w = random->nextRangeScalar(20.f, 1000.f);
+    SkScalar h = random->nextRangeScalar(20.f, 1000.f);
+    SkScalar r = random->nextRangeF(0, 9.f);

[bsalomon, 2014/04/23 19:50:30]

I think if r was actually 0 it would cause ::Create below to return NULL which
would cause the GLPrograms unit test to assert.

[humper, 2014/04/23 20:11:49]

Done.

+    SkScalar sigma = random->nextRangeF(1,20);
+    SkRRect rrect;
+    rrect.setRectXY(SkRect::MakeWH(w, h), r, r);
+    return GrRRectBlurEffect::Create(context, sigma, rrect);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+class GrGLRRectBlurEffect : public GrGLEffect {
+public:
+    GrGLRRectBlurEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
+
+    virtual void emitCode(GrGLShaderBuilder* builder,
+                          const GrDrawEffect& drawEffect,
+                          EffectKey key,
+                          const char* outputColor,
+                          const char* inputColor,
+                          const TransformedCoordsArray&,
+                          const TextureSamplerArray&) SK_OVERRIDE;
+
+    virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
+
+private:
+    GrGLUniformManager::UniformHandle   fProxyRectUniform;
+    GrGLUniformManager::UniformHandle   fCornerRadiusUniform;
+    GrGLUniformManager::UniformHandle   fBlurRadiusUniform;
+    typedef GrGLEffect INHERITED;
+};
+
+GrGLRRectBlurEffect::GrGLRRectBlurEffect(const GrBackendEffectFactory& factory,
+                             const GrDrawEffect& drawEffect)
+    : INHERITED (factory) {
+}
+
+void GrGLRRectBlurEffect::emitCode(GrGLShaderBuilder* builder,
+                             const GrDrawEffect& drawEffect,
+                             EffectKey key,
+                             const char* outputColor,
+                             const char* inputColor,
+                             const TransformedCoordsArray&,
+                             const TextureSamplerArray& samplers) {
+    const char *rectName;
+    const char *cornerRadiusName;
+    const char *blurRadiusName;
+
+    // The proxy rect has left, top, right, and bottom edges correspond to
+    // components x, y, z, and w, respectively.
+
+    fProxyRectUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
+                                            kVec4f_GrSLType,
+                                            "proxyRect",
+                                            &rectName);
+    fCornerRadiusUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
+                                                 kFloat_GrSLType,
+                                                 "cornerRadius",
+                                                 &cornerRadiusName);
+    fBlurRadiusUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
+                                                 kFloat_GrSLType,
+                                                 "blurRadius",
+                                                 &blurRadiusName);
+    const char* fragmentPos = builder->fragmentPosition();
+
+    // warp the fragment position to the appropriate part of the 9patch blur texture
+
+    builder->fsCodeAppendf("\t\tvec2 rectCenter = (%s.xy + %s.zw)/2.0;\n", rectName, rectName);
+    builder->fsCodeAppendf("\t\tvec2 translatedFragPos = %s.xy - %s.xy;\n", fragmentPos, rectName);
+    builder->fsCodeAppendf("\t\tfloat threshold = %s + 2.0*%s;\n", cornerRadiusName, blurRadiusName );
+    builder->fsCodeAppendf("\t\tvec2 middle = %s.zw - %s.xy - 2.0*threshold;\n", rectName, rectName );
+
+    builder->fsCodeAppendf("\t\tif (translatedFragPos.x >= threshold && translatedFragPos.x < (middle.x+threshold)) {\n" );
+    builder->fsCodeAppendf("\t\t\ttranslatedFragPos.x = threshold;\n");
+    builder->fsCodeAppendf("\t\t} else if (translatedFragPos.x >= (middle.x + threshold)) {\n");
+    builder->fsCodeAppendf("\t\t\ttranslatedFragPos.x -= middle.x;\n");
+    builder->fsCodeAppendf("\t\t}\n");
+
+    builder->fsCodeAppendf("\t\tif (translatedFragPos.y > threshold && translatedFragPos.y < (middle.y+threshold)) {\n" );
+    builder->fsCodeAppendf("\t\t\ttranslatedFragPos.y = threshold+1;\n");
+    builder->fsCodeAppendf("\t\t} else if (translatedFragPos.y >= (middle.y + threshold)) {\n");
+    builder->fsCodeAppendf("\t\t\ttranslatedFragPos.y -= middle.y;\n");
+    builder->fsCodeAppendf("\t\t}\n");
+
+    builder->fsCodeAppendf("\t\tvec2 proxyDims = vec2(2.0*threshold+1.0);\n");
+    builder->fsCodeAppendf("\t\tvec2 texCoord = translatedFragPos / proxyDims;\n");
+
+    builder->fsCodeAppendf("\t%s = ", outputColor);
+    builder->fsAppendTextureLookupAndModulate(inputColor, samplers[0], "texCoord");
+    builder->fsCodeAppend(";\n");
+}
+
+void GrGLRRectBlurEffect::setData(const GrGLUniformManager& uman,
+                                    const GrDrawEffect& drawEffect) {
+    const GrRRectBlurEffect& brre = drawEffect.castEffect<GrRRectBlurEffect>();
+    SkRRect rrect = brre.getRRect();
+
+    unsigned int blurRadius = 3*SkScalarCeilToInt(brre.getSigma()-1/6.0f);
+    uman.set1f(fBlurRadiusUniform, blurRadius);
+
+    SkRect rect = rrect.getBounds();
+    rect.outset(blurRadius, blurRadius);
+    uman.set4f(fProxyRectUniform, rect.fLeft, rect.fTop, rect.fRight, rect.fBottom);
+
+    SkScalar radius = 0;
+    SkASSERT(rrect.isSimpleCircular() || rrect.isRect());
+    radius = rrect.getSimpleRadii().fX;
+    uman.set1f(fCornerRadiusUniform, radius);
+}
+
+
 bool SkBlurMaskFilterImpl::directFilterRRectMaskGPU(GrContext* context,
                                                     GrPaint* grp,
                                                     const SkStrokeRec& strokeRec,
                                                     const SkRRect& rrect) const {
-    return false;
+    if (fBlurStyle != SkBlurMaskFilter::kNormal_BlurStyle) {
+        return false;
+    }
+
+    if (!strokeRec.isFillStyle()) {
+        return false;
+    }
+
+    SkRect proxy_rect = rrect.rect();
+    SkMatrix ctm = context->getMatrix();
+    SkScalar xformedSigma = this->computeXformedSigma(ctm);
+    unsigned int extra=3*SkScalarCeilToInt(xformedSigma-1/6.0f);
+    proxy_rect.outset(extra,extra);
+
+    SkAutoTUnref<GrEffectRef> effect(GrRRectBlurEffect::Create(
+            context, xformedSigma, rrect));
+    if (!effect) {
+        return false;
+    }
+
+    GrContext::AutoMatrix am;
+    if (!am.setIdentity(context, grp)) {
+       return false;
+    }
+
+    grp->addCoverageEffect(effect);
+
+    context->drawRect(*grp, proxy_rect);
+    return true;
 }
 
 bool SkBlurMaskFilterImpl::canFilterMaskGPU(const SkRect& srcBounds,