Improve GrPathRendererChain heuristics

Changes GrPathRenderer::canDrawPath to return a 'CanDrawPath' enum,
which contains a new kAsBackup value that means "I'm better than SW,
but give the path renderers below me a chance first."

Bug: skia:
Change-Id: I45aac5462ca1bc0bc839eb1c315db9493901a07e
Reviewed-on: https://skia-review.googlesource.com/42222
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>

18 files changed, 101 insertions, 66 deletions

diff --git a/src/gpu/ops/GrAAConvexPathRenderer.cpp b/src/gpu/ops/GrAAConvexPathRenderer.cpp
index 425dbae148..0fe74433ff 100644
--- a/src/gpu/ops/GrAAConvexPathRenderer.cpp
+++ b/src/gpu/ops/GrAAConvexPathRenderer.cpp
@@ -665,10 +665,14 @@ sk_sp<GrGeometryProcessor> QuadEdgeEffect::TestCreate(GrProcessorTestData* d) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-bool GrAAConvexPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
-    return (args.fCaps->shaderCaps()->shaderDerivativeSupport() &&
-            (GrAAType::kCoverage == args.fAAType) && args.fShape->style().isSimpleFill() &&
-            !args.fShape->inverseFilled() && args.fShape->knownToBeConvex());
+GrPathRenderer::CanDrawPath
+GrAAConvexPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+    if (args.fCaps->shaderCaps()->shaderDerivativeSupport() &&
+        (GrAAType::kCoverage == args.fAAType) && args.fShape->style().isSimpleFill() &&
+        !args.fShape->inverseFilled() && args.fShape->knownToBeConvex()) {
+        return CanDrawPath::kYes;
+    }
+    return CanDrawPath::kNo;
 }
 
 // extract the result vertices and indices from the GrAAConvexTessellator
diff --git a/src/gpu/ops/GrAAConvexPathRenderer.h b/src/gpu/ops/GrAAConvexPathRenderer.h
index 420ca60139..a31d6b9593 100644
--- a/src/gpu/ops/GrAAConvexPathRenderer.h
+++ b/src/gpu/ops/GrAAConvexPathRenderer.h
@@ -15,7 +15,7 @@ public:
     GrAAConvexPathRenderer();
 
 private:
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 };
diff --git a/src/gpu/ops/GrAAHairLinePathRenderer.cpp b/src/gpu/ops/GrAAHairLinePathRenderer.cpp
index e00ca3fd5d..ba72eacd7e 100644
--- a/src/gpu/ops/GrAAHairLinePathRenderer.cpp
+++ b/src/gpu/ops/GrAAHairLinePathRenderer.cpp
@@ -677,26 +677,27 @@ static void add_line(const SkPoint p[2],
 
 ///////////////////////////////////////////////////////////////////////////////
 
-bool GrAAHairLinePathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath
+GrAAHairLinePathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     if (GrAAType::kCoverage != args.fAAType) {
-        return false;
+        return CanDrawPath::kNo;
     }
 
     if (!IsStrokeHairlineOrEquivalent(args.fShape->style(), *args.fViewMatrix, nullptr)) {
-        return false;
+        return CanDrawPath::kNo;
     }
 
     // We don't currently handle dashing in this class though perhaps we should.
     if (args.fShape->style().pathEffect()) {
-        return false;
+        return CanDrawPath::kNo;
     }
 
     if (SkPath::kLine_SegmentMask == args.fShape->segmentMask() ||
         args.fCaps->shaderCaps()->shaderDerivativeSupport()) {
-        return true;
+        return CanDrawPath::kYes;
     }
 
-    return false;
+    return CanDrawPath::kNo;
 }
 
 template <class VertexType>
diff --git a/src/gpu/ops/GrAAHairLinePathRenderer.h b/src/gpu/ops/GrAAHairLinePathRenderer.h
index e2406a5c01..b52d5e9959 100644
--- a/src/gpu/ops/GrAAHairLinePathRenderer.h
+++ b/src/gpu/ops/GrAAHairLinePathRenderer.h
@@ -19,7 +19,7 @@ public:
     typedef SkTArray<float, true> FloatArray;
 
 private:
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 
diff --git a/src/gpu/ops/GrAALinearizingConvexPathRenderer.cpp b/src/gpu/ops/GrAALinearizingConvexPathRenderer.cpp
index c1fd4f7e65..d206951ce4 100644
--- a/src/gpu/ops/GrAALinearizingConvexPathRenderer.cpp
+++ b/src/gpu/ops/GrAALinearizingConvexPathRenderer.cpp
@@ -34,39 +34,46 @@ GrAALinearizingConvexPathRenderer::GrAALinearizingConvexPathRenderer() {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-bool GrAALinearizingConvexPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath
+GrAALinearizingConvexPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     if (GrAAType::kCoverage != args.fAAType) {
-        return false;
+        return CanDrawPath::kNo;
     }
     if (!args.fShape->knownToBeConvex()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     if (args.fShape->style().pathEffect()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     if (args.fShape->inverseFilled()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     if (args.fShape->bounds().width() <= 0 && args.fShape->bounds().height() <= 0) {
         // Stroked zero length lines should draw, but this PR doesn't handle that case
-        return false;
+        return CanDrawPath::kNo;
     }
     const SkStrokeRec& stroke = args.fShape->style().strokeRec();
 
     if (stroke.getStyle() == SkStrokeRec::kStroke_Style ||
         stroke.getStyle() == SkStrokeRec::kStrokeAndFill_Style) {
         if (!args.fViewMatrix->isSimilarity()) {
-            return false;
+            return CanDrawPath::kNo;
         }
         SkScalar strokeWidth = args.fViewMatrix->getMaxScale() * stroke.getWidth();
         if (strokeWidth < 1.0f && stroke.getStyle() == SkStrokeRec::kStroke_Style) {
-            return false;
+            return CanDrawPath::kNo;
         }
-        return strokeWidth <= kMaxStrokeWidth &&
-               args.fShape->knownToBeClosed() &&
-               stroke.getJoin() != SkPaint::Join::kRound_Join;
+        if (strokeWidth > kMaxStrokeWidth ||
+            !args.fShape->knownToBeClosed() ||
+            stroke.getJoin() == SkPaint::Join::kRound_Join) {
+            return CanDrawPath::kNo;
+        }
+        return CanDrawPath::kYes;
+    }
+    if (stroke.getStyle() != SkStrokeRec::kFill_Style) {
+        return CanDrawPath::kNo;
     }
-    return stroke.getStyle() == SkStrokeRec::kFill_Style;
+    return CanDrawPath::kYes;
 }
 
 // extract the result vertices and indices from the GrAAConvexTessellator
diff --git a/src/gpu/ops/GrAALinearizingConvexPathRenderer.h b/src/gpu/ops/GrAALinearizingConvexPathRenderer.h
index afee5db4d4..4fdcb12a26 100644
--- a/src/gpu/ops/GrAALinearizingConvexPathRenderer.h
+++ b/src/gpu/ops/GrAALinearizingConvexPathRenderer.h
@@ -15,7 +15,7 @@ public:
     GrAALinearizingConvexPathRenderer();
 
 private:
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 };
diff --git a/src/gpu/ops/GrDashLinePathRenderer.cpp b/src/gpu/ops/GrDashLinePathRenderer.cpp
index 38d486c79f..73c2b3e8f2 100644
--- a/src/gpu/ops/GrDashLinePathRenderer.cpp
+++ b/src/gpu/ops/GrDashLinePathRenderer.cpp
@@ -12,18 +12,22 @@
 #include "ops/GrDashOp.h"
 #include "ops/GrMeshDrawOp.h"
 
-bool GrDashLinePathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath
+GrDashLinePathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     SkPoint pts[2];
     bool inverted;
     if (args.fShape->style().isDashed() && args.fShape->asLine(pts, &inverted)) {
         if (args.fAAType == GrAAType::kMixedSamples) {
-            return false;
+            return CanDrawPath::kNo;
         }
         // We should never have an inverse dashed case.
         SkASSERT(!inverted);
-        return GrDashOp::CanDrawDashLine(pts, args.fShape->style(), *args.fViewMatrix);
+        if (!GrDashOp::CanDrawDashLine(pts, args.fShape->style(), *args.fViewMatrix)) {
+            return CanDrawPath::kNo;
+        }
+        return CanDrawPath::kYes;
     }
-    return false;
+    return CanDrawPath::kNo;
 }
 
 bool GrDashLinePathRenderer::onDrawPath(const DrawPathArgs& args) {
diff --git a/src/gpu/ops/GrDashLinePathRenderer.h b/src/gpu/ops/GrDashLinePathRenderer.h
index 11abf99396..23227bc824 100644
--- a/src/gpu/ops/GrDashLinePathRenderer.h
+++ b/src/gpu/ops/GrDashLinePathRenderer.h
@@ -14,7 +14,7 @@ class GrGpu;
 
 class GrDashLinePathRenderer : public GrPathRenderer {
 private:
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     StencilSupport onGetStencilSupport(const GrShape&) const override {
         return kNoSupport_StencilSupport;
diff --git a/src/gpu/ops/GrDefaultPathRenderer.cpp b/src/gpu/ops/GrDefaultPathRenderer.cpp
index e3b48a8db9..9741781013 100644
--- a/src/gpu/ops/GrDefaultPathRenderer.cpp
+++ b/src/gpu/ops/GrDefaultPathRenderer.cpp
@@ -609,15 +609,20 @@ bool GrDefaultPathRenderer::internalDrawPath(GrRenderTargetContext* renderTarget
     return true;
 }
 
-bool GrDefaultPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath
+GrDefaultPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     bool isHairline = IsStrokeHairlineOrEquivalent(args.fShape->style(), *args.fViewMatrix, nullptr);
     // If we aren't a single_pass_shape or hairline, we require stencil buffers.
     if (!(single_pass_shape(*args.fShape) || isHairline) && args.fCaps->avoidStencilBuffers()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // This can draw any path with any simple fill style but doesn't do coverage-based antialiasing.
-    return GrAAType::kCoverage != args.fAAType &&
-           (args.fShape->style().isSimpleFill() || isHairline);
+    if (GrAAType::kCoverage == args.fAAType ||
+        (!args.fShape->style().isSimpleFill() && !isHairline)) {
+        return CanDrawPath::kNo;
+    }
+    // This is the fallback renderer for when a path is too complicated for the others to draw.
+    return CanDrawPath::kAsBackup;
 }
 
 bool GrDefaultPathRenderer::onDrawPath(const DrawPathArgs& args) {
diff --git a/src/gpu/ops/GrDefaultPathRenderer.h b/src/gpu/ops/GrDefaultPathRenderer.h
index 7f7ab2a5e0..f7d98190c2 100644
--- a/src/gpu/ops/GrDefaultPathRenderer.h
+++ b/src/gpu/ops/GrDefaultPathRenderer.h
@@ -23,7 +23,7 @@ public:
 private:
     StencilSupport onGetStencilSupport(const GrShape&) const override;
 
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 
diff --git a/src/gpu/ops/GrMSAAPathRenderer.cpp b/src/gpu/ops/GrMSAAPathRenderer.cpp
index ef19367f61..b80a811430 100644
--- a/src/gpu/ops/GrMSAAPathRenderer.cpp
+++ b/src/gpu/ops/GrMSAAPathRenderer.cpp
@@ -682,15 +682,18 @@ bool GrMSAAPathRenderer::internalDrawPath(GrRenderTargetContext* renderTargetCon
     return true;
 }
 
-bool GrMSAAPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath GrMSAAPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     // If we aren't a single_pass_shape, we require stencil buffers.
     if (!single_pass_shape(*args.fShape) && args.fCaps->avoidStencilBuffers()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // This path renderer only fills and relies on MSAA for antialiasing. Stroked shapes are
     // handled by passing on the original shape and letting the caller compute the stroked shape
     // which will have a fill style.
-    return args.fShape->style().isSimpleFill() && (GrAAType::kCoverage != args.fAAType);
+    if (!args.fShape->style().isSimpleFill() || GrAAType::kCoverage == args.fAAType) {
+        return CanDrawPath::kNo;
+    }
+    return CanDrawPath::kYes;
 }
 
 bool GrMSAAPathRenderer::onDrawPath(const DrawPathArgs& args) {
diff --git a/src/gpu/ops/GrMSAAPathRenderer.h b/src/gpu/ops/GrMSAAPathRenderer.h
index 13d3e15a7e..1353867f16 100644
--- a/src/gpu/ops/GrMSAAPathRenderer.h
+++ b/src/gpu/ops/GrMSAAPathRenderer.h
@@ -15,7 +15,7 @@ class SK_API GrMSAAPathRenderer : public GrPathRenderer {
 private:
     StencilSupport onGetStencilSupport(const GrShape&) const override;
 
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 
diff --git a/src/gpu/ops/GrSmallPathRenderer.cpp b/src/gpu/ops/GrSmallPathRenderer.cpp
index cfdf8734c9..1b0648615d 100644
--- a/src/gpu/ops/GrSmallPathRenderer.cpp
+++ b/src/gpu/ops/GrSmallPathRenderer.cpp
@@ -81,30 +81,30 @@ GrSmallPathRenderer::~GrSmallPathRenderer() {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-bool GrSmallPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath GrSmallPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     if (!args.fCaps->shaderCaps()->shaderDerivativeSupport()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // If the shape has no key then we won't get any reuse.
     if (!args.fShape->hasUnstyledKey()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // This only supports filled paths, however, the caller may apply the style to make a filled
     // path and try again.
     if (!args.fShape->style().isSimpleFill()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // This does non-inverse coverage-based antialiased fills.
     if (GrAAType::kCoverage != args.fAAType) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // TODO: Support inverse fill
     if (args.fShape->inverseFilled()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // currently don't support perspective
     if (args.fViewMatrix->hasPerspective()) {
-        return false;
+        return CanDrawPath::kNo;
     }
 
     // Only support paths with bounds within kMaxDim by kMaxDim,
@@ -112,15 +112,18 @@ bool GrSmallPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     // The goal is to accelerate rendering of lots of small paths that may be scaling.
     SkScalar scaleFactors[2];
     if (!args.fViewMatrix->getMinMaxScales(scaleFactors)) {
-        return false;
+        return CanDrawPath::kNo;
     }
     SkRect bounds = args.fShape->styledBounds();
     SkScalar minDim = SkMinScalar(bounds.width(), bounds.height());
     SkScalar maxDim = SkMaxScalar(bounds.width(), bounds.height());
     SkScalar minSize = minDim * SkScalarAbs(scaleFactors[0]);
     SkScalar maxSize = maxDim * SkScalarAbs(scaleFactors[1]);
+    if (maxDim > kMaxDim || kMinSize > minSize || maxSize > kMaxSize) {
+        return CanDrawPath::kNo;
+    }
 
-    return maxDim <= kMaxDim && kMinSize <= minSize && maxSize <= kMaxSize;
+    return CanDrawPath::kYes;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/src/gpu/ops/GrSmallPathRenderer.h b/src/gpu/ops/GrSmallPathRenderer.h
index d10c4baa86..b958baa843 100644
--- a/src/gpu/ops/GrSmallPathRenderer.h
+++ b/src/gpu/ops/GrSmallPathRenderer.h
@@ -31,7 +31,7 @@ private:
         return GrPathRenderer::kNoSupport_StencilSupport;
     }
 
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 
diff --git a/src/gpu/ops/GrStencilAndCoverPathRenderer.cpp b/src/gpu/ops/GrStencilAndCoverPathRenderer.cpp
index 4d86efdc0e..3179ebacc8 100644
--- a/src/gpu/ops/GrStencilAndCoverPathRenderer.cpp
+++ b/src/gpu/ops/GrStencilAndCoverPathRenderer.cpp
@@ -31,18 +31,22 @@ GrStencilAndCoverPathRenderer::GrStencilAndCoverPathRenderer(GrResourceProvider*
     : fResourceProvider(resourceProvider) {
 }
 
-bool GrStencilAndCoverPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+GrPathRenderer::CanDrawPath
+GrStencilAndCoverPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
     // GrPath doesn't support hairline paths. An arbitrary path effect could produce a hairline
     // path.
     if (args.fShape->style().strokeRec().isHairlineStyle() ||
         args.fShape->style().hasNonDashPathEffect()) {
-        return false;
+        return CanDrawPath::kNo;
     }
     if (args.fHasUserStencilSettings) {
-        return false;
+        return CanDrawPath::kNo;
     }
     // doesn't do per-path AA, relies on the target having MSAA.
-    return (GrAAType::kCoverage != args.fAAType);
+    if (GrAAType::kCoverage == args.fAAType) {
+        return CanDrawPath::kNo;
+    }
+    return CanDrawPath::kYes;
 }
 
 static GrPath* get_gr_path(GrResourceProvider* resourceProvider, const GrShape& shape) {
diff --git a/src/gpu/ops/GrStencilAndCoverPathRenderer.h b/src/gpu/ops/GrStencilAndCoverPathRenderer.h
index c896e61545..dda0157a5c 100644
--- a/src/gpu/ops/GrStencilAndCoverPathRenderer.h
+++ b/src/gpu/ops/GrStencilAndCoverPathRenderer.h
@@ -28,7 +28,7 @@ private:
         return GrPathRenderer::kStencilOnly_StencilSupport;
     }
 
-    bool onCanDrawPath(const CanDrawPathArgs&) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 
diff --git a/src/gpu/ops/GrTessellatingPathRenderer.cpp b/src/gpu/ops/GrTessellatingPathRenderer.cpp
index 641a037bbe..2db4ffcd0d 100644
--- a/src/gpu/ops/GrTessellatingPathRenderer.cpp
+++ b/src/gpu/ops/GrTessellatingPathRenderer.cpp
@@ -132,27 +132,31 @@ private:
 GrTessellatingPathRenderer::GrTessellatingPathRenderer() {
 }
 
-bool GrTessellatingPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
-    // This path renderer can draw fill styles, and can do screenspace antialiasing via a
-    // one-pixel coverage ramp. It can do convex and concave paths, but we'll leave the convex
-    // ones to simpler algorithms. We pass on paths that have styles, though they may come back
-    // around after applying the styling information to the geometry to create a filled path. In
-    // the non-AA case, We skip paths thta don't have a key since the real advantage of this path
+GrPathRenderer::CanDrawPath
+GrTessellatingPathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
+    // This path renderer can draw fill styles, and can do screenspace antialiasing via a one-pixel
+    // coverage ramp. It can do convex and concave paths, but we'll give simpler algorithms a chance
+    // to draw the convex ones first. We pass on paths that have styles, though they may come back
+    // around after applying the styling information to the geometry to create a filled path. In the
+    // non-AA case, We skip paths that don't have a key since the real advantage of this path
     // renderer comes from caching the tessellated geometry. In the AA case, we do not cache, so we
     // accept paths without keys.
-    if (!args.fShape->style().isSimpleFill() || args.fShape->knownToBeConvex()) {
-        return false;
+    if (!args.fShape->style().isSimpleFill()) {
+        return CanDrawPath::kNo;
     }
     if (GrAAType::kCoverage == args.fAAType) {
         SkPath path;
         args.fShape->asPath(&path);
         if (path.countVerbs() > 10) {
-            return false;
+            return CanDrawPath::kNo;
         }
     } else if (!args.fShape->hasUnstyledKey()) {
-        return false;
+        return CanDrawPath::kNo;
     }
-    return true;
+    if (args.fShape->knownToBeConvex()) {
+        return CanDrawPath::kAsBackup;
+    }
+    return CanDrawPath::kYes;
 }
 
 namespace {
diff --git a/src/gpu/ops/GrTessellatingPathRenderer.h b/src/gpu/ops/GrTessellatingPathRenderer.h
index d5f2c7af9b..7dd50fc6eb 100644
--- a/src/gpu/ops/GrTessellatingPathRenderer.h
+++ b/src/gpu/ops/GrTessellatingPathRenderer.h
@@ -19,7 +19,7 @@ public:
     GrTessellatingPathRenderer();
 
 private:
-    bool onCanDrawPath(const CanDrawPathArgs& ) const override;
+    CanDrawPath onCanDrawPath(const CanDrawPathArgs&) const override;
 
     StencilSupport onGetStencilSupport(const GrShape&) const override {
         return GrPathRenderer::kNoSupport_StencilSupport;