Add new bench for occluded blurmaskfilter draws

bench/BlurOccludedRRectBench.cpp

Index: bench/BlurOccludedRRectBench.cpp
diff --git a/bench/BlurOccludedRRectBench.cpp b/bench/BlurOccludedRRectBench.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..db36c5f74d0e2cf755c25f59f4f0f39d8d2c3717
--- /dev/null
+++ b/bench/BlurOccludedRRectBench.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Benchmark.h"
+#include "SkBlurMaskFilter.h"
+#include "SkCanvas.h"
+#include "SkPaint.h"
+#include "SkRRect.h"
+#include "SkRect.h"
+
+// compute the intersection point between the diagonal and the ellipse in the
+// lower right corner
+static SkPoint intersection(SkScalar w, SkScalar h) {
+    SkASSERT(w > 0.0f || h > 0.0f);
+
+    return SkPoint::Make(w / SK_ScalarSqrt2, h / SK_ScalarSqrt2);
+}
+
+// Use the intersection of the corners' diagonals with their ellipses to shrink
+// the bounding rect
+static SkRect compute_central_occluder(const SkRRect& rr) {

[reed1, 2016/08/03 20:16:18]

This could be checked in centrally (but perhaps still privately) as a RRect
utility...?

[robertphillips, 2016/08/04 14:49:58]

Done.

+    const SkRect r = rr.getBounds();
+
+    SkScalar newL = r.fLeft, newT = r.fTop, newR = r.fRight, newB = r.fBottom;
+
+    SkVector radii = rr.radii(SkRRect::kUpperLeft_Corner);
+    if (!radii.isZero()) {
+        SkPoint p = intersection(radii.fX, radii.fY);
+
+        newL = SkTMax(newL, r.fLeft + radii.fX - p.fX);
+        newT = SkTMax(newT, r.fTop + radii.fY - p.fY);
+    }
+
+    radii = rr.radii(SkRRect::kUpperRight_Corner);
+    if (!radii.isZero()) {
+        SkPoint p = intersection(radii.fX, radii.fY);
+
+        newR = SkTMin(newR, r.fRight + p.fX - radii.fX);
+        newT = SkTMax(newT, r.fTop + radii.fY - p.fY);
+    }
+
+    radii = rr.radii(SkRRect::kLowerRight_Corner);
+    if (!radii.isZero()) {
+        SkPoint p = intersection(radii.fX, radii.fY);
+
+        newR = SkTMin(newR, r.fRight + p.fX - radii.fX);
+        newB = SkTMin(newB, r.fBottom - radii.fY + p.fY);
+    }
+
+    radii = rr.radii(SkRRect::kLowerLeft_Corner);
+    if (!radii.isZero()) {
+        SkPoint p = intersection(radii.fX, radii.fY);
+
+        newL = SkTMax(newL, r.fLeft + radii.fX - p.fX);
+        newB = SkTMin(newB, r.fBottom - radii.fY + p.fY);
+    }
+
+    return SkRect::MakeLTRB(newL, newT, newR, newB);
+}
+
+class BlurOccludedRRectBench : public Benchmark {
+public:
+    BlurOccludedRRectBench() {}
+
+    const char* onGetName() override {
+        return "bluroccludedrrect";
+    }
+
+    SkIPoint onGetSize() override {
+        return SkIPoint::Make(1024, 2048);
+    }
+
+    void onDraw(int loops, SkCanvas* canvas) override {
+        for (int l = 0; l < loops; ++l) {
+            canvas->clear(0xFFFAFAFA);
+
+            SkPaint opaque;
+            opaque.setAntiAlias(true);
+            opaque.setColor(SK_ColorWHITE);
+
+            const SkRect r = SkRect::MakeWH(480, 230);
+            const SkRRect rr = SkRRect::MakeRectXY(r, 8, 8);
+            SkRect occRect = compute_central_occluder(rr);
+
+            for (int i = 0; i < 2; ++i) {
+                canvas->save();
+
+                canvas->translate(i*502.0f+20, 10.0f);
+
+                for (int j = 0; j < 8; ++j) {
+                    canvas->save();
+
+                        canvas->translate(0.0f, j*256.0f);
+
+                        SkPaint firstBlur;
+                        firstBlur.setAntiAlias(true);
+                        firstBlur.setColor(0x09000000);
+                        firstBlur.setMaskFilter(SkBlurMaskFilter::Make(kNormal_SkBlurStyle,
+                                                                       2.5f));
+                                                                       //, occRect));
+
+                        canvas->drawRRect(rr, firstBlur);
+
+                        canvas->save();
+                            canvas->translate(1.5f, 1.5f);
+
+                            SkPaint secondBlur;
+                            secondBlur.setAntiAlias(true);
+                            secondBlur.setColor(0x30000000);
+                            secondBlur.setMaskFilter(SkBlurMaskFilter::Make(kNormal_SkBlurStyle,
+                                                                            6.0f));
+                                                                            //, occRect));
+
+                            canvas->drawRRect(rr, secondBlur);
+
+                        canvas->restore();
+
+                        canvas->drawRRect(rr, opaque);
+
+                    canvas->restore();
+                }
+
+                canvas->restore();
+            }
+        }
+    }
+
+private:
+    typedef Benchmark INHERITED;
+};
+
+DEF_BENCH(return new BlurOccludedRRectBench();)