Add back overdraw visualization for Skia BenchmarkingCanvas

skia/ext/benchmarking_canvas.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "skia/ext/benchmarking_canvas.h"
+#include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
+#include "third_party/skia/include/core/SkDrawFilter.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/core/SkRegion.h"
+#include "third_party/skia/include/core/SkString.h"
 #include "third_party/skia/include/core/SkTextBlob.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 
 namespace {
 
 class FlagsBuilder {
 public:
   FlagsBuilder(char separator)
       : separator_(separator) {}
 
@@ skipping 376 matching lines @@
 WARN_UNUSED_RESULT
 scoped_ptr<base::Value> AsListValue(const T array[], size_t count) {
   scoped_ptr<base::ListValue> val(new base::ListValue());
 
   for (size_t i = 0; i < count; ++i)
     val->Append(AsValue(array[i]).release());
 
   return val.Pass();
 }
 
+class OverdrawXfermode : public SkXfermode {
+public:
+  SkPMColor xferColor(SkPMColor src, SkPMColor dst) const override {
+    // This table encodes the color progression of the overdraw visualization
+    static const SkPMColor gTable[] = {
+      SkPackARGB32(0x00, 0x00, 0x00, 0x00),
+      SkPackARGB32(0xFF, 128, 158, 255),
+      SkPackARGB32(0xFF, 170, 185, 212),
+      SkPackARGB32(0xFF, 213, 195, 170),
+      SkPackARGB32(0xFF, 255, 192, 127),
+      SkPackARGB32(0xFF, 255, 185, 85),
+      SkPackARGB32(0xFF, 255, 165, 42),
+      SkPackARGB32(0xFF, 255, 135, 0),
+      SkPackARGB32(0xFF, 255,  95, 0),
+      SkPackARGB32(0xFF, 255,  50, 0),
+      SkPackARGB32(0xFF, 255,  0, 0)
+    };
+

[robertphillips, 2015/03/10 17:23:41]

// TODO: seems like there should be a far faster way to do this  

if (dst.blue / 42 > 0) {
    i = 7 - dst.blue/42;
} else if (dst.green / 45 >0) {
    i = 10 - dst.green / 42;
} else if (dst.red > 128) {
    i = 10;
} else {
    i = 0;
}
SkASSERT(gTable[i] == dst);

?

[f(malita), 2015/03/10 22:28:32]

Refactored to use interpolation instead of table lookup.

+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTable) - 1; ++i) {
+      if (gTable[i] == dst) {
+        return gTable[i + 1];
+      }
+    }
+
+    return gTable[SK_ARRAY_COUNT(gTable) - 1];
+  }
+
+  Factory getFactory() const override { return NULL; }
+#ifndef SK_IGNORE_TO_STRING
+  void toString(SkString* str) const override { str->set("OverdrawXfermode"); }
+#endif

[robertphillips, 2015/03/10 17:23:41]

private:
    typedef SkXfermode INHERITED;

?

[f(malita), 2015/03/10 22:28:32]

Done.

+};
+
+class OverdrawFilter : public SkDrawFilter {
+public:
+  OverdrawFilter() { fXferMode = skia::AdoptRef(new OverdrawXfermode); }
+
+  bool filter(SkPaint* p, Type) override {
+    p->setXfermode(fXferMode.get());
+    return true;
+  }
+
+private:
+  typedef SkDrawFilter INHERITED;
+
+  skia::RefPtr<SkXfermode> fXferMode;
+};
+
 } // namespace
 
 namespace skia {
 
 class BenchmarkingCanvas::AutoOp {
 public:
   AutoOp(BenchmarkingCanvas* canvas, const char op_name[],
          const SkPaint* paint = nullptr)
       : canvas_(canvas)
       , op_record_(new base::DictionaryValue())
@@ skipping 30 matching lines @@
   base::DictionaryValue* op_record_;
   base::ListValue* op_params_;
   base::TimeTicks start_ticks_;
 };
 
 BenchmarkingCanvas::BenchmarkingCanvas(SkCanvas* canvas, unsigned flags)
     : INHERITED(canvas->imageInfo().width(),
                 canvas->imageInfo().height())
     , flags_(flags) {
   addCanvas(canvas);
+
+  if (flags & kOverdrawVisualization_Flag) {
+    skia::RefPtr<SkDrawFilter> draw_filter = skia::AdoptRef(new OverdrawFilter);
+    this->setDrawFilter(draw_filter.get());
+  }
 }
 
 BenchmarkingCanvas::~BenchmarkingCanvas() {
 }
 
 size_t BenchmarkingCanvas::CommandCount() const {
   return op_records_.GetSize();
 }
 
 const base::ListValue& BenchmarkingCanvas::Commands() const {
@@ skipping 283 matching lines @@
   DCHECK(blob);
   AutoOp op(this, "DrawTextBlob", &paint);
   op.addParam("blob", AsValue(*blob));
   op.addParam("x", AsValue(x));
   op.addParam("y", AsValue(y));
 
   INHERITED::onDrawTextBlob(blob, x, y, paint);
 }
 
 } // namespace skia