Add SK_API to SkOverdrawCanvas and SkOverdrawColorFilter.

The SkiaRenderer in chromium is going to use the overdraw canvas and
filter for measuring overdraw. Move these headers out of src/ into
include/.

Bug: chromium:704285
Change-Id: I2abb1671b73e3d26552462cf700340a7e3b874f0
Reviewed-on: https://skia-review.googlesource.com/36160
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

2 files changed, 126 insertions, 0 deletions

diff --git a/include/core/SkOverdrawCanvas.h b/include/core/SkOverdrawCanvas.h
new file mode 100644
index 0000000000..284fe6cd97
--- /dev/null
+++ b/include/core/SkOverdrawCanvas.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkOverdrawCanvas_DEFINED
+#define SkOverdrawCanvas_DEFINED
+
+#include "SkNWayCanvas.h"
+
+/**
+ *  Captures all drawing commands.  Rather than draw the actual content, this device
+ *  increments the alpha channel of each pixel every time it would have been touched
+ *  by a draw call.  This is useful for detecting overdraw.
+ */
+class SK_API SkOverdrawCanvas : public SkNWayCanvas {
+public:
+    /* Does not take ownership of canvas */
+    SkOverdrawCanvas(SkCanvas*);
+
+    void onDrawText(const void*, size_t, SkScalar, SkScalar, const SkPaint&) override;
+    void onDrawPosText(const void*, size_t, const SkPoint[], const SkPaint&) override;
+    void onDrawPosTextH(const void*, size_t, const SkScalar[], SkScalar, const SkPaint&) override;
+    void onDrawTextOnPath(const void*, size_t, const SkPath&, const SkMatrix*,
+                          const SkPaint&) override;
+    void onDrawTextRSXform(const void*, size_t, const SkRSXform[], const SkRect*,
+                           const SkPaint&) override;
+    void onDrawTextBlob(const SkTextBlob*, SkScalar, SkScalar, const SkPaint&) override;
+    void onDrawPatch(const SkPoint[12], const SkColor[4], const SkPoint[4], SkBlendMode,
+                     const SkPaint&) override;
+    void onDrawPaint(const SkPaint&) override;
+    void onDrawRect(const SkRect&, const SkPaint&) override;
+    void onDrawRegion(const SkRegion&, const SkPaint&) override;
+    void onDrawOval(const SkRect&, const SkPaint&) override;
+    void onDrawArc(const SkRect&, SkScalar, SkScalar, bool, const SkPaint&) override;
+    void onDrawDRRect(const SkRRect&, const SkRRect&, const SkPaint&) override;
+    void onDrawRRect(const SkRRect&, const SkPaint&) override;
+    void onDrawPoints(PointMode, size_t, const SkPoint[], const SkPaint&) override;
+    void onDrawVerticesObject(const SkVertices*, SkBlendMode, const SkPaint&) override;
+    void onDrawAtlas(const SkImage*, const SkRSXform[], const SkRect[], const SkColor[],
+                     int, SkBlendMode, const SkRect*, const SkPaint*) override;
+    void onDrawPath(const SkPath&, const SkPaint&) override;
+    void onDrawImage(const SkImage*, SkScalar, SkScalar, const SkPaint*) override;
+    void onDrawImageRect(const SkImage*, const SkRect*, const SkRect&, const SkPaint*,
+                         SrcRectConstraint) override;
+    void onDrawImageNine(const SkImage*, const SkIRect&, const SkRect&, const SkPaint*) override;
+    void onDrawImageLattice(const SkImage*, const Lattice&, const SkRect&, const SkPaint*) override;
+    void onDrawBitmap(const SkBitmap&, SkScalar, SkScalar, const SkPaint*) override;
+    void onDrawBitmapRect(const SkBitmap&, const SkRect*, const SkRect&, const SkPaint*,
+                          SrcRectConstraint) override;
+    void onDrawBitmapNine(const SkBitmap&, const SkIRect&, const SkRect&, const SkPaint*) override;
+    void onDrawBitmapLattice(const SkBitmap&, const Lattice&, const SkRect&,
+                             const SkPaint*) override;
+    void onDrawDrawable(SkDrawable*, const SkMatrix*) override;
+    void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*) override;
+
+private:
+    void drawPosTextCommon(const void*, size_t, const SkScalar[], int, const SkPoint&,
+                           const SkPaint&);
+
+    inline SkPaint overdrawPaint(const SkPaint& paint);
+
+    SkPaint   fPaint;
+
+    typedef SkNWayCanvas INHERITED;
+};
+
+#endif
diff --git a/include/effects/SkOverdrawColorFilter.h b/include/effects/SkOverdrawColorFilter.h
new file mode 100644
index 0000000000..ac97821269
--- /dev/null
+++ b/include/effects/SkOverdrawColorFilter.h
@@ -0,0 +1,56 @@
+/*
+ * 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 "SkColorFilter.h"
+#include "SkFlattenable.h"
+
+#ifndef SkOverdrawColorFilter_DEFINED
+#define SkOverdrawColorFilter_DEFINED
+
+/**
+ *  Uses the value in the src alpha channel to set the dst pixel.
+ *  0             -> fColors[0]
+ *  1             -> fColors[1]
+ *  ...
+ *  5 (or larger) -> fColors[5]
+ *
+ */
+class SK_API SkOverdrawColorFilter : public SkColorFilter {
+public:
+    static constexpr int kNumColors = 6;
+
+    static sk_sp<SkOverdrawColorFilter> Make(const SkPMColor colors[kNumColors]) {
+        return sk_sp<SkOverdrawColorFilter>(new SkOverdrawColorFilter(colors));
+    }
+
+#if SK_SUPPORT_GPU
+    std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(GrContext*,
+                                                             SkColorSpace*) const override;
+#endif
+
+    void toString(SkString* str) const override;
+
+    static sk_sp<SkFlattenable> CreateProc(SkReadBuffer& buffer);
+    Factory getFactory() const override { return CreateProc; }
+    SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
+
+protected:
+    void flatten(SkWriteBuffer& buffer) const override;
+
+private:
+    SkOverdrawColorFilter(const SkPMColor colors[kNumColors]) {
+        memcpy(fColors, colors, kNumColors * sizeof(SkPMColor));
+    }
+
+    void onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*, bool) const override;
+
+    SkPMColor fColors[kNumColors];
+
+    typedef SkColorFilter INHERITED;
+};
+
+#endif // SkOverdrawColorFilter_DEFINED