[sksg] Add 'plane' geometry node

SG geometry corresponding to SkCanvas::drawPaint().

TBR=

Change-Id: I3b368adda187fb92f524756496a3694c03a3113d
Reviewed-on: https://skia-review.googlesource.com/108562
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

BUILD.gn

@@ -1401,6 +1401,7 @@ if (skia_enable_tools) {
       "experimental/sksg/geometry/SkSGGeometryTransform.cpp",
       "experimental/sksg/geometry/SkSGMerge.cpp",
       "experimental/sksg/geometry/SkSGPath.cpp",
+      "experimental/sksg/geometry/SkSGPlane.cpp",
       "experimental/sksg/geometry/SkSGRect.cpp",
       "experimental/sksg/geometry/SkSGText.cpp",
       "experimental/sksg/geometry/SkSGTrimEffect.cpp",

experimental/sksg/geometry/SkSGPlane.cpp

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkSGPlane.h"
+
+#include "SkCanvas.h"
+#include "SkPath.h"
+
+namespace sksg {
+
+Plane::Plane() = default;
+
+void Plane::onClip(SkCanvas*, bool) const {}
+
+void Plane::onDraw(SkCanvas* canvas, const SkPaint& paint) const {
+    canvas->drawPaint(paint);
+}
+
+SkRect Plane::onRevalidate(InvalidationController*, const SkMatrix&) {
+    SkASSERT(this->hasInval());
+
+    return SkRect::MakeLTRB(SK_ScalarMin, SK_ScalarMin, SK_ScalarMax, SK_ScalarMax);
+}
+
+SkPath Plane::onAsPath() const {
+    SkPath path;
+    path.setFillType(SkPath::kInverseWinding_FillType);
+
+    return path;
+}
+
+} // namespace sksg

experimental/sksg/geometry/SkSGPlane.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSGPlane_DEFINED
+#define SkSGPlane_DEFINED
+
+#include "SkSGGeometryNode.h"
+
+class SkCanvas;
+class SkPaint;
+
+namespace sksg {
+
+/**
+ * Concrete Geometry node, representing the whole canvas.
+ */
+class Plane final : public GeometryNode {
+public:
+    static sk_sp<Plane> Make() { return sk_sp<Plane>(new Plane()); }
+
+protected:
+    void onClip(SkCanvas*, bool antiAlias) const override;
+    void onDraw(SkCanvas*, const SkPaint&) const override;
+
+    SkRect onRevalidate(InvalidationController*, const SkMatrix&) override;
+    SkPath onAsPath() const override;
+
+private:
+    Plane();
+
+    using INHERITED = GeometryNode;
+};
+
+} // namespace sksg
+
+#endif // SkSGPlane_DEFINED

tools/viewer/SlideDir.cpp

@@ -14,6 +14,7 @@
 #include "SkSGColor.h"
 #include "SkSGDraw.h"
 #include "SkSGGroup.h"
+#include "SkSGPlane.h"
 #include "SkSGRect.h"
 #include "SkSGRenderNode.h"
 #include "SkSGScene.h"
@@ -110,7 +111,7 @@ public:
         fMap.setPts(kFocusCtrl1, kFocusCtrl0);
 
         fShadePaint = sksg::Color::Make(kFocusShade);
-        fShade = sksg::Draw::Make(sksg::Rect::Make(SkRect::MakeSize(dir->fWinSize)), fShadePaint);
+        fShade = sksg::Draw::Make(sksg::Plane::Make(), fShadePaint);
     }
 
     bool hasFocus() const { return fState == State::kFocused; }