2 files changed, 100 insertions, 0 deletions
diff --git a/experimental/sksg/effects/SkSGClipEffect.cpp b/experimental/sksg/effects/SkSGClipEffect.cpp
new file mode 100644
index 0000000000..b2d68fc8cf
--- /dev/null
+++ b/experimental/sksg/effects/SkSGClipEffect.cpp
@@ -0,0 +1,50 @@
+/*
+ * 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 "SkSGClipEffect.h"
+
+#include "SkCanvas.h"
+#include "SkPath.h"
+#include "SkSGGeometryNode.h"
+
+namespace sksg {
+
+ClipEffect::ClipEffect(sk_sp<RenderNode> child, sk_sp<GeometryNode> clip, bool aa)
+    : INHERITED(std::move(child))
+    , fClipNode(std::move(clip))
+    , fAntiAlias(aa) {
+    this->observeInval(fClipNode);
+}
+
+ClipEffect::~ClipEffect() {
+    this->unobserveInval(fClipNode);
+}
+
+void ClipEffect::onRender(SkCanvas* canvas) const {
+    if (this->bounds().isEmpty())
+        return;
+
+    SkAutoCanvasRestore acr(canvas, !fNoop);
+    if (!fNoop) {
+        fClipNode->clip(canvas, fAntiAlias);
+    }
+
+    this->INHERITED::onRender(canvas);
+}
+
+SkRect ClipEffect::onRevalidate(InvalidationController* ic, const SkMatrix& ctm) {
+    SkASSERT(this->hasInval());
+
+    const auto clipBounds = fClipNode->revalidate(ic, ctm);
+    auto childBounds = this->INHERITED::onRevalidate(ic, ctm);
+
+    fNoop = fClipNode->asPath().conservativelyContainsRect(childBounds);
+
+    return childBounds.intersect(clipBounds) ? childBounds : SkRect::MakeEmpty();
+}
+
+} // namespace sksg
diff --git a/experimental/sksg/effects/SkSGClipEffect.h b/experimental/sksg/effects/SkSGClipEffect.h
new file mode 100644
index 0000000000..674edb2b5c
--- /dev/null
+++ b/experimental/sksg/effects/SkSGClipEffect.h
@@ -0,0 +1,50 @@
+/*
+ * 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 SkSGClipEffect_DEFINED
+#define SkSGClipEffect_DEFINED
+
+#include "SkSGEffectNode.h"
+
+namespace sksg {
+
+class GeometryNode;
+
+/**
+ * Concrete Effect node, applying a clip to its descendants.
+ *
+ */
+class ClipEffect final : public EffectNode {
+public:
+    static sk_sp<ClipEffect> Make(sk_sp<RenderNode> child, sk_sp<GeometryNode> clip,
+                                  bool aa = false) {
+        return (child && clip)
+            ? sk_sp<ClipEffect>(new ClipEffect(std::move(child), std::move(clip), aa))
+            : nullptr;
+    }
+
+    ~ClipEffect() override;
+
+protected:
+    ClipEffect(sk_sp<RenderNode>, sk_sp<GeometryNode>, bool aa);
+
+    void onRender(SkCanvas*) const override;
+
+    SkRect onRevalidate(InvalidationController*, const SkMatrix&) override;
+
+private:
+    const sk_sp<GeometryNode> fClipNode;
+    const bool                fAntiAlias;
+
+    bool                      fNoop = false;
+
+    typedef EffectNode INHERITED;
+};
+
+} // namespace sksg
+
+#endif // SkSGClipEffect_DEFINED