Move clip off of draw target

include/gpu/GrClip.h

Index: include/gpu/GrClip.h
diff --git a/include/gpu/GrClip.h b/include/gpu/GrClip.h
new file mode 100644
index 0000000000000000000000000000000000000000..c7b05122c69697bfe33de877e7dda69c5d4009e4
--- /dev/null
+++ b/include/gpu/GrClip.h
@@ -0,0 +1,177 @@
+/*
+ * Copyright 2010 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrClip_DEFINED
+#define GrClip_DEFINED
+
+#include "SkClipStack.h"
+#include "GrSurface.h"
+
+struct SkIRect;
+
+/**
+ * GrClip encapsulates the information required to construct the clip
+ * masks. 'A GrClip is either wide open, just an IRect, just a Rect(TODO), a full clipstack, or
+ * empty.  If a clipstack than fOrigin' is only non-zero when saveLayer has been called

[bsalomon, 2015/02/23 22:04:19]

get rid of empty or mark as todo?

+ * with an offset bounding box. The clips in 'fClipStack' are in

[bsalomon, 2015/02/23 22:04:19]

The origin thing is confusing...

Howabout...

"""
If the clip is a clipstack and origin is used to translate the stack with
respect to device coordinates. This allows us to use a clip stack that is
specified for a root device with a layer device that is restricted to a subset
of the original canvas. For other clip types the origin will always be (0,0).
"""

+ * device coordinates (i.e., they have been translated by -fOrigin w.r.t.
+ * the canvas' device coordinates).
+ *
+ * NOTE: GrClip *must* point to a const clipstack
+ */
+class GrClip : SkNoncopyable {
+public:
+    GrClip() : fClipType(kWideOpen_ClipType) {}
+    GrClip(const SkIRect& rect) : fClipType(kIRect_ClipType) {
+        fClip.fIRect = rect;
+    }
+    ~GrClip() { this->reset(); }
+
+    const GrClip& operator=(const GrClip& other) {
+        this->reset();
+        fClipType = other.fClipType;
+        switch (other.fClipType) {
+            default:
+                SkFAIL("Incomplete Switch\n");
+            case kWideOpen_ClipType:
+                break;
+            case kClipStack_ClipType:
+                fClip.fClipStack.fStack = SkRef(other.clipStack());
+                fClip.fClipStack.fOrigin = other.origin();
+                break;
+            case kIRect_ClipType:
+                fClip.fIRect = other.irect();
+                break;
+        }
+        return *this;
+    }
+
+    bool operator==(const GrClip& other) const {
+        if (this->clipType() != other.clipType()) {
+            return false;
+        }
+
+        switch (fClipType) {
+            default:
+                SkFAIL("Incomplete Switch\n");
+                return false;
+            case kWideOpen_ClipType:
+                return true;
+            case kClipStack_ClipType:
+                if (this->origin() != other.origin()) {
+                    return false;
+                }
+
+                if (this->clipStack() && other.clipStack()) {
+                    return *this->clipStack() == *other.clipStack();
+                } else {
+                    return this->clipStack() == other.clipStack();
+                }
+                break;
+            case kIRect_ClipType:
+                return this->irect() == other.irect();
+                break;
+        }
+    }
+
+    bool operator!=(const GrClip& other) const {
+        return !(*this == other);
+    }
+
+    const SkClipStack* clipStack() const {
+        SkASSERT(kClipStack_ClipType == fClipType);
+        return fClip.fClipStack.fStack;
+    }
+
+    void setClipStack(const SkClipStack* clipStack, const SkIPoint* origin = NULL) {
+        if (clipStack->isWideOpen()) {
+            fClipType = kWideOpen_ClipType;
+        } else {
+            fClipType = kClipStack_ClipType;
+            fClip.fClipStack.fStack = SkRef(clipStack);
+            if (origin) {
+                fClip.fClipStack.fOrigin = *origin;
+            } else {
+                fClip.fClipStack.fOrigin.setZero();
+            }
+        }
+    }
+
+    const SkIRect& irect() const {
+        SkASSERT(kIRect_ClipType == fClipType);
+        return fClip.fIRect;
+    }
+
+    void reset() {
+        if (kClipStack_ClipType == fClipType) {
+            fClip.fClipStack.fStack->unref();
+            fClip.fClipStack.fStack = NULL;
+        }
+        fClipType = kUninitialized_ClipType;
+    }
+
+    const SkIPoint& origin() const {
+        SkASSERT(kClipStack_ClipType == fClipType);
+        return fClip.fClipStack.fOrigin;
+    }
+
+    bool isWideOpen(const SkRect& rect) const {
+        return (kWideOpen_ClipType == fClipType) ||
+               (kClipStack_ClipType == fClipType && this->clipStack()->isWideOpen()) ||
+               (kIRect_ClipType == fClipType && this->irect().contains(rect));
+    }
+
+    bool isWideOpen(const SkIRect& rect) const {
+        return (kWideOpen_ClipType == fClipType) ||
+               (kClipStack_ClipType == fClipType && this->clipStack()->isWideOpen()) ||
+               (kIRect_ClipType == fClipType && this->irect().contains(rect));
+    }
+
+    bool isWideOpen() const {
+        return (kWideOpen_ClipType == fClipType) ||
+               (kClipStack_ClipType == fClipType && this->clipStack()->isWideOpen()) ||
+               (kIRect_ClipType == fClipType && this->irect().isEmpty());
+    }
+
+    void getConservativeBounds(const GrSurface* surface,
+                               SkIRect* devResult,
+                               bool* isIntersectionOfRects = NULL) const {
+        this->getConservativeBounds(surface->width(), surface->height(),
+                                    devResult, isIntersectionOfRects);
+    }
+
+    void getConservativeBounds(int width, int height,
+                               SkIRect* devResult,
+                               bool* isIntersectionOfRects = NULL) const;
+
+    static const GrClip& WideOpen() {
+        static GrClip clip;
+        return clip;
+    }
+
+    enum ClipType {
+        kClipStack_ClipType,
+        kWideOpen_ClipType,
+        kIRect_ClipType,
+        kUninitialized_ClipType,
+    };
+
+    ClipType clipType() const { return fClipType; }
+
+private:
+    union Clip {
+        struct ClipStack {
+            const SkClipStack* fStack;
+            SkIPoint fOrigin;
+        } fClipStack;
+        SkIRect fIRect;
+    } fClip;
+
+    ClipType fClipType;
+};
+
+#endif