abstract name of clipping ops, to transtion to a more restricted set

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
 #include "SkTypes.h"
 #include "SkBitmap.h"
+#include "SkClipOp.h"
 #include "SkDeque.h"
 #include "SkImage.h"
 #include "SkPaint.h"
 #include "SkRefCnt.h"
 #include "SkRegion.h"
 #include "SkSurfaceProps.h"
 #include "SkXfermode.h"
 #include "SkLights.h"
 #include "../private/SkShadowParams.h"
 
@@ skipping 11 matching lines @@
 class SkPath;
 class SkPicture;
 class SkPixmap;
 class SkRasterClip;
 class SkRRect;
 struct SkRSXform;
 class SkSurface;
 class SkSurface_Base;
 class SkTextBlob;
 
+#define SK_SUPPORT_LEGACY_CLIP_REGIONOPS
+
 /** \class SkCanvas
 
     A Canvas encapsulates all of the state about drawing into a device (bitmap).
     This includes a reference to the device itself, and a stack of matrix/clip
     values. For any given draw call (e.g. drawRect), the geometry of the object
     being drawn is transformed by the concatenation of all the matrices in the
     stack. The transformed geometry is clipped by the intersection of all of
     the clips in the stack.
 
     While the Canvas holds the state of the drawing device, the state (style)
     of the object being drawn is held by the Paint, which is provided as a
     parameter to each of the draw() methods. The Paint holds attributes such as
     color, typeface, textSize, strokeWidth, shader (e.g. gradients, patterns),
     etc.
 */
 class SK_API SkCanvas : public SkRefCnt {
     enum PrivateSaveLayerFlags {
         kDontClipToLayer_PrivateSaveLayerFlag   = 1U << 31,
     };
-    
+
 public:
+#ifdef SK_SUPPORT_LEGACY_CLIP_REGIONOPS
+    typedef SkRegion::Op ClipOp;

[f(malita), 2016/09/19 15:39:25]

Any reason to use typedef + static consts instead of enum ClipOp?

[reed1, 2016/09/19 18:17:08]

I want an alias for whatever ClipOp is going to be (either SkClipOp or
SkRegion::Op). This way functions can take SkCanvas::ClipOp as a type, and
callers can use SkCanvas::kIntersect_Op either way

Eventually I will remove this aliasing entirely, and just land on SkClipOp.

[f(malita), 2016/09/19 19:43:24]

I see.  Would it work to typedef unsigned ClipOp for the legacy case?  I think
that would allow passing/comparing both enum types thanks to implicit enum
conversion?

+
+    static const ClipOp kDifference_Op         = SkRegion::kDifference_Op;

[f(malita), 2016/09/19 15:39:25]

constexpr?

[reed1, 2016/09/19 18:17:08]

Turns out the linker wants to see these as actual global variables, so I need
const.

+    static const ClipOp kIntersect_Op          = SkRegion::kIntersect_Op;
+    static const ClipOp kUnion_Op              = SkRegion::kUnion_Op;
+    static const ClipOp kXOR_Op                = SkRegion::kXOR_Op;
+    static const ClipOp kReverseDifference_Op  = SkRegion::kReverseDifference_Op;
+    static const ClipOp kReplace_Op            = SkRegion::kReplace_Op;
+#else
+    typedef SkClipOp ClipOp;
+
+    static const ClipOp kDifference_Op         = kDifference_SkClipOp;
+    static const ClipOp kIntersect_Op          = kIntersect_SkClipOp;
+    static const ClipOp kUnion_Op              = kUnion_SkClipOp;
+    static const ClipOp kXOR_Op                = kXOR_SkClipOp;
+    static const ClipOp kReverseDifference_Op  = kReverseDifference_SkClipOp;
+    static const ClipOp kReplace_Op            = kReplace_SkClipOp;
+#endif
     /**
      *  Attempt to allocate raster canvas, matching the ImageInfo, that will draw directly into the
      *  specified pixels. To access the pixels after drawing to them, the caller should call
      *  flush() or call peekPixels(...).
      *
      *  On failure, return NULL. This can fail for several reasons:
      *  1. invalid ImageInfo (e.g. negative dimensions)
      *  2. unsupported ImageInfo for a canvas
      *      - kUnknown_SkColorType, kIndex_8_SkColorType
      *      - kUnknown_SkAlphaType
@@ skipping 395 matching lines @@
       */
     sk_sp<SkLights> getLights() const;
 #endif
 
     /**
      *  Modify the current clip with the specified rectangle.
      *  @param rect The rect to combine with the current clip
      *  @param op The region op to apply to the current clip
      *  @param doAntiAlias true if the clip should be antialiased
      */
-    void clipRect(const SkRect& rect,
-                  SkRegion::Op op = SkRegion::kIntersect_Op,
-                  bool doAntiAlias = false);
+    void clipRect(const SkRect& rect, ClipOp op = kIntersect_Op, bool doAntiAlias = false);
 
     /**
      *  Modify the current clip with the specified SkRRect.
      *  @param rrect The rrect to combine with the current clip
      *  @param op The region op to apply to the current clip
      *  @param doAntiAlias true if the clip should be antialiased
      */
-    void clipRRect(const SkRRect& rrect,
-                   SkRegion::Op op = SkRegion::kIntersect_Op,
-                   bool doAntiAlias = false);
+    void clipRRect(const SkRRect& rrect, ClipOp op = kIntersect_Op, bool doAntiAlias = false);
 
     /**
      *  Modify the current clip with the specified path.
      *  @param path The path to combine with the current clip
      *  @param op The region op to apply to the current clip
      *  @param doAntiAlias true if the clip should be antialiased
      */
-    void clipPath(const SkPath& path,
-                  SkRegion::Op op = SkRegion::kIntersect_Op,
-                  bool doAntiAlias = false);
+    void clipPath(const SkPath& path, ClipOp op = kIntersect_Op, bool doAntiAlias = false);
 
     /** EXPERIMENTAL -- only used for testing
         Set to false to force clips to be hard, even if doAntiAlias=true is
         passed to clipRect or clipPath.
      */
     void setAllowSoftClip(bool allow) {
         fAllowSoftClip = allow;
     }
 
     /** EXPERIMENTAL -- only used for testing
         Set to simplify clip stack using path ops.
      */
     void setAllowSimplifyClip(bool allow) {
         fAllowSimplifyClip = allow;
     }
 
     /** Modify the current clip with the specified region. Note that unlike
         clipRect() and clipPath() which transform their arguments by the current
         matrix, clipRegion() assumes its argument is already in device
         coordinates, and so no transformation is performed.
         @param deviceRgn    The region to apply to the current clip
         @param op The region op to apply to the current clip
     */
-    void clipRegion(const SkRegion& deviceRgn,
-                    SkRegion::Op op = SkRegion::kIntersect_Op);
+    void clipRegion(const SkRegion& deviceRgn, ClipOp op = kIntersect_Op);
 
+#ifdef SK_LEGACY_SUPPORT_SETCLIPREGION

[f(malita), 2016/09/19 15:39:26]

SK_SUPPORT_LEGACY_SETCLIPREGION?

[reed1, 2016/09/19 18:17:08]

Done.

     /** Helper for clipRegion(rgn, kReplace_Op). Sets the current clip to the
         specified region. This does not intersect or in any other way account
         for the existing clip region.
         @param deviceRgn The region to copy into the current clip.
     */
     void setClipRegion(const SkRegion& deviceRgn) {
-        this->clipRegion(deviceRgn, SkRegion::kReplace_Op);
+        this->clipRegion(deviceRgn, kReplace_Op);
     }
+#endif
 
     /** Return true if the specified rectangle, after being transformed by the
         current matrix, would lie completely outside of the current clip. Call
         this to check if an area you intend to draw into is clipped out (and
         therefore you can skip making the draw calls).
         @param rect the rect to compare with the current clip
         @return true if the rect (transformed by the canvas' matrix) does not
                      intersect with the canvas' clip
     */
     bool quickReject(const SkRect& rect) const;
@@ skipping 912 matching lines @@
     virtual void onDrawBitmapNine(const SkBitmap&, const SkIRect& center, const SkRect& dst,
                                   const SkPaint*);
     virtual void onDrawBitmapLattice(const SkBitmap&, const Lattice& lattice, const SkRect& dst,
                                      const SkPaint*);
 
     enum ClipEdgeStyle {
         kHard_ClipEdgeStyle,
         kSoft_ClipEdgeStyle
     };
 
-    virtual void onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle edgeStyle);
-    virtual void onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyle edgeStyle);
-    virtual void onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle edgeStyle);
-    virtual void onClipRegion(const SkRegion& deviceRgn, SkRegion::Op op);
+    virtual void onClipRect(const SkRect& rect, ClipOp, ClipEdgeStyle);
+    virtual void onClipRRect(const SkRRect& rrect, ClipOp, ClipEdgeStyle);
+    virtual void onClipPath(const SkPath& path, ClipOp, ClipEdgeStyle);
+    virtual void onClipRegion(const SkRegion& deviceRgn, ClipOp);
 
     virtual void onDiscard();
 
     virtual void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*);
 
 #ifdef SK_EXPERIMENTAL_SHADOWING
     virtual void onDrawShadowedPicture(const SkPicture*,
                                        const SkMatrix*,
                                        const SkPaint*,
                                        const SkShadowParams& params);
@@ skipping 248 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif