MacViews: Clip contents for non-rectangular windows.

ui/gfx/path_mac.mm

Index: ui/gfx/path_mac.mm
diff --git a/ui/gfx/path_mac.mm b/ui/gfx/path_mac.mm
index 109f80741f4099ceea697953ac425e92719ed7de..711759469c23da01618581b0cdc3e0a5d5265ab1 100644
--- a/ui/gfx/path_mac.mm
+++ b/ui/gfx/path_mac.mm
@@ -4,8 +4,6 @@
 
 #import "ui/gfx/path_mac.h"
 
-#import <Cocoa/Cocoa.h>
-
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/gfx/path.h"
 
@@ -122,4 +120,42 @@ NSBezierPath* CreateNSBezierPathFromSkPath(const SkPath& path) {
   return result;
 }
 
+base::ScopedCFTypeRef<CGPathRef> CreateCGPathFromNSBezierPath(

[karandeepb, 2016/02/24 04:27:18]

This is slightly inspired from
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CocoaD....
Is that ok?

[tapted, 2016/02/24 05:05:03]

I think you can do

#import "third_party/google_toolbox_for_mac/src/AppKit/GTMNSBezierPath+CGPath.h"

in bridged_native_widget.mm then just call -[NSBezierPath gtm_CGPath]


(however, it seems to be missing the bit about the path being closed, so maybe a
helper function in an anonymous namespace is good for that)

[karandeepb, 2016/02/25 03:31:06]

Done. Weird that the src folder doesn't show up on code search -
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/google....

Don't think closing the path is necessary. That is only required during hit
testing. Here we are using the path to fill the mask layer, thereby changing its
alpha channel. And while filling, Quartz treats each subpath as closed.

+    NSBezierPath* path) {
+  base::ScopedCFTypeRef<CGMutablePathRef> result(CGPathCreateMutable());
+  NSPoint points[3];
+  bool path_closed = true;
+  for (int i = 0; i < [path elementCount]; i++) {
+    switch ([path elementAtIndex:i associatedPoints:points]) {
+      case NSMoveToBezierPathElement:
+        CGPathMoveToPoint(result, nullptr, points[0].x, points[0].y);
+        break;
+
+      case NSLineToBezierPathElement:
+        CGPathAddLineToPoint(result, nullptr, points[0].x, points[0].y);
+        path_closed = false;
+        break;
+
+      case NSCurveToBezierPathElement:
+        CGPathAddCurveToPoint(result, nullptr, points[0].x, points[0].y,
+                              points[1].x, points[1].y, points[2].x,
+                              points[2].y);
+        path_closed = false;
+        break;
+
+      case NSClosePathBezierPathElement:
+        CGPathCloseSubpath(result);
+        path_closed = true;
+        break;
+    }
+  }
+
+  // For valid hit detection, path must be closed.
+  if (!path_closed)
+    CGPathCloseSubpath(result);
+
+  // Return immutable copy of result.
+  return base::ScopedCFTypeRef<CGPathRef>(CGPathCreateCopy(result));
+}
+
 }  // namespace gfx