MacViews: Clip contents for non-rectangular windows.

ui/views/cocoa/bridged_content_view.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ui/views/cocoa/bridged_content_view.h"
 
 #include "base/logging.h"
 #import "base/mac/mac_util.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 210 matching lines @@
     [self addTrackingArea:cursorTrackingArea_.get()];
   }
   return self;
 }
 
 - (void)clearView {
   textInputClient_ = nullptr;
   hostedView_ = nullptr;
   [cursorTrackingArea_.get() clearOwner];
   [self removeTrackingArea:cursorTrackingArea_.get()];
+  windowMask_.reset();

[tapted, 2016/02/25 08:07:21]

is this needed here? (i.e. was it to fix an error?)

[karandeepb, 2016/03/04 03:01:55]

Not really. This is called here -
https://code.google.com/p/chromium/codesearch#chromium/src/ui/views/cocoa/bri...
and it has a comment to the effect that Cocoa may still have references to the
bridged_view_ object. Hence I thought we should free up windowMask_.

[tapted, 2016/03/04 04:15:01]

That shouldn't be necessary - if windowMask_ referred to some C++ object that
was about to be `delete`d by the caller we would, but since it's on ObjC object
we can just rely on the regular ObjC lifetime. So let's delete this line,
otherwise we're implying there's a more complicated lifetime issue than there
is.

 }
 
 - (void)processCapturedMouseEvent:(NSEvent*)theEvent {
   if (!hostedView_)
     return;
 
   NSWindow* source = [theEvent window];
   NSWindow* target = [self window];
   DCHECK(target);
 
@@ skipping 20 matching lines @@
     if (!view->GetTooltipText(viewPoint, &newTooltipText))
       DCHECK(newTooltipText.empty());
   }
   if (newTooltipText != lastTooltipText_) {
     std::swap(newTooltipText, lastTooltipText_);
     [self setToolTipAtMousePoint:base::SysUTF16ToNSString(lastTooltipText_)];
   }
 }
 
 - (void)updateWindowMask {
-  DCHECK(![self inLiveResize]);
-  DCHECK(base::mac::IsOSMavericksOrEarlier());
   DCHECK(hostedView_);
 
   views::Widget* widget = hostedView_->GetWidget();
   if (!widget->non_client_view())
     return;
 
   const NSRect frameRect = [self bounds];
   gfx::Path mask;
   widget->non_client_view()->GetWindowMask(gfx::Size(frameRect.size), &mask);
   if (mask.isEmpty())
     return;
 
   windowMask_.reset([gfx::CreateNSBezierPathFromSkPath(mask) retain]);
 
   // Convert to AppKit coordinate system.
   NSAffineTransform* flipTransform = [NSAffineTransform transform];
   [flipTransform translateXBy:0.0 yBy:frameRect.size.height];
   [flipTransform scaleXBy:1.0 yBy:-1.0];
   [windowMask_ transformUsingAffineTransform:flipTransform];
 }
 
+- (NSBezierPath*)windowMask {

[tapted, 2016/02/25 08:07:21]

nit: move up beneath clearView, since it roughly matches the declaration order
(initializers/dealloc should still always be before properties that aren't
synthesized)

[karandeepb, 2016/03/04 03:01:56]

Done.

+  return windowMask_.get();
+}
+
 // BridgedContentView private implementation.
 
 - (void)handleKeyEvent:(NSEvent*)theEvent {
   if (!hostedView_)
     return;
 
   DCHECK(theEvent);
   ui::KeyEvent event(theEvent);
   if (DispatchEventToMenu(hostedView_->GetWidget(), event.key_code()))
     return;
@@ skipping 124 matching lines @@
   [super setFrameSize:newSize];
   if (!hostedView_)
     return;
 
   hostedView_->SetSize(gfx::Size(newSize.width, newSize.height));
 }
 
 - (void)viewDidEndLiveResize {
   [super viewDidEndLiveResize];
 
-  // We prevent updating the window mask and clipping the border around the
-  // view, during a live resize. Hence update the window mask and redraw the
-  // view after resize has completed.
-  if (base::mac::IsOSMavericksOrEarlier()) {
-    [self updateWindowMask];
+  // During a live resize, we prevent clipping the border around the view, which
+  // is required to generate drop shadows on OSX 10.9. Hence redraw the view
+  // after resize has completed.
+  if (base::mac::IsOSMavericksOrEarlier())
     [self setNeedsDisplay:YES];
-  }
 }
 
 - (void)drawRect:(NSRect)dirtyRect {
   // Note that BridgedNativeWidget uses -[NSWindow setAutodisplay:NO] to
   // suppress calls to this when the window is known to be hidden.
   if (!hostedView_)
     return;
 
   if (drawMenuBackgroundForBlur_) {
     const CGFloat radius = views::MenuConfig::instance().corner_radius;
     [skia::SkColorToSRGBNSColor(0x01000000) set];
     [[NSBezierPath bezierPathWithRoundedRect:[self bounds]
                                      xRadius:radius
                                      yRadius:radius] fill];
   }
 
   // On OS versions earlier than Yosemite, to generate a drop shadow, we set an
   // opaque background. This causes windows with non rectangular shapes to have
   // square corners. To get around this, fill the path outside the window
   // boundary with clearColor and tell Cococa to regenerate drop shadow. See
   // crbug.com/543671.
   if (windowMask_ && ![self inLiveResize] &&
-      !IsRectInsidePath(dirtyRect, windowMask_)) {
-    DCHECK(base::mac::IsOSMavericksOrEarlier());
+      !IsRectInsidePath(dirtyRect, windowMask_) &&
+      base::mac::IsOSMavericksOrEarlier()) {
     gfx::ScopedNSGraphicsContextSaveGState state;
 
     // The outer rectangular path corresponding to the window.
     NSBezierPath* outerPath = [NSBezierPath bezierPathWithRect:[self bounds]];
 
     [outerPath appendBezierPath:windowMask_];
     [outerPath setWindingRule:NSEvenOddWindingRule];
     [[NSGraphicsContext currentContext]
         setCompositingOperation:NSCompositeCopy];
     [[NSColor clearColor] set];
@@ skipping 425 matching lines @@
   }
 
   return [super accessibilityAttributeValue:attribute];
 }
 
 - (id)accessibilityHitTest:(NSPoint)point {
   return [hostedView_->GetNativeViewAccessible() accessibilityHitTest:point];
 }
 
 @end