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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #import "chrome/browser/ui/cocoa/wrench_menu/menu_tracked_button.h"
      6 
      7 #include "base/mac/mac_util.h"
      8 
      9 @interface MenuTrackedButton (Private)
     10 - (void)doHighlight:(BOOL)highlight;
     11 - (void)checkMouseInRect;
     12 - (NSRect)insetBounds;
     13 @end
     14 
     15 @implementation MenuTrackedButton
     16 
     17 @synthesize tracking = tracking_;
     18 
     19 - (void)updateTrackingAreas {
     20   [super updateTrackingAreas];
     21   [self removeTrackingRect:trackingTag_];
     22   trackingTag_ = [self addTrackingRect:NSInsetRect([self bounds], 1, 1)
     23                                  owner:self
     24                               userData:NULL
     25                           assumeInside:NO];
     26 }
     27 
     28 - (void)viewDidMoveToWindow {
     29   [self updateTrackingAreas];
     30   [self doHighlight:NO];
     31 }
     32 
     33 - (void)mouseEntered:(NSEvent*)theEvent {
     34   if (!tracking_) {
     35     didEnter_ = YES;
     36   }
     37   [self doHighlight:YES];
     38   [super mouseEntered:theEvent];
     39 }
     40 
     41 - (void)mouseExited:(NSEvent*)theEvent {
     42   didEnter_ = NO;
     43   tracking_ = NO;
     44   [self doHighlight:NO];
     45   [super mouseExited:theEvent];
     46 }
     47 
     48 - (void)mouseDragged:(NSEvent*)theEvent {
     49   tracking_ = !didEnter_;
     50 
     51   NSPoint point = [self convertPoint:[theEvent locationInWindow] fromView:nil];
     52   BOOL highlight = NSPointInRect(point, [self insetBounds]);
     53   [self doHighlight:highlight];
     54 
     55   // If tracking in non-sticky mode, poll the mouse cursor to see if it is still
     56   // over the button and thus needs to be highlighted.  The delay is the
     57   // smallest that still produces the effect while minimizing jank. Smaller
     58   // values make the selector fire too close to immediately/now for the mouse to
     59   // have moved off the receiver, and larger values produce lag.
     60   if (tracking_) {
     61     [self performSelector:@selector(checkMouseInRect)
     62                withObject:nil
     63                afterDelay:0.05
     64                   inModes:[NSArray arrayWithObject:NSEventTrackingRunLoopMode]];
     65   }
     66   [super mouseDragged:theEvent];
     67 }
     68 
     69 - (void)mouseUp:(NSEvent*)theEvent {
     70   [self doHighlight:NO];
     71   if (!tracking_) {
     72     return [super mouseUp:theEvent];
     73   }
     74   [self performClick:self];
     75   tracking_ = NO;
     76 }
     77 
     78 - (void)doHighlight:(BOOL)highlight {
     79   [[self cell] setHighlighted:highlight];
     80   [self setNeedsDisplay];
     81 }
     82 
     83 // Checks if the user's current mouse location is over this button.  If it is,
     84 // the user is merely hovering here.  If it is not, then disable the highlight.
     85 // If the menu is opened in non-sticky mode, the button does not receive enter/
     86 // exit mouse events and thus polling is necessary.
     87 - (void)checkMouseInRect {
     88   NSPoint point = [NSEvent mouseLocation];
     89   point = [[self window] convertScreenToBase:point];
     90   point = [self convertPoint:point fromView:nil];
     91   if (!NSPointInRect(point, [self insetBounds])) {
     92     [self doHighlight:NO];
     93   }
     94 }
     95 
     96 // Returns the bounds of the receiver slightly inset to avoid highlighting both
     97 // buttons in a pair that overlap.
     98 - (NSRect)insetBounds {
     99   return NSInsetRect([self bounds], 2, 1);
    100 }
    101 
    102 @end
    103