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      1 // Copyright (c) 2010 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 <cmath>
      8 
      9 @interface MenuTrackedButton (Private)
     10 - (void)doHighlight:(BOOL)highlight;
     11 - (void)checkMouseInRect;
     12 - (NSRect)insetBounds;
     13 - (BOOL)shouldHighlightOnHover;
     14 @end
     15 
     16 @implementation MenuTrackedButton
     17 
     18 @synthesize tracking = tracking_;
     19 
     20 - (void)updateTrackingAreas {
     21   [super updateTrackingAreas];
     22   [self removeTrackingRect:trackingTag_];
     23   trackingTag_ = [self addTrackingRect:NSInsetRect([self bounds], 1, 1)
     24                                  owner:self
     25                               userData:NULL
     26                           assumeInside:NO];
     27 }
     28 
     29 - (void)viewDidMoveToWindow {
     30   [self updateTrackingAreas];
     31   [self doHighlight:NO];
     32 }
     33 
     34 - (void)mouseEntered:(NSEvent*)theEvent {
     35   if (!tracking_) {
     36     didEnter_ = YES;
     37   }
     38   [self doHighlight:YES];
     39   [super mouseEntered:theEvent];
     40 }
     41 
     42 - (void)mouseExited:(NSEvent*)theEvent {
     43   didEnter_ = NO;
     44   tracking_ = NO;
     45   [self doHighlight:NO];
     46   [super mouseExited:theEvent];
     47 }
     48 
     49 - (void)mouseDragged:(NSEvent*)theEvent {
     50   tracking_ = !didEnter_;
     51 
     52   NSPoint point = [self convertPoint:[theEvent locationInWindow] fromView:nil];
     53   BOOL highlight = NSPointInRect(point, [self insetBounds]);
     54   [self doHighlight:highlight];
     55 
     56   // If tracking in non-sticky mode, poll the mouse cursor to see if it is still
     57   // over the button and thus needs to be highlighted.  The delay is the
     58   // smallest that still produces the effect while minimizing jank. Smaller
     59   // values make the selector fire too close to immediately/now for the mouse to
     60   // have moved off the receiver, and larger values produce lag.
     61   if (tracking_ && [self shouldHighlightOnHover]) {
     62     [self performSelector:@selector(checkMouseInRect)
     63                withObject:nil
     64                afterDelay:0.05
     65                   inModes:[NSArray arrayWithObject:NSEventTrackingRunLoopMode]];
     66   }
     67   [super mouseDragged:theEvent];
     68 }
     69 
     70 - (void)mouseUp:(NSEvent*)theEvent {
     71   [self doHighlight:NO];
     72   if (!tracking_) {
     73     return [super mouseUp:theEvent];
     74   }
     75   [self performClick:self];
     76   tracking_ = NO;
     77 }
     78 
     79 - (void)doHighlight:(BOOL)highlight {
     80   if (![self shouldHighlightOnHover]) {
     81     return;
     82   }
     83   [[self cell] setHighlighted:highlight];
     84   [self setNeedsDisplay];
     85 }
     86 
     87 // Checks if the user's current mouse location is over this button.  If it is,
     88 // the user is merely hovering here.  If it is not, then disable the highlight.
     89 // If the menu is opened in non-sticky mode, the button does not receive enter/
     90 // exit mouse events and thus polling is necessary.
     91 - (void)checkMouseInRect {
     92   NSPoint point = [NSEvent mouseLocation];
     93   point = [[self window] convertScreenToBase:point];
     94   point = [self convertPoint:point fromView:nil];
     95   if (!NSPointInRect(point, [self insetBounds])) {
     96     [self doHighlight:NO];
     97   }
     98 }
     99 
    100 // Returns the bounds of the receiver slightly inset to avoid highlighting both
    101 // buttons in a pair that overlap.
    102 - (NSRect)insetBounds {
    103   return NSInsetRect([self bounds], 2, 1);
    104 }
    105 
    106 - (BOOL)shouldHighlightOnHover {
    107   // Apple does not define NSAppKitVersionNumber10_5 when using the 10.5 SDK.
    108   // The Internets have come up with this solution.
    109   #ifndef NSAppKitVersionNumber10_5
    110   #define NSAppKitVersionNumber10_5 949
    111   #endif
    112 
    113   // There's a cell drawing bug in 10.5 that was fixed on 10.6.  Hover states
    114   // look terrible due to this, so disable highlighting on 10.5.
    115   return std::floor(NSAppKitVersionNumber) > NSAppKitVersionNumber10_5;
    116 }
    117 
    118 @end
    119