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// Copyright (c) 2010 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 "chrome/browser/cocoa/draggable_button.h"
#include "base/logging.h"
#import "base/scoped_nsobject.h"
namespace {
// Code taken from <http://codereview.chromium.org/180036/diff/3001/3004>.
// TODO(viettrungluu): Do we want common, standard code for drag hysteresis?
const CGFloat kWebDragStartHysteresisX = 5.0;
const CGFloat kWebDragStartHysteresisY = 5.0;
}
@implementation DraggableButton
@synthesize draggable = draggable_;
- (id)initWithFrame:(NSRect)frame {
if ((self = [super initWithFrame:frame])) {
draggable_ = YES;
}
return self;
}
- (id)initWithCoder:(NSCoder*)coder {
if ((self = [super initWithCoder:coder])) {
draggable_ = YES;
}
return self;
}
- (void)mouseUp:(NSEvent*)theEvent {
// Make sure that we can't start a drag until we see a mouse down again.
mayDragStart_ = NO;
// This conditional is never true (DnD loops in Cocoa eat the mouse
// up) but I added it in case future versions of Cocoa do unexpected
// things.
if (beingDragged_) {
NOTREACHED();
return [super mouseUp:theEvent];
}
// There are non-drag cases where a mouseUp: may happen
// (e.g. mouse-down, cmd-tab to another application, move mouse,
// mouse-up). So we check.
NSPoint viewLocal = [self convertPoint:[theEvent locationInWindow]
fromView:[[self window] contentView]];
if (NSPointInRect(viewLocal, [self bounds])) {
[self performClick:self];
} else {
[self endDrag];
}
}
// Mimic "begin a click" operation visually. Do NOT follow through
// with normal button event handling.
- (void)mouseDown:(NSEvent*)theEvent {
mayDragStart_ = YES;
[[self cell] setHighlighted:YES];
initialMouseDownLocation_ = [theEvent locationInWindow];
}
// Return YES if we have crossed a threshold of movement after
// mouse-down when we should begin a drag. Else NO.
- (BOOL)hasCrossedDragThreshold:(NSEvent*)theEvent {
NSPoint currentLocation = [theEvent locationInWindow];
if ((abs(currentLocation.x - initialMouseDownLocation_.x) >
kWebDragStartHysteresisX) ||
(abs(currentLocation.y - initialMouseDownLocation_.y) >
kWebDragStartHysteresisY)) {
return YES;
} else {
return NO;
}
}
- (void)mouseDragged:(NSEvent*)theEvent {
if (beingDragged_) {
[super mouseDragged:theEvent];
} else if (draggable_ && mayDragStart_ &&
[self hasCrossedDragThreshold:theEvent]) {
// Starting drag. Never start another drag until another mouse down.
mayDragStart_ = NO;
[self beginDrag:theEvent];
}
}
- (void)beginDrag:(NSEvent*)dragEvent {
// Must be overridden by subclasses.
NOTREACHED();
}
- (void)endDrag {
beingDragged_ = NO;
[[self cell] setHighlighted:NO];
}
@end
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