Mac Panels interaction with Dock modifications. (step 1)

chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm

 // Copyright (c) 2011 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/ui/panels/panel_titlebar_view_cocoa.h"
 
 #include <Carbon/Carbon.h>  // kVK_Escape
 #import <Cocoa/Cocoa.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "chrome/browser/themes/theme_service.h"
 #import "chrome/browser/ui/cocoa/hover_image_button.h"
 #import "chrome/browser/ui/cocoa/nsview_additions.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
 #import "chrome/browser/ui/cocoa/tracking_area.h"
 #import "chrome/browser/ui/panels/panel_window_controller_cocoa.h"
 #include "grit/theme_resources_standard.h"
 #import "third_party/GTM/AppKit/GTMNSBezierPath+RoundRect.h"
 #include "ui/gfx/mac/nsimage_cache.h"
 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 
 const int kRoundedCornerSize = 3;
 const int kButtonPadding = 8;
 const int kIconAndTextPadding = 5;
 
+// Square of a distance that user needs to move the mouse in order to start the
+// drag. Threshold is needed to differentiate drags from attempts to click the
+// titlebar with a twitch of the mouse pointer.
+const int kDragThreasholdSquared = 9;

[jennb, 2011/11/17 23:45:40]

typo: Threshold

What's the logic behind using the square of the distance?

[Dmitry Titov, 2011/11/18 00:15:11]

I'm computing a distance and don't want to do sqrt...

+
 // Used to implement TestingAPI
 static NSEvent* MakeMouseEvent(NSEventType type,
                                NSPoint point,
                                int clickCount) {
   return [NSEvent mouseEventWithType:type
                             location:point
                        modifierFlags:0
                            timestamp:0
                         windowNumber:0
                              context:nil
@@ skipping 273 matching lines @@
   [self setNeedsDisplay:YES];
 }
 
 - (void)didChangeMainWindow:(NSNotification*)notification {
   [self setNeedsDisplay:YES];
   [self checkMouseAndUpdateSettingsButtonVisibility];
 }
 
 - (void)mouseDown:(NSEvent*)event {
   dragState_ = PANEL_DRAG_CAN_START;
+  dragStartLocation_ = [event locationInWindow];
 }
 
 - (void)mouseUp:(NSEvent*)event {
   DCHECK(dragState_ != PANEL_DRAG_IN_PROGRESS);
 
   if ([event clickCount] == 1)
     [controller_ onTitlebarMouseClicked];
 }
 
+- (BOOL)overDragThreshold:(NSPoint)mouseLocation {

[jennb, 2011/11/17 23:45:40]

exceedsDragThreshold? I'm not sure what overDragThreshold means.

[Dmitry Titov, 2011/11/18 00:15:11]

Done.

+  float deltaX = dragStartLocation_.x - mouseLocation.x;
+  float deltaY = dragStartLocation_.y - mouseLocation.y;
+  return deltaX*deltaX + deltaY*deltaY > kDragThreasholdSquared;

[jennb, 2011/11/17 23:45:40]

Please use parens rather than dropping the spacing around operators if you want
to make precedence more obvious.

[Dmitry Titov, 2011/11/18 00:15:11]

Done.

+}
+
 - (void)mouseDragged:(NSEvent*)event {
   // In addition to events needed to control the drag operation, fetch the right
   // mouse click events and key down events and ignore them, to prevent their
   // accumulation in the queue and "playing out" when the mouse is released.
   const NSUInteger mask =
       NSLeftMouseUpMask | NSLeftMouseDraggedMask | NSKeyUpMask |
       NSRightMouseDownMask | NSKeyDownMask ;
   BOOL keepGoing = YES;
 
   while (keepGoing) {
     base::mac::ScopedNSAutoreleasePool autorelease_pool;
 
     NSEvent* event = [NSApp nextEventMatchingMask:mask
                                         untilDate:[NSDate distantFuture]
                                            inMode:NSDefaultRunLoopMode
                                           dequeue:YES];
 
     switch ([event type]) {
       case NSLeftMouseDragged:
-        if (dragState_ == PANEL_DRAG_CAN_START)
-          [self startDrag];
+        if (dragState_ == PANEL_DRAG_CAN_START) {
+          if ([self overDragThreshold:[event locationInWindow]])

[jennb, 2011/11/17 23:45:40]

nit: How about reversing this conditional to make code easier to read?

[Dmitry Titov, 2011/11/18 00:15:11]

Done.

+            [self startDrag];
+          else
+            return;  // Don't start real drag yet.
+        }
         [self dragWithDeltaX:[event deltaX]];
         break;
 
       case NSKeyUp:
         if ([event keyCode] == kVK_Escape) {
           [self endDrag:YES];
           keepGoing = NO;
         }
         break;
 
       case NSLeftMouseUp:
+        if (dragState_ == PANEL_DRAG_CAN_START) {  // Drag didn't really start.
+          [self mouseUp:event];
+          return;

[jennb, 2011/11/17 23:45:40]

nit: I want to drop this return and add else clause around the last 2 lines.

[Dmitry Titov, 2011/11/18 00:15:11]

Done.

+        }
         [self endDrag:NO];
         keepGoing = NO;
         break;
 
       case NSRightMouseDownMask:
         break;
 
       default:
         // Dequeue and ignore other mouse and key events so the Chrome context
         // menu does not come after right click on a page during Panel
@@ skipping 89 matching lines @@
 }
 
 - (void)checkMouseAndUpdateSettingsButtonVisibility {
   BOOL mouseOverWindow = NSPointInRect([NSEvent mouseLocation],
                                        [[self window] frame]);
   [self updateSettingsButtonVisibility:mouseOverWindow];
 }
 
 @end