Find the topmost window under a mouse cursor

[Anthony Petrov]

On 3/27/2012 3:24 PM, Dmitry Cherepanov wrote:
> Anthony Petrov wrote:
>> On 3/27/2012 2:19 PM, Dmitry Cherepanov wrote:
>>>> I suggest to track the MouseIsOver state with a boolean flag per 
>>>> window, and send a synthetic Entered event upon receiving any other 
>>>> mouse event (Moved, Clicked, etc.)
>>>
>>> We should probably synthesize such mouse enter/exit events upon 
>>> changing window's bounds. Synthesizing the mouse enter/exit event 
>>> upon receiving any other mouse event wouldn't changes the mouse 
>>> cursor until the user performs any mouse action.
>>
>> Is this exact behavior specified anywhere (i.e. that the cursor must 
>> be updated as soon as a component appears under the mouse even if the 
>> mouse holds still)? If not, I'd just state that the behavior is 
>> platform-specific.
> 
> Looks like it's a part of the AWT specification:
> 
> http://docs.oracle.com/javase/7/docs/api/java/awt/Component.html#setCursor(java.awt.Cursor) 
> 
> 
> "This cursor image is displayed when the contains method for this 
> component returns true for the current cursor location, and this 
> Component is visible, displayable, and enabled"

The contains() method doesn't take into account if a component (or a 
window for that matter) is obscured by its siblings in the z-order. It 
seems that the spec needs to be clarified. As such, I'd suggest to 
specify that whether or not the cursor is updated instantly once the 
component becomes visible and appears right under the mouse cursor 
depends on the platform. Which is quite true.

--
best regards,
Anthony

> 
> Thanks,
> Dmitry
> 
>>
>> -- 
>> best regards,
>> Anthony
>>
>>>
>>> Thanks,
>>> Dmitry
>>>
>>>> if the flag indicates we haven't yet sent an Entered event for this 
>>>> window. The flag should be set/reset in the Entered/Exited mouse 
>>>> handlers.
>>>>
>>>> We use this approach in FX and everyone seems to be happy about that.
>>>>
>>>> -- 
>>>> best regards,
>>>> Anthony
>>>>
>>>> On 3/27/2012 12:08 PM, Alexander Scherbatiy wrote:
>>>>>
>>>>> Hello,
>>>>>
>>>>> Does the Mac OS X contains a method that allows to find the topmost 
>>>>> window under a mouse cursor?
>>>>>
>>>>> There is the issue when a window is created under a mouse cursor or 
>>>>> it is moved under a mouse cursor the system does not generate the 
>>>>> NSMouseEntered event.
>>>>>
>>>>> It is possible to synthetically generate the MouseEntered event 
>>>>> for  window creation and moving in Java because we need that a 
>>>>> window behavior on Mac OS X was the same as on others platforms.
>>>>> But it is necessary to have a way to know is this window the 
>>>>> topmost under a mouse cursor.
>>>>>
>>>>> Thanks,
>>>>> Alexandr.
>>>>>
>>>>>
>>>>>
>>>
>