RFR: 8345538: Robot.mouseMove doesn't clamp bounds on macOS when trying to move mouse off screen [v3]

[Phil Race]

On Fri, 20 Dec 2024 19:33:24 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> Yes, I'm running into NPE without as well as with the fix.
>
> Is the current behaviour even a bug? [`Robot.mouseMove`](https://docs.oracle.com/en/java/javase/23/docs/api/java.desktop/java/awt/Robot.html#mouseMove(int,int)) says nothing about invalid coordinates.
> 
>> @aivanov-jdk I see your point. But I'm running into NPE at `MouseInfo.getPointerInfo().getLocation()` without the fix as well (dual monitor, extended display setup)
> 
> It's probably even better…
> 
>> Is it expected of MouseInfo.getPointerInfo() to return null for off-screen coordinates (meaning does it consider it as mouse not available if it is outside the screen devices)?
>> 
>> PointerInfo has two things associated with it - screen device and a location, so if it is not able to associate the coordinate with any of the screen device (off-screen coordinate) is it suppose to return null in this case?
> 
> So, the mouse seems to be positioned outside of the virtual screen bounds. For this reason, `MouseInfo.getPointerInfo()` cannot return anything.
> 
> This again raises the question, why does it return a non-null value on macOS?
> 
> What do you see on the screen? Does the mouse cursor or its part remain visible on the screen? What happens when you start moving your mouse?

> Yes, I'm running into NPE without as well as with the fix.

Can you provide information on your multi-screen setup ?
how many displays ? what is the relative placement of the monitors ?
What are the virtual bounds of your setup ?

And the stack trace of the exception you get too.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22781#discussion_r1894333618