RFR: 8345538: Robot.mouseMove doesn't clamp bounds on macOS when trying to move mouse off screen [v11]

[Alisen Chung]

On Thu, 13 Mar 2025 16:27:48 GMT, Alexander Zvegintsev <azvegint at openjdk.org> wrote:

>> src/java.desktop/share/classes/java/awt/Robot.java line 258:
>> 
>>> 256: 
>>> 257:         if (leastXDiff > leastYDiff) {
>>> 258:             peer.mouseMove(finX2, finY2);
>> 
>> Let's say I have the following display configuration on Linux. Since it uses Xinerama, it shares the same coordinate system. 
>> 
>> java.awt.Rectangle[x=0,y=0,width=3440,height=1440]
>> java.awt.Rectangle[x=3440,y=0,width=1440,height=2560]
>> 
>> ![image](https://github.com/user-attachments/assets/1953442c-fa18-49a0-99eb-b633152d83f6)
>> 
>> When I try to move the mouse to `x=20000,y=200`, I see that it clamps to `x=3439,y=200` (a point between 2 screens), while before it was `x=4879,y=200`(a rightmost point).
>> 
>> The old behavior seems more logical to me.
>
> Here are a few cases where it still seems to fail after the update:
> 
> 
> Title: secondary above the primary
> Cmd: xrandr --output DP-0 --primary --pos 0x1440 --rotate normal --preferred --output DP-2 --pos 0x0 --rotate normal --preferred
> 
> screen #0 java.awt.Rectangle[x=0,y=1440,width=3440,height=1440]
> screen #1 java.awt.Rectangle[x=0,y=0,width=2560,height=1440]
> 
> 
> 
> x  20000 y    200 [moving to]
> - x   2559 y    200 [actual location] # before fix
> + x   3439 y   1440 [actual location] # after fix
> 
> 
> ---
> 
> 
> Title: primary above the secondary, right side aligned
> Cmd: xrandr --output DP-0 --primary --pos 0x0 --rotate normal --preferred --output DP-2 --pos 880x1440 --rotate normal --preferred
> 
> screen #0 java.awt.Rectangle[x=0,y=0,width=3440,height=1440]
> screen #1 java.awt.Rectangle[x=880,y=1440,width=2560,height=1440]
> 
> 
> 
> x    200 y  20000 [moving to]
> - x    200 y   1439 [actual location]
> + x    880 y   2879 [actual location]
> 
> 
> ---
> 
> 
> Title: secondary above the primary, right side aligned
> Cmd: xrandr --output DP-0 --primary --pos 0x1440 --rotate normal --preferred --output DP-2 --pos 880x0 --rotate normal --preferred
> 
> screen #0 java.awt.Rectangle[x=0,y=1440,width=3440,height=1440]
> screen #1 java.awt.Rectangle[x=880,y=0,width=2560,height=1440]
> 
> 
> 
> x -20000 y    200 [moving to]
> - x    880 y    200 [actual location]
> + x      0 y   1440 [actual location]
> 
> x    200 y -20000 [moving to]
> - x    200 y   1440 [actual location]
> + x    880 y      0 [actual location]

These failures when moving to the offscreen point are actually because the new onscreen point being moved to is closer distance-wise than the onscreen point it would have moved to before the fix.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/22781#discussion_r2067372976