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

[Harshitha Onkar]

On Thu, 23 Jan 2025 01:00:00 GMT, Harshitha Onkar <honkar at openjdk.org> wrote:

>> Interesting. Does this also happen after the fix with Robot clamping coordinates in shared code?
>
> @alisenchung 
> 
>> I also tested windows and found different behavior from what Harshitha found - robot.mouseMove was already clamping on my primary screen, would not move to the second monitor, and did not throw any NPEs.
> 
> Tested it on windows again on different scales and found a possible rounding error that might be the cause for NPE on windows. [Corner case]
> 
> To save time you can run the test with multiple `@run` and different uiScales and do not have to change it manually in settings.
> 
> 
>  * @run main/othervm -Dsun.java2d.uiScale=1    MouseMoveOffScreen
>  * @run main/othervm -Dsun.java2d.uiScale=1.25 MouseMoveOffScreen
>  * @run main/othervm -Dsun.java2d.uiScale=1.75 MouseMoveOffScreen
>  * @run main/othervm -Dsun.java2d.uiScale=2    MouseMoveOffScreen
>  * @run main/othervm -Dsun.java2d.uiScale=1.5  MouseMoveOffScreen
> 
> 
> Following are the logs. 
> Observe the width of the primary screen and the point returned from fillPointWithCoords() in getPointerInfo().
> 
> uiScale: 1 - Passes
> Win32GraphicsDevice[screen=0]:java.awt.Rectangle[x=-1920,y=363,width=1920,height=1080]
> Win32GraphicsDevice[screen=1]:java.awt.Rectangle[x=0,y=0,**width=3440**,height=1440]
> Point: java.awt.Point[**x=3439**,y=200] 
> 
> uiScale: 1.25 - Passes
> Win32GraphicsDevice[screen=0]:java.awt.Rectangle[x=-1920,y=363,width=1536,height=864]
> Win32GraphicsDevice[screen=1]:java.awt.Rectangle[x=0,y=0,**width=2752**,height=1152]
> Point: java.awt.Point[**x=2751**,y=200]
> 
> **uiScale: 1.5 - Fails**
> Win32GraphicsDevice[screen=0]:java.awt.Rectangle[x=-1920,y=363,width=1280,height=720]
> Win32GraphicsDevice[screen=1]:java.awt.Rectangle[x=0,y=0,**width=2293**,height=960]
> Point: java.awt.Point[**x=2293**,y=200] =>  **Since x coordinate = width, bounds.contains(point) returns false for point on the edge/bounds of the screen.**
> 
> uiScale: 1.75 - Passes
> Win32GraphicsDevice[screen=0]:java.awt.Rectangle[x=-1920,y=363,width=1097,height=617]
> Win32GraphicsDevice[screen=1]:java.awt.Rectangle[x=0,y=0,width=1966,height=823]
> Point: java.awt.Point[x=0,y=200] => clamps to zero once coordinates are past the width of the screen.
> 
> We probably need to look into `fillPointWithCoords()`  too and check if is implemented differently on different platforms.

MouseMoveOffScreen.java still fails on windows on uiScale =1.5, 2.5 for reasons mentioned above.

Since the fix is macOS specific:
To handle this corner case either the test can be made macOS specific OR another way is to set uiScale=1 and run on all platforms. Maybe we can see what other reviewers suggest.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22781#discussion_r2109750018