RFR: 8345538: Robot.mouseMove doesn't clamp bounds on macOS when trying to move mouse off screen [v7]

[Alexey Ivanov]

On Tue, 28 Jan 2025 04:43:44 GMT, Alisen Chung <achung at openjdk.org> wrote:

>> Currently on macOS when mouseMove is given an offscreen coordinate to move the mouse to, mouseMove will physically clamp to the edge of the screen, but if you try to grab the mouse location immediately after by using MouseInfo.getPointerInfo().getLocation() you will get the value of the offscreen point.
>> 
>> Windows and linux do this clamping and coordinate handling for us, but new distributions may not necessarily handle clamping the same way, so Robot should be checking for clamping rather than delegating it to native.
>> 
>> This fix updates shared code to cache the screen bounds and adds a check to not exceed the bounds in mouseMove. The caching is done in the Robot constructor, so if the screen bounds changes the constructor must be called again to update to the new bounds.
>
> Alisen Chung has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - robot update
>  - Revert "robot multimonitor fix"
>    
>    This reverts commit 5734165881a66dc48d5a9f19e02bf63fac57cdc9.
>  - Revert "init finX, finY"
>    
>    This reverts commit 0eb4226fe6d3cf7406bf0124d4871388fb04a77e.

Changes requested by aivanov (Reviewer).

src/java.desktop/share/classes/java/awt/Robot.java line 234:

> 232:         for (Rectangle screenBounds : allScreenBounds) {
> 233:             int closestX = Math.min(Math.max(x, screenBounds.x), screenBounds.x + screenBounds.width);
> 234:             int closestY = Math.min(Math.max(y, screenBounds.y), screenBounds.y + screenBounds.height);

I propose moving the code which calculates the closest — _final_ — position of the mouse to a helper method, it would make the logic cleaner.

src/java.desktop/share/classes/java/awt/Robot.java line 242:

> 240:                 mouseMove(x,y);
> 241:                 afterEvent();
> 242:                 return;

So, now you recursively call `mouseMove` again…

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PR Review: https://git.openjdk.org/jdk/pull/22781#pullrequestreview-2579171240
PR Review Comment: https://git.openjdk.org/jdk/pull/22781#discussion_r1932710714
PR Review Comment: https://git.openjdk.org/jdk/pull/22781#discussion_r1932708226