On Mon, 15 Dec 2025 15:23:27 GMT, John Hendrikx <[email protected]> wrote:
> When a Window is created with a certain X/Y coordinate to place it on a > specific screen, and is subsequently shown for the first time, one of the > first things it does is size the window according to the size of the Scene. > It does this based on the render scale of the *primary* screen as it has not > moved the peer yet to the correct screen. After the scene has been sized, it > is moved to the correct screen, triggering a change of render scale, but not > a resizing of the Window (as this is only done once). > > The result of this is that due to slight difference in render scale, the size > calculated for the scene may be a few pixels off. As the scene's preferred > size is used for this calculation, even a few pixels too small can result in > Labels being shown with ellipsis on the intended target screen with a > different render scale. > > When observing the render scale X or Y property, one can observe a change > from 1.0 (the default value) to 2.0 (the primary screen's render scale) to > another value (depending on the target screen). However, the Window involved > (being positioned by the user using setX()/setY() before it is shown) was > never shown on the primary screen, yet the size calculation assumed it was. > > To solve this problem, the peer should be moved to the correct screen > **before** asking the Scene for its preferred size to use as the initial > Window size. Doing so (by adding an additional `applyBounds` call) also > results in the render scale properties to only change once (or not at all) > from their default value to the target screen's value (or not at all if the > target screen is 1.0 scale). This fix introduces another issue in the monkey tester, breaking the layout (see the screenshot below). The failure can be seen when the MT window appears on the primary (scale=2) as well as on the secondary (scale=1) monitor, running macOS 26.1. The layout gets fixed when the user resizes the window. Interestingly, moving the window to another screen with a different scale **does not** fixes the issue. <img width="1380" height="623" alt="Screenshot 2025-12-15 at 10 47 46" src="https://github.com/user-attachments/assets/0af65495-7e28-428d-9001-a94c68917833"; /> ------------- PR Comment: https://git.openjdk.org/jfx/pull/2007#issuecomment-3657112663
