RFR: 8252255: Blurry rendering of SwingNode with HiDPI scaling in JavaFX

[Prasanta Sadhukhan]

On Fri, 3 Mar 2023 08:07:12 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

> Refactor-ed Swing interop was calling `JLightweightFrame.notifyDisplayChanged()` with [wrong scale factor](https://github.com/openjdk/jfx/blob/master/modules/javafx.swing/src/main/java/com/sun/javafx/embed/swing/newimpl/SwingNodeInteropN.java#L71-L76) 
> as it was passing integer scale and not double so scalefactor of 1.25 is being passed as 1.0 to JLightwieightFrame
> Due to this, the `imagebuffer `which is created for lightweight container to paint its content to an offscreen image 
> is created with wrong[ width/height ](https://github.com/openjdk/jdk/blob/master/src/java.desktop/share/classes/sun/swing/JLightweightFrame.java#L457)
> Fix is made to have Swing interop call double version of the method to get correct scale factor and set the imagebuffer properly.
> 
> I guess we could remove the int version of the method (which anyways is deprecated) and cleanup Swing interop code to just utilise the double version, as all platforms we support uses floating scale, but that cleanup can be done separately for another day

I guess it will require a FX testcase and will not run via jtreg so I will like to address that as a separate issue..

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PR: https://git.openjdk.org/jdk/pull/12848