<Swing Dev> [9] Review request for 8142966 Wrong cursor position in text components on HiDPI display

Phil Race philip.race at oracle.com
Tue May 31 19:54:33 UTC 2016

This looks reasonable except I am not sure when gc would be null here :-

1062     private static FontRenderContext getFRCProperty(JComponent c) {
1063         if (c != null) {
1065             GraphicsConfiguration gc = c.getGraphicsConfiguration();
1066             AffineTransform tx = (gc == null) ? null : 

if it is only in some case such as where Swing is rendering in headless 
mode that should be OK


On 05/04/2016 10:42 PM, Alexandr Scherbatiy wrote:
> Hello,
> Could you review the fix:
>   bug: https://bugs.openjdk.java.net/browse/JDK-8142966
>   webrev: http://cr.openjdk.java.net/~alexsch/8142966/webrev.02
>   Swing uses a font rendering context which does not take the graphics 
> configuration transform into account.
>   This lead to the situation when text size is measured by one font 
> rendering context and drawn by another. As the result the calculated 
> text size can differ from the drawn text size.
>   For this issue it means that a cursor position can be farther away 
> from the char position.
>   This is the initial fix where graphics configuration transform is 
> included into the Swing font rendering context.
>   There is one more issue related to the fact that glyph advances are 
> calculated in dev space and then transformed to the user space. Char 
> width can have fractional value in user space if dev transform is not 
> identity.
>   It means that Swing should be able to draw a cursor at or select a 
> text from a fractional position.
>   These issues will be considered in separated fixes.
>  Thanks,
>  Alexandr.

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