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

[Alexandr Scherbatiy]

On 5/31/2016 10:54 PM, Phil Race wrote:
>
>
> 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) {
> 1064
> 1065             GraphicsConfiguration gc = c.getGraphicsConfiguration();
> 1066             AffineTransform tx = (gc == null) ? null : 
> gc.getDefaultTransform();
>
>
> if it is only in some case such as where Swing is rendering in 
> headless mode that should be OK
     It happens when a size of a component is requested but the 
component has not been added to a frame yet. This is a case where a text 
component size can differ before it is added to a frame and after that.

   Thanks,
   Alexandr.
>
> -phil.
>
> 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.
>>
>