<Swing Dev> [9] Review request for 8142966 Wrong cursor position in text components on HiDPI display
Alexandr Scherbatiy
alexandr.scherbatiy at oracle.com
Wed Jun 1 05:50:08 UTC 2016
On 6/1/2016 12:26 AM, Phil Race wrote:
> On 5/31/2016 1:36 PM, Alexandr Scherbatiy wrote:
>> 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.
>
> I do not know the flow here but it seems like you need to be careful
> that anything
> dependent on this needs to be updated once the component is added to a
> parent.
It is covered by the changes in PlainView.updateMetrics() method.
Thanks,
Alexandr.
>
>
> -phil.
>
>>
>> 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.
>>>>
>>>
>>
>
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