RFR: 8309460: JScrollBar leaves behind clutter for non-integer UI scales

[Harshitha Onkar]

On Tue, 23 Jan 2024 04:31:45 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> Lines  are left behind when moving the scrollbar in the positive direction. but are cleaned up on mouse release. 
>> Additonally, with right arrow clicks too, the lines are left behind.
>> Seems like for mouseDragged and scrollByUnit, the dirty region of the scrollbar is not repainted leading to artifacts
>> which is being done in this fix..
>
> Looks to be related to 
> 8032219: [macosx] Scrollbars looks bad under retina 
> which changes the way scrollbar is drawn for Metal and Motif L&F by using fillRect instead of drawLine
> 
> and the current issue also happens for Metal and Motif L&F
> but not for say, Windows and Nimbus L&F

@prsadhuk @aivanov-jdk I have a clarification regarding the proposed fix.

With the original solution the scrollbar repaint is done only when mouse is released or scrolled by a block, with the proposed fix the repaint is called continuously as long as the mouse is dragged or scrolled by a unit. Won't this create a lot of calls to repaint and thus cause an overhead?

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PR Comment: https://git.openjdk.org/jdk/pull/17484#issuecomment-1908821523