<Swing Dev> [13] RFR JDK-8213535:Windows HiDPI html lightweight tooltips are truncated

[Sergey Bylokhov]

On 4/5/20 11:08 pm, Prasanta Sadhukhan wrote:
> 
> On 05-Apr-20 10:29 AM, Sergey Bylokhov wrote:
>> On 4/2/20 8:59 pm, Prasanta Sadhukhan wrote:
>>
>>>> If we GC is correct in reset/pack step, but the View calculate wrong size(and update it only after "graphicsConfiguration" property change) means that we calculate the size of the View using wrong GC, why?
>>>
>>> It's not the size of View, it's the preferredSize that is wrong. This is because tip's GC is null before the tip is shown, so View's span is calculated accordingly. Only when View isupdated when "graphicsConfiguration" is fired, then Tooltip GC is updated and preferredSpan is calculated correctly.
>>>
>>> It's to be remembered that the issue happens only when html text is shown in ToolTip. If normal text is shown , there is no issue. I guess if it's a question of wrong GC during popup reset/pack, then it will cause problem during normal text rendering also, no?
>>
>> If GC of the tip is null before showing then can we use default screen GC by default? Same as in the java.awt.Window.initGC().
> 
> I tried but SwingUtilities.windowForComponent(tip) returns null so there is no "Window" parent associated with tooltip so initGC() cannot be called on tip, as I see.
> 
> Also, tip GC is null for normal text too, where it works. Only difference between normal and html text is in calculation of getPreferredSize/MaximumSize/MinimumSize where the size is updated based on updated span calculation, so I have used updated preferredSize in my fix.

The normal text may work because the text and font metrics produce the "correct" size which is not changed on the scaled screen, while the HTML produce different size depending on the font metrics. Note that you should not call Window.initGC() but use the similar logic somewhere in the code which initialize/show tip.


-- 
Best regards, Sergey.