<Swing Dev> [11] Review Request: 8201552 Ellipsis in "Classical" label in SwingSet2 demo with Windows L&F at Hidpi

Sergey Bylokhov Sergey.Bylokhov at oracle.com
Thu Jun 28 22:14:00 UTC 2018

On 28/06/2018 14:20, Phil Race wrote:
> 2336 var newGC = (GraphicsConfiguration) oldValue; 2337 var oldGC = 
> (GraphicsConfiguration) newValue; 2338 var newTx = newGC != null ? 
> newGC.getDefaultTransform() : null;
> 2339 var oldTx = oldGC != null ? oldGC.getDefaultTransform() : null;
> 2340 return !Objects.equals(newTx, oldTx); var ?? I suppose it I can 
> infer what the type of newTx and oldTx is because I know the API, but 
> for someone else this makes it less readable.

The type of "newGC/oldGC" is on the right where we apply the cast:
var newGC = (GraphicsConfiguration) oldValue;

The type of newTx/oldTx is not so important since we only check they are 
equivalent оr not. It will works even if the type will be Object instead 
of var.

> I suppose your comments 
> below are discussing the effect of line 2340 We generally consider a 
> null TX to mean identity and so consider them equal but this would do 
> the opposite .. and you say this is what Swing wants ? -phil.

In theory Swing wants to consider null as a identity TX, but in practice 
if we skip such validation we will expose other bugs like JDK-8206024. 
The change of "GC=null" to "GC=non-null" is occurred when the component 
id added to the parent and is used as a last chance to update the state 
of the component before show it to the user.

For example:
1 Jtree tree;
2 Dimension before = component.getPreferredSize();
3 tree.setFont(new Font());
.... some other initialization....
4 Dimension after = component.getPreferredSize();
5 frame.add(tree);

In line 3 the components should be revalidated because the font which 
affects the size was changed. But this validation can be skipped because 
of the some bugs. And it is not visible to the user just because we do 
validation at step 5(when the GC=null will be replaced by the 
GC=non-null). Before my fix it it was done using "ancestor" property(in 
some cases)

> On 6/28/2018 1:54 PM, Sergey Bylokhov wrote:
>> Hi, Phil.
>> The new webrev:
>> http://cr.openjdk.java.net/~serb/8201552/webrev.03/
>> I have checked why validation of the component is necessary, when the 
>> "ancestor" is changed (I removed it, but the new validation on GC 
>> change null->non-null is equivalent).
>> Such validation is used as a last chance to update the state of the 
>> component before show it to the user. In theory it is not necessary 
>> but some components skips validation on font change(like jtree) and 
>> maybe other properties. I have files a separate bug for that: 
>> https://bugs.openjdk.java.net/browse/JDK-8206024
>>  - In the fix I have moved these checks to SwingU2.
>>  - TODO block for JSpinner: is removed because this bug was fixed
>> https://bugs.openjdk.java.net/browse/JDK-8205144
>> On 22/06/2018 16:54, Philip Race wrote:
>>> It is not really the GC .. there is no GC .. but because of that the
>>> code uses a default FontRenderContext.
>>> I think Swing is conflating GC + FRC but given that, then the logic
>>> to recalculate based on graphicsconfiguration should be fine, although
>>> maybe you can check if we really need to trigger it ..
>>> if the screen we are shown on has no scale (ie uiScale == 1) then
>>> we may be triggering a pointless invalidation with consequent overhead.
>>> Can  you check if we can skip it in some cases ?
>>> -phil.
>>> On 6/22/18, 4:16 PM, Sergey Bylokhov wrote:
>>>> The place where the current graphicsConfiguration of the component 
>>>> is matter:
>>>>  - JComponent.getFontMetrics(Font)
>>>>  -- SwingUtilities2.getFontMetrics(this, font)
>>>>  --- SwingUtilities2.getFRCProperty(JComponent c)
>>>>     if (c != null) {
>>>>         GraphicsConfiguration gc = c.getGraphicsConfiguration();
>>>>         AffineTransform tx = (gc == null) ? null : 
>>>> gc.getDefaultTransform();
>>>>         Object aaHint = c.getClientProperty(KEY_TEXT_ANTIALIASING);
>>>>         return getFRCFromCache(tx, aaHint);
>>>>     }
>>>> When the bug is reproduced we calculated the size of the tree based 
>>>> on one GC and draw it using another GC. The first GC which is used 
>>>> for size calculation may be null or it maybe a non-null value 
>>>> pointed to another screen, for example if the jtree was shown on one 
>>>> screen and then dragged to another.
>>>> On 22/06/2018 14:40, Sergey Bylokhov wrote:
>>>>> In the SwingSet2 the bug is visible only if the user switches the 
>>>>> L&F immediately before switching to the tree demo. And is not 
>>>>> reproduced if the user switches to the tree demo and then change 
>>>>> the L&F.
>>>>>   - If the tree is not visible then it will calculate the size of 
>>>>> the text based on some default GC, and will not update this size 
>>>>> when it will be added to the frame(which has another actual GC). So 
>>>>> the tree will use the size calculated using one GC, and will draw 
>>>>> the text using another GC. If the user will switch L&F the size 
>>>>> will be recalculated using correct GraphicsConfiguration.
>>>>>> -phil.
>>>>>> On 06/22/2018 01:48 PM, Sergey Bylokhov wrote:
>>>>>>> Any volunteers for review?
>>>>>>> =)
>>>>>>> On 17/06/2018 15:37, Sergey Bylokhov wrote:
>>>>>>>> Unfortunately after additional testing I found a bug in our text 
>>>>>>>> related components. In the JTextPane the text looks broken if we 
>>>>>>>> request some change in the component after it is became visible.
>>>>>>>> For example if we change the font then the text will be 
>>>>>>>> overlapping. So if I will be applied this fix, which will force 
>>>>>>>> text component to relayout(because of the change in graphics 
>>>>>>>> config), then the text will be broken from the beginning.
>>>>>>>> But before the fix it will be broken only if the application 
>>>>>>>> will change the pane after it became visible(BTW text rendering 
>>>>>>>> during editing is broken in both cases).
>>>>>>>> So I temporary reverted the changes in the text related components:
>>>>>>>> http://cr.openjdk.java.net/~serb/8201552/webrev.02
>>>>>>>> Two follow bugs were created:
>>>>>>>>   - Text components: 
>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8205143
>>>>>>>>   - JSpinner: https://bugs.openjdk.java.net/browse/JDK-8205144
>>>>>>>> On 15/06/2018 23:31, Sergey Bylokhov wrote:
>>>>>>>>> Hello.
>>>>>>>>> Please review the fix for jdk11.
>>>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8201552
>>>>>>>>> Webrev: http://cr.openjdk.java.net/~serb/8201552/webrev.01/
>>>>>>>>> Short description:
>>>>>>>>> This fix enhance implementation of JDK-8178025[1] for most of 
>>>>>>>>> our Swing components. The main rule which I tried to follow:
>>>>>>>>> "If layout of the component depends from the font then it 
>>>>>>>>> should depend on the current graphics configuration as well, 
>>>>>>>>> because FontMetrics depends on graphics configuration".
>>>>>>>>> Long description:
>>>>>>>>> The fix for JDK-8178025 added a special property 
>>>>>>>>> "graphicsConfiguration" which: fired when the 
>>>>>>>>> graphicsConfiguration is changed from one non-null value to 
>>>>>>>>> another non-null value.
>>>>>>>>> Those fix also updated some of the components(to 
>>>>>>>>> refresh/re-validate its states when the "graphicsConfiguration" 
>>>>>>>>> or "ancestor" were changed).
>>>>>>>>> The usage of "ancestor" was not obvious, so I modify the code 
>>>>>>>>> to fire "graphicsConfiguration" every time, this cover a 
>>>>>>>>> situation when the "GC=null" is changed to 
>>>>>>>>> "GC=non-null"(previously it was covered by "ancestor" 
>>>>>>>>> property). So after this fix our components will listen only 
>>>>>>>>> "font" and "graphicsConfiguration".
>>>>>>>>> In implementation of JDK-8178025 the "graphicsConfiguration" is 
>>>>>>>>> fired immediately after GC is changed, it caused the issues in 
>>>>>>>>> some containers like JTree. When the container get such 
>>>>>>>>> notification it usually tries to get some information from 
>>>>>>>>> children, but in this moment children had previous graphic 
>>>>>>>>> config, so the result calculated(and usually cached) in the 
>>>>>>>>> container was wrong. In this fix I changed implementation of 
>>>>>>>>> this property. Now it will fired only when the container and 
>>>>>>>>> all its children are updated.
>>>>>>>>> ===
>>>>>>>>> Note that the new test StalePreferredSize.java has a TODO 
>>>>>>>>> block. Because JSpinner does not work properly even after the 
>>>>>>>>> current fix. The reason is that during validation it is 
>>>>>>>>> unexpectedly change the font from normal to bold(I'll fix this 
>>>>>>>>> in a separate bug)
>>>>>>>>> [1] https://bugs.openjdk.java.net/browse/JDK-8178025

Best regards, Sergey.

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