<Swing Dev> [10][JDK-8178430] JMenu in GridBagLayout flickers when label text shows "..." and is updated

Krishna Addepalli krishna.addepalli at oracle.com
Fri Nov 17 09:49:31 UTC 2017 

The problem is because the label text is too long to be shown in the current window size. Hence, the renderer asks for the minimum size for all the components.
The default minimum size for JMenu (which is from BasicMenuItemUI) is 1x1, which is what has been rendered as. The proposed fix is if the JMenu is a toplevel menu, then instead of returning the default minimum size, return the preferred size, so that the component can be rendered correctly at reasonable minimum size of the window.

-----Original Message-----
From: Sergey Bylokhov 
Sent: Friday, November 17, 2017 6:20 AM
To: Semyon Sadetsky <semyon.sadetsky at oracle.com>; Krishna Addepalli <krishna.addepalli at oracle.com>; swing-dev at openjdk.java.net
Subject: Re: <Swing Dev> [10][JDK-8178430] JMenu in GridBagLayout flickers when label text shows "..." and is updated

On 16/11/2017 09:17, Semyon Sadetsky wrote:
>> This will not be a bug, if the application thinks that 2x2 or 200x200 
>> are reasonable values for maximum/minimum/preferred sizes and will 
>> set it, then these values will be used.
> But according to the layout constraints there enough space for 
> preferred size. Why it shrinks to the minimum size?

Why minimum size cannot be used if the component reports this small size? Its the problem of the component if it reports the size which broke the appearance of the component.

>>
>>>>
>>>>>
>>>>> --Semyon
>>>>>
>>>>>
>>>>> On 11/15/2017 08:24 AM, Sergey Bylokhov wrote:
>>>>>> Looks fine.
>>>>>>
>>>>>> On 15/11/2017 07:26, Krishna Addepalli wrote:
>>>>>>> Hi Sergey,
>>>>>>>
>>>>>>> Per our conversation, I have added the volatile keyword to the 
>>>>>>> Boolean flag. Here is the updated webrev:
>>>>>>> http://cr.openjdk.java.net/~kaddepalli/8178430/webrev04/
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Krishna
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Krishna Addepalli
>>>>>>> Sent: Wednesday, November 15, 2017 6:07 PM
>>>>>>> To: Sergey Bylokhov <sergey.bylokhov at oracle.com>; 
>>>>>>> swing-dev at openjdk.java.net
>>>>>>> Subject: RE: <Swing Dev> [10][JDK-8178430] JMenu in 
>>>>>>> GridBagLayout flickers when label text shows "..." and is 
>>>>>>> updated
>>>>>>>
>>>>>>> Hi Sergey,
>>>>>>>
>>>>>>> I have modified the code as per your requests, and here is the 
>>>>>>> updated webrev:
>>>>>>> http://cr.openjdk.java.net/~kaddepalli/8178430/webrev03/
>>>>>>>
>>>>>>> However, I have a couple questions regarding the fix:
>>>>>>> 1. Why was it considered good to fix it in BasicMenuUI rather 
>>>>>>> than in BasicMenuUIItem?
>>>>>>> 2. While using Robot.waitForIdle(), I came across the function 
>>>>>>> "Suntoolkit.flushPendingEvents" function. But this is a private 
>>>>>>> function and applications cannot use this. Is it expected that 
>>>>>>> the applications should import the robot module to flush the 
>>>>>>> events, considering that mostly it is used for testing purposes?
>>>>>>> If this is the case, then "Suntoolkit.flushPendingEvents" 
>>>>>>> becomes a valuable tool, given that Swing rendering happens in 
>>>>>>> an EDT that is separate from MainThread.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Krishna
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Sergey Bylokhov
>>>>>>> Sent: Wednesday, November 15, 2017 2:23 AM
>>>>>>> To: Krishna Addepalli <krishna.addepalli at oracle.com>; 
>>>>>>> swing-dev at openjdk.java.net
>>>>>>> Subject: Re: <Swing Dev> [10][JDK-8178430] JMenu in 
>>>>>>> GridBagLayout flickers when label text shows "..." and is 
>>>>>>> updated
>>>>>>>
>>>>>>> Hi, Krishna.
>>>>>>> Small comments: I think that this code
>>>>>>> "(JMenu)menuItem).isTopLevelMenu() == true"
>>>>>>> can be simplified to
>>>>>>> (JMenu)menuItem).isTopLevelMenu().
>>>>>>>
>>>>>>> In the test you create and dispose JFrame and other components 
>>>>>>> outside of EDT thread. I suggest to use invokeAndWait() which 
>>>>>>> will work synchronously. Instead of sleep() you van use 
>>>>>>> Robot.waitForIdle();
>>>>>>>
>>>>>>>
>>>>>>> On 12/11/2017 22:45, Krishna Addepalli wrote:
>>>>>>>> Hi Sergey,
>>>>>>>>
>>>>>>>> Gentle reminder! Could you review the fix?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Krishna
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: Krishna Addepalli
>>>>>>>> Sent: Wednesday, November 8, 2017 8:22 PM
>>>>>>>> To: Sergey Bylokhov <sergey.bylokhov at oracle.com>; 
>>>>>>>> swing-dev at openjdk.java.net
>>>>>>>> Subject: RE: <Swing Dev> [10][JDK-8178430] JMenu in 
>>>>>>>> GridBagLayout flickers when label text shows "..." and is 
>>>>>>>> updated
>>>>>>>>
>>>>>>>> Hi Sergey,
>>>>>>>>
>>>>>>>> Are the changes fine now?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Krishna
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: Krishna Addepalli
>>>>>>>> Sent: Monday, November 6, 2017 9:02 PM
>>>>>>>> To: Sergey Bylokhov <sergey.bylokhov at oracle.com>; 
>>>>>>>> swing-dev at openjdk.java.net
>>>>>>>> Subject: RE: <Swing Dev> [10][JDK-8178430] JMenu in 
>>>>>>>> GridBagLayout flickers when label text shows "..." and is 
>>>>>>>> updated
>>>>>>>>
>>>>>>>> Hi Sergey,
>>>>>>>>
>>>>>>>> As per your recommendation I have done the following changes:
>>>>>>>> 1. Moved the fix to BasicMenuUI.
>>>>>>>> 2. Corrected the test to:
>>>>>>>>     a. Access the UI elements only in the EDT.
>>>>>>>>     b. Made sure that the main thread doesn't exit till the 
>>>>>>>> test is complete.
>>>>>>>>
>>>>>>>> Here is the updated webrev:
>>>>>>>> http://cr.openjdk.java.net/~kaddepalli/8178430/webrev02/
>>>>>>>>
>>>>>>>> However, I was wondering, why it is good to fix in BasicMenuUI? 
>>>>>>>> Also, while writing the testcase, I couldnot find any 
>>>>>>>> functionality like "flush" on the event queue, which will 
>>>>>>>> execute all the pending events. Is it by design?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Krishna
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: Sergey Bylokhov
>>>>>>>> Sent: Friday, November 3, 2017 11:24 PM
>>>>>>>> To: Krishna Addepalli <krishna.addepalli at oracle.com>; 
>>>>>>>> swing-dev at openjdk.java.net
>>>>>>>> Subject: Re: <Swing Dev> [10][JDK-8178430] JMenu in 
>>>>>>>> GridBagLayout flickets when label text shows "..." and is 
>>>>>>>> updated
>>>>>>>>
>>>>>>>> Hi, Krishna.
>>>>>>>> A few notes:
>>>>>>>>     - Looks like the bug can be reproduced in JMenu only? Then 
>>>>>>>> it will be good to fix it in BasicMenuUI, moreover it is 
>>>>>>>> already implemented a
>>>>>>>> getMaximumSize() in a similar way as in your fix.
>>>>>>>>     - In the test some of the Swing components are accessed on 
>>>>>>>> non-EDT thread. Also note that when you start the Thread you 
>>>>>>>> will exit
>>>>>>>> invokeAndWait() and it is possible that the test will end 
>>>>>>>> before the Thread complete(jtreg will kill the test when the 
>>>>>>>> main thread is
>>>>>>>> completed)
>>>>>>>>
>>>>>>>> On 31/10/2017 05:00, Krishna Addepalli wrote:
>>>>>>>>> Hi Sergey,
>>>>>>>>>
>>>>>>>>> Thanks for pointing that out. Fixed the test case and created 
>>>>>>>>> a new webrev here:
>>>>>>>>> http://cr.openjdk.java.net/~kaddepalli/8178430/webrev01/
>>>>>>>>>
>>>>>>>>> Now, the testcase throws an exception and also after a few 
>>>>>>>>> trials, closes on its own.
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Krishna
>>>>>>>>>
>>>>>>>>> -----Original Message-----
>>>>>>>>> From: Sergey Bylokhov
>>>>>>>>> Sent: Tuesday, October 31, 2017 1:13 AM
>>>>>>>>> To: Krishna Addepalli <krishna.addepalli at oracle.com>; 
>>>>>>>>> swing-dev at openjdk.java.net
>>>>>>>>> Subject: Re: <Swing Dev> [10][JDK-8178430] JMenu in 
>>>>>>>>> GridBagLayout flickets when label text shows "..." and is 
>>>>>>>>> updated
>>>>>>>>>
>>>>>>>>> Hi, Krishna.
>>>>>>>>> Can you please clarify in what situation the test will stop 
>>>>>>>>> working(it does not have any assertions)?
>>>>>>>>>
>>>>>>>>> On 27/10/2017 02:45, Krishna Addepalli wrote:
>>>>>>>>>> Hi All,
>>>>>>>>>>
>>>>>>>>>> Please review the fix for bug:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Bug: JDK-8178430: 
>>>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8178430
>>>>>>>>>>
>>>>>>>>>> Webrev: 
>>>>>>>>>> http://cr.openjdk.java.net/~kaddepalli/8178430/webrev00/
>>>>>>>>>>
>>>>>>>>>> Summary:
>>>>>>>>>>
>>>>>>>>>> The issue is when the label text width is more than the
>>>>>>>>>> container(JPanel) width, the container tries to render with 
>>>>>>>>>> minimum width for all the components. In such case, the 
>>>>>>>>>> JMenuItem, which is added to the JMenuBar also returns its 
>>>>>>>>>> height dimension as 1 (the default minimum). The test case 
>>>>>>>>>> alternates between the short text and long text on the label, 
>>>>>>>>>> and it gives a flickering effect of the Menu.
>>>>>>>>>> The fix is to return preferred size from JMenuItem, if its 
>>>>>>>>>> parent is a JMenuBar, since JMenuBar is added to the top 
>>>>>>>>>> level window.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>>
>>>>>>>>>> Krishna
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> -- 
>>>>>>>>> Best regards, Sergey.
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> -- 
>>>>>>>> Best regards, Sergey.
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -- 
>>>>>>> Best regards, Sergey.
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
> 


-- 
Best regards, Sergey.

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