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Re: Drawing problem

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  To: comp.lang.java.gui
Knute Johnson wrote:
>> So: Are there any guarantees that the EDT paint operation draws a 
>> BufferedImage that is in a state as it was before any Graphics 
>> (created via the BufferedImage) method was started that has not yet 
>> finished?
> 
> If you don't call repaint() until you are done drawing on it I doubt it. 

The underlying system might cause a repaint, too.

>  If you queued a repaint() from another thread while you were in the 
> process of doing a draw I don't think you could guarantee where in the 
> draw you would be.  If multiple threads kept multiple copies of the same 
> BufferedImage object then I think you could have a situation where you 
> draw on your copy and the other thread doesn't see it yet.  I'm not 
> really clear on when that can happen but synchronizing the code will 
> certainly prevent that.  In reality I don't think it will ever be a 
> problem.

I used the EDT to serialize subsequent calls to Graphics-methods to 
prevent synchronizing. This way it's guaranteed that there's no drawXXX 
method running while paintComponent draws the image.

But you're right. I can't imagine a situation in which it would be a 
real problem if the Graphics-method was called from a non EDT-thread.

Thanks for clarifying this topic.

Bye
Michael

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Drawing problem "Robert Sturzenegger" <robert.sturzenegger@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
  Re: Drawing problem "Andrew Thompson" <andrew.thompson@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
    Re: Drawing problem "Robert Sturzenegger" <robert.sturzenegger@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
  Re: Drawing problem "Michael Rauscher" <michael.rauscher@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
    Re: Drawing problem "Robert Sturzenegger" <robert.sturzenegger@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
      Re: Drawing problem "Michael Rauscher" <michael.rauscher@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
        Re: Drawing problem "Knute Johnson" <knute.johnson@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
          Re: Drawing problem "Michael Rauscher" <michael.rauscher@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
            Re: Drawing problem "Knute Johnson" <knute.johnson@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
              Re: Drawing problem "Michael Rauscher" <michael.rauscher@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
                Re: Drawing problem "Knute Johnson" <knute.johnson@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
                Re: Drawing problem "Michael Rauscher" <michael.rauscher@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000
        Re: Drawing problem "Robert Sturzenegger" <robert.sturzenegger@THRWHITE.remove-dii-this> - 2011-04-27 15:31 +0000

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