Re: ImageListener

Posted by Michael Schmid on Feb 28, 2014; 5:08pm
URL: http://imagej.273.s1.nabble.com/ImageListener-tp5006715p5006720.html

Hi Philippe,

it seems to me that there must be an event that sets your variable 'iwantToStopmyProgram'.
In the code that sets 'iwantToStopmyProgram', instead of setting the variable, you could also interrupt a thread, notify a waiting thread, etc.

So I think you don't need a timeout.

But it is still unclear to me what exactly you want to do.

Is it previewing the result of processing?
ImageJ has all the infrastructure for previewing if you have an ExtendedPlugInFilter with a GenericDialog; you need not care about anything except for checking from time to time whether the processing thread was interrupted (simply abort processing in that case).

Michael
________________________________________________________________
On Feb 28, 2014, at 17:53, Philippe GENDRE wrote:

> Dear Michael,
>
> Thank you for your very didactic and efficient answer.
>
> According to do exactly what I want : to stop the program at any time by
> user interaction (when the image is updated or not) and to avoid image
> processing on not updated image after each timeout, I adapted the code like
> this :
>
> img.addImageListener(this);
> waitingThread = Thread.currentThread();
>
> do {
>
>                doUpdate=false;
>                synchronized(this){
>                    while (doUpdate==false){
>                        try {
>                            wait(1000);
>                            if (iwantToStopmyProgram==true) break;
>                        }
>                        catch(InterruptedException e) {
>                            continue;
>                        }
>                    }
>                }
>
> //image processing on updated image
>
> }while (iwantToStopmyProgram==false)
>
> public synchronized void imageUpdated(ImagePlus img) {
>        if (img == this.img && waitingThread != null){
>            waitingThread.interrupt();
>            doUpdate=true;
>        }
> }
>
> Best regards,
>
> Philippe
>
>
>
> 2014-02-28 15:35 GMT+01:00 Michael Schmid <[hidden email]>:
>
>>> I would like to exit from a synchronized  while (image not updated)
>>> wait() (until the image is updated) loop when the image is not updated.
>>
>> Hi Philippe,
>>
>> it seems that you need some timeout, otherwise you can't know whether an
>> update is still to come.  Maybe roughly like this:
>>
>> //class variables ('global')
>>    ImagePlus theImageIamWaitingFor;
>>    Thread waitingThread;
>>
>>    public void imageUpdated(ImagePlus imp) {
>>        if (imp == theImageIamWaitingFor && waitingThread != null)
>>            waitingThread.interrupt();
>>    }
>>
>> //main processing code
>>    ...
>>    waitingThread = Thread.currentThread();
>>    theImageIamWaitingFor = ...
>>    while (true) {   //might be also while (!closed) etc.
>>        //do some analysis on updated image
>>        synchronized(this) {
>>            //wait for image update, but no longer than 1000 millesec:
>>            try {
>>                wait(1000);
>>            } catch (InterruptedException e) {
>>                continue; //loop again after update
>>            }
>>            break; //timeout, leave the while loop
>>        }
>>    }
>>
>> Michael
>> ________________________________________________________________
>> On Feb 28, 2014, at 14:05, Philippe GENDRE wrote:
>>
>>> Dear List,
>>>
>>> I would like to exit from a synchronized  while (image not updated)
>> wait()
>>> (until the image is updated) loop when the image is not updated.
>>>
>>> Is it possible and how to ?
>>>
>>> Thanks.
>>>
>>> Philippe
>>>
>>> --
>>> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>>
>> --
>> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>>
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html

--
ImageJ mailing list: http://imagej.nih.gov/ij/list.html