[svn:bz-trunk] 21048: moving the locking of MessageService. subscribeLock one level up in the for loop.

Question

Revision: 21048
Revision: 21048
Author:   [email protected]
Date:     2011-04-08 06:47:21 -0700 (Fri, 08 Apr 2011)
Log Message:
moving the locking of MessageService.subscribeLock one level up in the for loop.
in case of multiple subscribers, we only lock once
checkintests pass
Modified Paths:
    blazeds/trunk/modules/core/src/flex/messaging/services/MessageService.java

Answer 1

I have finally been able to replicate the behavior that you are seeing on another computer once the image was large enough.  Here are a few notes about this behavior:
First. The UI only slows down when the images are large, 16 bit images.  The reason why this is unique to 16 bit images is that they can only be displayed on the front panel as 8 bit images.  The workaround that Weiyuan suggested to change the 16 bit display mapping hints towards the root of the problem...that any time a mouse runs over the indicator, Windows asks the entire image to re-draw (having a separate indicator overlapping the image will create the same behavior).  With a 16 bit image, not only does the image have to re-draw on the screen but the 16 bit pixels need to be mapped to 8 bits.  When setting the 16 bit display mapping to Full Dynamic, this requires mor computation/pixel than 90% dynamic or one of the other mapping schemes.
This is expected behavior if your program is running and you're trying to display a large 16 bit image.  To fix this behavior there are a couple options:
Change the 16 bit display mapping to something other than full dynamic.  You can choose which 8 bits to display or if you want to map the bits. 
Resize the image just for viewing purposes on your front panel (since you aren't going to view every single pixel of you image on the screen). You can use the IMAQ Resample.vi to do this.  This will allow you to take your 1500x1500 pixel image and only display a 500x500 pixel version.
If you are interested in viewing small details of the large image, consider just displaying a smaller region of interest at a time.
Let me know if any of these solutions work for you.  Good luck on your application.
Zach C.
Field Engineer
Greater Los Angeles