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liuzhe02 / bigbluebutton

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Whiteboard redaws are very laggy #1883

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
What steps will reproduce the problem?
1. Upload 6 presentations with one of them being 30+ pages
2. Show your 30 page presentation
3. Draw some lines on the whiteboard (See WhiteboardDrawings.png)
4. Zoom in with your mouse

What is the expected output? What do you see instead?
The zoom should happen near instantaneously, but instead the client stutters 
and takes a while to update.

You can see the problem very clearly if you download the debug version of Flash 
Player (https://www.adobe.com/support/flashplayer/downloads.html) and use Vizzy 
Flash Tracer (https://code.google.com/p/flash-tracer/) to see the console logs. 
You can see what part of the log looks like after zooming in once here, 
http://pastebin.com/v4Gz0zeP.

There are optimizations that could be done to reduce the time it takes to 
redraw.

Original issue reported on code.google.com by capil...@gmail.com on 17 Feb 2015 at 8:28

Attachments:

GoogleCodeExporter commented 8 years ago 
I think it should be noted that the use of Flash Tracer/Flash Player (debug 
version) also significantly slows down the zoom due to the overhead incurred by 
logging all the trace statements, I assume.

When in the normal Flash player without looking to debug, zoom still happens 
almost instantaneously. At least from my end. Can we get a confirmation of this?

Original comment by ajgopi...@gmail.com on 20 Feb 2015 at 5:55

GoogleCodeExporter commented 8 years ago 
That's a really good point. I always run with the debug version of Flash and I 
didn't consider the differences. After switching to the basic version the lag 
is gone. It looks like it is all of the console.log calls causing the slowdowns.

Original comment by capil...@gmail.com on 20 Feb 2015 at 6:45

GoogleCodeExporter commented 8 years ago 
I think there's also a mxmlc option to remove debug trace for production builds.

Original comment by ritza...@gmail.com on 20 Feb 2015 at 6:51

GoogleCodeExporter commented 8 years ago 
Leaving the debug lines in for production builds is fine I think. The large 
majority of people won't be running the debug version of the player so they 
won't even see the slowdowns. Having access to the debug info has proven useful 
in the past when trying to look into a bug.

Original comment by capil...@gmail.com on 20 Feb 2015 at 7:02