100% CPU utilization when SELECTION is a large area

[georgetasker]

Hi all,

First, kudos on a great product! I love it!

One problem I am seeing though, previously with v3.31, and also with 3.35 Beta. I have a 2GHz Pentium M single core processor, 2GB of memory, running on WinXP professional with SP3. I have a dual monitor configuration with both monitors running at 1280x1024.

If I take a screenshot using SHIFT-PRINTSCREEN, I get the contents of both monitors. If I then open Paint.NET and paste the image, I get a prompt asking what to do with the canvas, and I choose EXPAND. The image pastes in fine, and I get the rectangular rubberband selection area around my image (2560x1024 is the canvas size). Note that the image appears in Paint.NET at 50% size so that the entire image is visible.

At this point, the CPU goes to 99% utilization, and stays there. TaskManager shows that is Paint.NET using all the CPU. Even if I click over to a different app so that Paint.NET is running in the background, it keeps using 99%.

If I change to the selection tool, and click in the image to remove the full-size selection box around my image, CPU utilization drops back to normal. Pressing CTRL-A to select the entire image again results in CPU going back up some (about 27% being used by Paint.NET). This is much better in 3.35 than it was in 3.31 as far as the CTRL-A behavior. It used to go back to 99% on CTRL-A with a large image also.

Thanks

George

[Joey]

This is due to the crawling ants around the selection. You can slow down PDN to a crawl when doing Add Noise and then click somewhere in the image with the magic wand (many selection outlines). Minimizing PDN should solve it if you don't want to lose the selection (programs can't draw to a minimized window).

PDN isn't shy of using your CPU when no-one else will but this particular issue is a bit nagging, especially since the ant-drawing is done in the UI thread and thus menus, dialogs, &c. are unresponsive as well.