ID:113048
 
BYOND Version:482
Operating System:Windows XP Pro
Web Browser:Firefox 4.0.1
Applies to:Dream Seeker
Status: Unverified

Thus far we've been unable to verify or reproduce this bug. Or, it has been observed but it cannot be triggered with a reliable test case. You can help us out by editing your report or adding a comment with more information.
Descriptive Problem Summary:

When scrolling an output box that is in a transparent window or when restoring a transparent window after minimizing it, there are huge lag spikes.


Numbered Steps to Reproduce Problem:
1. create a project that includes a window with transparency.
2. Include an output box in the transparent window (the output box is also partially transparent)
3. scroll the output box (after enough text is available to scroll) OR minimize then restore the window.


Expected Results:
Scrolling of the output box is smooth and behaves as usual, window restores to previous size without delay.

Actual Results:

Huge CPU crippling lag spikes.

it always happens under these conditions.
I couldn't verify any lag spikes in a test project. A demo project will be required to investigate further.
http://dl.dropbox.com/u/25108410/Transparency%20test.zip

Here is a test world which simulates the effect, and after doing some testing myself it only happens when there is two windows. Also, there is no lag spike when the window is restored, however upon restoring the window you will need to switch to another window on your computer (like a web browser) and then switch back, for the dream seeker windows to re-appear.

scrolling the output box more than a few lines will still cause lag, though it may have to do with certain types of CPU. (Me: 3.6ghz Single Core SSE2)

This demo can also be used to test the temporary on-move feature I suggested, testwindow() will move the transparency window to match the main, so calling it with on-move would produce the results that most people wanted. (transparent chat boxes)
While watching the task manager closely, I was only able to experience a lag spike at one point--all other times, the window scrolled smoothly. I believe however that what I saw was an artifact of the system having trouble handling that display while another app (probably Firefox) temporarily demanded attention. After that it never recurred. After that, scrolling up and down rapidly, making selections, or anything else had no effect on application speed or DS's CPU usage in the task manager.
After doing some more testing it only seems to spike when you have highlighted text on the output and then you scroll past it. I've tried it with and without separate programs and it seems to lag consistently. sometimes even crashing.
Yep, you're right. When highlighted text leaves or enters the viewing rectangle, DS freezes. Without source I can't really play with this too easily to tell if translucency is the culprit, but I suspect ultimately this is a Windows display issue and not something we can address.