Hi
I have a canvas called Host with many UIComponents as children, sometimes up to 1000 or 3000 items. This is fine for now, as they are not interactive.
But, I have added a 'marker line' (a 1 pixel wide UI Component with a colored background) to the canvas which follows the mouse movement. When this UIComponent is added to the Host canvas and moves, everything slow down to a crawl i.e. takes ages for the UIComponent to move.
What do you think could be causing this? or how to avoid?
Every time you move the mouse, you are probably causing the measure and updateDisplayList methods of every one of those UIComponents to be called. So you may be causing those thousands of components to renegotiate their positions and dimensions with their neighbors.
Without seeing your code I can't get too specific in recommending a solution, but you might try placing a Canvas with a transparent background over the canvas that houses the thousands of components, matching its dimensions and location, and use that to move the marker line.
I assume of your 1000 items, only a small portion are on the screen at one time?
If you have that many components, a slow down is expected. I suggest looking into using a ListBased Class. Therefore only the items on screen are renderered and you will not have a lot of components hanging out in memory.