On Sun, Oct 19, 2008 at 9:06 PM, Ian was here <[EMAIL PROTECTED]> wrote: > I have a drawing application that uses a pen tool to do free style drawing. I > am using Quartz in OS X 10.4 (NSBezierPath). The initial problem I had was > not getting enough points between event cycles if the user moved the mouse > too quickly. I turned off mouse coalescing with a call to > SetMouseCoalescingEnabled( false, NULL ). This gave me beautiful drawing. > Only problem is that it's slow and takes a while to catch up after the mouse > up event. > > This is kind of an off the wall question, but is there another way to do > this? I feel my only other option may be to use OPenGL, where the drawing > would happen much faster.
As you hint, the problem is not mouse coalescing but performance. OpenGL won't help with this, because your drawing performance is going to be tied to the refresh rate of your monitor anyway. So how do you fix it? Make your event handler run faster. But how can you do that if you can't make drawing go faster? Easy: decouple mouse event handling from drawing. You'll want to disable coalescing as you have done. But then in the event handler, you do *not* want to redraw every time you get a mouse moved event. Doing so guarantees that once the rate of mouse-moved events exceeds your monitor's refresh rate (or your ability to draw, if it happens to be worse) then lag will develop. Instead, do what I'd call "display coalescing". Don't redraw with every event. Instead, have a drawing flag. When you get a mouse event and the flag isn't set, set it and then post a custom event to the event queue. Then when you receive that custom event, redraw. This will essentially coalesce all the mouse moved events that were received while drawing so that you stay up to date with them. You will have to ensure that the non-drawing parts of your code always run faster than mouse events come in, but that should be trivial if you're just adding points to some sort of data structure. Mike _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
