Re: Mouse Coalescing
Re: Mouse Coalescing
- Subject: Re: Mouse Coalescing
- From: Graham Cox <email@hidden>
- Date: Mon, 20 Oct 2008 12:17:23 +1100
On 20 Oct 2008, at 12:06 pm, Ian was here wrote:
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.
I suspect the problem isn't the number of mouse events, but the number
of points on the path this leads to. A path with more than a thousand
or so points will become slow to draw.
Instead of using many points with straight line segments, how about
using fewer points but calculating where the bezier control points
should be and use curve segments? It will still be smooth but have
much fewer "waypoints" and thus draw a lot faster.
Control points can be placed by using the fact that the line between
the control point and the end (or start) point of the curve is the
tangent to the curve, and this can be found by detecting the direction
the mouse was travelling in. You can obtain this from the deltaX and
deltaY parameters of the mouse event.
hth,
Graham
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