On 31/07/2011, at 1:23 PM, Scott Steinman wrote: > I have drawn text into a CALayer. I'd like to allow the user select the type > of animation effect displayed, such as fading the text in/out by changing the > CALayer's opacity.
Do you mean CATextLayer? It's already optimised for displaying text and is really easy to use. > One of the effects I'm trying to do is a ticker tape display where a line of > text is scrolled repeatedly from off-screen on the right side to off-screen > on the left side. What would be a good approach for this? > > 1. Use a CALayer whose width is that of its containing NSView, with its > position animated from off-screen on the right, across the screen, then > off-screen to the left? I can't find any documentation that would suggest > that a CALayer's starting position can be off-screen past the edges of its > containing NSView (with the contents of the CALayer clipped to the edges of > the NSView). This will work. You can simply set the position property to place it within the view. It's OK if it's "off the edge", it will be clipped to the view's frame. > 3. Use a CALayer that is scrolled by translating in 3D space, or would this > preclude using other animation effects, such as fading the text in and out by > changing transparency? This amounts to the same thing. You can either translate the layer's transform, or simply set its position property. All properties such as transparency are independent of each other. --Graham _______________________________________________ Cocoa-dev mailing list ([email protected]) 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]
