Ticker tape display
Ticker tape display
- Subject: Ticker tape display
- From: Scott Steinman <email@hidden>
- Date: Sat, 30 Jul 2011 22:23:36 -0500
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.
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).
2. Make the containing NSView's width three times the width of the screen (so the CALayer has enough room to be off the screen to the left and to the right)? That would be very expensive memory-wise, so I'm hesitant to do it.
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?
I hope I've made myself clear enough. All I'm asking for is advice for a starting point to use. I'll do the research and coding after that so I can learn Core Animation.
Thanks in advance for your help.
Scott
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