Floating pictures screensaver on Mac OS X

I'm just learning to use XCode and program in Objective-C (my plan is to write a an app we need for my business since I can't find one that does what I need). It's going well and as an exercise I've been playing with database apps and screensavers.

I'm trying to write a screensaver that all it does is to show 3 or 4 pictures randomly floating on the screen. Similar to the out of the box开发者_JAVA百科 pictures screensaver that comes with Mac OS X.

I've played with the code in http://cocoadevcentral.com/articles/000088.php and while very informative I still don't know how to add those 3 or 4 pictures and make them move.

Anyone out there can point me to sample code? Or a project that I can use as reference?

Again, this is just self learning.

Thank you!

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This will probably be your first port of call.

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My approach to this was to create a Quartz Composition using Quartz composer. I found this easier than figuring out how to draw and animate everything by hand.

You can display a quartz composition inside a ScreensaverView by using the QCView class. This setup worked well for me.