Comments on: Marching Ants With Core Animation

By: andrewzboard

andrewzboard — Sat, 03 Apr 2010 00:43:50 +0000

Ha! That’s a presumption.. but in this case correct.

By: Matt Long

Matt Long — Sat, 03 Apr 2010 00:33:02 +0000

@andrewzboard

At least you're not taking your laptop. ;-) Hope you enjoy the book.

-Matt

By: andrewzboard

andrewzboard — Sat, 03 Apr 2010 00:27:47 +0000

Just got the book. Nice work, dude! I am going camping this weekend and (nerd that I am) I am taking the book. :)

By: Matt Long

Matt Long — Tue, 30 Mar 2010 20:15:17 +0000

@andrewzboard

I'm actually not sure why the would be. I would think you would need to specify it explicitly. I'm wondering if there has been an update to the way CA layer bounds work in more recent versions as I don't recall anything in the docs when I was researching writing the CA book. Will poke around when I have a few minutes and see if I can figure it out.

-Matt

By: andrewzboard

andrewzboard — Tue, 30 Mar 2010 19:34:11 +0000

Matt, I have a question now. I am loving this retro look of having marching ants walk around newly-created objects in my app... but what I find is that in order for the ants' path to align perfectly with the new object (a button in this case), the code has to read as follows:

[shapeLayer setBounds:CGRectMake(0, 0, 0, 0)];

Somehow this wasn't intuitive; I had previously set the bounds to be the same as those of the button, or the content view, or this and that. Of course, none of those worked. Why the empty or null bounds?

By: andrewzboard

andrewzboard — Mon, 29 Mar 2010 17:53:01 +0000

Ah, my ants are marching now! This is going to be fun to play with. Many thanks. My eyes have been enlightened by this.

By: andrewzboard

andrewzboard — Sun, 28 Mar 2010 16:06:35 +0000

BTW, I ordered a copy of your book. On Amazon, it also suggested “You might also like…” and listed my own book! (Obj-C Pocket Ref.) Ah, little pleasures…

By: andrewzboard

andrewzboard — Sun, 28 Mar 2010 00:21:00 +0000

Thanks, setWantsLayer is at the least necessary if not sufficient. I’ll look more closely at his implementation.

By: Matt Long

Matt Long — Sat, 27 Mar 2010 22:26:30 +0000

@andrewzboard I'm not sure exactly what issues you are having without seeing code, but I can tell you on the desktop if you want to work with layers, you have to make sure your view is layer backed by calling [view setWantsLayer:YES] on it. Look at the earlier comment by John Wight and what he's linked to. The video he has shows this working on an OS X app.

-Matt

By: andrewzboard

andrewzboard — Sat, 27 Mar 2010 22:07:33 +0000

I tried reimplementing this as a desktop (i.e. non-Touch) app, and am not quite there. I made the obvious changes, some of which I'll note here. But a pointer to any gotchas I have missed will be welcome.

viewDidLoad -> awakeFromNib UIWindow -> NSWindow [[UIColor clearColor] CGColor] -> CGColorGetConstantColor(kCGColorClear)

I instantiated a controller, but did it in the MainMenu.xib file rather than creating a new .xib file, hope that's OK. Wasn't sure how to rewrite the code in applicationDidFinishLaunching to be appropriate to AppKit. Suggestions?

By: schwa

schwa — Wed, 21 Oct 2009 13:23:36 +0000

You can see the same effect here:

http://www.flickr.com/photos/jwight/3826876252/

And the code for it (from my MOOF project) is online here:

http://bitbucket.org/schwa/moof/src/tip/Source/CGameView/CGameMapView.m (grep for highlightLayerForLayer:)