CALayer drawing transition effect?
I am subclassing CALayer, and overriding -drawInContext: to perform my drawing. I'm noticing that whenever my -drawInContext gets called (in response to calling -setNeedsDisplay) that there appears to be an actual animated fade-out / fade-in of of the old content and the new content. I do not see this transition effect documented anywhere, so I'm wondering if I'm doing something wrong. Or, if this is the correct behavior, how do I turn it off? It's really quite an eye-catching effect, but it's not desirable in this particular case; I need the layer content to show up immediately. I've got several instances of my CALayer subclass as sublayers of an NSView with -setWantsLayer:YES. The reason I subclass CALayer is merely as a convenience. I pass off drawing to a C++ object, and rather than create an objective C proxy which delegates drawing from a CALayer which it owns, I collapsed it into a subclass. But if this is the culprit, I'll go ahead w/ the proxy object. Thanks in advance, Joe K. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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]
Re: CALayer drawing transition effect?
On 31 Jul '08, at 10:24 AM, Joseph Kelly wrote: I'm noticing that whenever my -drawInContext gets called (in response to calling -setNeedsDisplay) that there appears to be an actual animated fade-out / fade-in of of the old content and the new content. I do not see this transition effect documented anywhere, so I'm wondering if I'm doing something wrong. Or, if this is the correct behavior, how do I turn it off? The content of a layer is an animatable property, so by default, changing the content will do a crossfade. It seems that applies to custom content (drawn by -drawInContext:) as well as the content property. There are a couple ways to suppress animations. You can use the CAContext API to disable all animations while you make your changes, or you can use the layer's actions dictionary to override the animation for the content transition. —Jens___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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]
Re: CALayer drawing transition effect?
On Jul 31, 2008, at 11:07 AM, Jens Alfke wrote:
The content of a layer is an animatable property, so by default,
changing the content will do a crossfade. It seems that applies to
custom content (drawn by -drawInContext:) as well as the content
property.
There are a couple ways to suppress animations. You can use the
CAContext API to disable all animations while you make your changes,
or you can use the layer's actions dictionary to override the
animation for the content transition.
Thanks!
I tried the following which seems to work. I'm not sure if it's the
approved way or not:
- (idCAAction)actionForKey:(NSString *)event
{
if ([event isEqualToString:@contents])
return nil;
return [super actionForKey:event];
}
(there was some mention of returning [NSNull null] to terminate
further searching, but it just crashed when I did that)
Joe K.
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