Re: XC & IB 3.2 overlapping siblings
Re: XC & IB 3.2 overlapping siblings
- Subject: Re: XC & IB 3.2 overlapping siblings
- From: Erik Buck <email@hidden>
- Date: Fri, 11 Sep 2009 09:44:46 -0400
Remember that all controls are views. Overlapping sibling controls
have a definite user interface smell.
Assuming that the overlapping controls are visible at the same time,
the appearance is likely to be unsatisfactory. Issues of mouse based
picking arise. Which control will be hit by which mouse click
particularly when controls have transparent rounded edges etc? If
nothing else, this will be a violation of the Aqua user interface
guidelines, and that might matter to some users.
Assuming that the overlapping controls are not visible at the same
time, the issues of user discoverability and disappearing user
interface elements mentioned earlier in this thread arise.
Regarding views in general:
Overlapping sibling views degrade direct frame buffer operations such
as the ones used by movie views and open gl views. That may or may
not be an issue. Overlapping sibling views degrade operations like
copy on scroll when a sibling of a clip view overlaps a scroll/clip
view. Overlapping sibling views that accept mouse input may have
issues with picking etc.
Regarding the specific example of controls that appear over a movie
view:
I suppose it is common enough behavior now that it won't surprise
users although I am still surprised every time the mouse is jiggled
(by the dog or the wind or a child or turbulence) while I am watching
a show (Glee) in iTunes and a translucent panel obscures my view of
the show (Cheerleaders).
Nevertheless, the solution from both a performance and user interface
perspective is to use an "overlay" view implemented with Cocoa's child
windows as demonstrated here: http://developer.apple.com/mac/library/samplecode/GLChildWindowDemo/
Modern Core Animation layers are also a good choice (that uses the
same technique) if your movie view is also a layer.
I don't think it ever makes sense for a movie view to have an
overlapping sibling view.
_______________________________________________
Cocoa-dev mailing list (email@hidden)
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:
This email sent to email@hidden