Re: NSRegion
Re: NSRegion
- Subject: Re: NSRegion
- From: Timothy Carl Buchheim <email@hidden>
- Date: Tue, 23 Mar 2004 11:25:12 -0800
On Mar 23, 2004, at 1:03 AM, Allan Odgaard wrote:
On 23. Mar 2004, at 8:49, Tom Bernard wrote:
What is the status of NSRegion?
Pure speculation, but Panther did introduce the optimized refresh
discussed in the posts you linked to, so most likely they have done so
by creating the NSRegion class.
They also did add a few methods to work with rectangle lists, although
nothing fancy like AND, OR, and XOR of regions. In my experience such
stuff is mostly needed by the implementation of the window/view/layer
system and not really useful in application code, so the NSRegion
class will probably remain private.
From a class-dump of NSRegion it looks like you might be right .. the
methods they implemented look to be exactly the sorts of things which
you'd expect to see for window management. (try "class-dump -C
NSRegion /System/Library/Frameworks/AppKit.framework/AppKit" if you
want to take a look)
On the other hand, it appears to be a wrapper around CGRegion (also
undocumented) which, based on the symbols defined in CoreGraphics,
appears to have a full set of region manipulation functions. Hopefully
this will be made public in future releases, along with an enhanced
NSRegion.
(If you're curious about CoreGraphics regions, try running "strings
/System/Library/Frameworks/ApplicationServices.framework/Frameworks/
CoreGraphics.framework/CoreGraphics|grep -i region")
Interestingly I needed such functions myself not long ago, and did
exhaustive searching on the net before writing my own, and did not
find any source at all which implemented it -- maybe I was just bad at
searching, or my thesis holds that this is really a rare requirement
;)
Regions can be useful when you want to implement pixel-accurate hit
testing. (For example, if your application has icons which can be
selected like the Finder, or if you have irregularly shaped controls
such as the Mac OS 9 tab control.) On the other hand, they are
resolution dependent (after all, they're really just a form of
compressed bitmap) and are thus not appropriate for high quality
drawing. Apple may avoid making them available because people might
start using them where they're not really appropriate.
I believe the QuickDraw region patent (US Patent 4,622,545) has
recently expired, so if anyone wants to write a Cocoa implementation it
would probably be legal.
--
Tim Buchheim System Administrator
Computer Science Department Phone: (909) 607-3485
Harvey Mudd College Fax: (909) 607-8364
1250 N Dartmouth Ave E-mail: email@hidden
Claremont, CA 91711
http://www.cs.hmc.edu/~tcb/
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| References: | |
| | >NSRegion (From: Tom Bernard <email@hidden>) |
| | >Re: NSRegion (From: Allan Odgaard <email@hidden>) |