Comments on: Creating a Custom Control with NSView http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/ Developing Interfaces with Cocoa Fri, 05 Sep 2008 19:45:25 +0000 http://wordpress.org/?v=2.5 By: Cathy http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-190 Cathy Thu, 22 May 2008 15:37:45 +0000 http://katidev.com/blog/?p=67#comment-190 Hi J, Yeah, there are several usability problem with this control... Your suggestion is really good and I'll give it a try when I get around to updating this project. Thanks :) Hi J,

Yeah, there are several usability problem with this control…

Your suggestion is really good and I’ll give it a try when I get around to updating this project.

Thanks :)

]]> By: J Nozzi http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-189 J Nozzi Thu, 22 May 2008 14:50:13 +0000 http://katidev.com/blog/?p=67#comment-189 Cathy, this is a great post and I know I'm late to the party, but I think from a usability standpoint, your control is missing something. In the context of the CITwirlDistortion, perhaps it would be good to draw a straight grid within the perimeter of the circle, then distort *it* with CITwirlDistortion depending on the control's setting. This way, there's a distinct visual representation of the effect in real time. Intense distortion is immediately distinguished from mild as opposed to relying on the orientation of the drag handle (which gives no cue as to what's "minimum" or "maximum"). Cathy, this is a great post and I know I’m late to the party, but I think from a usability standpoint, your control is missing something. In the context of the CITwirlDistortion, perhaps it would be good to draw a straight grid within the perimeter of the circle, then distort *it* with CITwirlDistortion depending on the control’s setting.

This way, there’s a distinct visual representation of the effect in real time. Intense distortion is immediately distinguished from mild as opposed to relying on the orientation of the drag handle (which gives no cue as to what’s “minimum” or “maximum”).

]]> By: L Raney http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-180 L Raney Sat, 26 Apr 2008 04:28:21 +0000 http://katidev.com/blog/?p=67#comment-180 Great stuff. There just isn't enough of it out there for new Mac dev people... which is growing. I have a question, sorry-- I have a multi doc app. When I create new window with custom view I get keyDown events. But if I bring into focus previous created window. keyDown goes to the old window. - yes I was a windows guy. Thanks lar Great stuff. There just isn’t enough of it out there for new Mac dev people… which is growing. I have a question, sorry– I have a multi doc app. When I create new window with custom view I get keyDown events. But if I bring into focus previous created window. keyDown goes to the old window. - yes I was a windows guy.

Thanks
lar

]]> By: Elliott Harris http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-125 Elliott Harris Sun, 30 Mar 2008 19:52:11 +0000 http://katidev.com/blog/?p=67#comment-125 Great stuff, I'm really looking forward to your articles concerning Core Animation - I'm a big proponent having done a lot of mixed content (Quartz, Cocoa, and OpenGL) in the past, and it makes it VASTLY easier, and doesn't seem to incur any major performance hit. Nice article. Keep it up. Great stuff, I’m really looking forward to your articles concerning Core Animation - I’m a big proponent having done a lot of mixed content (Quartz, Cocoa, and OpenGL) in the past, and it makes it VASTLY easier, and doesn’t seem to incur any major performance hit. Nice article. Keep it up.

]]> By: John C. Randolph http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-112 John C. Randolph Tue, 25 Mar 2008 09:37:23 +0000 http://katidev.com/blog/?p=67#comment-112 "It always seemed easier to subclass NSView to accomplish my goals, " That's probably because it is. ;-) -jcr “It always seemed easier to subclass NSView to accomplish my goals, ”

That’s probably because it is. ;-)

-jcr

]]> By: John C. Randolph http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-111 John C. Randolph Tue, 25 Mar 2008 09:36:14 +0000 http://katidev.com/blog/?p=67#comment-111 "A control is an interface element that allows users to manipulate data in an application." Well, I'd state it a bit more precisely than that: in Cocoa, a control is a view that accepts user input events, and has a target, an action, and usually a cell. Personally, I rarely derive new UI objects directly from NSControl, because it's one of those AppKit classes that has accumulated a *lot* of cruft over the years. If I'm writing a view that is similar to an existing control, I'll start there instead. One thing that really drives me up the wall about most NSControls w/r/t subclassing them, is that they have a bad habit of grabbing the whole event loop. Send [super mouseDown:], and it's game over. -jcr “A control is an interface element that allows users to manipulate data in an application.”

Well, I’d state it a bit more precisely than that: in Cocoa, a control is a view that accepts user input events, and has a target, an action, and usually a cell.

Personally, I rarely derive new UI objects directly from NSControl, because it’s one of those AppKit classes that has accumulated a *lot* of cruft over the years. If I’m writing a view that is similar to an existing control, I’ll start there instead.

One thing that really drives me up the wall about most NSControls w/r/t subclassing them, is that they have a bad habit of grabbing the whole event loop. Send [super mouseDown:], and it’s game over.

-jcr

]]> By: Cathy http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-92 Cathy Sun, 23 Mar 2008 20:54:46 +0000 http://katidev.com/blog/?p=67#comment-92 Yes, that's true. I see what you're saying. So you would just abandon the cell altogether and do all the same stuff I've done here with NSView. I'm going to try that out : ) Yes, that’s true. I see what you’re saying. So you would just abandon the cell altogether and do all the same stuff I’ve done here with NSView. I’m going to try that out : )

]]> By: Patrick http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-91 Patrick Sun, 23 Mar 2008 20:23:15 +0000 http://katidev.com/blog/?p=67#comment-91 Well, you could equally swap between NSControl and NSOpenGLView as superclass, as long as you don't depend on any of the API promised by NSControl. I think there is also no requirement to override any of the NSControl methods when subclassing (although the documentation doesn't clearly state that, I believe). Well, you could equally swap between NSControl and NSOpenGLView as superclass, as long as you don’t depend on any of the API promised by NSControl. I think there is also no requirement to override any of the NSControl methods when subclassing (although the documentation doesn’t clearly state that, I believe).

]]> By: Cathy http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-90 Cathy Sun, 23 Mar 2008 14:52:40 +0000 http://katidev.com/blog/?p=67#comment-90 Hi Patrick : ) It is true that NSControl provides many useful convieniences. But, I didn't choose NSControl because of the fact that it is an NSView subclass and will only draw with Quartz. As it is, I could change the example control's super class to NSOpenGLView, replace the Core Graphics drawing code with OpenGL drawing code and it should work the same (I havn't tested that). I want to leave the example control open to this possibility, even if I didn't take advantage of it in this project, it'll come in handy for an OpenGL example in the future. Hi Patrick : )

It is true that NSControl provides many useful convieniences. But, I didn’t choose NSControl because of the fact that it is an NSView subclass and will only draw with Quartz. As it is, I could change the example control’s super class to NSOpenGLView, replace the Core Graphics drawing code with OpenGL drawing code and it should work the same (I havn’t tested that). I want to leave the example control open to this possibility, even if I didn’t take advantage of it in this project, it’ll come in handy for an OpenGL example in the future.

]]> By: Patrick http://katidev.com/blog/2008/03/07/how-to-create-a-custom-control-with-nsview/#comment-89 Patrick Sun, 23 Mar 2008 14:26:22 +0000 http://katidev.com/blog/?p=67#comment-89 Hi Cathy, Since NSControl is itself a subclass of NSView I would prefer subclassing NSControl. Using an NSCell subclass with your control is optional;not even all of Apple's NSControls use cells, so why should we? Subclassing NSControl more clearly communicates the role/function of your class, not only to other coders but to the framework as well. For example, one advantage of subclassing NSControl is that it plays nicely with -[NSWindow setMovableByWindowBackground:]. When you make a window movable by its background, it stops passing drag events to NSViews, breaking your KDTwirlDistortionControl. NSControl subclasses, on the other hand, continue to receive these events. It took me quite a while to figure this out, but it does make sense when you think about it. If it looks like a control, and it works like a control, just subclass NSControl ;-) Great blog, looking forward to future installments! Hi Cathy,

Since NSControl is itself a subclass of NSView I would prefer subclassing NSControl. Using an NSCell subclass with your control is optional;not even all of Apple’s NSControls use cells, so why should we?

Subclassing NSControl more clearly communicates the role/function of your class, not only to other coders but to the framework as well. For example, one advantage of subclassing NSControl is that it plays nicely with -[NSWindow setMovableByWindowBackground:]. When you make a window movable by its background, it stops passing drag events to NSViews, breaking your KDTwirlDistortionControl. NSControl subclasses, on the other hand, continue to receive these events. It took me quite a while to figure this out, but it does make sense when you think about it.

If it looks like a control, and it works like a control, just subclass NSControl ;-)

Great blog, looking forward to future installments!

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