Looking for info on custom drawing of interface components (Cocoa) - objective-c

It seems like more and more OS X apps these days are doing all kinds of fancy drawing stuff for custom controls. Apps like Twitterific, Things, EventBox, Versions just to name a few....
So basically I'm looking for any information on how to get started doing this kind of thing. Not sure if it is just done by subclassing controls and using custom drawing or if it is something entirely different.
Any help is greatly appreciated. THanks!

It depends entirely on what you want to do.
The "Show Raw Properties" button in Versions for instance is an NSButton subclass, because basically what we needed is standard button behavior with our own look.  One way to subclass a button is to simply implement your own -drawRect:(NSRect)rect method in the NSButton subclass, but we decided to stick with the way NSButton is implemented in Cocoa, meaning most drawing is done by the button's cell, so the implementation looks like this:
In the NSButton subclass:
+ (Class) cellClass
{
return [OurButtonCell class];
}
- (void)drawRect:(NSRect)rect
{
// first get the cell to draw inside our bounds
// then draw a focus ring if that's appropriate
}
In the NSButtonCell subclass (OurButtonCell):
- (void)drawInteriorWithFrame: (NSRect) rect inView: (NSView *) controlView
{
// a bunch of drawing code
}
The Timeline view in Versions is actually a WebView, the page that you see in it uses javascript to collapse headers you click on.
The rule of thumb I use for where to start out with a custom control is:
To customize the look of a standard Cocoa control:
subclass the appropriate control (like e.g. NSButton and NSButtonCell)
stick as close as makes sense to the way the default control is implemented (e.g. in a buttoncell, start from the existing attributedTitle instance method to draw the button title, unless you always want to draw with the same attributes regardless of what's set up in IB or if you need to draw with different attributes based on state, such as with the trial expiration button in Versions' main window)
Creating an entirely new UI element:
subclass NSView and implement pretty much all mouse and key event handling (within the view, no need to redo "hitTest:") and drawing code yourself.
To present something that's complex, of arbitrary height, but isn't a table:
See if you can do it in HTML, CSS and JS and present it in a WebView.  The web is great at laying out text, so if you can offload that responsibility to your WebView, that can be a huge savings in pain in the neck.
Recommended reading on learning how to draw stuff in your own custom view's drawing methods: Cocoa Drawing Guide
Customizing the look of for instance an NSTableView is an entirely other cup of tea, thanks to the complexity of a tableview, that can happen all over the place.  You'll be implementing your own custom cells for some things you want to do in a table, but will have to change the way rows are highlighted in a subclass of the actual NSTableView object itself.  See for instance the source code for iTableView on Matt Gemmell's site for a clear example of where to draw what.
Finally, I think Abizer's suggestion to go check out the code of BWToolkit is a great idea.  It might be a bit overwhelming at first, but if you can read and understand that code you'll have no trouble implementing your own custom views and controls.

Have a look at some excellent example code: BWToolkit

Related

How to create custom NSStepper and NSTabView

I want re-draw these two controls, but I can not find the method to do that, anyone can give me idea to do that?
I have found some app has re-draw these controls, you can look the screenshot.
the first one is NSStepper, the second one is NSTabView,the NSTabViewItem is also be re-drawed.
You have to Subclass most of the GUI classes, if you need to customize.
For NSTabView, this is one of the class where you have to do a lot of thing yourself.
You have to draw yourself ( using beziers path )
Need to implement many methods of NSView & NSResponder for drawing and event handling.
Kindly check these links :
NSTabView with background color
http://www.positivespinmedia.com/dev/PSMTabBarControl.html
https://github.com/aaroncrespo/WILLTabView/

Handling mouse events on NSButton created in Interface Builder

I had a class project consisting in programming a swype-like. I had to do it in java, and you can have a look at it (with the code) here. For this summer, I'd like to port it in ObjC/Cocoa, and then improve it. I intend to use NSButtons for the keyboard keys, like the "Gradient Button" proposed by Interface Builder.
So, I looked about how to handle mouse events (I need mouse pressed, entered, exited, and released). For some objects, it looks like you have to use a delegate, but for NSButton, looks like the methods like -mouseDown and related are in the object itself.
My question is, how do I override the methods in interface builder objects ? I tried creating a subclass of NSButton, and setting my button's class to this subclass, but without results. Maybe trying to override the methods is not the right way to do it at all, I'm open to every suggestion, even if it is not event-handling related. And if it is relevant, I'm running OS X 10.6, with XCode 4.
Thanks for your time !
A lot will depend on why you need all of the various events. NSButton is a control, and as such works differently than a standard NSView.
If you mostly need to figure out when the button is pressed, you can do this by assigning an action in IB. This is done by creating a void method in your controller class of the form:
- (IBAction) myMouseAction:(id)sender
and then having it do what you need based on receiving the click. Then in IB, you can hook up this action to the button by control-clicking on the button and dragging to your controller class (likely the owner) and selecting your new method when prompted.
If you need fine-grained control, you should consider creating your own NSView subclass and handling the mouse actions yourself, as trying to override controls is a pretty complicated matter. OS X controls were architected for extreme performance, but they're a bit anachronistic now and generally not worth the work to create your own.
One other thing is that the mouseEntered:, mouseMoved: and mouseExited: events are for handling mouse movement with the mouse button up.
You are going to want to pay attention to: mouseDown:, mouseUp: and mouseDragged: in order to handle events while the mouse button is being held down.

Create custom buttons for Interface Builder

Does anyone know how to create custom buttons for Interface Builder? Like instead of have just a regular Round Rect Button, I want to have like a custom 3D button and some random image background for that button. How to do this?
You will either need to find a third-party class (ideally with an Interface Builder plug-in so you can see it live in the IB file) or subclass UIButton or NSButton/NSButtonCell for Mac and provide your own 3D rainbow unicorn drawing behavior. :-)
Interface Builder can only show you classes it knows about - you can't add behavior / modify existing drawing behavior there because that's the wrong tool for the job. You'll need to find someone else's or subclass your own in code then let IB know about it.
Update based on OP's comment
You can use -setImage:forState: to supply your custom image for the given states.
To do it in Interface Builder is prohibitively complicated (writing an Interface Builder plugin is a non-trivial task). However, you can subclass UIControl (which is just a UIView) and define your custom drawing in the subclass.
Then, in Interface Builder, change the class of the object you've subclassesed to your new class, and everything should work correctly.
Relevant reading:
How to override -drawrect in UIButton subclass?
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIControl_Class/Reference/Reference.html
http://www.cocoabuilder.com/archive/cocoa/284622-how-to-subclass-uibutton.html (If you really need to subclass UIButton instead)
It's probably easiest to use an image as the background for the button. For example you can use this tool to easily generate buttons with gradients, http://itunes.apple.com/us/app/uibutton-builder/id408204223?mt=8
If you want anything more fancy it's probably time to start Photoshop ;-)

Custom Views or Custom Cells

I have a question about creating custom views. I wanted to implement an interface where I want to have different objects configured in one place, each of them with it's own controls. Kind of like in automator, on the right side view where the workflow is shown with different actions. Are those NSView or NSCell subclasses ?
Any example will be appreciated !
Ken
Here's how you can tell an NSCell and an NSView apart:
NSCells are basically stamps. Given a certain value/object, the NSCell knows how to draw that on the screen how you want it. Like NSTextCells know how to draw NSString's on the screen how you want them. NSCells don't have state, don't remember anything, they're just a one-shot set of drawing instructions that get executed with a given value/object. The idea is to reuse NSCells as much as possible to make drawing things on the screen super simple.
NSViews are sort of logical containers for what goes on on your screen. They can technically do their own drawing, but quite a few of them use NSCells to do their drawing. For example, NSTextField uses an NSTextCell to draw it's text on the screen, it also contains the extra logic necessary to toggle between editing and not-editing by displaying the text box you can type in during editing and using the NSTextCell when you're not editing. NSViews are also part of the responder chain and can respond to mouse-clicks, keyboard events, and the sort.
You're probably going to end up with both, NSViews to hold all the controls you want to use to configure each object and NSCells to draw custom UI elements (like if you use non-standard controls).

Any "fundamentals-oriented" example of NSScroller out there?

I'm looking for some kind of a basic, straightforward example of how to work with a pair of NSScrollers in an NSScrollView with a custom NSView.
There are sporadic examples out there, largely consisting of contrived examples using programatically created interfaces, or based on the assumption that the developer is working with a typical ImageView or TextView. Even the Sketch example is based on an NSView that uses the Page Setup in the Print dialog for the bounds, and everything is managed by Cocoa. So there's no real discussion or examples anywhere of how make it all work using a custom Model (though that may be part of the problem, because what does one base the Model on?). Even Apple's own documentation is dodgy here.
Essentially, I have a sub-classed NSView enbedded in an NSScrollView (per the Scoll View Guide), that a user can click in the view to create, edit and delete objects, much like an illustration program. The Model is those objects that are just data wrappers that simply record their position for drawRect: to use. The height and width are based on custom values that are being translated into pixels as needed.
My problem is that all of the examples I have found are based on either a text editor, an image viewer, or uses the standard document sizes in the Page Setup dialog. Because these are common document types, Cocoa basically manages for the developer, so the interaction code is more or less hidden (or I'm just not seeing it for what it is). My project doesn't fit any of those needs, and I have no need for printing. Thrusting my Model into the documentView property wouldn't work.
I'm just looking for a simple example on how to initialize the NSScrollers with a custom, object-oriented Model (the documentView), and handle scrolling and updating based on user action, such as when the user drags a smattering of objects off to the left or down or the window gets resized. I think I'm close to getting it all together, but I'm missing the jumping off point that ties the controls to document.
(Not that it matters in a Cocoa question, but when I did this in REALbasic, I would simply calculate and apply the MaxX, MaxY to a ScrollBar's Maximum value based on user actions, watch the position in the ScrollBar when the user clicks, and draw as needed. NSScrollers in the NSScrollView context aren't nearly as obvious to me, it seems.)
I appreciate the time taken by everyone, but I'm updating with more information in the hopes of getting an answer I can use. I'm sorry, but none of this is making sense, Apple's documents are obtuse, but perhaps I'm missing something painfully obvious here...
I have an array of objects sitting in a subclassed NSDocument which are data holders that tell drawRect what and where to draw. This is straight from the Sketch example. The Sketch example uses the document sizes in the Page Setup dialog for the size, so there's nothing to show here. I'm cool with Cocoa handling the state of the scroll bars, but how do I link up the ScrollView to see the initial editor's state held in the NSDocument and updates to those objects and the editor? Do I calculate my own NSRect and pass that to the NSScrollView? Where and how? Am I doing this in my custom NSView which has been embedded in the NSScrollView or my NSDocument in init? The NSScrollView isn't created programmatically (there's no easy way of doing that), so it's all sitting in Interface Builder waiting to be hooked up. I'm missing the hook up bit.
Perhaps I'm wearing my "I don't get it" cap this week, but this can't be this difficult. Illustration apps, MIDI Editors, and countless other similar custom apps do this all the time.
SOLVED (mostly):
I think I have this sorted out now, though it's probably not the best implementation.
My document class now has a NSRect DocumentRect property that looks at all of its objects and gives back a new NSRect based on their location. I call it in my subclassed NSView's mouse events with
[self setFrame:[[self EditorDocument] DocumentRect]];
This updates the size of the View based on user interaction, and the window now handles the scrolling where it didn't before. At this point I'm figuring out how to get the frame to expand while dragging, but at least I now have the fundamental concept I was missing.
The answer given pointed me in the direction I needed to go here (documentView requiring a view, which translated to looking at the NSView class), so Peter gets the credit. Thanks so much for help.
The document view isn't a model, it's a view. That's why it's called the document view.
The reason there are so few examples on working with NSScrollers directly is because you normally don't. You work with NSScrollView and let it handle the scrollers for you.
All you need to do is make a view big enough to show the entire model, then set that as the document view of the scroll view. From there, it should Just Work. You don't need to manage any of the scrolling-related numbers yourself; Cocoa handles them for you.
For details, see the Scroll View Programming Guide.