How can I make my NSScroller subclass have a different width?

Question

I am trying to create a custom subclass of NSScroller. I have created the class, and set it as the vertical scroller on an NSScrollView in IB. When I run my project, the drawRect: method is called for my subclass, so I know that it is properly connected.

Now, How do I change the width of my fancy new NSScroller? No matter what I do to its bounds and frame, it always wants to draw in a rectangle 15 pixels wide (the size of the default NSScroller).

Answer 1

In your NSScroller subclass, you have to override scrollerWidth:

+(CGFloat)scrollerWidth
{
    return 30.0;
}

This is the value that NSScrollView uses to define the frame for your component when it sets it up.

Answer 2

You can use categories to override the scroller width method for all NSScrollers.

Eg. In NSScroller-MyScroller.h:

#import <Cocoa/Cocoa.h>

@interface NSScroller (MyScroller)

+ (CGFloat)scrollerWidth;
+ (CGFloat)scrollerWidthForControlSize: (NSControlSize)controlSize;

@end

In NSScroller-MyScroller.m:

#import "NSScroller-MyScroller.h"
#define SCROLLER_WIDTH 30.0

@implementation NSScroller (MyScroller)

+ (CGFloat)scrollerWidth {
    return SCROLLER_WIDTH;
}

+ (CGFloat)scrollerWidthForControlSize: (NSControlSize)controlSize {
    return SCROLLER_WIDTH;
}

@end