I subclassed NSView in IB, calling it VisualizationView. I instantiated it and connected it to an outlet of my controller object.

In Xcode I created the following header:

/* VisualizationView */

#import <Cocoa/Cocoa.h>

@interface VisualizationView : NSView { float originalSizeAspectRatio, finalSizeAspectRatio; }

• (void)setOriginalSizeAspectRatio:(float)ratio;
• (void)setFinalSizeAspectRatio:(float)ratio;
• (void)showOriginalSizeAspectRatio;
• (void)showFinalSizeAspectRatio; @end

The relevant parts of my implementation reads as such:

#import “VisualizationView.h”

@implementation VisualizationView

• (id)initWithFrame:(NSRect)frameRect { if ((self = [super initWithFrame:frameRect]) != nil) { // Add initialization code here } return self; }

• (void)drawRect:(NSRect)rect { NSRect originalRect = NSMakeRect(20, 13, 50, (50 * originalSizeAspectRatio)); NSRect finalRect = NSMakeRect(20, 0, 50, (50 * finalSizeAspectRatio));

  NSDictionary *attribs = [[NSDictionary alloc] init]; NSString *originalString = [NSString stringWithString: @”aspect ratio of original”];

  NSLog(@”originalSizeAspectRatio = %f”, originalSizeAspectRatio);

// [[NSColor whiteColor] set]; // NSRectFill(rect); [[NSColor redColor] set]; NSRectFill(originalRect); [[NSColor colorWithDeviceRed: 0 green: 1 blue: 0 alpha: .8] set]; NSRectFill(finalRect); [originalString drawAtPoint: NSMakePoint(20, 0) withAttributes: attribs];

}

• (void)setOriginalSizeAspectRatio:(float)ratio { originalSizeAspectRatio = ratio; [self setNeedsDisplay: YES]; NSLog(@”original aspect ratio = %f”, originalSizeAspectRatio); }

Now… the NSLog() call in my -setOriginalSizeAspectRatio: method shows that originalSizeAspectRatio is getting set to the value of “ratio” when the method is invoked.

However, in my -drawRect function the NSLog() call shows originalSizeAspectRatio is 0.0

What am I doing wrong?

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Could it be that you are not actually calling setOriginalSIzeAspectRatio anywhere in drawRect: ? Or anywhere else? At least I don’t see where you’ve done it in the above code.

If so, this is not really an NSViewSubclassProblem AFAICS. initWithFrame might be a good place to initialize the aspect ratio variables.

Did you drag a custom view into your IB window and set the custom class of that object? It’s a little ambiguous the way you wrote it.

Also: What do the show…S**‘izeAspectRatio methods do?

Are you sure your invocation of drawRect: takes place after the call to setOriginalSizeAspectRatio:? Sometimes my logs have been screwed up, especially in a multi-threaded application (which I doubt you have, but it’s a possibility). Try triggering drawRect again by resizing the window or something, or use a BOOL as a flag to see which method is being called first. For the second idea, just set the variable to YES in setOriginalSizeAspectRatio:, then print it in drawRect: along with the aspect ratio (note: BOOLs are integers . Because you aren’t using it anywhere else, there is *almost no chance of the BOOL being corrupted, although your float might be (through some other call). –JediKnil*

Well, -drawRect is getting called when -setNeedsDisplay: is set in the - setOriginalSizeAspectRatio: method, after the float variable is getting set.

UPDATE: Fixed. I think that I didn’t make all of my connections properly in IB.