[artOf...]

Hi all,

the question might seem unclear or too simple at first, so I will elaborate.
In my application I have a window with certain background color, I have put a custom view in the upper area of the window. After that I wrote a class 'DrawBackground' subclassing NSView(in IB I specified the custom view's class to be 'DrawBackground'). This class simply overwrites the method '-drawRect' and places a background picture on the entire area of the custom view. On this custom view I place 10-15 NSImageViews with transparent background color. Everything worked just fine until I decided to attach a timer to one of the pictures and make it animate(I change 2-3 different images via the timer tick: method). This made the background area of the the animated picture, to inherit the background image of the custom view in smaller scale.
Here are some screen shots:

http://i26.tinypic.com/auazpy.jpg //no custom view, no background => no bug(Animation state1)
http://i28.tinypic.com/2u5ximr.jpg //no custom view, no background => no bug(Animation state2)
http://i31.tinypic.com/33fepsy.jpg // custom view with background => bug(Animation state1)
http://i31.tinypic.com/52gebb.jpg // custom view with background => bug(Animation state2)

I guess my question is how can I get rid of the inherited background and just show my blinking picture as it actually is(with transparent background color).
Any suggestions will be appreciated! Thank you.

Kind Regards

artOf...

[Chuckit]

What does it mean to attach a timer to a picture? It's hard to diagnose a bug without seeing the relevant code.

[artOf...]

Thank you for your answer. Here is the code for my DrawBackground class and beneath it is the code where I use an NSTimer to change the picture in my NSImageView:

Code:
#import <Cocoa/Cocoa.h>


@interface DrawBackgroundController : NSView {
	
}

@end

#import "DrawBackgroundController.h"


@implementation DrawBackgroundController

- (id)initWithFrame: (NSRect)frame 
{
    self = [super initWithFrame:frame];
    if (self) 
	{
    }
    return self;
}

- (void)drawRect: (NSRect)rect
{
	// Load the image.
    NSImage *anImage = [NSImage imageNamed:@"background.png"];
	
	// Find the point at which to draw it.
    NSPoint backgroundCenter;
    backgroundCenter.x = [self bounds].size.width / 2;
    backgroundCenter.y = [self bounds].size.height / 2;
    
    NSPoint drawPoint = backgroundCenter;
    drawPoint.x -= [anImage size].width / 2;
    drawPoint.y -= [anImage size].height / 2;
    
	// Draw it.
	[anImage drawInRect:rect fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
}

@end

//Both functions beneath are called from my main application controller
//this function is called when the image should start animating
- (void) setPicture
{
	int lb = [[leCamera camProp] lightBalance];
	if(lb > 6)
	{
                NSTimer* t1 = [NSTimer timerWithTimeInterval: 0.1 target: self selector: @selector(tick: ) userInfo: nil repeats: YES];
		[self setLBTimer:t1]; 
		[[NSRunLoop currentRunLoop] addTimer:lbTimer forMode:NSDefaultRunLoopMode]; 
		[lbTimer fire];
	}
	else if (lb < -6) 
	{
                NSTimer* t1 = [NSTimer timerWithTimeInterval: 0.1 target: self selector: @selector(tick: ) userInfo: nil repeats: YES];
		[self setLBTimer:t1]; 
		[[NSRunLoop currentRunLoop] addTimer:lbTimer forMode:NSDefaultRunLoopMode]; 
		[lbTimer fire];
	}
	else
	{
                //IBOutlet NSImageView* lightBalanceImage; connected via IB, NSMutableArray* pics = [[NSMutableArray alloc] initWithCapacity:13];
                // pics has most of the NSImage objects that I need for my animation
		[lightBalanceImage setImage: [pics objectAtIndex: (lb + 6)]]; 
	}
}

//this function is called when my timer is started
- (void) tick: (NSTimer*) input
{
	indexOutOfRange++;
	indexOutOfRange %= 2;
	if([[leCamera camProp] lightBalance] > 6)
	{
                //NSMutableArray* outOfRangeNegPics = [[NSMutableArray alloc] initWithCapacity:2];, contains the rest from the NSImage objects, needed
                //NSMutableArray*  outOfRangePosPics = [[NSMutableArray alloc] initWithCapacity:2];, contains the rest from the NSImage objects, needed
		[lightBalanceImage setImage:[outOfRangePosPics objectAtIndex:indexOutOfRange]];
	}
	else if([[leCamera camProp] lightBalance] < -6)
	{
		[lightBalanceImage setImage:[outOfRangeNegPics objectAtIndex:indexOutOfRange]];
	}
	else
	{
		[self setPicture];
	}
}

Hope that the qustion is clear, if anything else looks wierd I will be happy to clarify. This problem bothers me really, I think, I do something wrong... May be I should define all of the NSImages in my DrawBackground class? I am not sure, thank you.