Fading Paths ???

Hello everyone,

i would like to know how to code for this: everytime i click generate i want the previous path's colors to change into a different color.

THANKS



#import "RanWithParameters.h"


@implementation RanWithParameters

- (id)initWithFrame:(NSRect)rect
{
NSLog(@"-------------initWithFrame------------------");
if (self = [super initWithFrame:rect])
{
transform = [[NSAffineTransform alloc] init];
path = [[NSBezierPath alloc] init];
}
return self;
}



- (IBAction)generate:(id)sender
{
NSLog(@"generate");
[self drawRandomLine];
[self setNeedsDisplay:YES];

}



- (void)drawRandomLine
{
int i;
NSPoint p;

//Create a path object
[path setLineWidth:2.0];
p = [self randomPoint:0];
[path moveToPoint: p];

for (i = 0; i <= 10; i++)
{
p = [self randomPoint:i];
[path lineToPoint: p];
}
}



// randomPoint returns a random point inside the view
- (NSPoint)randomPoint:(long)index
{
NSPoint result;
result.y = (random() % 100) -50;
result.x = index + 0;

return result;
}



//Setting scales
- (void)setScale:(NSRect)bounds
{
NSAffineTransformStruct I, unitsToPix;

NSLog(@"setScale");

I.m11 = 1;
I.m12 = 0;
I.m21 = 0;
I.m22 = 1;
I.tX = 0;
I.tY = 0;

[transform setTransformStruct:I];
[transform translateXBy: bounds.origin.x yBy: bounds.origin.y + bounds.size.height/2.0];
[transform scaleXBy: bounds.size.width/10 yBy: bounds.size.height/100];

unitsToPix = [transform transformStruct];

NSLog(@"unitsToPix.m11=%f unitsToPix.m12=%f unitsToPix.m21=%f unitsToPix.m22=%f unitsToPix.tX=%f unitsToPix.tY=%f",
unitsToPix.m11, unitsToPix.m12, unitsToPix.m21, unitsToPix.m22, unitsToPix.tX, unitsToPix.tY);
}


- (void)drawRect:(NSRect)rect
{
NSRect bounds;

NSLog(@"======= drawRect ======");

bounds = [self bounds];

[self setScale:bounds];

//Fill the view with black
[[NSColor blackColor] set];
[NSBezierPath fillRect:bounds];

// Draw the path red
[[NSColor greenColor] set];

[path transformUsingAffineTransform: transform]; // transform path in units to path in pixels
[path stroke]; // draw path in pixels
[transform invert]; // invert transform to go from pixels to units
[path transformUsingAffineTransform: transform]; // transform path in pixels back to path in units
[transform invert]; // invert transform back to take us from units to pixels
}


- (void)dealloc
{
[path release];
[transform release];
[super dealloc];
}



@end

If this problem is not solved, please IM me;-)