Help with ending a drawing state on a UIView

- (void) drawHighlight{
//Create drawing view
 HighlightView *hl = [[HighlightView alloc] initWithFrame:self.view.bounds];

//Add to VC's scrollview
    [self.scrollView addSubview:hl];
  
//Store in a nice array  
    [self.highlightViews addObject:hl];

//Ensure it's on top
    [self.scrollView bringSubviewToFront:hl];

//Finish
    [hl release];
}

#import \"HighlightView.h\"

@implementation HighlightView
@synthesize context, canvas, swiped;

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        NSLog(@\"%s\", __PRETTY_FUNCTION__);   
        currentStart = CGPointZero;
        self.backgroundColor = [UIColor clearColor];

//Make a canvas to draw on
        canvas = [[UIImageView alloc] initWithImage:nil];
        canvas.frame = self.frame;
        [self addSubview:canvas];
        
    }
    return self;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
{
    swiped = NO;
    UITouch *touch = [touches anyObject];
    
    if ([touch tapCount] == 2) {
        //canvas.image = nil;
        return;
    }
    
    currentEnd = [touch locationInView:self];
    currentEnd.y -= 20;
    
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{
    swiped  = YES;
    UITouch *touch = [touches anyObject];   
    CGPoint currentPoint = [touch locationInView:self];
    currentPoint.y -= 20;
    
    UIGraphicsBeginImageContext(self.frame.size);
    [canvas.image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0);
    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0);
    CGContextBeginPath(UIGraphicsGetCurrentContext());
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), currentEnd.x, currentEnd.y);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
    CGContextStrokePath(UIGraphicsGetCurrentContext());
    canvas.image = UIGraphicsGetImageFromCurrentImageContext();
    //UIGraphicsEndImageContext();
    
    currentEnd = currentPoint;    
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
{
    UITouch *touch = [touches anyObject];
    
//How do I stop the drawing?

    if ([touch tapCount] == 2) 
    {
       // canvas.image = nil;
         return;
    }
    
  
}