Freehand Draw Issue ?

Hi ...

I am using the below code for free hand draw , but the image is getting squized during drawing and this problem is happening for only rectangular shaped images . But there is no problem with Square shape size image.

This code is used in touchesmoved event.

UIGraphicsBeginImageContext(self.imageview.frame.size);

CGContextRef context = UIGraphicsGetCurrentContext();

[imageview.imagedrawInRect:CGRectMake(0, 0, self.imageview.frame.size.width, self.imageview.frame.size.height)]; //originally

CGContextSetLineCap(context, kCGLineCapRound); //kCGLineCapSquare, kCGLineCapButt, kCGLineCapRound

//line width

CGContextSetLineWidth(context, -1.0); // for size

//line colour

CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0); //values for R, G, B, and Alpha

//starting point

CGContextBeginPath(context);

//end point

CGContextMoveToPoint(context, previousPoint.x, previousPoint.y);

//add the points to make line

CGContextAddLineToPoint(context, movePoint.x, movePoint.y);

CGContextStrokePath(context);

m_pViewPortImageView.image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

previousPoint = movePoint;

Is there any way for freehand drawing on CALayer like satraight line or elipse draw ? Please guide me .

Thanks