title: IOS: color with a pattern image
body: <p>I have this code to colour with a simply line:</p>
  
  <pre><code>- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  mouseSwiped = YES;
  
  UITouch *touch = [touches anyObject];   
  CGPoint currentPoint = [touch locationInView:drawImage];
  
  UIGraphicsBeginImageContext(drawImage.frame.size);
  [drawImage.image drawInRect:CGRectMake(0, 0, drawImage.frame.size.width, drawImage.frame.size.height)];
  CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
  CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 15.0);
  
  
  //eraser
  /*
  if (eraser){
      CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0, 0, 0, 0);
      CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy);
  }*/
  
  CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0, 0, 0, 1.0); //black
  
  CGContextBeginPath(UIGraphicsGetCurrentContext());
  CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
  CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
  CGContextStrokePath(UIGraphicsGetCurrentContext());
  drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
  
  UIGraphicsEndImageContext();
  
  lastPoint = currentPoint;
  }
  </code></pre>
  
  <p>with this code I'm able to color in a view or imageview; I can choose color and size; but now I want to use a specific pattern to color this view; a specific png to use when touchmoved is called; can you help me?</p>