rantlab post 1.2

gistfile1.m

- (void)mouseDown:(NSEvent *)event
{
  arrow = [CAShapeLayer layer];
  
  CGFloat minMagnitude = 20;
  CGPoint middle = CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds));
  CGPoint vector = CGPointMake(target.x-middle.x, target.y-middle.y);
  CGFloat magnitude = sqrt(vector.x*vector.x+vector.y*vector.y);
  CGPoint start = CGPointMake(middle.x+vector.x/magnitude*minMagnitude, middle.y+vector.y/magnitude*minMagnitude);
  
  CGPathRef startPath = [RLArrowView createPathWithArrowFromPoint:middle
															toPoint:start
															tailWidth:2.0
															headWidth:10.0
															headLength:20.0
															wiggle:0];
  arrow.path = startPath;
  arrow.fillColor = [NSColor redColor].CGColor;
  arrow.lineWidth = 1;
  arrow.fillRule = kCAFillRuleNonZero;
  [self.layer addSublayer:arrow];
}