How to draw a line with an array of CGPoint

Question

I have an array of CGpoint and I want to connect these points to create a line. I know how to do it by subclass the UIView. but what I want to do here is that I　already have an array of CGPoint and I have a button, when I click the button the line will be shown.

I don't know how to do this.

However I try something like following: (aLine is the array with CGPoint)

#define POINT(X) [[aLine objectAtIndex:X]CGPointValue]


CGContextRef context = UIGraphicsGetCurrentContext();
for (int i = 0;i < (aLine.count-1);i++){
     CGPoint pt1 = POINT(i);
     CGPoint pt1 = POINT(i+1);
     CGContextMoveToPoint(context,pt1.x,pt1.y);
     CGContextAddLineToPoint(context,pt2.x,pt2.y);
     CGContextStrokePath(context);
}

Anyone can help me? thanks.

You should be doing this drawing inside a drawRect callback, not inside a UIButton delegate when a button is clicked. Are you? — hotpaw2, Apr 09 '11 at 17:46

score 0 · Answer 1 · answered Apr 08 '11 at 07:18

You're almost there! Firstly you need to set the stroke colour...

CGContextSetStrokeColor(context, CGColorGetComponents([colour CGColor]));

Then when you're done connecting your points (exactly what your code is currently doing) just close the path and stroke it...

CGContextClosePath(context);
CGContextDrawPath(context, kCGPathStroke);

How to draw a line with an array of CGPoint

1 Answers1