CODEWITHSUNDEEP
swiftcore-graphics
chris
chris

Reputation: 5006

CGContextDrawPath won't fill

I'm trying to fill some triangles I have drawn, however they aren't filling. Below is the code which draws in the context, and as you can see in the picture the path strokes fine.

func draw(context:CGContextRef) {
    CGContextBeginPath(context)
    CGContextMoveToPoint(context, self.peak.x, self.peak.y)
    CGContextAddLineToPoint(context, self.left.x,self.left.y)
    CGContextMoveToPoint(context, self.left.x, self.left.y)
    CGContextAddLineToPoint(context, self.right.x,self.right.y)
    CGContextMoveToPoint(context, self.right.x, self.right.y)
    CGContextAddLineToPoint(context, self.peak.x,self.peak.y)
    CGContextSetStrokeColorWithColor(context,UIColor.blackColor().CGColor)
    CGContextSetFillColorWithColor(context,UIColor.redColor().CGColor)
    CGContextDrawPath(context, kCGPathFillStroke)
}

I call that function twice and the output is this.

enter image description here

I'm reading the Quartz2D programming guide but can't see why this wouldn't fill. This is just happening in a playground in a class that inherits from UIView, nothing fancy.

Upvotes: 1

Views: 655

Answers (1)

Martin R
Martin R

Reputation: 540105

Each call to CGContextMoveToPoint() starts a new subpath, which is then filled as if you had closed it (and there is nothing to see if you fill a single line segment). To stroke and fill a triangle, use:

CGContextBeginPath(context)

CGContextMoveToPoint(context, self.peak.x, self.peak.y)
CGContextAddLineToPoint(context, self.left.x,self.left.y)
CGContextAddLineToPoint(context, self.right.x,self.right.y)
CGContextClosePath(context)

CGContextSetStrokeColorWithColor(context,UIColor.blackColor().CGColor)
CGContextSetFillColorWithColor(context,UIColor.redColor().CGColor)
CGContextDrawPath(context, kCGPathFillStroke)

Upvotes: 3

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