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@mwermuth
Created September 11, 2014 14:01
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Drawing an Arrow with Swift
extension UIBezierPath {
class func getAxisAlignedArrowPoints(inout points: Array<CGPoint>, forLength: CGFloat, tailWidth: CGFloat, headWidth: CGFloat, headLength: CGFloat ) {
let tailLength = forLength - headLength
points.append(CGPointMake(0, tailWidth/2))
points.append(CGPointMake(tailLength, tailWidth/2))
points.append(CGPointMake(tailLength, headWidth/2))
points.append(CGPointMake(forLength, 0))
points.append(CGPointMake(tailLength, -headWidth/2))
points.append(CGPointMake(tailLength, -tailWidth/2))
points.append(CGPointMake(0, -tailWidth/2))
}
class func transformForStartPoint(startPoint: CGPoint, endPoint: CGPoint, length: CGFloat) -> CGAffineTransform{
let cosine: CGFloat = (endPoint.x - startPoint.x)/length
let sine: CGFloat = (endPoint.y - startPoint.y)/length
return CGAffineTransformMake(cosine, sine, -sine, cosine, startPoint.x, startPoint.y)
}
class func bezierPathWithArrowFromPoint(startPoint:CGPoint, endPoint: CGPoint, tailWidth: CGFloat, headWidth: CGFloat, headLength: CGFloat) -> UIBezierPath {
let xdiff: Float = Float(endPoint.x) - Float(startPoint.x)
let ydiff: Float = Float(endPoint.y) - Float(startPoint.y)
let length = hypotf(xdiff, ydiff)
var points = [CGPoint]()
self.getAxisAlignedArrowPoints(&points, forLength: CGFloat(length), tailWidth: tailWidth, headWidth: headWidth, headLength: headLength)
var transform: CGAffineTransform = self.transformForStartPoint(startPoint, endPoint: endPoint, length: CGFloat(length))
var cgPath: CGMutablePathRef = CGPathCreateMutable()
CGPathAddLines(cgPath, &transform, points, 7)
CGPathCloseSubpath(cgPath)
var uiPath: UIBezierPath = UIBezierPath(CGPath: cgPath)
return uiPath
}
}
@mwermuth
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Author

Use it like this

let arrowPath = UIBezier. bezierPathWithArrowFromPoint(CGPointMake(0,0), CGPointMake(0,20), 4, 8, 6)

@boyxgc
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boyxgc commented Oct 3, 2014

Good job!

@arbel03
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arbel03 commented Apr 20, 2016

Perfect job 💯

@sivamurugan
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Excellent "mwermuth" Awesome work ... Helps me lot ... Please let me know this to draw in the real time drawing from one point to another point ... thanks in advance.

@gsujathap
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How to use it between views?

@lehuudungle
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how to draw curved arrow ???

@Akash20395
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Akash20395 commented Jan 12, 2018

let arrowPath = UIBezier. bezierPathWithArrowFromPoint(CGPointMake(0,0), CGPointMake(0,20), 4, 8, 6)

How overlay this arrowPath on UIImageView() ?

@jcfrank77
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Updated for Swift 5:

`extension UIBezierPath {
class func getAxisAlignedArrowPoints(points: inout [CGPoint], forLength: CGFloat, tailWidth: CGFloat, headWidth: CGFloat, headLength: CGFloat) {
let tailLength = forLength - headLength
points.append(CGPointMake(0, tailWidth / 2))
points.append(CGPointMake(tailLength, tailWidth / 2))
points.append(CGPointMake(tailLength, headWidth / 2))
points.append(CGPointMake(forLength, 0))
points.append(CGPointMake(tailLength, -headWidth / 2))
points.append(CGPointMake(tailLength, -tailWidth / 2))
points.append(CGPointMake(0, -tailWidth / 2))
}

class func transformForStartPoint(startPoint: CGPoint, endPoint: CGPoint, length: CGFloat) -> CGAffineTransform {
    let cosine: CGFloat = (endPoint.x - startPoint.x) / length
    let sine: CGFloat = (endPoint.y - startPoint.y) / length

    return CGAffineTransformMake(cosine, sine, -sine, cosine, startPoint.x, startPoint.y)
}

class func bezierPathWithArrowFromPoint(startPoint: CGPoint,
                                        endPoint: CGPoint,
                                        tailWidth: CGFloat,
                                        headWidth: CGFloat,
                                        headLength: CGFloat) -> UIBezierPath
{
    let xdiff = Float(endPoint.x) - Float(startPoint.x)
    let ydiff = Float(endPoint.y) - Float(startPoint.y)
    let length = hypotf(xdiff, ydiff)

    var points = [CGPoint]()
    getAxisAlignedArrowPoints(points: &points, forLength: CGFloat(length), tailWidth: tailWidth, headWidth: headWidth, headLength: headLength)

    let transform: CGAffineTransform = transformForStartPoint(startPoint: startPoint, endPoint: endPoint, length: CGFloat(length))

    let cgPath = CGMutablePath()
    cgPath.addLines(between: points, transform: transform)
    cgPath.closeSubpath()

    let uiPath = UIBezierPath(cgPath: cgPath)
    return uiPath
}

}`

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