Created
December 28, 2015 17:37
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distance to point
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func distanceToPoint(point p: CGPoint, fromLineSegmentBetween l1: CGPoint, and l2: CGPoint) -> Float { | |
let a = p.x - l1.x | |
let b = p.y - l1.y | |
let c = l2.x - l1.x | |
let d = l2.y - l1.y | |
let dot = a * c + b * d | |
let lenSq = c * c + d * d | |
let param = dot / lenSq | |
var xx:CGFloat! | |
var yy:CGFloat! | |
if param < 0 || (l1.x == l2.x && l1.y == l2.y) { | |
xx = l1.x | |
yy = l1.y | |
} else if (param > 1) { | |
xx = l2.x | |
yy = l2.y | |
} else { | |
xx = l1.x + param * c | |
yy = l1.y + param * d | |
} | |
let dx = Float(p.x - xx) | |
let dy = Float(p.y - yy) | |
return sqrtf(dx * dx + dy * dy) | |
} |
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