Bitmap/Bézier curves/Cubic: Difference between revisions

=={{header|F#}}==

<lang f#>

/// Uses Vector<float> from Microsoft.FSharp.Math (in F# PowerPack)

module CubicBezier

/// Create bezier curve from p1 to p4, using the control points p2, p3

/// Returns the requested number of segments

let cubic_bezier (p1:vector) (p2:vector) (p3:vector) (p4:vector) segments =

[0 .. segments - 1]

|> List.map(fun i ->

let t = float i / float segments

let a = (1. - t) ** 3.

let b = 3. * t * ((1. - t) ** 2.)

let c = 3. * (t ** 2.) * (1. - t)

let d = t ** 3.

let x = a * p1.[0] + b * p2.[0] + c * p3.[0] + d * p4.[0]

let y = a * p1.[1] + b * p2.[1] + c * p3.[1] + d * p4.[1]

vector [x; y])

</lang>

<lang f#>

// For rendering..

let drawPoints points (canvas:System.Windows.Controls.Canvas) =

let addLineToScreen (v1:vector) (v2:vector) =

canvas.Children.Add(new System.Windows.Shapes.Line(X1 = v1.[0],

Y1 = -v1.[1],

X2 = v2.[0],

Y2 = -v2.[1],

StrokeThickness = 2.)) |> ignore

let renderPoint (previous:vector) (current:vector) =

addLineToScreen previous current

current

points |> List.fold renderPoint points.Head

</lang>