Bitmap/Bézier curves/Cubic: Difference between revisions

=={{header|Nim}}==

{{Trans|Ada}}

We use module “bitmap” for bitmap management and module “bresenham” to draw segments.

<lang Nim>import bitmap

import bresenham

import lenientops

proc drawCubicBezier*(

image: var Image; pt1, pt2, pt3, pt4: Point; color: Color; nseg: Positive = 20) =

var points = newSeq[Point](nseg + 1)

for i in 0..nseg:

let t = i / nseg

let u = (1 - t) * (1 - t)

let a = (1 - t) * u

let b = 3 * t * u

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

let d = t * t * t

points[i] = (x: (a * pt1.x + b * pt2.x + c * pt3.x + d * pt4.x).toInt,

y: (a * pt1.y + b * pt2.y + c * pt3.y + d * pt4.y).toInt)

for i in 1..points.high:

image.drawLine(points[i - 1], points[i], color)

#———————————————————————————————————————————————————————————————————————————————————————————————————

when isMainModule:

var img = initImage(16, 16)

img.fill(White)

img.drawCubicBezier((0, 15), (3, 0), (15, 2), (10, 14), Black)

img.print</lang>

{{out}}

<pre>................

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...H.......H....

..H........H....

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.H.........H....

.H.........H....

.H.........H....

H.........H.....

H...............</pre>