BitmapCanvas

Bitmap offscreen drawing in Swift for OS X

Description

A clear, simple and concise API over a CoreGraphics bitmap context.
Loosely inspired by the ImageDraw Python library.
Especially useful for easy data visualizations.

Features

upper-left corner based coordinates
pixel perfect drawing of points, lines, rectangles, ellipses and texts
colors as NSColor, hex strings "#AA00DF" or X11 names "SkyBlue"
save as PNG
usable with regular CoreGraphics code

Examples

	let b = BitmapCanvas(32, 32, "PapayaWhip")
	b[1,1] = NSColor.black b[1,3] = "red" b[2,3] = "#00FF00" b[3,3] = NSColor.blue
	b.line(P(1,1), P(10,10)) b.line(P(1,10), P(10,19), "red") b.lineHorizontal(P(1,21), width:20) b.lineVertical(P(20, 1), height:19, "blue")
	b.rectangle(R(5,5,20,10)) b.rectangle(R(10,10,20,10), stroke:"blue", fill:"magenta")
	b.ellipse(R(5,5,20,10)) b.ellipse(R(10,10,18,21), stroke:"blue", fill:"magenta")
	let b = BitmapCanvas(32, 32, "PapayaWhip") b.line(P(10,0), P(25,31), "red") b.ellipse(R(15,10,15,15)) b.fill(P(30,1), color:"yellow")
	b.text("hi", P(5,10)) b.text("hello", P(20,30), rotationDegrees: -90, font: NSFont(name: "Helvetica", size: 10)!, color: NSColor.red)
	b.image(fromPath:"/usr/share/httpd/icons/sphere2.png", P(0,0))
	let b = BitmapCanvas(32, 32, "PapayaWhip") b.setAllowsAntialiasing(true) let points = [P(3,3), P(28,5), P(25,22), P(12,18)] b.polygon(points, stroke:"blue", fill:"SkyBlue") b.save("/tmp/polygon.png", open:true)
	b.setAllowsAntialiasing(true) NSColor.orangeColor().setFill() let bp = NSBezierPath() bp.moveToPoint(P(2,2)) bp.curveToPoint(P(20,14), controlPoint1: P(14,30), controlPoint2: P(15,30)) bp.curveToPoint(P(32,13), controlPoint1: P(24,14), controlPoint2: P(24,19)) bp.closePath() bp.fill() bp.stroke()
	let b = BitmapCanvas(32, 32, "PapayaWhip") let c = b.cgContext c.addEllipse(in: R(2, 2, 24, 24)) c.strokePath() b.setAllowsAntialiasing(true) c.setStrokeColor(NSColor.blue.cgColor) c.addEllipse(in: R(12, 12, 24, 24)) c.strokePath() b.save("/tmp/cgcontext.png")
	b.save("/tmp/image.png", open:true)

You can also dump the X11 color list with:

X11Colors.dump("/opt/X11/share/X11/rgb.txt", outPath:"/tmp/X11.clr")

or download the file directly X11.clr.zip

Other images with sample code:

let (w, h) = (255, 255)

let b = BitmapCanvas(w, h)
for i in 0..<w {
    for j in 0..<h {
        b[i,j] = NSColor(i,j,100)
    }
}

b.save("/tmp/gradient.png")

let w = 255
let h = 255
let n = 25

let b = BitmapCanvas(w, h)

var pointsColors : [(NSPoint, NSColor)] = []

for _ in 0...n {
    let p = RandomPoint(maxX: w, maxY: h)
    let c = NSColor.randomColor
    pointsColors.append((p,c))
}

for x in 0...w-1 {
    for y in 0...h-1 {
        let distances = pointsColors.map { hypot($0.0.x - x, $0.0.y - y) }
        b[x,y] = pointsColors[distances.indexOf(distances.minElement()!)!].1
    }
}

for (p,_) in pointsColors {
    let rect = R(p.x-1, p.y-1, 3, 3)
    b.ellipse(rect, stroke:"black", fill:"black")
}

b.save("/tmp/voronoi.png")

Other pictures with source code in the project:

Swift implementation of Nadieh Bremer's work "Exploring the Art hidden in Pi".

"Schotter" by Georg Nees where the idea is that randomness for x, y and rotation does increase at each row. Also created a rainbow-colored version.

nst/BitmapCanvas

nst

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BitmapCanvas

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