Messy Circle Drawer

hello_pdf.js

var plask = require('plask');

plask.SkPath.prototype.splineTo = function(vertices){
    var nv = vertices.length;
    if(nv >= 3){
        var p0, p1, p2;
        for(var i = 1, n = nv - 1; i <= n; i++){
            p0 = vertices[i - 1];
            p1 = vertices[i];
            if(i == n){  // finish him
                this.cubicTo(
                    (2 * p0.x + p1.x) / 3, (2 * p0.y + p1.y) / 3,
                    (2 * p1.x + p0.x) / 3, (2 * p1.y + p0.y) / 3,
                    p1.x, p1.y
                );
            }
            else{
                p2 = vertices[i + 1];
                this.cubicTo(
                    (2 * p0.x + p1.x) / 3, (2 * p0.y + p1.y) / 3,
                    (2 * p1.x + p0.x) / 3, (2 * p1.y + p0.y) / 3,
                    (p0.x + 4 * p1.x + p2.x) / 6, (p0.y + 4 * p1.y + p2.y) / 6
                );
            }
        }
    }
}

var _width  = 500;
var _height = 500;

var window = plask.simpleWindow({
    settings: {
        type:   '2d',
        title:  'hello pdf',
        width:  _width,
        height: _height
    },
    init: function(){
        var canvas = this.canvas, paint = this.paint;
        paint.setFlags(paint.kAntiAliasFlag);

        this.on('keyDown', function(e){
            switch(e.str){
                case ' ':
                    render(canvas, paint);
                    window.redraw();
                    break;
                case 's':
                    var pdf = plask.SkCanvas.createForPDF(canvas.width, canvas.height);
                    render(pdf, paint);
                    pdf.writePDF("hello.pdf");
                    break;
            }
        });

        render(canvas, paint);
    }
});

function rand2(min, max){
    return min + Math.random() * (max - min);
}

function render(canvas, paint){
    canvas.drawColor(255,255,255);

    paint.setStyle(paint.kStrokeStyle);

    var verts = [];
    var radius = Math.min(_width, _height) * 0.3;
    var revolutions = rand2(1, 10);
    var facets      = rand2(4, 8);
    var messyness   = radius / facets * 2;
    for(var i = 0, n = facets * revolutions; i < n; ++i){
        var t = i / (n - 1) * Math.PI * 2 * revolutions;
        verts.push({
            x: Math.sin(t) * radius + rand2(-messyness, messyness),
            y: Math.cos(t) * radius + rand2(-messyness, messyness)
        })
    }

    canvas.save();
    canvas.translate(_width / 2, _height / 2);

    var guide = new plask.SkPath();
    guide.moveTo(verts[0].x, verts[0].y);
    for(var i = 1; i < verts.length; ++i)
        guide.lineTo(verts[i].x, verts[i].y);
    paint.setColor(230,230,230);
    paint.setStrokeWidth(2);
    canvas.drawPath(paint, guide);

    var path = new plask.SkPath();
    path.moveTo(verts[0].x, verts[0].y);
    path.splineTo(verts);
    paint.setColor(255,0,0);
    paint.setStrokeWidth(5);
    canvas.drawPath(paint, path);

    canvas.restore();
}

http://f.cl.ly/items/2B382Z1i180P2N0T043k/hello.pdf