35 lines
1013 B
JavaScript
35 lines
1013 B
JavaScript
var Shape = require('./generic');
|
|
|
|
module.exports = Shape(function(innerRadius, outerRadius, startAngle, endAngle){
|
|
|
|
var circle = Math.PI * 2,
|
|
radiansPerDegree = Math.PI / 180,
|
|
sa = startAngle * radiansPerDegree % circle || 0,
|
|
ea = endAngle * radiansPerDegree % circle || 0,
|
|
ir = Math.min(innerRadius || 0, outerRadius || 0),
|
|
or = Math.max(innerRadius || 0, outerRadius || 0),
|
|
a = sa > ea ? circle - sa + ea : ea - sa;
|
|
|
|
this.width = this.height = or * 2;
|
|
var path = this.path;
|
|
|
|
if (a >= circle){
|
|
|
|
path.move(0, or).arc(or * 2, 0, or).arc(-or * 2, 0, or);
|
|
if (ir) path.move(or - ir, 0).counterArc(ir * 2, 0, ir).counterArc(-ir * 2, 0, ir);
|
|
|
|
} else {
|
|
|
|
var ss = Math.sin(sa), es = Math.sin(ea),
|
|
sc = Math.cos(sa), ec = Math.cos(ea),
|
|
ds = es - ss, dc = ec - sc, dr = ir - or,
|
|
large = a > Math.PI;
|
|
|
|
path.move(or + or * ss, or - or * sc).arc(or * ds, or * -dc, or, or, large).line(dr * es, dr * -ec);
|
|
if (ir) path.counterArc(ir * -ds, ir * dc, ir, ir, large);
|
|
|
|
}
|
|
|
|
path.close();
|
|
|
|
}); |