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