25 lines
603 B
JavaScript
25 lines
603 B
JavaScript
import {sin, cos, sqrt, pi, tau} from "../math.js";
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const ka = 0.89081309152928522810;
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const kr = sin(pi / 10) / sin(7 * pi / 10);
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const kx = sin(tau / 10) * kr;
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const ky = -cos(tau / 10) * kr;
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export default {
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draw(context, size) {
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const r = sqrt(size * ka);
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const x = kx * r;
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const y = ky * r;
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context.moveTo(0, -r);
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context.lineTo(x, y);
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for (let i = 1; i < 5; ++i) {
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const a = tau * i / 5;
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const c = cos(a);
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const s = sin(a);
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context.lineTo(s * r, -c * r);
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context.lineTo(c * x - s * y, s * x + c * y);
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}
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context.closePath();
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}
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};
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