46 lines
854 B
JavaScript
46 lines
854 B
JavaScript
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import {Adder} from "d3-array";
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import {sqrt} from "../math.js";
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import noop from "../noop.js";
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var lengthSum = new Adder(),
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lengthRing,
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x00,
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y00,
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x0,
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y0;
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var lengthStream = {
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point: noop,
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lineStart: function() {
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lengthStream.point = lengthPointFirst;
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},
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lineEnd: function() {
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if (lengthRing) lengthPoint(x00, y00);
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lengthStream.point = noop;
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},
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polygonStart: function() {
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lengthRing = true;
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},
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polygonEnd: function() {
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lengthRing = null;
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},
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result: function() {
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var length = +lengthSum;
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lengthSum = new Adder();
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return length;
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}
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};
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function lengthPointFirst(x, y) {
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lengthStream.point = lengthPoint;
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x00 = x0 = x, y00 = y0 = y;
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}
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function lengthPoint(x, y) {
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x0 -= x, y0 -= y;
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lengthSum.add(sqrt(x0 * x0 + y0 * y0));
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x0 = x, y0 = y;
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}
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export default lengthStream;
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