50 lines
1.4 KiB
JavaScript
50 lines
1.4 KiB
JavaScript
var Class = require('../core/class');
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var Path = require('../core/path');
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var Transform = require('../core/transform');
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module.exports = Class(Path, {
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onReset: function(){
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this.points = [];
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this.left = this.top = Infinity;
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this.right = this.bottom = -Infinity;
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this.width = this.height = 0;
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this.length = 0;
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},
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onMove: function(sx, sy, ex, ey){
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this.points.push(this.length, ex, ey);
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},
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onLine: function(sx, sy, ex, ey){
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var x = ex - sx, y = ey - sy;
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this.points.push((this.length += Math.sqrt(x * x + y * y)), ex, ey);
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this.left = Math.min(this.left, sx, x);
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this.right = Math.max(this.right, sx, x);
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this.top = Math.min(this.top, sy, y);
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this.bottom = Math.max(this.bottom, sy, y);
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this.width = this.right - this.left;
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this.height = this.bottom - this.top;
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},
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point: function(lengthToPoint){
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// TODO: Binary search, store last distance-and-index to make second look ups faster
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var points = this.points, last = points.length - 3, next;
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if (last < 3) return null;
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for (var i = 3; i < last; i+=3)
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if (points[i] >= lengthToPoint)
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break;
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var l = points[i],
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x = points[i+1], y = points[i+2],
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dl = l - points[i-3],
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dx = x - points[i-2], dy = y - points[i-1];
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var offset = (l - lengthToPoint) / dl,
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cos = dx / dl, sin = dy / dl;
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x -= dx * offset; y -= dy * offset;
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return new Transform(cos, sin, -sin, cos, x, y);
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}
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}); |