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48 lines
1.3 KiB
JavaScript
48 lines
1.3 KiB
JavaScript
(function (exports) {
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'use strict';
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/**
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* Draws (prints) the given coordinates
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* @param {number} x The first coordinate of the point
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* @param {number} y The second coordinate of the point
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*/
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function drawPoint(x, y) {
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console.log(x, y);
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}
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/**
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* Bresenham's line drawing algorithm.
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* It has complexity O(n)
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* @param {number} x1 The first coordinate of the beginning of the line
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* @param {number} y1 The second coordinate of the beginning of the line
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* @param {number} x2 The first coordinate of the end of the line
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* @param {number} y2 The second coordinate of the end of the line
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* @param {function} draw Optional custom drawing function.
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*/
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function drawLine(x1, y1, x2, y2, draw) {
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var drawPointStrategy = draw || drawPoint;
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var dx = Math.abs(x2 - x1);
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var dy = Math.abs(y2 - y1);
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var cx = (x1 < x2) ? 1 : -1;
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var cy = (y1 < y2) ? 1 : -1;
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var error = dx - dy;
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var doubledError;
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while (x1 !== x2 || y1 !== y2) {
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drawPointStrategy(x1, y1);
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doubledError = error + error;
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if (doubledError > -dy) {
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error -= dy;
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x1 += cx;
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}
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if (doubledError < dx) {
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error += dx;
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y1 += cy;
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}
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}
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}
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exports.drawLine = drawLine;
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}(typeof exports === 'undefined' ? window : exports));
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