points.js

来自「对java中如何使用Ajax技术」· JavaScript 代码 · 共 55 行

/*
	Copyright (c) 2004-2006, The Dojo Foundation
	All Rights Reserved.

	Licensed under the Academic Free License version 2.1 or above OR the
	modified BSD license. For more information on Dojo licensing, see:

		http://dojotoolkit.org/community/licensing.shtml
*/

dojo.provide("dojo.math.points");
dojo.require("dojo.math");

dojo.math.points = {
	translate: function(/* array */a, /* array */b) {
		//	summary
		//	translate a by b, and return the result.
		if( a.length != b.length ) {
			dojo.raise("dojo.math.translate: points not same size (a:[" + a + "], b:[" + b + "])");
		}
		var c = new Array(a.length);
		for(var i = 0; i < a.length; i++) {
			c[i] = a[i] + b[i];
		}
		return c;	//	array
	},

	midpoint: function(/* array */a, /* array */b) {
		//	summary
		//	Find the point midway between a and b
		if( a.length != b.length ) {
			dojo.raise("dojo.math.midpoint: points not same size (a:[" + a + "], b:[" + b + "])");
		}
		var c = new Array(a.length);
		for(var i = 0; i < a.length; i++) {
			c[i] = (a[i] + b[i]) / 2;
		}
		return c;	//	array
	},

	invert: function(/* array */a) {
		//	summary
		//	invert the values in a and return it.
		var b = new Array(a.length);
		for(var i = 0; i < a.length; i++) { b[i] = -a[i]; }
		return b;	//	array
	},

	distance: function(/* array */a, /* array */b) {
		//	summary
		//	Calculate the distance between point a and point b
		return Math.sqrt(Math.pow(b[0]-a[0], 2) + Math.pow(b[1]-a[1], 2));	// 	float
	}
};