获取画布中两点之间的距离 [英] Get distance between two points in canvas

问题描述

我有画布绘图选项卡，并希望 lineWidth 基于最近两次鼠标移动坐标更新之间的距离.我会自己将距离转换为宽度，我只需要知道如何获得这些点之间的距离(我已经有了这些点的坐标).

I have canvas drawing tab and want lineWidth to be based on distance between two last mousemove coordinate updates. I will make translation of distance to width myself, I just need to know how to get distance between those points (I already have coordinates of those pointes).

推荐答案

你可以用毕达哥拉斯定理来做

You can do it with pythagoras theorem

如果你有两个点 (x1, y1) 和 (x2, y2)然后你可以计算出 x 的差值和 y 的差值，我们称它们为 a 和 b.

If you have two points (x1, y1) and (x2, y2) then you can calculate the difference in x and difference in y, lets call them a and b.

var a = x1 - x2;
var b = y1 - y2;

var c = Math.sqrt( a*a + b*b );

// c is the distance

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