javascript中中心到矩形边缘上任意点的距离 [英] Distance between center to any point on edge of rectangle in javascript

问题描述

如上图所示，假设有一束光线从中心发出并在矩形的边缘发生碰撞.所以我想计算它在哪一点碰撞，以便能够计算出边缘上的点与中心之间的距离.

As you can see in above picture, suppose that there is a ray emitted from center and collides at edge of rectangle. so I want to calculate at which point it collides, so that I could be able to calculate distance between point on edge and center.

• 我们知道什么?
  • 矩形的宽度和高度
  • 学位& b度(如上图所示)
  • centerX，centerY
  • What we know?
    • width and height of rectangle
    • a degree & b degree (as shown in above figure)
    • centerX, centerY

    推荐答案

    让我们的中心为(0，0)，射线角度为phi.伪代码:

    Let's center is (0, 0) and ray angle is phi. Pseudocode:

    c = Cos(phi)
    s = Sin(phi)
    if Width * Abs(s) < Height * Abs(c) then
       x = Sign(c) * Width / 2
       y = Tan(phi) * x
    else
       y = Sign(s) * Height / 2
       x = CoTan(phi) * y
    

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