点对点矩形测试 [英] Point-in-rectangle testing

问题描述

我有这个矩阵

/// as if the create a rectangle
int [][] loc = {
  {5, 15},//(x1, y1)
  {5, 30}, // (x1, y2)
  {20, 15},// (x2, y1)
  {20, 30}, // (x2, y2)
}

// this are the point that i want to check if they are in the rectangular range or not
int [] [] point = {
  {6, 16}, //(x, y)
  {3, 17}, //(x, y)
} 

我想要的方法可以取点并搜索是否在loc范围内或不使用
x1< x< x2 和 y1< y< y2

I want i method that can take the point and search if it in the loc range or not by using x1<x<x2 and y1<y<y2

推荐答案

点（x，y）位于矩形（x1，y1） - （x2，y2）内，如果

A point (x, y) is inside a rectangle (x1,y1) - (x2, y2) if

（x1< = x< = x2）和（y1< = y< = y2）

(x1 <= x <= x2) and (y1 <= y <= y2)

您的代码应如下所示（这实际上是C代码，但JavaScript不应该有太大差异）：

Your code should look like this (this actually is C code, but JavaScript shouldn't be much different):

 x1 = loc[0][0];
 x2 = loc[2][0];
 y1 = loc[0][1];
 y2 = loc[2][1];
 for (int i = 0; i < num_points; i++) {
   if ((x1 <= point[i][0]) && (point[i][0] <= x2) && 
       (y1 <= point[i][1]) && (point[i][1] <= y2)) {
     // This point is inside the rectangle - insert code here
   } else {
     // This point is not inside the rectangle - insert code here
   }
 }

请注意，这只适用于（x1< = x2）和（y1< = y2），所以你可能会这样做也许通过使用它来确保上面的前四行：

Note that this will only work if (x1 <= x2) and (y1 <= y2), so you might perhaps make sure by using this instead the first four lines above:

x1 = Math.Min(loc[0][0], loc[2][0]);
x2 = Math.Max(loc[0][0], loc[2][0]);
y1 = Math.Min(loc[0][1], loc[2][1]);
y2 = Math.Max(loc[0][1], loc[2][1]);

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