如何用线方程分割线段？

Question

我在坐标定义的平面上有四个部分：

A <- matrix(c(0, 4, 4, 0, 0,            # x    
              0, 0, 3, 3, 0), ncol=2)   # y

x <- A[,1]
y <- A[,2]
n <- dim(x)

xx <- c()
yy <- c()

该段的长度很大1。我注意用步长1分割所有分段。

我的尝试在下面。我已经计算了第i个分段dist的长度，现在仅处理水平分段。我应该添加x-coordinats的新值，然后将dist-1-coordinat重复y次。

for (i in 1:n-1){
dist <- sqrt((x[i] - x[i+1])^2 + (y[i] - y[i+1])^2)
if (!is.null(dist) & length(dist) > 0 & dist[1] > 1)
    {   
        # horizontal segment, 'y' is const
        if (y[i] - y[i+1] == 0)
        {    
            # split a horizontal segment on (dist-1) parts with step 1

            tmp <- c(seq(from = min(x[i], x[i+1]),
                            to   = max(x[i], x[i+1])))

            # remove 1st and last elements
            xx <- c(xx, tmp[2 : (length(tmp)-1)]) 
            yy <- c(yy, rep(y[i], dist-1));
         } # if
    } #if
#} # i
xx;yy;

输出为：

> x
[1] 1 2 3 1 2 3
> y
[1] 0 0 0 3 3 3

C <- matrix(c(x,y), ncol=2)

plot(A, col='red', type= 'l', xlim=c(min(A[,1]),max(A[,1])),
      ylim=c(min(A[,2]),max(A[,2])), xlab='x', ylab='y'); 
points(A, col='black', pch = 22); 

points(C, col='red', pch = 21); 
grid()

问题。如何通过线方程从2个点分割线段？

https://algs4.cs.princeton.edu/91primitives/

Answer 1

对不起，但是我对您明确想要的东西的理解并不完美。但是，也许是查找所有等式或跟踪上述示例中两点之间的所有线段？ 如果我在R中使用segments函数来跟踪10 * 10段，这是您想要的吗？

all_points <- unique(rbind(A, C))

indices <- expand.grid(1:10, 1:10)
plot(all_points, xlim = c(0, 4), ylim = c(0, 3), xlab = "X", ylab = "Y")
for(i in 1:10){
  segments(x0 = all_points[indices[i, 1], 1],
           y0 = all_points[indices[i, 1], 2],
           x1 = all_points[indices[i, 2], 1],
           y1 = all_points[indices[i, 2], 2]
           )
}