如何在R中的矩形内写入文本

我希望每个矩形都包含一个数字，这样第一个打印的矩形将包含：rect1第二个rect2等等，但我不知道如何在矩形中插入文本

require(grDevices)
## set up the plot region:

plot(c(0, 250), c(0, 250), type = "n",
     main = "Exercise 1: R-Tree Index Question C")

rect(0.0,0.0,40.0,35.0, , text= "transparent")
rect(10.0,210.0,45.0,230.0)
rect(170.0,50.0,240.0,150.0)
rect(75.0,110.0,125.0,125.0)
rect(50.0,130.0,65.0,160.0)
rect(15.0,140.0,30.0,150.0)
rect(100.0,50.0,130.0,90.0)
rect(150.0,40.0,155.0,60.0)
rect(52.0,80.0,75.0,90.0)
rect(62.0,65.0,85.0,75.0)
rect(20.0,75.0,25.0,80.0)
rect(30.0,40.0,50.0,80.0)
rect(102.0,155.0,113.0,217.0)



par(op)

我们选择x，y作为矩形的质心。您可以定义一个函数来绘制

矩形

，然后将

文本

放置在其质心处

注意：这些坐标是大的；这将显示在正常视图之外。因此，您需要缩放以查看它，或者将坐标缩放到0.0..1.0的范围

顺便说一下，读一下

我们选择x，y作为矩形的质心。您可以定义一个函数来绘制

矩形

，然后将

文本

放置在其质心处

注意：这些坐标是大的；这将显示在正常视图之外。因此，您需要缩放以查看它，或者将坐标缩放到0.0..1.0的范围

顺便说一下，阅读您需要使用

text（）

作为单独的图形调用

coords <- matrix(
c(0.0,0.0,40.0,35.0,
    10.0,210.0,45.0,230.0,
    170.0,50.0,240.0,150.0,
    75.0,110.0,125.0,125.0,
    50.0,130.0,65.0,160.0,
    15.0,140.0,30.0,150.0,
    100.0,50.0,130.0,90.0,
    150.0,40.0,155.0,60.0,
    52.0,80.0,75.0,90.0,
    62.0,65.0,85.0,75.0,
    20.0,75.0,25.0,80.0,
    30.0,40.0,50.0,80.0,
    102.0,155.0,113.0,217.0),
ncol=4,byrow=TRUE)

 plot(c(0, 250), c(0, 250), type = "n",
         main = "Exercise 1: R-Tree Index Question C")
rfun <- function(x,i) {
    do.call(rect,as.list(x))
}
apply(coords,1,rfun)
text((coords[,1]+coords[,3])/2,
     (coords[,2]+coords[,4])/2,
     seq(nrow(coords)))

coords您需要使用
text（）
作为单独的图形调用

coords <- matrix(
c(0.0,0.0,40.0,35.0,
    10.0,210.0,45.0,230.0,
    170.0,50.0,240.0,150.0,
    75.0,110.0,125.0,125.0,
    50.0,130.0,65.0,160.0,
    15.0,140.0,30.0,150.0,
    100.0,50.0,130.0,90.0,
    150.0,40.0,155.0,60.0,
    52.0,80.0,75.0,90.0,
    62.0,65.0,85.0,75.0,
    20.0,75.0,25.0,80.0,
    30.0,40.0,50.0,80.0,
    102.0,155.0,113.0,217.0),
ncol=4,byrow=TRUE)

 plot(c(0, 250), c(0, 250), type = "n",
         main = "Exercise 1: R-Tree Index Question C")
rfun <- function(x,i) {
    do.call(rect,as.list(x))
}
apply(coords,1,rfun)
text((coords[,1]+coords[,3])/2,
     (coords[,2]+coords[,4])/2,
     seq(nrow(coords)))

coords与其他答案一样，您可以使用您给
rect
的坐标将文本放置在相对位置

plot(c(0, 250), c(0, 250), type = "n",
     main = "Exercise 1: R-Tree Index Question C")
rect(0.0,0.0,40.0,35.0)
center <- c(mean(c(0, 40)), mean(c(0, 35)))
text(center[1], center[2], labels = 'hi')

像其他答案提到的一样，您可以使用给
rect
的坐标将文本放置在相对位置

plot(c(0, 250), c(0, 250), type = "n",
     main = "Exercise 1: R-Tree Index Question C")
rect(0.0,0.0,40.0,35.0)
center <- c(mean(c(0, 40)), mean(c(0, 35)))
text(center[1], center[2], labels = 'hi')


recttext(50, 0, 100, 35, 'hello',
         rectArgs = list(col = 'red', lty = 'dashed'),
         textArgs = list(col = 'blue', cex = 1.5))