小编Alm*_*rup的帖子

这应该相当容易,但我找不到我的方式.

tri_fill <- structure(
  list(x= c(0.75, 0.75, 2.25, 3.25), 
       y = c(40, 43, 43, 40)), 
  .Names = c("x", "y"),
  row.names = c(NA, -4L), class = "data.frame",Integrated=NA, Related=NA)

# install.packages("ggplot2", dependencies = TRUE)
require(ggplot2)


  ggplot(data=tri_fill,aes(x=x, y=y))+ 
      geom_polygon() + 
      scale_fill_gradient(limits=c(1, 4), low = "lightgrey", high = "red")

我想要的是沿着x轴的渐变,但是上面我只得到一个带有渐变的图例和带有实心填充的多边形.