改变grob背景渐变的方向

Question

令我感到惊讶的是,从颜色矢量创建的以下简单grob几乎按照要求工作.

但是,我想从左到右,而不是从上到下制作渐变.

library(ggplot2) 
library(grid)
grad = colorRampPalette(c("red", "yellow"))(10)

ggplot(df, aes(x,y)) + 
  annotation_custom(rasterGrob(grad, 
                        width=unit(1,"npc"), 
                        height=unit(1,"npc"))) +
  scale_x_continuous(limits = c(0,1)) +
  scale_y_continuous(limits = c(0,1))

Answer 1

答案是 t

你必须转置你的grad矢量(输入到rasterGrob):

library(ggplot2)
ggplot() + 
    annotation_custom(rasterGrob(t(grad), 
                                 width = unit(1, "npc"), height = unit(1, "npc")))