ggplot2 - curveGrob - annotation_custom

Question

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类似的问题

Plot curved lines between two locations in ggplot2

简而言之，我想从点（5,5）到（10,0）绘制一条向下倾斜的曲线，但是从（5,0）到（10,5）继续得到一条曲线。

require(grid)
g<-qplot(c(0,10),c(0,10))
myCurve<-curveGrob(0, 0, 1, 1, default.units = "npc",
           curvature = 0.3, angle = 90, ncp = 20, shape = 1,
           square = FALSE, squareShape = 1,
           inflect = FALSE, arrow = arrow(), open = TRUE,
           debug = FALSE,
           name = NULL, gp = gpar(col="blue", lwd=5), vp = NULL)

myCurve2<-curveGrob(0, 0, 1, 1, default.units = "npc",
           curvature = 0.3, angle = 90, ncp = 20, shape = 1,
           square = FALSE, squareShape = 1,
           inflect = FALSE, arrow = arrow(), open = TRUE,
           debug = FALSE,
           name = NULL, gp = gpar(col="red", lwd=5), vp = NULL)

g + 
  annotation_custom(grob=myCurve,0,10,0,10) + # plot from 0,0 to 10,10
  annotation_custom(grob=myCurve2,5,10,5,0) # expected a red curve from (5,5) to (10,0) 
                                            # but draws from (5,0) to (10,0). 

我该如何解决？ curveGrob 中参数的任何变化？