-
-
Save scipionesarlo/ae171c06aba9f29cd7ef260860dd0964 to your computer and use it in GitHub Desktop.
Function to plot secondary axis in ggplot2
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| library(ggplot2) | |
| library(gtable) | |
| library(grid) | |
| library(ggthemes) | |
| # extract gtable | |
| ggplot_second_axis <- function(p1, p2){ | |
| p2 <- p2 + theme() %+replace% | |
| theme(panel.background = element_rect(fill = NA)) | |
| grid.newpage() | |
| g1 <- ggplot_gtable(ggplot_build(p1)) | |
| g2 <- ggplot_gtable(ggplot_build(p2)) | |
| # overlap the panel of 2nd plot on that of 1st plot | |
| pp <- c(subset(g1$layout, name == "panel", se = t:r)) | |
| g <- gtable_add_grob(g1, g2$grobs[[which(g2$layout$name == "panel")]], pp$t, | |
| pp$l, pp$b, pp$l) | |
| # axis tweaks | |
| ia <- which(g2$layout$name == "axis-l") | |
| ga <- g2$grobs[[ia]] | |
| ax <- ga$children[[2]] | |
| ax$widths <- rev(ax$widths) | |
| ax$grobs <- rev(ax$grobs) | |
| ax$grobs[[1]]$x <- ax$grobs[[1]]$x - unit(1, "npc") + unit(0.15, "cm") | |
| g <- gtable_add_cols(g, g2$widths[g2$layout[ia, ]$l], length(g$widths) - 1) | |
| g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b) | |
| ia2 <- which(g2$layout$name == "ylab") | |
| ga2 <- g2$grobs[[ia2]] | |
| ga2$rot <- 90 | |
| g <- gtable_add_cols(g, g2$widths[g2$layout[ia2, ]$l], length(g$widths) - 1) | |
| g <- gtable_add_grob(g, ga2, pp$t, length(g$widths) - 1, pp$b) | |
| return(g) | |
| } | |
| # two plots | |
| p1 <- ggplot(mtcars, aes(mpg, disp)) + geom_line(colour = "blue") | |
| p2 <- ggplot(mtcars, aes(mpg, drat)) + geom_line(colour = "red") | |
| f <- ggplot_second_axis(p1,p2) | |
| grid.draw(f) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment