match_margins.R

library(ggplot2)
library(grid)
library(gtable)

ex <- data.frame(xmin=1, xmax=100, ymin=0, ymax=15)

p <- ggplot(ex, aes(xmin=xmin, xmax=xmax, ymin=ymin, ymax=ymax)) +
  theme_minimal() +
  theme(plot.margin=margin(l=2.0, unit="cm"),
        panel.margin=margin(l=2.0, r=0, unit="cm"),
        panel.grid.major.x=element_blank(), panel.grid.minor.x=element_blank(),
        panel.border=element_blank(), panel.background = element_blank(),
        axis.text.y=element_text(margin=margin(l=0.0, r=0.0, unit="cm")),
        axis.ticks=element_line(size=0.25),
        axis.ticks.x=element_line(), axis.ticks.y=element_line(),
        axis.ticks.length=unit(0.1, units="cm")) +
  scale_x_continuous(expand = c(0, 0)) +
  scale_y_continuous(expand = c(0, 0)) +
  geom_rect()


ex_ann <- data.frame(xmin=10, xmax=50, ymin=0, ymax=1)

ann <- ggplot(ex_ann, aes(xmin=xmin, xmax=xmax, ymin=ymin, ymax=ymax)) +
  theme_minimal() +
  theme(plot.margin=margin(l=2.0, unit="cm"),
        panel.margin=margin(l=2.0, unit="cm"),
        panel.background=element_rect(fill="grey", colour="white"),
        panel.grid.major.x=element_blank(), panel.grid.minor.x=element_blank(),
        panel.grid.major.y=element_blank(), panel.grid.minor.y=element_blank(),
        panel.border=element_blank(), panel.background=element_blank(),
        # axis.text.y=element_text(margin=margin(r=0, l=0.5)), panel.margin=unit(0, units="cm"),
        axis.ticks=element_line(size = 0.25),
        axis.ticks.x=element_line(), axis.ticks.y=element_blank(),
        axis.text.y=element_blank(),
        axis.ticks.length=unit(0.0, units="cm")) +
  scale_x_continuous(limits=c(1, 100), expand = c(0, 0)) +
  scale_y_continuous(limits=c(0, 1), expand = c(0, 0)) +
  geom_rect()

gr <- ggplotGrob(p)
gr_ann <- ggplotGrob(ann)

g <- gtable(widths=unit(c(1), "null"), heights=unit(c(1, 0.1), "null"))
g <- gtable_add_grob(g, list(gr, gr_ann), t=c(1, 2), l=c(1, 1), r=c(1, 1), b=c(1, 2))

grid.newpage()
grid.draw(g)