How do I get annotation_custom () grob to display along with scale_y_reverse () using R and ggplot2?

Question

I am new to ggplot2and relatively new to R. I can take a picture on the graph, and I can take a reverse scale of the y axis, but I don’t know how to do it at the same time. For example:

library(ggplot2)

y=c(1,2,3)
x=c(0,0,0)
d=data.frame(x=x, y=y)

#following http://stackoverflow.com/questions/9917049/inserting-an-image-to-ggplot2/9917684#9917684
library(png)
library(grid)
img <- readPNG(system.file("img", "Rlogo.png", package="png"))
g <- rasterGrob(img, interpolate=TRUE)

#these work fine - either reversing scale, or adding custom annotation
ggplot(d, aes(x, y)) + geom_point()
ggplot(d, aes(x, y)) + geom_point() + scale_y_reverse()
ggplot(d, aes(x, y)) + geom_point() + annotation_custom(g, xmin=.23, xmax=.27, ymin=1.8, ymax=2.2)

#these don't...combining both reverse scale and custom annotation
ggplot(d, aes(x, y)) + geom_point() + annotation_custom(g, xmin=.23, xmax=.27, ymin=1.8, ymax=2.2) + scale_y_reverse()
ggplot(d, aes(x, y)) + geom_point() + annotation_custom(g, xmin=.23, xmax=.27, ymin=2.2, ymax=1.8) + scale_y_reverse()

I am sure that I am missing something quite simple. Where should I start looking to display my small graphics on the graph in the opposite scale, and also better understand things under the hood?

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Answer 1

scale_y_reverse y- annotation_custom .

library(ggplot2)
y=c(1,2,3)
x=c(0,0,0)
d=data.frame(x=x, y=y)


library(png)
library(grid)
img <- readPNG(system.file("img", "Rlogo.png", package="png"))
g <- rasterGrob(img, interpolate=TRUE)

ggplot(d, aes(x, y)) + geom_point() + 
   annotation_custom(g, xmin=.20, xmax=.30, ymin=-2.2, ymax=-1.7) + 
   scale_y_reverse()

? y . :

(p = ggplot(d, aes(x=x, y=y)) + geom_point() + scale_y_reverse())
y.axis.limits = ggplot_build(p)$layout$panel_ranges[[1]][["y.range"]]
y.axis.limits

, grob rasterGrob.

g <- rasterGrob(img, x = .75, y = .5, height = .1, width = .2, interpolate=TRUE)

ggplot(d, aes(x, y)) + geom_point() + 
   annotation_custom(g) +
   scale_y_reverse()