draw_image: Draw an image
In Alik-V/heor: HEOR tools

Places an image somewhere onto the drawing canvas. By default, coordinates run from 0 to 1, and the point (0, 0) is in the lower left corner of the canvas. Requires the 'magick' package to work, and fails gracefully if that package is not installed.

draw_image(
  image,
  x = 0,
  y = 0,
  width = 1,
  height = 1,
  scale = 1,
  clip = "inherit",
  interpolate = TRUE,
  hjust = 0,
  vjust = 0
)

`image`	The image to place. Can be a file path, a URL, or a raw vector with image data, as in 'magick::image_read()'. Can also be an image previously created by 'magick::image_read()' and related functions.
`x`	The x location of the image. (Left side if 'hjust = 0'.)
`y`	The y location of the image. (Bottom side if 'vjust = 0'.)
`width`	Width of the image.
`height`	Height of the image.
`scale`	Scales the image relative to the rectangle defined by 'x', 'y', 'width', 'height'. A setting of 'scale = 1' indicates no scaling.
`clip`	Set to "on" to clip the image relative to the box into which it is draw (useful for 'scale > 1'). Note that clipping doesn't always work as expected, due to limitations of the grid graphics system.
`interpolate`	A logical value indicating whether to linearly interpolate the image (the alternative is to use nearest-neighbour interpolation, which gives a more blocky result).
`hjust`	Horizontal justification relative to x.
`vjust`	Vertical justification relative to y.

library(ggplot2)

# Use image as plot background
p <- ggplot(iris, aes(x = Sepal.Length, fill = Species)) +
  geom_density(alpha = 0.7) +
  scale_y_continuous(expand = expand_scale(mult = c(0, 0.05))) +
  theme_half_open(12)

logo_file <- system.file("extdata", "logo.png", package = "cowplot")
ggdraw() +
  draw_image(logo_file, scale = .7) +
  draw_plot(p)

# Make grid with plot and image

cow_file <- system.file("extdata", "cow.jpg", package = "cowplot")
p2 <- ggdraw() + draw_image(cow_file, scale = 0.9)
plot_grid(
  p + theme(legend.position = c(1, 1), legend.justification = c(1, 1)),
  p2,
  labels = "AUTO"
)

# Manipulate images and draw in plot coordinates
if (requireNamespace("magick", quietly = TRUE)){
  img <- magick::image_transparent(
    magick::image_read(logo_file),
    color = "white"
  )
  img2 <- magick::image_negate(img)
  ggplot(data.frame(x = 1:3, y = 1:3), aes(x, y)) +
    geom_point(size = 3) +
    geom_abline(slope = 1, intercept = 0, linetype = 2, color = "blue") +
    draw_image(img , x = 1, y = 1, scale = .9) +
    draw_image(img2, x = 2, y = 2, scale = .9)
}