Raster annotations: annotation_raster
Mix.install([
{:giggly, path: Path.join(__DIR__, "..")},
{:kino, "~> 0.19"}
])About this notebook
This notebook follows the examples on ggplot2's reference page for
annotation_raster(), in the
order the page gives them. Each example shows ggplot2's code first and then Giggly's. An example
Giggly cannot draw yet keeps its ggplot2 code and names what it is waiting for, so the page is
also a list of what remains.
annotation_raster() draws a raster, a bitmap image given as a matrix of colours, in a rectangle
given in data coordinates, the same in every panel. It is a faster geom_raster() for static
annotations: it does not change the scales, so the axes do not grow to fit it, and its colours
are its own rather than mapped; -Inf and Inf stretch it to the panel's edges. Giggly has none
of it yet.
An image in a rectangle
# Generate data
rainbow <- matrix(hcl(seq(0, 360, length.out = 50 * 50), 80, 70), nrow = 50)
ggplot(mtcars, aes(mpg, wt)) +
geom_point() +
annotation_raster(rainbow, 15, 20, 3, 4)
R's hcl() turns hues from 0 to 360 into the colours of a rainbow, and matrix() lays them out
in 50 rows.
Not in Giggly yet: annotation_raster() and the raster it draws, a matrix of colours. The points
already work.
Filling the panel
# To fill up whole plot
ggplot(mtcars, aes(mpg, wt)) +
annotation_raster(rainbow, -Inf, Inf, -Inf, Inf) +
geom_point()
Added before the points, the raster is drawn under them.
Not in Giggly yet: annotation_raster().
Interpolating
rainbow2 <- matrix(hcl(seq(0, 360, length.out = 10), 80, 70), nrow = 1)
ggplot(mtcars, aes(mpg, wt)) +
annotation_raster(rainbow2, -Inf, Inf, -Inf, Inf) +
geom_point()
rainbow2 <- matrix(hcl(seq(0, 360, length.out = 10), 80, 70), nrow = 1)
ggplot(mtcars, aes(mpg, wt)) +
annotation_raster(rainbow2, -Inf, Inf, -Inf, Inf, interpolate = TRUE) +
geom_point()
A single row of colours stretched over the panel shows as bands; interpolate = TRUE blends each
into the next.
Not in Giggly yet: annotation_raster() and its interpolate option.
