This filter adds an inner glow to your layer with a specific colour and size. The best effect is often had by drawing the stroke separately so the glow is only applied to the fill.
with_inner_glow(x, colour = "black", sigma = 3, expand = 0, ...)
A ggplot2 layer object, a ggplot, a grob, or a character string naming a filter
The colour of the glow
The standard deviation of the gaussian kernel. Increase it to apply more blurring. If a numeric it will be interpreted as given in pixels. If a unit object it will automatically be converted to pixels at rendering time
An added dilation to the glow mask before blurring it
Arguments to be passed on to methods. See the documentation of supported object for a description of object specific arguments.
Depending on the input, either a
Layer, list of
element object. Assume the output can be used in the same
context as the input.
Other glow filters:
library(ggplot2) ggplot(mtcars, aes(as.factor(gear), disp)) + with_inner_glow( geom_boxplot(), colour = 'red', sigma = 10 ) # This gives a red tone to the lines as well which may not be desirable # This can be fixed by drawing fill and stroke separately ggplot(mtcars, aes(as.factor(gear), disp)) + with_inner_glow( geom_boxplot(colour = NA), colour = 'red', sigma = 10 ) + geom_boxplot(fill = NA)