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, ...)Arguments
- x
A ggplot2 layer object, a ggplot, a grob, or a character string naming a filter
- colour
The colour of the glow
- sigma
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
- expand
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.
Value
Depending on the input, either a grob, Layer, list of Layers,
guide, or element object. Assume the output can be used in the same
context as the input.
See also
Other glow filters:
with_outer_glow()
Examples
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)
