This filter adds an outer glow to your layer with a specific colour and size. For very thin objects such as text it may be beneficial to add some expansion. See the examples for this.
with_outer_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_inner_glow()
Examples
library(ggplot2)
ggplot(mtcars, aes(as.factor(gear), disp)) +
with_outer_glow(
geom_boxplot(),
colour = 'red',
sigma = 10
)
# For thin objects (as the whiskers above) you may need to add a bit of
# expansion to make the glow visible:
ggplot(mtcars, aes(mpg, disp)) +
geom_point() +
with_outer_glow(
geom_text(aes(label = rownames(mtcars))),
colour = 'white',
sigma = 10,
expand = 10
)
