ggplot – how to "highlight" one segment of a curve

I have a plot like this:

library(ggplot2)

ggplot() +
  geom_function(fun = ~ 2*-.x^2 + 2*.x + 3)

Now I want to "highlight" one segment of the curve as on the following photo made in Paint:

How can I achieve that?

>Solution :

You can add an xlim argument to a second geom_function

library(ggplot2)

ggplot() +
  geom_function(fun = ~ 2*-.x^2 + 2*.x + 3) +
  geom_function(fun = ~ 2*-.x^2 + 2*.x + 3, xlim=c(.25, .5), color = 'blue', size = 2)

^{Created on 2022-11-15 by the reprex package (v2.0.0)}