ref_hline creates a layer of horizontal reference lines to be plotted behind
a layer of glyphs. Each line spans the full width of the glyph. The thickness
of the line can be adjusted with the thickness argument. Reference lines make it
easier to determine the location of an object within a glyph and to compare
objects across glyphs. Reference lines can also convey information on their
own through fill, colour, alpha, linetype, and (line) size mappings. By
default the fill parameter of a reference line is set to white.
Usage
ref_hline(mapping = NULL, thickness = 0.2, fill = "white", ...)
Arguments
mapping
An aesthetic mapping, usually constructed with
aes.
thickness
the thickness of the line as a proportion of the overall
glyph height. Defaults to 0.2.
fill
The color, as a character string, to be used as the fill if fill
is not specified in the mapping
...
other arguments to be used as parameters in the reference box
layer
Details
ref_hline is a second order function. It returns a function that can be used
to create a layer of reference lines with the specified mapping and
parameters. The output of ref_hline is intended to be passed as the reference
argument for geom_subplot or geom_subplot2d.