The color vector of the histogram. If the number of colors is
less than break.n, the color will be reused. If the number of colors is
greater than break.n, only the previous break.n colors will be used.
breakNum
the number of cells for the histogram. The default value
is 15.
file.type
A string or NULL is used to determine the type of output
file. Can be "jpg", "pdf", "tiff". If it is NULL, it will use
dev.new() to create a new graphics device
in the current environment, which may be RStudioGD or the default
device of the system.
dpi
The resolution of the image, specifying how many pixels
per inch.