output slot.reactivePlot(func, width = "auto", height = "auto", ...)'auto' to use the offsetWidth of the
HTML element that is bound to this plot. You can also
pass in a function that returns the width in pixels or
'auto'; in the 'auto' to use the offsetHeight of the
HTML element that is bound to this plot. You can also
pass in a function that returns the width in pixels or
'auto'; in thpng. These can be used to set
the width, height, background color, etc.div or
img and have the CSS class name
shiny-plot-output.