[R] Issue increasing DPI on a png output of a plot

[Peter Langfelder]

On Mon, Sep 27, 2010 at 8:48 AM, Justin Fincher <fincher at cs.fsu.edu> wrote:
> Howdy,
>  I have created a set of plots, but I wish to increase the dpi to 300
> (instead of the default 72).  From the documentation, I thought that
> the "res" parameter to png should accomplish this, but it appears to
> greatly alter the appearance of my plot. (plot area becomes smaller,
> plot lines become thicker, etc.)  It is my understanding that
> increasing the dpi should not change the look of the plot, just the
> quality.  Any help in recreating my plots in 300 dpi would be greatly
> appreciated.

In short, instead of increasing "res", increase width and height. The
difference is that if you increase res, font sizes, line thicknesses
etc scale up in pixels so as to remain constant in terms of inches
(since you are increasing the number of pixels per inch). When you
increase width and height, the font sizes etc. remain constant in
terms of pixels since resolution also remains constant.

Peter