[R] barplot - change width of bar outline

[Marc Schwartz]

On Jun 2, 2011, at 10:54 PM, Rolf Turner wrote:

> On 03/06/11 10:26, CAB wrote:
>> Dear R users
>> I am modifying a column chart which I have created in R using barplot to
>> make it clearer. I have been able to change the settings to increase the
>> width of the axes lines and the text size but I cannot find the code to
>> change the width of the lines which create the bars/columns themselves. Can
>> anyone point me in the right direction please?
> 
> As the code currently stands, it would appear that you *can't* change
> the widths of the lines which create the bars.
> 
> However, it wouldn't be too hard to hack the code to make this possible.   One
> thing that makes it slightly tricky is that the code allows for cross-hatching
> of the bars, and that is effected by the rect() function.  The lwd argument
> to rect() has an impact upon both the perimeter of the rectangle and
> the cross-hatch lines.  Presumably you don't want to increase the line width
> of the latter.  Hence you'd have to make two calls to rect() --- one to
> draw the perimeter with the line width increased, and no cross-hatching,
> and then again with the line width as usual and with the specification of the
> cross-hatching included.
> 
> The code for barplot.default() is all in raw R (no mucking around with
> calls to .Internal() !!!) and is pretty straightforward, so the hack won't
> be too hard to implement.
> 
> Good luck.
> 
>    cheers,
> 
>        Rolf Turner


If you need the 'density' cross hatching, there is a workaround:

  par(lwd = 3)
  barplot(1:5, col = "white")
  par(lwd = 1)
  barplot(1:5, density = 10, add = TRUE)


If you don't need the cross hatching, just use the first two lines.

HTH,

Marc Schwartz