Re: presentation graphics

[Peter S Galbraith <GalbraithP@dfo-mpo.gc.ca>]

Russell Coker wrote:

> I want to produce some simple bar charts showing the difference between
> different products.  Gnuplot doesn't seem to be able to do what I want (just
> nice clean bars with numbers at the tops and descriptions at the bottom).

Ok, here's my shoot at it using `gri' 

 http://www.debian.org/Packages/unstable/math/gri.html
 http://www.phys.ocean.dal.ca/~kelley/gri/

(See http://www.debian.org/~psg for a pointer to a slink version)

Note that gri, like gnuplot I assume, doesn't have the concept of a
bar chart.  Yet you can easily program it to do what you want (and
further customize fonts, line widths, colours, etc)

Assume the two data files:

--- bar.dat ---
15
13.5
18
5
10.2
--- bar.dat ---


--- bar.labels ---
widget
bidget
squidget
midget
didget
--- bar.labels ---

Run the following bar.gri file like so:

$ gri bar.gri

to produce bar.ps

--- bar.gri ---
set x margin 5
set y margin 8
set x axis 0 10 
set y axis 0 20
set x size 10
set y size 15

.xLeft. = 1
.toggle. = 0
open bar.dat
open bar.labels
while 1
    read from bar.labels
    read \label
    if ..eof..
        break
    end if
    read from bar.dat
    read .val.
    set color hsb {rpn .xLeft. 1 - 6 /} 1 1 
    draw box filled .xLeft. 0   {rpn .xLeft. .9 +} .val.
    set color black
    draw box        .xLeft. 0   {rpn .xLeft. .9 +} .val.
    sprintf \.val. "%.1lf" .val.
    draw label "\.val." centered at \
        {rpn .xLeft. .45 + xusertocm} \
        {rpn .val. yusertocm .2 +} cm
    if .toggle.
        draw label "\label" centered at \
            {rpn .xLeft. .45 + xusertocm} \
            {rpn ..ymargin.. .7 -} cm
        .toggle. = 0
    else
        draw label "\label" centered at \
            {rpn .xLeft. .45 + xusertocm} \
            {rpn ..ymargin.. 1.2 -} cm        
        .toggle. = 1
    end if
    .xLeft. += 1
end while
--- bar.gri ---

Peter Galbraith, the Debian maintainer for gri.