! Example with stacked bars.
! Author: Francois Tonneau

size 11 9

set font ss cap round

amove 2 2.25
begin graph
    size 8 6
    fullsize

    xaxis min -0.3 max 17.5 ftick 1 dticks 1
    yaxis min 0 max 120

    x2axis off
    y2axis off
    xside  off
    xticks off

    ! We use the 'angle' axis subcommand to rotate x labels by 60 degrees. As
    ! the first column of our data file (stacks.dat) consists of non-numeric
    ! strings, GLE interprets them as x labels without further ado.

    xaxis angle 60

    ysubticks length 0.07
    xtitle "Ratio component (X) of tandem VI X" dist 0.3
    ytitle "Responses per minute" dist 0.4

    data "stacks.dat"

    ! GLE has different types of bar commands. A bar command such as:
    !
    ! bar dm
    !
    ! produces a single set of bars.

    ! A bar command such as:
    !
    ! bar dm,dn
    !
    ! produces grouped bars.

    ! A bar command such as:
    !
    ! bar dn from dm
    !
    ! produces stacked bars. In this case, however, GLE does not stack dn above
    ! dm; rather, GLE stacks the *difference*, dn - dm, above dm.

    ! Accordingly, if we want to plot d2 above d1 (as in the present example),
    ! we must first cumulate the two datasets. GLE allows us do this with the
    ! 'dn = dm...-expression' syntax. Here our expression is the sum, 'd1+d2':

    bar d1 width 0.9 fill lightsteelblue

    let d2 = d1+d2

    bar d2 from d1 width 0.9 fill cadetblue
end graph

amove 2 2.25
rline 0.1 0

! We conclude with plot decorations:

amove 2.7 7.75
box 0.4 0.4 just bl fill cadetblue
box 0.4 0.4 just tl fill lightsteelblue
rmove 0.7 0
set just bl
write "Key B"
rmove 0 -0.08
set just tl
write "Key A"

! Done. We have learned how to plot stacked bars.