[ferret_users] Viewport : Relation between size and boundaries

[Jaison Kurian <jaison@xxxxxxxxxxxxxxxxxx>]

Hi,
    I want to make two viewports, a big one and a smaller one such
that the smaller one should just fit inside at the lower-right
corner of the bigger one. A direct attempt goes like this ...

  ! Remove tics and Labels
       ppl tics 0 0 0 0 0 0
       ppl axlsze 0, 0

  ! A big viewport
       define view/xlim=0.0:1.0/ylim=0.0:1.0 vbig ; set view vbig
       fill/nolab/nokey/pal=white I[I=1:10]*J[J=1:10]

  ! A small one on lower right corner
       let fgn_xlo = `($VP_XHI)-0.25`
       let fgn_xhi = `($VP_XHI)`
       let fgn_ylo = `($VP_YLO)`
       let fgn_yhi = `($VP_YLO)+0.25`
       define view/xlim=`fgn_xlo`:`fgn_xhi`/\
                       ylim=`fgn_ylo`:`fgn_yhi` vsmall
       set view vsmall
       fill/nolab/nokey/pal=white I[I=1:10]*J[J=1:10]

Now the smaller one is gone outside the boundaris of bigger one !!!

   1. Why should the rightern boundaries be different for the bigger
        one and smaller one  (i mean ..what is the advantage over
        size independant boundary) ??. What is the relation between
        viewport size and its boundaries ??

   2. How to fit the smaller one to the lower-right corner of bigger one ?
        I want the script to calculate the values needed to define the
        smaller viewport, **STRICTLY** based on the information available
        in ppl symbols about the first drawn bigger view port.

   3. If there is an /AXES qualifier to "define viewport", then the
        values returned by pplus symbols like $VP_XHI, $VP_XLO will be
        different than the values supplied to the define command.
        What is the relation between these given value and value available
        in pplus symbols ?

Regards,

Jaison