       FORMAT of the Choices and colours files for PolyDraw version 3.00
                             15 March 2001

     The text file (Choices) defines the starting conditions for the
program. These can be changed interactively from the icon bar or window
menus at any time; save them for future use from the icon bar menu.

     You do not need to know how the Choices file is arranged to use the
program.

     The rest of this gives more technical details for users who like to
know about such things.

    The file is made of lines each starting with a keyword possibly followed
by qualifiers.

     The default file is:

list PolyList
3D 1
net 1
desc 1
end

which selects:

  the file Polylists.PolyList for the list of polyhedra
  the 3D plots appear with 'wire' display
  the net plots appear with 'wire' display
  the descriptive text window is opened

    Here is a list of the possible keywords, their qualifiers and how they
are used.


type    description of data
------------------------------

list       Polylist file name
            (<=10 characters for file in <PolyDraw$Dir>.Polylists
            default is PolyList)

3D         information describing the way the 3D image is to be plotted
            (is integer ISTK3D at the moment, no '3d' means no 3D window)

net        information describing the way the net image is to be plotted
            (is integer ISTKNT at the moment, no 'net' means no net window)

desc       information describing what is shown in the description window
            (is integer ISTEXT at the moment, no 'decs' means no descriptor
            window)

sel        single letter descriptors of types of solids to be selected
            (no 'sel' card means all types)

name       string required to be part of the Polyhedra names selected
            (<=20 lower case characters with no blank; no 'name means all
            names are allowed)

sides      lowest and highest number of sides allowed for any face
            (two integers with blank between; no 'sides' means all are allowed)

faces      lowest and highest number of faces allowed
            (two integers with blank between; no 'faces' means all are allowed)

beep       (no qualifier) turn on the beep

tools      (no qualifier) turn on the tools pane for the 3D window

light      x and y directions cosines of the light direction for shaded 3D plot

persp      perpsective view of 3D solid

rot        rotation angle in degrees (1,2,5,10,90)

linewidth  widths of the 3D and net lines

3Dwindow   size of the 3D window (OS units) 

end        end of choices (optional)
            anything after this line is ignored


   None of the choice lines is essential, (even the file is not necessary).
The defaults are:

list    Polylist
3D        1
net       1
desc      1
sel       0 (= All solids)
name      ' ' (no name selection)
sides     (given by the min and max in the polylist file)
faces     (given by the min and max in the polylist file)
beep      (off)
tools     (off)
light     0.6 0.6
persp     (off)
linewidth 0 0
rot       10
3Dwindow  800

Note: One of the 3 display windows must be selected, so if the Choices file
does not include '3D', 'net', or 'desc', the default of all three is used.

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                  Resources.Colours file

 The colours are stored as hexadecimal numbers in the form BBGGRRxx, so that
the amounts of Red, Green and Blue can take any values up to 255 (decimal).
the value of 'xx' is usually 0 but is 255 if the face colour is 'clear'. it is ignored for anything other than external face colours.

 The lines in the file containthe following colours:

1)   (3 colours) 3D window background, the 'single' face colour, the colour of
         the inside of the faces.
2+3) (16 colours) the 'data' colours. 
4)   (8 colours) the '#sides' colours.
5+6) (16 colours) the 'plane' colours.
7+8) (16 colours) the 'compound' colours.
9)   (4 colours) the 'component' colours.
10)  (4 colours) line colours: solid edges, front wire, inside solid edges,
         back wire.
11)  (3 colours) for the R/G stereo: window background, 'red', 'green'
