xbs readme information
The following contains the `README' information from the xbs standard package .
There is no facility in the program to change the linewidth for the
postscript output, but this can be easily acheived by editing the
postscript file. Just after the line
%%EndPageSetup
add the line
n setlinewidth,
where n is an integer (the default vaue being 1). Typical
values are 2-4.
XBS BALL-AND-STICKS PLOTTING PROGRAM (M. Methfessel Nov. 1995)
This program uses X-window graphics to produce ball-and-sticks plots.
It reads coordinates and other data from an input file (ie. ch4.bs)
and possibly different "frames" with shifted coordinates from an
auxillary move file (ie. ch4.mv). The default files are in.bs and
in.mv.
INSTALLATION
Compile by command 'cx xbs'. This compiles the C program together with
the X-Window includes and libraries. If everything works properly,
you can do 'cx -O xbs' in a second step to optimize. Possibly the
settings inside cx have to be changed for some operating
systems. Presently cx is set up for IBM AIX. There is a second
version called cx.sgi which is set up for Silicon Graphics
workstations.
INPUT
In a simple case, a file ch4.bs could look like this:
atom C 0.000 0.0000.000
atom H 1.155 1.1551.155
atom H -1.155 -1.1551.155
atom H 1.155 -1.155-1.155
atom H -1.155 1.155-1.155
spec C 1.000 0.7
spec H 0.700 0.7
bonds C C 0.0004.000 0.109 1.00
bonds C H 0.0003.400 0.109 1.00
bonds H H 0.0002.800 0.109 1.00
This sets the coordinates in the format
atom species x y z
and how to draw each atomic species, in the format
spec name radius color
and how to draw bonds, in the format
bonds name1 name2 min-length max-length radius color
A move file contains additional frames like this:
frame This is frame number two
0.000 0.000 0.000 1.155 1.155 1.155
-1.155 -1.155 1.155 1.155 -1.155 -1.155
-1.155 1.155 -1.155
After the keyword 'frame' comes an indentifying string,
then come the coordinates for all the atoms. Line breaks can
appear anywhere between the coordinates.
Other input lines are also possible, namely the lines which set
parameters (see below). Example: 'inc 5' sets the increment
for the rotation to 5 degrees.
In both files, lines starting with * and blank lines are comments.
USAGE
After starting the program with 'xbs ch4' the plot can be controlled
directly by selected keys. For example, to rotate the molecule use the
cursor keys and the keys "," and "." The last two were chosen because
they are below "<" and ">" whch look like arrows. To step through the
frames to show a "movie", use keys '[' and ']'. A number of other
keys are defined to function directly. More complicated functions are
done by pressing 'i' to get an input line and then typing a
command. Use 'xbs -hh' to get information on keys and
commands.
Sizing: Keys '+' and '-' make
the plot bigger or smaller.
Perspective: Key p
switches the perspective. Default is off. For pseudoperspective, the
sphere sizes depend on the distance to the viewer but the positions on
the page are unchanged. For true perspective, the sizes and the
positions both change. The strength of the perspective effect depends
on the distance to the viewer, which is shown in the status line. It
is changed with keys 'd' and 'D' or can be set directly with command
'dist'. (Note: if you come too close and put the viewpoint inside an
atom, the program will try to color the whole universe, which takes
very long).
Lighting: command 'gramp slope
middle' greys out the atoms in the back by an exponential
ramp. Command 'light x y z' shades the atoms somewhat as if light
shines along vector (x,y,z). These commands only work in black/white
mode. To switch back to normal coloring, enter 'gramp' or 'light'
without arguments.
Positioning: Keypad keys
8,6,4,2 move the plot about by an increment dpos (which can be set by
the command 'dpos'). Keypad key '*' saves the current position as
'home' (or use command 'pos' to set the home position
directly). Keypad key 7 moves the plot home. Positions are relative
to the center of the window.
Saving: command
'save' writes the data to a file (default Save.bs). If there are
multiple frames, a move file is also written. The 'save' command has
some options, see below.
Printing: the command
'print' writes output to a postscript file, by default the file
'Bs.ps'. A print file stays open until it is explicitly closed. In
this way several plots can be superimposed on the same page, using the
keypad cursor keys to shift the subplots on the page. The 'print'
command has some options, see below.
GETTING HELP
Typing 'xbs -h' and 'xbs -hh' gives short respectively long help.
After starting xbs, key 'h' toggles an overview. This is the same
information as is obtained with 'xbs -hh'.
On the input line, use 'help print' or 'print ?' or even 'print -h'
to get help on a specific command such as (in this case) print.
This help also shows any possible options for the command.
The space bar toggles extra information about the plot written
into the window.
SOME MORE DETAILS AND RECENT CHANGES
-
Color:
-
A color is specified either as a number between 0 and 1 (gray value),
three numbers between 0 and 1 (red, green, blue values or RGB),
or as a color name from the file /usr/lib/X11/rgb.txt (or similar).
- In the input file, the color of each species or bond is set
in these three ways.
- The following xbs options are related to color:
| -color | enable colors (default) |
| -bw | uses greys only |
| -st | uses grays only, stippled from a few values |
| -rv | reverse all colors |
| -auto | choose own colors. |
You can change these interactively with the update command.
For consistency, black is now 0 and white is 1. The -rv option
switches this. The only reason for using -bw or -st is that
the commands 'light' and 'gramp' do not work with colors.
- The '-auto' option is used to color the atoms in some standard way.
These colors are set in routine 'set_auto_colors' in file subs.h.
Starting from the species label (ie. Pd3 or Mg-a) the leading
alpha part is extracted and capitalized (ie. PD or MG) and
this string is used to select a color.
The idea is to put one's favorite colors into the routine
and then recompile xbs.
- The command 'color' changes the colors of atoms interactively,
ie. 'color C* green' changes the color of all matching species.
To show the color of a species, use the command without
specifying a color (ie. 'color C1' or 'color C-a').
- When data is saved with the 'save' command, the current colors
(as set with 'color') are saved as a string.
With 'save -rgb' the RGB values are written instead of color names.
If the -rv option is used, the reversed colors are saved as RGB values.
-
Some commands have options, eg. print, save, update.
For example:
|
print -T | print and add some info as title
|
|
print -t 'text .... ' | print and put text as title
|
|
update -rv | update but switch on reversing
|
|
update +rv | update but switch off reversing
|
|
update -bw | update but switch to black/white
|
|
save -rgb | save with colors as rgb values
|
|
save -step n | save with only every n'th frame
(good to compress a big .mv file).
|
Use 'help update' etc on the input line to see the options.
- Pattern matching for atom labels: * matches any string, + any char.
This can be used in the 'color' command and in the 'bonds' lines
in the input file (which determine what bonds are drawn).
For example, 'bonds C* H* ...' selects all bonds between
atoms like C1 and H34 etc. and 'bonds * * ...' selects all pairs.
-
Other miscellaneous changes:
- Key 'a' displays the axis directions.
- Key 'n' shows atom names or numbers. Key 'c' shows the coordinates.
- To close a postscript print file, use command 'close'.
- Command 'dup x y z' duplicates all atoms shifted by (x,y,z).
- Command 'cut x y z a b' cuts to those atoms between a and b
along the vector (x,y,z).
- The input line has a history list to retrieve old commands.
Use the up and down arrows when the input line is active.
- On some systems, the backspace key does not work to edit the
input line. Therefore the left-arrow key was defined to have
the backspace function also.
Last modified: Mon Mar 27 08:04:59 2000
by
Jonathan Goss
goss@excc.ex.ac.uk
validate