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Customizing EXPGUI and Associated Programs

The EXPGUI GSAS graphical user interface can be modified in many ways quite easily. This document describes how the GUI works and how to modify the menus without significant reprogramming. A little bit of programming in Tcl/Tk can go a long way in adding new features. See the Customizing examples, below.


The main GUI is created by file expgui, which in turn uses the following files sequentially: Two additional files are read if they are found:

The first three files, (readexp.tcl, gsascmds.tcl, gsasmenu.tcl) must be located in the same directory where the expgui file is found. The localconfig file also is read from this directory, if it exists. The final file, .gsas_config, is read from the user's login directory (UNIX) or C:\ (Windows). The localconfig and .gsas_config are intended to contain system-wide and user-level default values for parameters that are described in this document. Most routines have a "Save Options" command that writes some of the current parameters to file .gsas_config. Note that information in .gsas_config overrides that in localconfig. No error occurs if either of these files are not found.

The readexp.tcl and gsascmds.tcl files contain tcl procedures that are used for more than one application, so it is convenient to place them in separate files. They are only of interest to someone trying to debug or add new functionality to expgui.

The gsasmenu.tcl file defines the contents of the menu bar, the contents of the button bar and definitions for each command. The contents of this file are designed to be modified and extended by users, either by editing the file, or by overriding definitions in the localconfig or .gsas_config files. The important variables defined in the gsasmenu.tcl file are:

This list defines the menu bar headings other than File, Options & Help
Each array element, e.g. expgui_menulist(file) and expgui_menulist(powder), defines commands to be added to a menu heading. Each command will appear as an array element in expgui_cmdlist.
Each array element, e.g. expgui_cmdlist(Save) or expgui_cmdlist(expnam) contains two items. The first defines a tcl procedure to be executed when the command is invoked, or "-" if no command will be invoked and the second contains help information describing what the command does. Note that when menu item is selected the variable cmd is set to the name of the command, so
    expgui_cmdlist(powpref) {{runGSASwEXP $cmd} {Powder data preparation}}
means that "runGSASwEXP powpref" will be invoked when powpref is invoked. . For example, when powpref is selected, the tcl command "runGSASwEXP $cmd" is invoked, where variable cmd is set to "powpref".
This list defines the commands that will appear on the button bar where each item that appears on the button bar must have a matching pair of entries in expgui_cmdlist. Thus if the command
   set expgui(buttonlist) {expnam expedt genles ortep fourier forsrh forplot lstview}
is placed in the localconfig or .gsas_config files this will redefine the contents of the button bar.
In addition to the variables defined in the previous file, expgui, uses a small number of array elements for other configuration options. They are:
This determines where files such as readexp.tcl, etc. are located. This defaults to the location where expgui is located so it rarely needs to be changed.
This contains the location of the GSAS directory, if it is not the parent director where expgui is found. This determines where a number of GSAS data files will be located. If expedt crashes when you try to add new atoms, this is probably wrong.
This determines where the GSAS executable files are located. You might want to change this is you keep multiple versions of GSAS around or if you keep the GSAS files in a different location than the default or want to keep the tcl files somewhere other than in a subdirectory of the GSAS files.
Sets the background color for the bottom box on the phase pane. The default value, #fdf, is a light violet that will probably drive some folks nuts, but is a good contrast to the yellow of the refinement flags.
Sets the default histogram used for liveplot
Sets the default value for display of the legend in liveplot
Defines commands to be executed by EXPGUI after all other commands have been run. This is used to define initialization commands in the localconfig or .gsas_config files that cannot be run at the time when the files are sourced. (added in EXPGUI v1.21)
The following variables are written to .gsas_config when "Save Options" is used. These variables are all set from the GUI and therefore do not need to be edited manually.
This defines the default state for the archive flag, where 0 is off and 1 is on. When archive is on, a copy of the .EXP file is saved before a new version of the file is saved in EXPGUI.
This determines the base font used in the programs. You conceivably could want to use an integer value not present in the "Options/Screen Font" menu command.
This determines the atom sort mode.
This determines the histogram sort mode.
This determines the default file sorting mode for the expnam command.
If set to 1, the experiment file is automatically reread after GSAS programs modify it. (UNIX only)
If set to 1, output from EXPTOOL is shown after the program is run. This is probably needed only for debugging purposes.
Used only for UNIX: This determines if the default definition for the backspace key is overridden; some UNIX systems need this so that expedt and other terminal-oriented programs work correctly and other systems do not. You can toggle this option using the "Override Backspace" option on the file menu to see what works for you.

Coordinate import routines for EXPGUI New!

Currently two formats are supported, the Crystallographic Information File (CIF) and .CEL files from PowderCell. It is possible to define new formats for EXPGUI to use for importing phase/coordinate information. This is done by creating a file named import_xxxx.tcl (where xxxx is arbitrary) in the EXPGUI directory. See the file import_cell.tcl as an example. The file must contain four items:


The localconfig and .gsas_config files are read, if present. The following options are available for customization in these files:
This limits the number of entries that can exist in a menu. For example, the default is 25, so when more than 25 cycles are found in a .LST file, only the last 25 are listed in the "Go To"/cycle submenu.
This limits the maximum number of characters that will be read from an existing .LST file to speed the start of the program. The default is ~1Mb for UNIX systems and ~200K for Windows.
The following variables are written to .gsas_config when "Save Options" is used. These variables can be set from the GUI and therefore do not need to be edited manually.
This sets the initial value for the "Auto Advance" button in the "Go To" menu. When this is true, the program will show the last cycle in the file. As new cycles are added, the "view" is advanced.
This sets the font used for LSTVIEW. See documentation on the font command in Tk for details on font naming.
One additional variable is present that I don't suggest using at present:


A description of the customization options for LIVEPLOT can be found in the LIVEPLOT description.


The widplt script is used to display the FWHM for one or more histograms from a .EXP file. At this point it only works for CW data. It is often convenient to add for reference the expected instrumental curves as options to the menu. This can be done by creating a file called widplot_name. For example, renaming the example_widplt_BT1 file supplied with the distribution to widplt_BT1 will cause the FWHM curves for the NIST BT-1 instrument to be added to the menu of defined FWHM values.

Creating such a file is easy. To add a entry define the following five array elements using a single, unique element name and then append that element name to variable datalist. Define

    set UVWP(Ge15) {398.5 -343.2  163.0 0}
    set XY(Ge15) {0 0}
    set wave(Ge15) 2.0775
    set lblarr(Ge15) "BT-1 Ge(311) 15'"
    set ttrange(Ge15) "5 160"
    lappend datalist Ge15 
Array element UVWP(item) contains the (Gaussian) GU, GV, GW and GP values, while XY(item) contains the (Lorentzian) LX and LY terms. Array element wave(item) contains a wavelength, array element lblarr(item) contains the text to be shown on the "Plot Contents" menu and ttrange(item) defines the range the function is valid.

The following variables are written to .gsas_config when "Save Options" is used. These variables are all set from the GUI and therefore do not need to be edited manually.

This is set to 1 if PostScript files will be printed and 0 if they will be written to disk (for Windows all files should be written to disk).
This is the default for the file name used when PostScript files will be written to disk.
This is the default for the command used to print PostScript files (Unix only).
Sets the default value for display of the legend in liveplot and widplt.
Sets the units used for displaying the data. Values are "d", "q", "", for d-space, Q and 2-theta, respectively.
Sets the wavelength used for displaying data, if blank, no conversion is done and data are shown in their original wavelength.

Customizing Example 1: Adding a new button to the button bar

When a LeBail extraction is used to refine lattice constants, profile terms, ... It is always a good idea to run GENLES a few times after running POWPREF. This is because GENLES sets the extracted intensities back to their crystallographic values, during the first GENLES cycle after POWPREF has been run. Refining anything until the extracted intensities return to reasonable values is a really bad idea. Forturnately, running GENLES with the number of cycles set to zero gives the Le Bail extraction a head start.

The code below can be used to define a new command, leBail. The first command adds a command to the button bar and the second one defines what will be done when it is invoked (the number of cycles is set to zero and GENLES is run three times). It also defines the help entry. Note that commands must start with a lower case letter even though Armel LeBail's last name does not.

    lappend expgui(buttonlist) leBail
    set expgui_cmdlist(leBail) {
	{set entryvar(cycles) 0; runGSASwEXP "genles genles genles"}
	{Converges GENLES with LeBail extractions; 
	  Sets the number of cycles to zero and runs GENLES 3 times.}

To make this customization, put the above in the localconfig file or the ~/.gsas_config or (or C:\GSAS\EXPGUI\.gsas_config) file.

Customizing Example 2: Putting DISAGL Results in a Separate Box

Barbara Reisner has been asking me to put the output from DISAGL in a separate window. Sounds like a pretty reasonable request. Here is an example with code to do that as a customization option. Please note that this has now been incorporated into EXPGUI, so do not use this example.
  set expgui(disaglSeparateBox) 1
  set expgui_cmdlist(disagl) {rundisagl {Hacked Distance/angle calculations}}
  proc rundisagl {} {
    global expgui txtvw tcl_version tcl_platform
    if {$expgui(disaglSeparateBox) && $tcl_platform(platform) != "windows"} {
	set root [file root $expgui(expfile)] 
	catch {file rename $root.LST $root.OLS}
	runGSASwEXP disagl
	catch {file rename $root.LST $root.DIS}
	catch {file rename $root.OLS $root.LST}

	# open a new window
	catch {toplevel .disagl}
	catch {eval grid forget [grid slaves .disagl]}
	text .disagl.txt -width 100 -wrap none \
		-yscrollcommand ".disagl.yscroll set" \
		-xscrollcommand ".disagl.xscroll set" 
	if {$tcl_version >= 8.0} {.disagl.txt config -font $txtvw(font)}
	scrollbar .disagl.yscroll -command ".disagl.txt yview"
	scrollbar .disagl.xscroll -command ".disagl.txt xview" -orient horizontal
	grid .disagl.xscroll -column 0 -row 2 -sticky ew
	grid .disagl.txt -column 0 -row 1 -sticky nsew
	grid .disagl.yscroll -column 1 -row 1 -sticky ns
	grid columnconfigure .disagl 0 -weight 1
	grid rowconfigure .disagl 1 -weight 1
	wm title .disagl "DISAGL results $expgui(expfile)"
	wm iconname .disagl "DISAGL $root"
	set in [open $root.DIS r]
	.disagl.txt insert end [read $in]
	close $in
	bind all  {destroy .disagl}
	bind .disagl  ".disagl.txt yview scroll -1 page"
	bind .disagl  ".disagl.txt yview scroll 1 page"
	bind .disagl  ".disagl.txt xview scroll 1 unit"
	bind .disagl  ".disagl.txt xview scroll -1 unit"
	bind .disagl  ".disagl.txt yview scroll -1 unit"
	bind .disagl  ".disagl.txt yview scroll 1 unit"
	bind .disagl  ".disagl.txt yview 0"
	bind .disagl  ".disagl.txt yview end"
	# don't disable in Win as this prevents the highlighting of selected text
	if {$tcl_platform(platform) != "windows"} {
	    .disagl.txt config -state disabled
    } else {
	runGSASwEXP disagl

if {$tcl_platform(platform) != "windows"} {
  append expgui(initstring) {
      $expgui(fm) add checkbutton  -label "DISAGL window" \
	      -variable expgui(disaglSeparateBox) -underline 0;

To make this customization, put the above in the localconfig file or the ~/.gsas_config or (or C:\GSAS\EXPGUI\.gsas_config) file.

Note that the expgui(initstring) option became available in EXPGUI version 1.21. (Previous versions will ignore this). This code must be executed after all the menus and other GUI code has been run. When executed, it creates a checkbutton on the Options menu to turn the "separate DISAGL window mode" mode on and off.

Customizing Example 3: Adding a new page to EXPGUI

The steps for creating support for additional functionality, implementation of atom constraints, is outlined here. Routines described here can be found in file atomcons.tcl unless otherwise noted.
  1. Create a routine to read and write the appropriate records from the .EXP file. In this case, a new routine, constrinfo, was added to file readexp.tcl. This takes considerable care and manual testing.
  2. Create a routine that places the appropriate widgets into a frame (in this case MakeAtomsConstraintsPane). This routine will be called only once. Note that in this example expcons(atommaster) is defined to be the name of the frame.
  3. Create a routine to display and edit the information shown in the frame. In this case, DisplayAtomConstraints. This routine will be called each time the page is displayed. Note that this routine and the previous can be tested in a separate toplevel until they work well.
  4. In this particular example, the previous frame is located on a notebook widget that in turn placed on a notebook page, so MakeConstraintsPane is used to create this inner notebook when the "Constraints" notebook page is first shown. This in turn calls MakeAtomsConstraintsPane and DisplayAtomConstraints. To update this page each time it is displayed, DisplayConstraintsPane is called.
  5. Edit file expgui to make the following changes:

Customizing Example 4: Changing the fonts used in the GUI

Question: I am not happy with the fonts available via the Option/Screen Font menu option. Is there a way to select different font size(s)/families?

GSAS is written by Allen C. Larson and Robert B. Von Dreele, MS-H805, Los Alamos National Laboratory, Los Alamos, NM 87545. Problems, questions or kudos concerning GSAS should be sent to Robert B. Von Dreele at

This GUI is written by Brian H. Toby of the NIST Center for Neutron Research, Brian.Toby@NIST.GOV.

GSAS is Copyright, 1984-1997, The Regents of the University of California. The GSAS software was produced under a U.S. Government contract (W-7405-ENG-36) by the Los Alamos National Laboratory, which is operated by the University of California for the U.S. Department of Energy. The U.S. Government is licensed to use, reproduce, and distribute this software. Permission is granted to the public to copy and use this software without charge, provided that this notice and any statement of authorship are reproduced on all copies. Neither the Government nor the University makes any warranty, express or implied, or assumes any liability or responsibility for the use of this software.

The GUI is not subject to copyright. Have fun.

Brian Toby (Brian.Toby@NIST.GOV)
$Revision: 461 $ $Date: 2009-12-04 23:06:33 +0000 (Fri, 04 Dec 2009) $