Combining tools in one session

Some tools are really a small workbench: three to five programs on one session desktop, with a way to switch between them. nanoWhim is the window manager that does the switching.

What it does

nanoWhim puts a combobox at the top of the session desktop. Each entry in it is a separate application; picking one brings it up. Windows an application opens are managed as tabs, so a popup does not obscure the window it came from.

It was written for nanoHUB, to let a few related applications share one tool session without a full window manager's furniture. It is based on the Whim window manager, written in Tcl/Tk; Whim's own site is no longer online.

Berkeley Computational Nanoscience Class Tools on nanoHUB is the example the original documentation used: several separate Rappture applications on one desktop.

Switching between applications

The example below is a Rappture application that opened a separate Jmol window for molecular visualisation. Jmol gets its own tab, and the tabs switch between them. The x on a tab closes that application.

The combobox at the very top switches to a different application altogether, with its own inputs and outputs.

Each program runs independently and their outputs stay separate. Coming back to one finds it as you left it.

Configuring it

nanoWhim needs two files in the tool's middleware directory: nanowhimrc and invoke.

nanowhimrc

This file lists the applications. A minimal one:

# set an icon
set.config controls_icon header.gif

# first app is an xterm
start.app "Terminal Window" xterm

# second app is a web browser
start.app "Web Browser" firefox

Lines beginning with # are comments.

set.config controls_icon sets the icon in the top-left corner of the window. A relative filename is resolved against the location of nanowhimrc itself, so header.gif here means one sitting beside it in middleware.

Each start.app line adds an application. The quoted first argument is the label in the combobox; the rest is the Unix command that starts it. $dir stands for the directory holding nanowhimrc.

A fuller example, from a tool made of several Rappture applications:

#
# Customize the nanoWhim window manager
#
set.config controls_icon header.gif

start.app "Average" \
  /usr/bin/invoke_app -t ucb_compnano -T $dir/../rappture/avg

start.app "Molecular Dynamics (Lennard-Jones)" \
  /usr/bin/invoke_app -t ucb_compnano -T $dir/../rappture/ljmd

start.app "Molecular Dynamics (LAMMPS)" \
  /usr/bin/invoke_app -t ucb_compnano -T $dir/../rappture/lammps -u lammps-12Feb07

start.app "Monte Carlo (Hard Sphere)" \
  /usr/bin/invoke_app -t ucb_compnano -C "java -jar $dir/../bin/ising-1.0.jar"

Each line calls invoke_app with -t naming the tool and -T naming the directory holding that application's tool.xml. The -u in the LAMMPS line loads an environment package; the version there is from 2007 and is an example of the form, not a package to copy.

The invoke script

nanowhimrc configures the window manager; middleware/invoke starts it. The original documentation gave this form:

#!/bin/sh

/apps/share/nanowhim/invoke_app "$@" -t ucb_compnano

-t is the tool alias you registered. The script finds middleware/nanowhimrc in the tool's own directory and launches nanoWhim with it.

Testing

Individual applications can be tested one at a time in a workspace, the way any tool is. The combined desktop cannot: nanoWhim only comes together once the tool is installed on the hub.

So get the contribution to the Installed state, then use the Launch tool button on the tool's status page — the same button you would use to test any tool before approving it. See The contribution process for the states, the hub managers' walkthrough for the administrator's side, and the lecture on uploading and publishing new tools.