Python GUI Tools

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Revision as of 12:36, 6 July 2009 by Patmarion (Talk | contribs)

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New tools in python shell

A new set of tabs has been added to the python shell. The python shell is accessed from the main paraview menu: Tools --> Python Shell. The new tabs are:

  • Directory view
  • Macros
  • Trace

Directory View

This tab has a text entry box to enter a script directory. By default, it is set to a 'demos' subfolder inside the paraview python module directory. Only files in the script directory ending with .py are displayed. The following buttons are available:

  • Refresh - refreshes the directory view, for convenience if you change something on disk that paraview doesn't know about
  • New script - launches the built in editor and displays a new document
  • Run selected - runs the python script currently selected in the directory view
  • Add to macros - adds the currently selected python script to the macro set

Python files in the directory view can be double clicked to open them in the editor.


Python files in the directory view can be added to the macros set. The current macros set is displayed in the listbox in the macros tab. You can double click a macro to edit its assigned name. The file on disk corresponding to a macro is displayed in the tooltip if you mouseover a macro in the listbox.

Macros are displayed in the macros menu and the macros toolbar. The macro menu is shown/hidden by a checkbox in the macros tab. The macros toolbar can be shown/hidden from the paraview main menu: View --> Toolbars --> Macro Toolbar. Both toolbar and menu are hidden by default, but if you show them it will be remembered between sessions.

Macros are saved between sessions using the ParaView Settings Files. Macros are referenced by absolute filename, so if the python file moves on disk the macro will no longer function.

Note: python is not initialized until you open the python shell for the first time. If you run a macro from the macro toolbar or menu before the python shell has been opened for the first time, you will notice a slight delay as python initializes itself. You should see a wait cursor while python is initializing.


Trace is a new module. It can be imported with 'from paraview import smtrace', but normally the user never needs to directly use the trace module. The trace tab provides buttons for controlling trace:

  • Start trace - starts trace. If an active trace was previously started, it will be stopped, cleared, and restarted.
  • Stop trace- stops trace. The trace output generated so far will not be cleared until trace is started again or the python shell is reset. Some internal trace data structures hold references to c++ objects, so if you want to make sure everything is cleaned up try resetting the shell.
  • Show trace- prints the current trace output in the python shell for display
  • Edit trace- opens the built in editor, creates a new document and fills it with the current trace output
  • Save trace- opens a prompt for the user to specify a filename and saves trace to disk. The trace script is now available in the directory view.

TIP: It's a good idea to stop trace before executing a trace script you just recorded. What I do is click the Disconnect server button in the paraview toolbar. This will clear the current pipeline objects, stop trace, and reset the python interpreter.

Trace verbosity

Because of the way the GUI initializes certain proxies, some parts of the trace will be more verbose than others. For example, every time a data representation is created, seven or eight properties related to selection are modified. It might be a nice feature to provide the user with a way to specify property suppressions.

Trace can run with different verbose levels. In full property verbose mode, trace records all properties of a proxy when the proxy is registered. Normally, trace only records properties when they are modified from their default values. Control over the verbosity level is not currently available in the gui, but you can start trace manually in verbose mode using the python shell:

from paraview import smtrace

# actions in the gui


Known issues with trace

It is possible to perform actions in the GUI that do not translate properly to trace. Here is a list of things that do not currently work:

  • renaming an object in the pipeline browser
  • filters that use glyphs
  • views other than 3D render view (also have not tested mpi render view)
  • time
  • scalar bar does work, but only if it's the last thing you add to the view

New built in editor

For convenience there is a new built in script editor. When the editor is opened on OSX, the editor's menubar temporarily replaces paraview's menubar. If this becomes too obtrusive the menu could be replaced by toolbar buttons. It might be a nice feature to allow the user to specify a command to launch an external editor.

UI issues

The new tab widget is embeded in the python shell dialog using a QSplitter. The tabs can be hidden completely by collapsing the splitter. The splitter state should be remembered between sessions. So should the size/position of the python dialog, and the size/position of the script editor. Please report any ui issues with the new python gui, and include your platform and qt version.

New C++ API

New classes have been introduced under Qt/Python. They depend on classes in Qt/Core but not Qt/Components. A new class named pqPythonManager is available globally through the pqApplicationCore instance:

  pqPythonManager* manager = qobject_cast<pqPythonManager*>(

The python manager has a public method:

  pqPythonDialog* pythonShellDialog();

Calling this method will return the python shell. Python will be initialized on the first call to this method and the returned pqPythonDialog will be ready to use. pqPythonDialog offers public methods for executing python files and strings of python code.

If you plan to call methods in the python c api, you must make the python interpreter active:

  pqPythonDialog* dialog = manager->pythonShellDialog();

  // Calls to python c api


When the python interpreter is reset, pqPythonDialog emits a signal 'interpreterInitialized()'. The pqPythonManager listens for this signals and imports the paraview modules. So when this signal is triggered, it is not guaranteed that paraview python modules have been imported yet. After the paraview python modules are imported, the pqPythonManager emits a signal 'paraviewPythonModulesImported()'.