From free-cad

PyQt is a python module that allows python applications to create, access and modify Qt applications. You can use it for example to create your own Qt programs in python, or to access and modify the interface of a running qt application, like FreeCAD.

By using the PyQt module from inside FreeCAD, you have therefore full control over its interface. You can for example:

• Add your own panels, widgets and toolbars
• Add or hide elements to existing panels
• Change, redirect or add connections between all those elements

PyQt has an extensive API documentation, and there are many tutorials on the net to teach you how it works.

If you want to work on the FreeCAD interface, the very first thing to do is create a reference to the FreeCAD main window:

import sys
from PyQt4 import QtGui
app = QtGui.qApp
mw = app.activeWindow()

Then, you can for example browse through all the widgets of the interface:

for child in mw.children():
   print 'widget name = ', child.objectName(), ', widget type = ', child

The widgets in a Qt interface are usually nested into "containers" widgets, so the children of our main window can themselves contain other children. Depending on the widget type, there are a lot of things you can do. Check the API documentation to see what is possible.

Adding a new widget, for example a dockWidget (which can be placed in one of FreeCAD's side panels) is easy:

myWidget = QtGui.QDockWidget()
mw.addDockWidget(QtCore.Qt.RightDockWidgetArea,myWidget)

You could then add stuff directly to your widget:

  myWidget.setObjectName("my Nice New Widget")
  myWidget.resize(QtCore.QSize(300,100)) # sets size of the widget
  label = QtGui.QLabel("Hello World", myWidget) # creates a label
  label.setGeometry(QtCore.QRect(50,50,200,24)) # sets its size
  label.setObjectName("myLabel") # sets its name, so it can be found by name

But a preferred method is to create a UI object which will do all of the setup of your widget at once. The big advantage is that such an UI object can be created graphically with the Qt Designer program. A typical object generated by Qt Designer is like this:

class myWidget_Ui(object):
  def setupUi(self, myWidget):
    myWidget.setObjectName("my Nice New Widget")
    myWidget.resize(QtCore.QSize(300,100).expandedTo(myWidget.minimumSizeHint())) # sets size of the widget

    self.label = QtGui.QLabel(myWidget) # creates a label
    self.label.setGeometry(QtCore.QRect(50,50,200,24)) # sets its size
    self.label.setObjectName("label") # sets its name, so it can be found by name

  def retranslateUi(self, draftToolbar): # built-in QT function that manages translations of widgets
    myWidget.setWindowTitle(QtGui.QApplication.translate("myWidget", "My Widget", None, QtGui.QApplication.UnicodeUTF8))
    self.label.setText(QtGui.QApplication.translate("myWidget", "Welcome to my new widget!", None, QtGui.QApplication.UnicodeUTF8))

To use it, you just need to apply it to your freshly created widget like this:

myNewFreeCADWidget = QtGui.QDockWidget() # create a new dckwidget
myNewFreeCADWidget.ui = myWidget_Ui() # load the Ui script
myNewFreeCADWidget.ui.setupUi(myNewFreeCADWidget) # setup the ui
FCmw.addDockWidget(QtCore.Qt.RightDockWidgetArea,myNewFreeCADWidget) # add the widget to the main window