pydraw wxpython example application the above illustrates what happens when the user presses and releases mouse button over the drawing panelto create new figure when the user presses the mouse buttona mouse clicked message is sent to the drawingcontrollerwhich decides what action to perform in response (see abovein pydrawit obtains the cursor point at which the event was generated by calling the getposition(method on the mouse_event the controller then calls its own add(method passing in the current mode and the current mouse location the controller obtains the current mode (from the pydrawcontroller using the method callback provided when the drawingcontroller is instantiatedand adds the appropriate type of figure to the drawingmodel the add(method then adds new figure to the drawing model based on the specified mode the classes this section presents the classes in the pydraw application as these classes build on concepts already presented in the last few they shall be presented in their entirety with comments highlighting specific points of their implementations note that the code imports the wx module from the wxpython librarye import wx the pydrawconstants class the purpose of this class is to provide set of constants that can be referenced in the remainder of the application it is used to provide constants for the ids used with menu items and toolbar tools it also provides constants used to represent the current mode (to indicate whether linesquarecircle or test should be added to the displayclass pydrawconstantsline_id square_id circle_id text_id square_mode 'squareline_mode 'linecircle_mode 'circletext_mode 'text