Motif Multi-Document Interface (MDI)

## The Motif Multi-Document Interface

The Motif Multi-Document Interface (MDI) is a collection of C++ classes that emulates the behavior of the Multi-Document Interface in Microsoft Windows. The MDI framework allows a user to view multiple documents (windows) constrained to a single parent window.

CLASS STRUCTURE:

Figure 1. Inheritance Graph for MDI classes

The XsMDICanvas is a self-contained component used to display and manage any number of child document windows. All documents windows are derived from the abstract base-class XsMDIWindow. To get the Motif-like functionality, document windows should be derived from the XsMotifWindow class.

EXAMPLE:

The process of building and displaying a Multi-Document Interface using MDI consists of the following steps:

1. Creating the application document(s)
2. Creating the MDI canvas
3. Adding the document(s) to the canvas

    #include "XsMDICanvas.h"
    #include "XsMotifWindow.h"

    // Application document (derived from XsMotifWindow)

    class MyDocument : public XsMotifWindow {
       public:
          MyDocument (const char *name);
          virtual ~MyDocument ( );
       protected:
          virtual void _buildClientArea (Widget parent);
    };

    void createCanvas (Widget parent) {

    // Create documents

       MyDocument *doc1 = new MyDocument ("doc1");
       MyDocument *doc2 = new MyDocument ("doc2");

    // Create the canvas

       XsMDICanvas *canvas = new XsMDICanvas ("canvas", parent);

    // Add documents to canvas

       canvas->add (doc1);
       canvas->add (doc2);

    // Show the canvas

       canvas->show ( );
    }

In this example, the application document MyDocument is derived from XsMotifWindow. This provides a Motif-like window suitable for use with the XsMDICanvas.

Next, two MyDocument objects are created along with the XsMDICanvas. The two documents are then added to the canvas using the add member-function of the canvas. Lastly, the canvas is shown (managed) using the show member-function.

Creating the document MyDocument does not automatically create any widgets. Rather, it only initializes internal variables. The widgets are not created until the document is added to the canvas. The XsMDICanvas is responsible for calling XsMotifWindow::_buildClientArea() at an appropriate time. In this member-function, the application can create the actual contents of the document.

The member-function _buildClientArea is passed a widget to be used as the parent of the document contents. This parent widget is an unmanaged XmForm widget. The application is free to create whatever contents it needs as a child of the XmForm parent.

CLASS REFERENCES:

Of the classes in the MDI package, only the following should be of interest to MDI library users:

- XsMDICanvas
- XsMotifWindow

EXPLORING RESOURCES:

The MDI classes support a number of different X-resources (please refer to the class manual pages for complete details). In order to get a feel for the customization capabilities of the MDI library, try running the test program (MDItest) with the following command-line options:

  MDItest -xrm "*showBorder:false"
  MDItest -xrm "*showTitle:false" -xrm "*showResize:false"
  MDItest -xrm "*showMenu:false" -xrm "*showMaximize:false"
  MDItest -xrm "*borderSize:4" -xrm "*buttonSize:14"
  MDItest -xrm "*lowerOnIconify:true" -xrm "*title:Hello World"

ADDITIONAL IINFORMATION:

The test program MDItest.C gives a complete example of an MDI application. It should serve as a good reference/example of the MDI library.