Scrolling

This is actually very simple. You just take the widget in which you want to be able to scroll, and instead of linking it to the form, you create a Viewport widget which you link to the form, and then you link your widget to the viewport.

Basically, instead of:

  form = XtVaCreateManagedWidget ("form", formWidgetClass, toplevel, NULL);
  blaat = XtVaCreateManagedWidget ("blaat", blaatWidgetClass, form, NULL);

you write:

  form = XtVaCreateManagedWidget ("form", formWidgetClass, toplevel, NULL);
  vp = XtVaCreateManagedWidget ("vp", viewportWidgetClass, form, NULL);
  blaat = XtVaCreateManagedWidget ("blaat", blaatWidgetClass, vp, NULL);

The Viewport widget has a few interesting resources that you can use for scrolling. Here are a few of them:

• The allowHoriz and allowVert, set to False by default, determine whether there should be a scroll bar in both directions. If they are set to True, they will create a scroll bar in their respective direction, but only when needed;
• If you want to have scroll bars no matter what, you must set the forceBars resource to True;
• The useBottom and useRight resources will, when set to True make the scroll bars appear at the bottom and right of the window instead of the default top or left.

Last updated: January 31, 2003 by Jaap Boender