Not every user interface can be made using widgets. Take the desktop of Windows XX for example; it consists of a number of icons that have to be clicked to do something. Such an interface can not be constructed with the standard user interface widgets like buttons, listboxes, scrollbars, etc. The canvas can help us out. A canvas can be used to put items on a window. Items are standard elements of drawing: lines, rectangles, arcs, etc. If actions are bound to some events on these items, an alternative user interface can be made.