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>Chapter 8. The <SPAN
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>GnomeCanvas</SPAN
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>	The <SPAN
CLASS="TYPE"
>GnomeCanvas</SPAN
> widget is a high-level engine for
	creating structured graphics.  A canvas displays a collection of
	items, which can be lines, rectangles, ellipses, and text.
	Items have attributes associated to them that you can change,
	like fill color, position, and size.  Items may be moved and
	re-stacked in the canvas, and organized in hierarchical groups.
	You can receive mouse and keyboard events from the items and
	perform actions on them based on these events.
      </P
><P
>	The canvas is useful for when you want to create interactive
	graphics displays which would be hard or cumbersome to implement
	with raw calls to Gdk, or when writing a custom widget for Gtk
	is inconvenient.
      </P
><P
>	The canvas is also useful to create displays of graphs,
	diagrams, and many other types of structured drawings.  It can
	even be used as a general display engine &#8212; for example,
	the Gnumeric spreadsheet and the Achtung presentations program
	both use the GnomeCanvas widget as their display engine.
      </P
><P
>	If the predefined canvas item types do not suit your needs, you
	can easily write new item types.  These can be primitive items,
	which paint their own displays, or composite items, which are
	built on top of canvas item groups.
      </P
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