DESIGN (xvobjects) functions


LIBRARY ROUTINE

xvw_create_canvas - create a canvas object

LIBRARY CALL

xvobject xvw_create_canvas(
   xvobject parent,
   char     *name)

INPUT

OUTPUT

none

RETURN VALUE

The canvas object on success, NULL on failure

DESCRIPTION

The canvas object is essentially a manager object combined with a virtual window size. The virtual window is a viewport where a canvas may contain a vertical scrollbar, a horizontal scrollbar, or both. In general, it is used to confine large visual displays to a predefined area. The canvas object may have one or many children; usually, the object(s) created inside the canvas will take up more space than the canvas itself, so that the scrollbar(s) of the canvas may be used to view the entire display. The canvas object is similar to the viewport object, except the canvas provides an area for displaying graphical objects, while the viewport object is typically only used to contain GUI objects. The canvas object allows the application to set a default width and height, while the viewport will shrink its area to the minimum size required to lay out all its children.

The canvas object also offers a global clipboard, which acts as a common cut and paste area for use by all canvas objects that may be displayed at the same time, providing an easy method for the user to transfer objects from one canvas to another.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

none

MODIFICATION

none

FILES

$DESIGN/objects/library/xvobjects/src/Canvas.c

SEE ALSO

xvobjects(3)

COPYRIGHT

Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.