bbox2(3G)							     bbox2(3G)

NAME    [Toc]    [Back]

     bbox2, bbox2i, bbox2s - culls and prunes to bounding box and minimum
     pixel radius

C SPECIFICATION    [Toc]    [Back]

     void bbox2(xmin, ymin, x1,	y1, x2,	y2)
     Screencoord xmin, ymin;
     Coord x1, y1, x2, y2;

     void bbox2i(xmin, ymin, x1, y1, x2, y2)
     Screencoord xmin, ymin;
     Icoord x1,	y1, x2,	y2;

     void bbox2s(xmin, ymin, x1, y1, x2, y2)
     Screencoord xmin, ymin;
     Scoord x1,	y1, x2,	y2;

     All of the	above routines are functionally	the same.  They	differ only in
     the declaration types of their parameters.

PARAMETERS    [Toc]    [Back]

     xmin   expects the	width, in pixels, of the smallest displayable feature.

     ymin   expects the	height,	in pixels, of the smallest displayable
	    feature.

     x1	    expects the	x coordinate of	a corner of the	bounding box.

     y1	    expects the	y coordinate of	a corner of the	bounding box.

     x2	    expects the	x coordinate of	a corner of the	bounding box. The
	    corner referenced by this parameter	must be	diagonally opposite
	    the	corner referenced by the x1 and	 y1 parameters.

     y2	    expects the	y coordinate of	a corner of the	bounding box. The
	    corner referenced by this parameter	must be	diagonally opposite
	    the	corner referenced by the x1 and	 y1 parameters.

DESCRIPTION    [Toc]    [Back]

     bbox2 performs the	graphical functions known as culling and pruning.
     Culling prevents the system from drawing objects that are less than the
     minimum feature size (xmin	and ymin). Pruning prevents the	system from
     drawing objects that lie completely outside the viewport.

     To	determine whether or not to cull an object, bbox2 tests	whether	or not
     the display of a rectangle	the size of the	bounding box is	smaller	than
     the minimum feature size. To determine whether or not to prune an object,
     bbox2 tests whether or not	the bounding box is completely outside the
     viewport.






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bbox2(3G)							     bbox2(3G)



     Call bbox2	within the definition for an object, just after	the call to
     makeobj.  If the object must be pruned or culled, the remainder of	the
     object definition is ignored.

SEE ALSO    [Toc]    [Back]

     makeobj

NOTES    [Toc]    [Back]

     This routine does not function in immediate mode.

     This routine is not a free	test.  If you use bbox2	too freely, your
     performance can suffer.  Reserve bbox2 for	complicated object definitions
     only.


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