gselect(3G)

NAME
     gselect - puts the system in selecting mode

C SPECIFICATION
     void gselect(buffer, numnam)
     short buffer[];
     long numnam;

PARAMETERS
     buffer   expects the buffer into which you want the system to save the
              contents of the names stack.  A name is a 16-bit number, that
              you load on the name stack just before you called a drawing
              routine.

     numname  expects the maximum number of names that you want the system to
              save.  This number must not exceed the number of elements in
              buffer.

DESCRIPTION
     gselect turns on the selecting mode.  When in selecting mode, the system
     notes when a drawing routine intersects the selecting region and writes
     the contents of the names stack to the specified buffer. If you push a
     name onto the names stack just before you call each drawing routine, you
     can record which drawing routines intersected the selecting region.

     Use the current viewing matrix to define the selecting region.

     gselect and pick are identical except gselect allows you to create a
     viewing matrix in selecting mode.  To end select mode, call endselect.

SEE ALSO
     endpick, endselect, pick, picksize, initnames, pushname, popname,
     loadname

NOTE
     This routine is available only in immediate mode.

     In order to select a large point or a wide line in selecting mode, the
     selecting region must intersect the displayed point center or the
     displayed line center respectively.  The displayed point center is the
     imaginary point of size 1 specified by the same vertex as the displayed
     point.  The displayed line center is the imaginary line of width 1
     specified by the same vertices as the displayed line.  In case of a very
     large point or very wide line, you may want to consider drawing a filled
     circle or a filled rectangle respectively instead.