%N pgstbg %F $MIR/src/pgstbg.f
%D Set text background color index
%B
      SUBROUTINE PGSTBG (TBCI)
      INTEGER  TBCI

 Set the Text Background Color Index for subsequent text. By default
 text does not obscure underlying graphics. If the text background
 color index is positive, however, text is opaque: the bounding box
 of the text is filled with the color specified by PGSTBG before
 drawing the text characters in the current color index set by PGSCI.
 Use color index 0 to erase underlying graphics before drawing text.

 Argument:
  TBCI   (input)  : the color index to be used for the background
                    for subsequent text plotting:
                      TBCI < 0  => transparent (default)
                      TBCI >= 0 => text will be drawn on an opaque
                    background with color index TBCI.
