MPE_Draw_line
Draws a line on an X11 display 
Synopsis
#include "mpe.h" 
int MPE_Draw_line( handle, x1, y_1, x2, y_2, color )
MPE_XGraph handle;
int        x1, y_1, x2, y_2;
MPE_Color  color;
Input Parameters
- handle 
- MPE graphics handle 
- x1,y_1 
- pixel position of one end of the line to draw.  Coordinates are 
upper-left origin (standard X11)
- x2,y_2 
- pixel position of the other end of the line to draw.  Coordinates 
are upper-left origin (standard X11)
- color 
- Color `index` value.  See 'MPE_MakeColorArray'.  
By default, the colors
'MPE_WHITE', 'MPE_BLACK', 'MPE_RED', 'MPE_YELLOW', 'MPE_GREEN', 'MPE_CYAN',
'MPE_BLUE',  'MPE_MAGENTA', 'MPE_AQUAMARINE', 
'MPE_FORESTGREEN', 'MPE_ORANGE', 'MPE_VIOLET', 'MPE_BROWN', 
'MPE_PINK', 'MPE_CORAL' and 'MPE_GRAY' are defined.
Notes For Fortran Interface 
The Fortran interface to this routine is different from its C
counterpart and it has an additional argument, ierr, at the end
of the argument list, i.e. the returned function value (the error
code) in C interface is returned as the additional argument in
Fortran interface.  The Fortran interface is invoked with the
CALL statement.
All MPI and MPE objects, MPI_Comm, MPE_XGraph and MPE_Color, are
of type INTEGER in Fortran.
Location:../src/graphics/src/mpe_graphics.c