#include <graphics.h>
void setviewport(int left, int top, int right, int bottom, int clip);
 

setviewport establishes a new viewport for graphics output.
The viewport corners are given in absolute screen coordinates by
(left,top) and (right,bottom). The current position (CP) is moved to
(0,0) in the new window.
The parameter clip determines whether drawings are clipped (truncated) at
the current viewport boundaries. If clip is nonzero, all drawings will be
clipped to the current viewport.

/* setviewport example */
 
#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
 
#define CLIP_ON 1/* activates clipping in viewport */
 
int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
 
 
   /* initialize graphics and local variables */
   initgraph(&gdriver, &gmode, "");
 
   /* read result of initialization */
   errorcode = graphresult();
   if (errorcode != grOk)    /* an error occurred */
   {
printf("Graphics error: %s\n", grapherrormsg(errorcode));
 
printf("Press any key to halt:");
getch();
exit(1);   /* terminate with an error code */
   }
 
   setcolor(getmaxcolor());
 
   /* message in default full-screen viewport */
   outtextxy(0, 0, "* <-- (0, 0) in default viewport");
 
   /* create a smaller viewport */
   setviewport(50, 50, getmaxx()-50, getmaxy()-50, CLIP_ON);
 
   /* display some text */
   outtextxy(0, 0, "* <-- (0, 0) in smaller viewport");
 
   /* clean up */
   getch();
 
   closegraph();
   return 0;
}

clearviewport getviewsettings graphresult

  no output of example at the moment
  do not hesitate and add it...