/* Screen functions for the VT100 terminal
 *
 * JWD - 11/12/18
 *
 * ANSI Escape Sequences
 *
 * cursor position - ESC[n;nH where n is in ASCII
 * erase in line - ESC[K
 * clear screen - ESC[nJ where n is 2 for clear all
 * line insert - ESC[L
 */

char bep[1];
char eol[3];
char clr[4];
char ins[3];
char sup[3];

scr_init ()
{
   eol[0] = clr[0] = ins[0] = sup[0] = 0x1b;
   eol[1] = clr[1] = ins[1] = sup[1] = '[';
   eol[2] = 'K';
   clr[2] = '2';
   clr[3] = 'J';
   ins[2] = 'L';
   sup[2] = 'S';
   bep[0] = 0x07;
}

scr_curs (y, x) int y, x;
{
   /* xy cursor position */

   char curs[9];

   sprintf (curs, "\x1b[%d;%dH", y+1, x+1);

   write (1, curs, strlen(curs));
}

scr_beep ()
{
   /* ring the bell */

   write (1, bep, 1);
}

scr_eol ()
{
   /* erase from cursor to end of line */

   write (1, eol, 3);
}


scr_clear ()
{
   /* clear the screen */

   write (1, clr, 4);

   scr_curs (0, 0);
}

scr_linsert ()
{
   /* line insert */

   write (1, ins, 3);
}

scr_scrlup ()
{
   /* scroll up */

   write (1, sup, 3);
}