/*
SG C Tools 1.1

(C) 1993 Steve Goldsmith
All Rights Reserved

Example scrolling regions of the screen.

Compiled with HI-TECH C 3.09 (CP/M-80).

To compile with HI-TECH C and SG C Tools source on same disk use:
C SCROLL.C -LC128
*/

#include <stdlib.h>
#include <hitech.h>
#include <conio.h>
#include <vdc.h>

#define appClrScrCh 32

void scrolltext(void);

extern uchar  vdcScrHorz;
extern uchar  vdcScrVert;

char appScrlStr1[] = {
"This is a string used to test scrolling VDC display memory."
};
char appScrlStr2[] = {
"You can scroll any region of the screen too!"
};

main()
{
  srand(99);
  savevdc();                         /* save vdc regs and set global vars */
  clrscrvdc(137);                    /* clear screen */
  clrattrvdc(vdcAltChrSet);          /* clear attributes */
  setcursorvdc(0,0,vdcCurNone);      /* turn cursor off */
  outvdc(vdcFgBgColor,vdcDarkGreen); /* set new screen color */
  printstrvdc(0,0,vdcAltChrSet,
  "VDC scrolling example.  Press [RETURN] to start.");
  while (getch() != 0x0D);          /* wait for return press */
  scrolltext();                     /* scrolling demo */
  restorevdc();                     /* restore registers saved by savevdc() */
  clrscrvdc(appClrScrCh);
  clrattrvdc(vdcAltChrSet+vdcWhite);
}

/* scroll whole screen up and down then just a window region */

void scrolltext(void)
{
  uchar I;

  printstrvdc(0,vdcScrVert-1,vdcAltChrSet,appScrlStr1);
  for (I = 1; I <= 23; I++)
    scrollupvdc(0,1,vdcScrHorz-1,vdcScrVert-1);
  for (I = 1; I <= 24; I++)
    scrolldownvdc(0,0,vdcScrHorz-1,vdcScrVert-2);
  printstrvdc(0,vdcScrVert-1,vdcAltChrSet,appScrlStr1);
  for (I = 1; I <= 24; I++)
    scrollupvdc(0,1,vdcScrHorz-1,vdcScrVert-1);
  clrscrvdc(137);
  clrwinvdc(17,7,60,18,appClrScrCh);
  for (I = 1; I <= 100; I++)
  {
    scrollupvdc(17,8,60,18);
    if (rand() > 16384)
      printstrvdc(17,17,vdcAltChrSet+(uchar) (rand() >> 11),appScrlStr2);
  }
  while (getch() != 0x0D);          /* wait for return press */
}