#include "stdio.h"
#include "dos.h"
#include "stdlib.h"

#define BORDER 1
#define ESC 27
#define REV_VID 0X70
#define NORM_VID 7

void save_video(),restore_video();
void goto_xy(),cls(),write_video();
void display_menu(),draw_border();

char *fruit[]={
        "Apple",
        "Orange",
        "Pear",
        "Grape",
        "Raspberry",
        "Strawberry"
    };

char *color[]={
        "Red",
        "Yellow",
        "Orange",
        "Green"
    };

 char *apple_type[]={
        "Red delicious",
        "Jonathan",
        "Winesap",
        "Rome"
    };

void  main()
	{
	int i;
	cls();
	goto_xy(0,0);
	for (i=0;i<25;i++)
/*	  printf("this is a test of the pop-up windows routine.\n");*/
	popup(fruit,"aopgrs",6,1, 3,BORDER);
	popup(color, "ryog",4,5,10,BORDER);
	popup(apple_type,"rjwr",4,10,18,BORDER);
	}

    int popup(menu,keys,count,x,y,border)
	char * menu[];
	char * keys;
	int count;
	int x,y;
	int border;
  {

        register int i,len;
	int endx,endy,choice;
	unsigned int *p;

        if((x>24)||(x<0)||(y>79)||(y<0))
            {   printf("range error");    
                return -2;
            }

	  len=0;
	  for(i=0;i<count;i++)
	    if(strlen(menu[i])>len)  len=strlen(menu[i]);
          endy=len+2+y;
          endx=count+1+x;
	    if((endx+1>24)||(endy+1>79))
               {   printf("menu won't fit");     
                   return -2;
               }

	 p=(unsigned int *)malloc((endx-x+1)*(endy-y+1));
	 if(!p) exit(1);

         save_video(x,endx+1,y,endy+1,p);

         if(border) draw_border(x,y,endx,endy);

         display_menu(menu,x+1,y+1,count);

	 choice=get_resp(x+1,y,count,menu,keys);

	 restore_video(x,endx+1,y,endy+1,(char *)p);
	 free(p);
	 return choice;
    }

    void display_menu(menu,x,y,count)
	char *menu[];
	int x,y,count;
        {
		register int i;

		for(i=0;i<count;i++,x++)
		{
		    goto_xy(x,y);
		    printf(menu[i]);
		}
	 }

    void draw_border(startx,starty,endx,endy)
        int  startx,starty,endx,endy;
    {
        register int i;
	for(i=startx+1;i<endx;i++)
	 {      goto_xy(i,starty);
		putchar(179);
		goto_xy(i,endy);
		putchar(179);
	  }

	for(i=starty+1;i<endy;i++)
	  {     goto_xy(startx,i);
		putchar(196);
		goto_xy(endx,i);
		putchar(196);
	  }
	goto_xy(startx,startx);putchar(218);
	goto_xy(startx,  endy);putchar(191);
	goto_xy(  endx,starty);putchar(192);
	goto_xy(  endx,  endy);putchar(217);
      }

       get_resp(x,y,count,menu,keys)
        int x,y,count;
        char *menu[];
        char *keys;
       {
                union inkey
                {    char  ch[2];
                     int  i;
		 }      c;

         int arrow_choice=0,key_choice;

	 y++;

         goto_xy(x,y);
	 write_video(x,y,menu[0],REV_VID);
	 for(;;)        {
		while(!bioskey(1));
		c.i=bioskey(0);

                goto_xy(x+arrow_choice,y);
		write_video(x+arrow_choice,y,menu[arrow_choice],NORM_VID);
		if(c.ch[0])
		{
		key_choice=is_in(keys,tolower(c.ch[0]));
		   if(key_choice)   return key_choice-1;
			switch(c.ch[0]) {
                                case '\r':return arrow_choice;
                                case ' ': arrow_choice++;
                                break;
                                case ESC:return -1;
                                         }
		  }

                 else   {
                        switch(c.ch[1])
                            {     case 72:arrow_choice--;
                                  break;
                                  case 80:arrow_choice++;
                                  break;
                             }
			  }

                 if(arrow_choice==count)  arrow_choice=0;
                 if(arrow_choice<0)       arrow_choice=count-1;

                 goto_xy(x+arrow_choice,y);
	     write_video(x+arrow_choice,y,menu[arrow_choice],REV_VID);

	    }
      }


 void write_video(x,y,p,attrib)
    int x,y;
    char *p;
    int attrib;
    {
	union REGS r;
	register int i,j;
	for(i=y;*p;i++)
		{   goto_xy(x,i);
                    r.h.ah=9;
		    r.h.bh=0;
		    r.x.cx=1;
		    r.h.al=*p++;
		    r.h.bl=attrib;
		    int86(0x10,&r,&r);
		 }
    }

void save_video(startx,endx,starty,endy,buf_ptr)
     int startx,starty,endx,endy;
     unsigned char *buf_ptr;
     {
	union REGS r;
	register int i,j;

	for(i=starty;i<endy;i++)
	    for(j=startx;j<endx;j++)
	    {   goto_xy(j,i);
		r.h.ah=8;
		r.h.bh=0;
		*buf_ptr++=int86(0x10,&r,&r);
		putchar(' ');
	    }
      }

void restore_video(startx,endx,starty,endy,buf_ptr)
     int startx,starty,endx,endy;
     unsigned char *buf_ptr;
     {
	union REGS r;
	register int i,j;

	for(i=starty;i<endy;i++)
	    for(j=startx;j<endx;j++)
	    {    goto_xy(j,i);
		 r.h.ah=9;
		 r.h.bh=0;
		 r.x.cx=1;
		 r.h.al=*buf_ptr++;
		 r.h.bl=*buf_ptr++;
		 int86(0x10,&r,&r);
	     }
    }

void cls()
    {
	union   REGS r;

        r.h.ah=6;
        r.h.al=0;
        r.h.ch=0;
        r.h.cl=0;
        r.h.dh=24;
        r.h.dl=79;
        r.h.bh=7;
        int86(0x10,&r,&r);
     }

void goto_xy(x,y)
     int x,y;
    {
	union REGS r;

        r.h.ah=2;
	r.h.dl=y;
	r.h.dh=x;
	r.h.bh=0;
       int86(0x10,&r,&r);
    }


is_in(s,c)
    char *s,c;
    {
    register int i;

    for(i=0;*s;i++) if(*s++==c) return i+1;
    return 0;
    }

bioskey(c)
     int c;
     {
	switch(c)
	{    case 0:return get_key();
	     case 1:return kbhit();
	 }
       }

get_key()
     {
	union REGS r;
	r.h.ah=0;
	return int86(0x16,&r,&r);
      }