/* 871K EXAM  -  DRAW program with ellipse implemented */

/* COMPILER DIRECTIVES */
#include <graphics.h>
#include <bios.h>
#include <stdio.h>
#include <math.h>

#define TITLE 22                         /* Number of characters in the title */
#define NUMBER(array) sizeof(array)/sizeof(array[0])
#define TRUE 1
#define FALSE 0
#define HERC_G 99
#define CGA_G 4
#define EGA_G 13
#define VGA_G 18
#define BULLET 16
#define CURSOR 95
#define SPACE 32
#define BACKSPACE_KEY 8
#define ENTER_KEY 13
#define ESCAPE_KEY 27
#define FLINE 0
#define FCIRCLE 1
#define FRECTANGLE 2
#define FELLIPSE 3    /* NEW DEFINITION for saving/retrieving purposes */

/* FUNCTION PROTOTYPES */
void Delay(int);
void Comment_Line(char);
int Get_Choice(int,int,int,int);
void Make_Menu(int,int,int,int,int,int);
void Graphics_Setup();
void Clean_Slate();
void Input_Box();
void File_IO(int);
int Get_Coords(int);
void Canvas_Restore();
void Shape_Maker(int);
void Line_Maker(int);

/* DECLARATION OF GLOBAL VARIABLES */
int choices[2], cursor_x, cursor_y, color;
char menu_buf[2][120][64];
int menu_para[2][4];
int element_buffer[4000], element_pntr, bufull_flag;
char filename[26]="DRAW.DAT";

struct vconfig screen; /* Holds xpixels, ypixels, textcols, textrows,
                          colors, bitsperpixel, pages, colormask,
                          aspect_v, aspect_h */

char clean[6][6]= {{0,0,0,0,0,0},
                  {0,0,0,0,0,0},
                  {0,0,0,0,0,0},
                  {0,0,0,0,0,0},
                  {0,0,0,0,0,0},
                  {0,0,0,0,0,0}};

char *menu_items[4][5] = {{"MAIN MENU","Lines","Shapes","Files","Exit"},
                          {"LINES","Draw","Endpoints","",""},
                          {"SHAPES","Circle","Rectangle","Ellipse",""},
                          {"FILES","Save","Save as","Get",""}};

/* FUNCTION DEFINITIONS */
main()                                                 /* Controling routine */
{
   int parent_x=16, parent_y=16, items, menu_number=0;
   int level=0, max_chars=11, items_count[4]={5,3,4,4};
   char title="SIMPLE DRAWING PROGRAM";
   int i, j, x, y;
   int menu_x, menu_y, right_edge, bottom_edge;

       /* Autodetection of graphics hardware and enter optimum graphics mode */
   Graphics_Setup();
   cursor_x=screen.xpixels/2;
   cursor_y=screen.ypixels/2;
   color=15;
   element_pntr=0;

                                      /* Create screen environment for menus */
   pen_color(3);
   move_to(1,1);
   line_to(screen.xpixels-1,1);
   line_to(screen.xpixels-1,screen.ypixels-1);
   line_to(1,screen.ypixels-1);
   line_to(1,1);
   move_to(1,screen.ypixels-14);
   line_to(screen.xpixels-1,screen.ypixels-14);
   move_to(1,11);
   line_to(screen.xpixels-1,11);
   move_to(((screen.xpixels-(TITLE*8))/2),3);
   plots(title);
   pen_color(color);

                                        /* Begin main program control loop */
   while(TRUE)
   {
      menu_number=0;
      level=0;
      items=items_count[menu_number];
      Make_Menu(parent_x,parent_y,items,menu_number,level,max_chars);

      do {
         menu_number=0;
         level=0;
         items=items_count[menu_number];
         menu_number=Get_Choice(parent_x, parent_y, items, level);
         choices[0]=menu_number;

         if (choices[0] == 4) {
            setvmode(DEFAULTMODE);
            exit(0);
         }

         level=1;
         items=items_count[menu_number];
         Make_Menu(parent_x,parent_y,items,menu_number,level,max_chars);

         menu_number=Get_Choice(parent_x, parent_y, items, level);
         choices[1]=menu_number;

          /* Here the Esc key was hit, so restore screen area behind the menu */

         if (menu_number == 0) {
            j=0;
            menu_x=menu_para[level][0];
            menu_y=menu_para[level][1];
            right_edge=menu_para[level][2];
            bottom_edge=menu_para[level][3];

            for(y=menu_y;y<=bottom_edge;y++){
               i=0;
               for(x=menu_x;x<=right_edge;x++){
                  pen_color((int)menu_buf[level][i][j]);
                  setpixel(x,y);
                  i++;
                }
             j++;
             }
         }
      } while (menu_number == 0);

                                                                    /* Menu 1 */
      if (choices[0]==1){
         Canvas_Restore();
         Line_Maker(choices[1]);
      }

                                                                    /* Menu 2 */
      if (choices[0]==2){
         Canvas_Restore();
         Shape_Maker(choices[1]);
      }

                                                                   /* Menu 3 */
      if (choices[0]==3){
         Canvas_Restore();
         File_IO(choices[1]);
      }

   }

}
Graphics_Setup()                    /* Autodetect and establish graphics mode */
{
   int mode;

   if(setvmode(VGA_G) == VGA_G)
      goto Graphics_mode;
   else if(setvmode(EGA_G) == EGA_G)
      goto Graphics_mode;
   else if(setvmode(CGA_G) == CGA_G)
      goto Graphics_mode;
   else if(setvmode(HERC_G) == HERC_G)
      goto Graphics_mode;
   else {
      printf("You don't have a graphics card installed");
      exit(0);
   }

Graphics_mode:
   getvconfig(&screen);
   mode=getvmode();
   clrscrn2(0);
   return;
}

                                              /* Put the menu on the screen */
Make_Menu(parent_x,parent_y,items,menu_number,level,max_chars)
{
   int i, j, x, y, right_edge, bottom_edge;
   int menu_x=parent_x+level*24, menu_y=parent_y+level*24;
   int width=max_chars*8+16, height=items*8+16;

   j=0;
   right_edge=menu_x+width;
   bottom_edge=menu_y+height;
   menu_para[level][0]=menu_x;
   menu_para[level][1]=menu_y;
   menu_para[level][2]=right_edge;
   menu_para[level][3]=bottom_edge;

                                         /* Store what's underneath the menu */
   for(y=menu_y;y<=bottom_edge;y++){
      i=0;
      for(x=menu_x;x<=right_edge;x++){
         menu_buf[level][i][j]=(char)getpixel(x,y);
         i++;
       }
       j++;
   }

                                                      /* Make the menu boxes */
   fill_style(clean,6,6);
   move_to(menu_x, menu_y);
   box(width, height, 1);
   move_to(menu_x+4, menu_y+4);
   box(width-8, height-8, 0);

                                                     /* Write the menu items */
   for(i=0;i<items;i++) {
      move_to(menu_x+24, menu_y+8+8*i);
      plots(menu_items[menu_number][i]);
   }
}

Get_Choice(parent_x, parent_y, numitems, level)      /* Choose item from menu */
{
   int choice_number=0, keyput=0;
   int bullet_x=parent_x+level*24+8, bullet_y=parent_y+level*24+16;

   pen_color(color);
   move_to(bullet_x, bullet_y);
   plotch(BULLET);

   while(keyput != ENTER_KEY) {
      keyput=getch();
      if (keyput == 72) --choice_number;
      if (keyput == 80) ++choice_number;

      if (choice_number<0) choice_number=numitems-2;
      if (choice_number>numitems-2) choice_number=0;

      move_to(bullet_x, bullet_y);
      plotch(SPACE);
      bullet_y=parent_y+level*24+16+choice_number*8;
      move_to(bullet_x, bullet_y);
      plotch(BULLET);

      if (keyput == ESCAPE_KEY) {
         choice_number=-1;
         keyput = ENTER_KEY;
      }
  }
  move_to(bullet_x, bullet_y);
  plotch(SPACE);
  return choice_number+1;

}

Comment_Line(message)    /* Print message on comment line at bottom of screen */
{
   move_to(8,screen.ypixels-10);
   fill_style(clean,6,6);
   flood(312,8);
   move_to(8,screen.ypixels-10);
   plots(message);
}

Delay(delay)                                            /* Pause in execution */
{
   int i, j, a;
   for (i=0; i<delay; i++) {
      for (j=0; j<1000; j++) ++a;
   }

}

Canvas_Restore()
{
     int i, j, x, y;
     int menu_x, menu_y, right_edge, bottom_edge;
     int level;

     j=0;
     level=1;
     menu_x=menu_para[level][0];
     menu_y=menu_para[level][1];
     right_edge=menu_para[level][2];
     bottom_edge=menu_para[level][3];

     for(y=menu_y;y<=bottom_edge;y++){
          i=0;
          for(x=menu_x;x<=right_edge;x++){
               pen_color((int)menu_buf[level][i][j]);
               setpixel(x,y);
               i++;
          }
          j++;
     }

     j=0;
     level=0;
     menu_x=menu_para[level][0];
     menu_y=menu_para[level][1];
     right_edge=menu_para[level][2];
     bottom_edge=menu_para[level][3];

     for(y=menu_y;y<=bottom_edge;y++){
          i=0;
          for(x=menu_x;x<=right_edge;x++){
               pen_color((int)menu_buf[level][i][j]);
               setpixel(x,y);
               i++;
          }
          j++;
     }
     pen_color(color);
}

Get_Coords(draw_flag)
{
     int keyput=0, pixel_buf[5], old_cursor_x, old_cursor_y, cursor_speed;
     int wink_color=0, pen_flag=TRUE;
     char count;

     old_cursor_x=cursor_x;
     old_cursor_y=cursor_y;
     cursor_speed=screen.xpixels/200;
     pixel_buf[0]=getpixel(cursor_x-1,cursor_y);
     pixel_buf[1]=getpixel(cursor_x,cursor_y);
     pixel_buf[2]=getpixel(cursor_x+1,cursor_y);
     pixel_buf[3]=getpixel(cursor_x,cursor_y-1);
     pixel_buf[4]=getpixel(cursor_x,cursor_y+1);
     pen_color(color);

     if (draw_flag) Comment_Line("Use '/' to pick up or put down pen");

     while ((keyput != ENTER_KEY) && (keyput != ESCAPE_KEY))
     {
          setpixel(cursor_x-1,cursor_y);
          setpixel(cursor_x,cursor_y);
          setpixel(cursor_x+1,cursor_y);
          setpixel(cursor_x,cursor_y-1);
          setpixel(cursor_x,cursor_y+1);

          keyput=getkey();
          if ((keyput == 47) && (draw_flag)) {
             if (pen_flag) pen_flag=FALSE;
             else pen_flag=TRUE;
          }

          if (keyput==72) cursor_y-=cursor_speed;
          if (keyput==73){
             cursor_y-=cursor_speed;
             cursor_x+=cursor_speed;
             }
          if (keyput==77) cursor_x+=cursor_speed;
          if (keyput==81){
             cursor_y+=cursor_speed;
             cursor_x+=cursor_speed;
             }
          if (keyput==80) cursor_y+=cursor_speed;
          if (keyput==79){
             cursor_y+=cursor_speed;
             cursor_x-=cursor_speed;
             }
          if (keyput==75) cursor_x-=cursor_speed;
          if (keyput==71){
             cursor_y-=cursor_speed;
             cursor_x-=cursor_speed;
             }
          if (keyput==56) cursor_y-=4*cursor_speed;
          if (keyput==57){
             cursor_y-=4*cursor_speed;
             cursor_x+=4*cursor_speed;
             }
          if (keyput==54) cursor_x+=4*cursor_speed;
          if (keyput==51){
             cursor_y+=4*cursor_speed;
             cursor_x+=4*cursor_speed;
             }
          if (keyput==50) cursor_y+=4*cursor_speed;
          if (keyput==49){
             cursor_y+=4*cursor_speed;
             cursor_x-=4*cursor_speed;
             }
          if (keyput==52) cursor_x-=4*cursor_speed;
          if (keyput==55){
             cursor_y-=4*cursor_speed;
             cursor_x-=4*cursor_speed;
             }

          if (cursor_x < 3) cursor_x=3;
          if (cursor_x > screen.xpixels-3) cursor_x=screen.xpixels-3;
          if (cursor_y < 13) cursor_y=13;
          if (cursor_y > screen.ypixels-16) cursor_y=screen.ypixels-16;

          if ((cursor_x!=old_cursor_x) || (cursor_y!=old_cursor_y)){
             pen_color(pixel_buf[0]);
             setpixel(old_cursor_x-1,old_cursor_y);
             pen_color(pixel_buf[1]);
             setpixel(old_cursor_x,old_cursor_y);
             pen_color(pixel_buf[2]);
             setpixel(old_cursor_x+1,old_cursor_y);
             pen_color(pixel_buf[3]);
             setpixel(old_cursor_x,old_cursor_y-1);
             pen_color(pixel_buf[4]);
             setpixel(old_cursor_x,old_cursor_y+1);
             if (draw_flag && pen_flag) {
                if (element_pntr < NUMBER(element_buffer)-8*sizeof(int)) {
                   pen_color(color);
                   move_to(old_cursor_x, old_cursor_y);
                   line_to(cursor_x, cursor_y);
                   element_buffer[++element_pntr]=FLINE;
                   element_buffer[++element_pntr]=old_cursor_x;
                   element_buffer[++element_pntr]=old_cursor_y;
                   element_buffer[++element_pntr]=cursor_x;
                   element_buffer[++element_pntr]=cursor_y;
                }
                else {
                   Comment_Line("*** Element buffer is full ***");
                   Delay(1000);
                   keyput=ESCAPE_KEY;
                }
             }
             old_cursor_x=cursor_x;
             old_cursor_y=cursor_y;
             pixel_buf[0]=getpixel(cursor_x-1,cursor_y);
             pixel_buf[1]=getpixel(cursor_x,cursor_y);
             pixel_buf[2]=getpixel(cursor_x+1,cursor_y);
             pixel_buf[3]=getpixel(cursor_x,cursor_y-1);
             pixel_buf[4]=getpixel(cursor_x,cursor_y+1);
          }

          count+=16;
          if (count > 200) pen_color(wink_color);
             else pen_color(color);

     }
     pen_color(pixel_buf[0]);
     setpixel(cursor_x-1,cursor_y);
     pen_color(color);
     setpixel(cursor_x,cursor_y);
     pen_color(pixel_buf[2]);
     setpixel(cursor_x+1,cursor_y);
     pen_color(pixel_buf[3]);
     setpixel(cursor_x,cursor_y-1);
     pen_color(pixel_buf[4]);
     setpixel(cursor_x,cursor_y+1);
     pen_color(color);
     Comment_Line("                                     ");
     return(keyput);
}

Shape_Maker(menu_choice)
{
     int center_x, center_y, edge_x1, edge_y1;
     int edge_x2, edge_y2, radius_x, radius_y;
     int width, height;

     if (element_pntr > NUMBER(element_buffer)-8*sizeof(int)) {
        Comment_Line("*** The element buffer is FULL ***");
        return;
     }

     if (menu_choice == 1){

        element_buffer[++element_pntr]=FCIRCLE;
        Comment_Line("Mark center of circle");
        Get_Coords(0);
        element_buffer[++element_pntr]=cursor_x;
        element_buffer[++element_pntr]=cursor_y;
        center_x=cursor_x;
        center_y=cursor_y;
        setpixel(center_x,center_y);
        Comment_Line("Mark left or right edge of circle");
        Get_Coords(0);
        move_to(center_x,center_y);
        radius_y=abs(cursor_x-center_x);
        element_buffer[++element_pntr]=radius_y;
        circle(radius_y,color);

     }
     if (menu_choice == 2) {
        element_buffer[++element_pntr]=FRECTANGLE;
        Comment_Line("Mark left-top corner of box");
        Get_Coords(0);
        element_buffer[++element_pntr]=cursor_x;
        element_buffer[++element_pntr]=cursor_y;
        edge_x1=cursor_x;
        edge_y1=cursor_y;
        setpixel(edge_x1,edge_y1);
        Comment_Line("Mark right_bottom of box");
        Get_Coords(0);
        height=cursor_y-edge_y1;
        width=cursor_x-edge_x1;
        move_to(edge_x1,edge_y1);
        box(width, height, 0);
        element_buffer[++element_pntr]=width;
        element_buffer[++element_pntr]=height;
     }
     if (menu_choice == 3) {
        element_buffer[++element_pntr]=FELLIPSE;
        Comment_Line("Mark center of ellipse");
        Get_Coords(0);
        element_buffer[++element_pntr]=cursor_x;
        element_buffer[++element_pntr]=cursor_y;
        center_x=cursor_x;
        center_y=cursor_y;
        setpixel(center_x,center_y);
        Comment_Line("Mark left or right edge of ellipse");
        Get_Coords(0);
        edge_x1=cursor_x;
        edge_y1=cursor_y;
        setpixel(edge_x1,edge_y1);
        radius_x=abs(cursor_x-center_x);
        element_buffer[++element_pntr]=radius_x;
        Comment_Line("Mark top or bottom edge of ellipse");
        Get_Coords(0);
        radius_y=abs(cursor_y-center_y);
        element_buffer[++element_pntr]=radius_y;
        move_to(center_x,center_y);
        ellipse(radius_x,radius_y,color);
     }
}

Line_Maker(menu_choice)
{
   int x1,y1,x2,y2,keyget=0;

   if (element_pntr > NUMBER(element_buffer)-8*sizeof(int)) {
      Comment_Line("*** The element buffer is FULL ***");
      return;
   }

   if (menu_choice == 1) {
      Get_Coords(1);
   }

   if (menu_choice == 2){
      while (keyget != ESCAPE_KEY)
      {
         element_buffer[++element_pntr]=FLINE;
         Comment_Line("Enter first endpoint, Esc to exit");
         keyget=Get_Coords(0);
         element_buffer[++element_pntr]=cursor_x;
         element_buffer[++element_pntr]=cursor_y;
         setpixel(cursor_x,cursor_y);
         x1=cursor_x;
         y1=cursor_y;
         if (keyget != ESCAPE_KEY){
            Comment_Line("Enter second endpoint, Esc to exit");
            keyget=Get_Coords(0);
            element_buffer[++element_pntr]=cursor_x;
            element_buffer[++element_pntr]=cursor_y;
            x2=cursor_x;
            y2=cursor_y;
            move_to(x1,y1);
            line_to(x2,y2);
         }
         else element_pntr-=3;
         if (element_pntr > NUMBER(element_buffer)-8*sizeof(int)) {
            Comment_Line("*** The element buffer is FULL ***");
         }
      }
   }
}

Input_Box()
{
   int keyget, cursor_pntr=0;

   Comment_Line("Input filename: ");
   while (keyget != ENTER_KEY) {
      keyget=getch();
      if ((keyget == BACKSPACE_KEY) && (cursor_pntr >0)) {
         plotch(SPACE);
         move_by(-16,0);
         plotch(CURSOR);
         move_by(-8,0);
         --cursor_pntr;
      }
      if (keyget == ESCAPE_KEY) {
         keyget=ENTER_KEY;
         filename[0]=0;
         Comment_Line("                                    ");
      }
      if ((isalnum(keyget) || isgraph(keyget)) && cursor_pntr < 25) {
         plotch(keyget);
         plotch(CURSOR);
         move_by(-8,0);
         filename[cursor_pntr++]=keyget;
      }
   }
   filename[cursor_pntr]=0;
   return(&filename);
   Comment_Line("                                    ");
}

File_IO(menu_choice)
{
     int i, number_items;
     int center_x, center_y, edge_x1, edge_y1;
     int edge_x2, edge_y2, radius_x, radius_y;
     int x1,y1,x2,y2,keyget=0;

     if (menu_choice == 1){
        FILE *fp;
        size_t count;

        element_buffer[0]=element_pntr+1;
        fp = fopen(filename,"wb");
        if (fp != NULL) {
           count = fwrite(element_buffer,sizeof(int),NUMBER(element_buffer),fp);
           if (count == NUMBER(element_buffer))
              Comment_Line("File saved");
           else Comment_Line("*** Couldn't save file ***");
        }
        fclose(fp);
        Clean_Slate();
        element_pntr=0;
        Delay(600);
        Comment_Line("                                    ");

     }

     if (menu_choice == 2){
        FILE *fp;
        size_t count;

        element_buffer[0]=element_pntr+1;
        Input_Box();
        if (filename[0] == 0) return;
        fp = fopen(filename,"wb");
        if (fp != NULL) {
           count = fwrite(element_buffer,sizeof(int),NUMBER(element_buffer),fp);
           if (count == NUMBER(element_buffer))
              Comment_Line("File saved");
           else Comment_Line("*** Couldn't save file ***");
        }
        fclose(fp);
        Clean_Slate();
        element_pntr=0;
        Delay(600);
        Comment_Line("                                    ");

     }

     if (menu_choice == 3){
        FILE *fp;

        Input_Box();
        if (filename[0] == 0) return;
        fp = fopen(filename,"rb");
        if (fp == NULL) {
           Comment_Line("*** Could not open file ***");
           return(0);
        }
        Comment_Line("Reading file");
        fread(element_buffer, sizeof(int), 1, fp);
        number_items=element_buffer[0];
        fclose(fp);
        fp = fopen(filename,"rb");
        fread(element_buffer, sizeof(int), number_items, fp);
        fclose(fp);
        element_pntr=1;
        Comment_Line("Clearing off the board              ");
        Clean_Slate();
        Comment_Line("                                    ");

        while (element_pntr < number_items){

           if (element_buffer[element_pntr] == FCIRCLE){
              center_x=element_buffer[++element_pntr];
              center_y=element_buffer[++element_pntr];
              radius_y=element_buffer[++element_pntr];
              move_to(center_x,center_y);
              circle(radius_y,color);
              ++element_pntr;
           }
           if (element_buffer[element_pntr] == FLINE){
              x1=element_buffer[++element_pntr];
              y1=element_buffer[++element_pntr];
              x2=element_buffer[++element_pntr];
              y2=element_buffer[++element_pntr];
              move_to(x1,y1);
              line_to(x2,y2);
              ++element_pntr;
           }
           if (element_buffer[element_pntr] == FRECTANGLE){
              x1=element_buffer[++element_pntr];
              y1=element_buffer[++element_pntr];
              x2=element_buffer[++element_pntr];
              y2=element_buffer[++element_pntr];
              move_to(x1,y1);
              box(x2,y2,0);
              ++element_pntr;
           }
           if (element_buffer[element_pntr] == FELLIPSE){
              center_x=element_buffer[++element_pntr];
              center_y=element_buffer[++element_pntr];
              radius_x=element_buffer[++element_pntr];
              radius_y=element_buffer[++element_pntr];
              move_to(center_x,center_y);
              ellipse(radius_x,radius_y,color);
              ++element_pntr;
           }
        
        }

     element_pntr=number_items-1;
     }

}

Clean_Slate(void)
{
   move_to(4,12);
   line_to(screen.xpixels-4,screen.ypixels-20);
   move_to(4,screen.ypixels-20);
   line_to(screen.xpixels-4,12);
   move_to(2,12);
   flood(screen.xpixels-4, screen.ypixels-26);
}