#define RGB_RESET 0x03C6
#define RGB_READ 0x03C7
#define RGB_WRITE 0x03C8
#define RGB_DATA 0x03C9

#include <dir.h>
#include <math.h>
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <process.h>
#include <graphics.h>
#include <iostream.h>
#include "svgautil.h"
#include "svgautil.c"
#include "svga256.h"

typedef struct tagBITMAPFILEHEADER
 {
  unsigned int  bfType;
  unsigned long bfSize;
  unsigned int  bfReserved1;
  unsigned int  bfReserved2;
  unsigned long bfOffBits;
 } BITMAPFILEHEADER;

typedef struct tagBITMAPINFOHEADER
 {
  unsigned long biSize;
  unsigned long biWidth;
  unsigned long biHeight;
  unsigned int  biPlanes;
  unsigned int  biBitCount;
  unsigned long biCompression;
  unsigned long biSizeImage;
  unsigned long biXPelsPerMeter;
  unsigned long biYPelsPerMeter;
  unsigned long biClrUsed;
  unsigned long biClrImportant;
 } BITMAPINFOHEADER;

typedef struct tagRGBQUAD
 {
  unsigned char rgbBlue;
  unsigned char rgbGreen;
  unsigned char rgbRed;
  unsigned char rgbReserved;
 } RGBQUAD;

FILE             *ptr;
BITMAPFILEHEADER bmfh;
BITMAPINFOHEADER bmih;
RGBQUAD          rgbq[256];
char files[100][14];
int height;

void putPixel(int& i, int& j, char tmp2, int flag)  // draws a pixel in
 {                                                  // correct color from
  putpixel(j, i, tmp2 + 1 - flag);                  // color table at
  j++;                                              // desired location
  if (j == (getmaxx() + bmih.biWidth) / 2)          // on screen.
   {
    j = (getmaxx() - bmih.biWidth) / 2;
    i--;
    height++;
    switch(bmih.biBitCount)  // so that new line is aligned at long word boundary.
     {
      case 8 : if ((bmih.biWidth % 4) != 0)      // for 8-bit BMP.
		for (int k = 4; k > (bmih.biWidth % 4); k--)
		 getc(ptr);
	       break;
      case 4 : if (((bmih.biWidth / 2) % 4) != 0)        // for 4-bit BMP.
		for (int k = 4; k > ((bmih.biWidth / 2) % 4); k--)
		 getc(ptr);
	       break;
     }
   }
 }

void getDir(int& i)                  // gets the contents of a directory
 {                                   // and stores them in the array 'files'.
  struct ffblk ffblk;
  int done;
  for (done = 0; done < 100; done++)   // initialising file array.
   files[done][13] = ' ';
  done = findfirst("*", &ffblk, FA_DIREC);  // for getting sub-directories.
  while (!done)
   {
    if (strcmp(ffblk.ff_name, ".") && !(ffblk.ff_fsize))
     {
      strcpy(files[i], ffblk.ff_name);
      files[i][13] = '\\';
      i++;
     }
    done = findnext(&ffblk);
   }
  done = findfirst("*.bmp", &ffblk, 0);      // for .BMP files.
  while (!done)
   {
    strcpy(files[i], ffblk.ff_name);
    i++;
    done = findnext(&ffblk);
   }
 }

void highlight()               // highlights selected file or directory.
 {
  textbackground(YELLOW);
  textcolor(BLUE);
 }

void normal()                  // removes highlight.
 {
  textbackground(BLUE);
  textcolor(YELLOW);
 }

int huge DetectVGA256()
 {
  int Vid = 2;
  return Vid;
 }

void setPalette(int index, int red, int green, int blue)
 {
  outp(RGB_RESET, 0xFF);     //Prepare the VGA card for the color change
  outp(RGB_WRITE, index);    //Tell which palette register to write to
  outp(RGB_DATA, red);       //change the red value
  outp(RGB_DATA, green);     //change the green value
  outp(RGB_DATA, blue);      //change the blue value
 }

main()
 {
  FILE *p;
  unsigned char tmp1, tmp2;
  int i, j, k, flag, no_files;          // flag checks if color table is of max. size.
  char filename[14], ch;
  char *path, drive[2], dir[100], file[10], ext[4];
  path = searchpath("svga256.bgi");
  fnsplit(path, drive, dir, file, ext);
  getcwd(path, 100);
start :
  _setcursortype(_NOCURSOR);
  normal();
  clrscr();
  cprintf("ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍËÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍËÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»\r\n");
  cprintf("   BMPview Version 2.3   º   Developed by Vineet Verma\r\n");
  cprintf("ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÊÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ\r\n");
  gotoxy(2, 22);
  cprintf("ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ\r\n");
  cprintf("  Esc - exit; Arrow keys - navigate; Enter - select file");
  for (i = 2; i < 24; i++)
   {
    gotoxy(1, i);
    if ((i == 22) || (i == 3)) putch('Ì');
     else putch('º');
    gotoxy(58, i);
    if ((i == 22) || (i == 3)) putch('¹');
    else putch('º');
    gotoxy(79, i);
    putch('º');
   }
  gotoxy(1, 24);
  cprintf("ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÊÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ");
  j = k = no_files = 0;       // 'j' keeps track of which one is highlighted.
  getDir(no_files);           // 'k' keeps track of which one is at top of page.
  window(60, 2, 78, 23);
  do
   {
    clrscr();
    for (i = 1; i < 23; i++)
     {
      if ((i + k) > no_files) break;
      gotoxy(1, i);
      if ((i + k - 1) == j) highlight();
      if ((files[i - 1 + k][13] == '\\') && (strcmp(files[i - 1 + k], "..")))
       cprintf("\\");
      cprintf(files[i - 1 + k]);
      normal();
     }
    switch(ch = getch())
     {
      case 72 : if (j)                           // UP arrow.
		 {
		  if (j == k)
		   {
		    j--;
		    k--;
		   }
		   else
		    j--;
		 }
		break;
      case 80 : if (j != (no_files - 1))         // DOWN arrow.
		 {
		  if (j == (k + 21))
		   {
		    j++;
		    k++;
		   }
		   else
		    j++;
		 }
		break;
      case 73 : if (k < 22)                      // Page Up.
		 {
		  k = 0;
		  if (j < 22) j = 0;
		   else j -= 22;
		 }
		 else
		  {
		   j -= 22;
		   k -= 22;
		  }
		break;
      case 81 : if ((no_files - j) < 23)         // Page Down.
		 {
		  j = no_files - 1;
		  if ((no_files - k) > 21) k = no_files - 1;
		 }
		 else
		  {
		   j += 22;
		   k += 22;
		  }
		break;
      case 13 : if (files[j][13] == '\\')        // Enter pressed.
		 {                               // if directory selected,
		  chdir(files[j]);               // change directory.
		  j = k = no_files = 0;
		  getDir(no_files);
		  break;
		 }
		 else
		  {                              // if file selected,
		   strcpy(filename, files[j]);   // exit loop to display
		   ch = 27;                      // image.
		   break;
		  }
		break;
      case 27 : window(1, 1, 80, 24);            // Esc.
		textbackground(BLACK);
		textcolor(WHITE);
		lowvideo();
		_setcursortype(_NORMALCURSOR);
		clrscr();
		chdir(path);
		exit(0);
		break;
     }
   }
  while (ch != 27);

// start reading the file.

  window(1, 1, 80, 24);
  normal();
  gotoxy(1, 8);
  ptr = fopen(filename, "rb");
  flag = 0;

  fread(&bmfh, sizeof(bmfh), 1, ptr);  // read bitmap file header.
  fread(&bmih, sizeof(bmih), 1, ptr);  // read bitmap information header.

  if (bmfh.bfType != 19778)           // BMP signature.
   {
    cprintf("\r\nº   %s is not a BMP file!", filename);
    gotoxy(3, 23);
    cprintf("Esc - exit program; Any other key - continue");
    tmp1 = getch();
    if (tmp1 == 27)
     {
      clrscr();
      exit(0);
     }
     else
      goto start;
   }
  cprintf("\r\nº   Image information\r\n");
  cprintf("º   ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ\r\n\r\n");
  cout << "º   File size   : " << bmfh.bfSize << " bytes.\n";
  cout << "º   Image size  : " << bmih.biWidth << " X " << bmih.biHeight << " pixels.\n";
  cout.setf(ios::fixed, ios::floatfield);
  cout << "º   Colors      : " << pow(2, bmih.biBitCount) << " (" << bmih.biBitCount << " bits per pixel).\n";
  if (bmih.biBitCount > 8)
   {
    cprintf("\r\nº   Cannot read 24-bit BMP!");
    gotoxy(3, 23);
    cprintf("Esc - exit program; Any other key - continue          ");
    tmp1 = getch();
    if (tmp1 == 27)
     {
      clrscr();
      exit(0);
     }
     else
      goto start;
   }

  cprintf("º   Compression : ");
  if (bmih.biCompression == 0) cprintf("None.\r\n\r\n");
   else cprintf("Run Length Encoded.\r\n\r\n");

  if (bmih.biClrUsed == 0) bmih.biClrUsed = pow(2, bmih.biBitCount);
  if (bmih.biClrUsed > 254) flag = 1;

  gotoxy(3, 23);
  cprintf("Esc - Don't view; Enter - View; F2 - Save as grayscale");
  while ((ch = getch()) != 13)
   switch(ch)
    {
     case 27 : goto start;          // (Esc) - refresh display since image is not to be displayed.
     case 60 : fclose(ptr);                  // (F2) - replace color table
	       ptr = fopen(filename, "rb");  // of image by a grayscale
	       p = fopen("temp", "wb");      // color table to convert it
	       for (i = 0; i < 54; i++)      // to grayscale. `temp' is a
		putc(getc(ptr), p);          // temporary file for conversion.
	       for (i = 0; i < bmih.biClrUsed; i++)  // reading original image
		{                                    // to extract rgb values
		 tmp1 = 0;                           // and getting grayscale
		 for (j = 0; j < 3; j++)             // value (r+g+b)/3.
		  tmp1 += getc(ptr) / 3;
		 getc(ptr);               // reserved byte.
		 for (j = 0; j < 3; j++)  // writing grayscale value
		  putc(tmp1, p);          // in color table of output file.
		 putc(0, p);              // reserved byte.
		}
	       while (!feof(ptr))         // copying rest of BMP
		putc(getc(ptr), p);       // to output file.
	       fclose(ptr);
	       fclose(p);
	       p = fopen("temp", "rb");        // writing data into file
	       ptr = fopen(filename, "wb");    // to complete conversion.
	       while (!feof(p))
		putc(getc(p), ptr);
	       fclose(ptr);
	       fclose(p);
	       remove("temp");
	       ptr = fopen(filename, "rb"); // getting file into state
	       for (i = 0; i < 54; i++)     // it was in before conversion
		getc(ptr);                  // i.e. pointer is at start of
	       gotoxy(5, 18);               // color table.
	       cprintf("Conversion complete.");
	       break;
    }
  rgbq[0].rgbRed = rgbq[0].rgbBlue = rgbq[0].rgbGreen = 0;  // set first entry in palette to black for black background.
  for (i = 1 - flag; i < bmih.biClrUsed + 1 - flag; i++)    // storing the color table.
   {
    rgbq[i].rgbBlue = getc(ptr);
    rgbq[i].rgbGreen = getc(ptr);
    rgbq[i].rgbRed = getc(ptr);
    tmp1 = getc(ptr);
   }
  for (i = bmih.biClrUsed + 1 - flag; i < 255 + flag; i++)    // initialising unused entries.
   rgbq[i].rgbRed = rgbq[i].rgbBlue = rgbq[i].rgbGreen = 0;
  if (!flag) rgbq[255].rgbRed = rgbq[255].rgbBlue = rgbq[255].rgbGreen = 255; // set last entry in palette to white for white foreground.


  int gd = DETECT, gm;               // enter graphics mode to display image.
  installuserdriver("Svga256", DetectVGA256);
  initgraph(&gd, &gm, dir);
  outtextxy(1, 1, "Please wait while image loads...");
  for (i = 0; i < 256; i++)
   setPalette(i, rgbq[i].rgbRed / 4, rgbq[i].rgbGreen / 4, rgbq[i].rgbBlue / 4);
  clearviewport();

  i = (getmaxy() + bmih.biHeight) / 2;        // start display of image.
  j = (getmaxx() - bmih.biWidth) / 2;
  height = 0;                           // height keeps track of how many lines have been drawn.
  while (!feof(ptr))
   {
    tmp1 = getc(ptr);               // read character from file.
    switch(bmih.biBitCount)
     {
      case 8 : if (height == bmih.biHeight) break;
	       if (bmih.biCompression == 1)       // for 8-bit BMP.
		{                                 // (RLE encoded).
		 tmp2 = getc(ptr);
		 if (tmp1 == 0)
		  {
		   switch(tmp2)
		    {
		     case 0  : i--;               // end of line.
			       j = (getmaxx() - bmih.biWidth) / 2;
			       break;
		     case 1  : goto finish;       // end of BMP.
			       break;
		     case 2  : j += getc(ptr);    // offset of next pixel.
			       i -= getc(ptr);
			       break;
		     default : for (k = 0; k < tmp2; k++)
				putPixel(i, j, getc(ptr), flag);
			       if ((tmp2 % 2) != 0) getc(ptr);
		    }
		  }
		  else
		   {
		    for (k = 0; k < tmp1; k++)
		     putPixel(i, j, tmp2, flag);
		   }
		}
		else                              // not encoded.
		 {
		  tmp2 = tmp1;
		  putPixel(i, j, tmp2, flag);
		 }
	       break;
      case 4 : if (height == bmih.biHeight) break;   // for 4-bit BMP.
	       tmp2 = tmp1 >> 4;
	       putPixel(i, j, tmp2, flag);
	       if (height == bmih.biHeight) break;
	       tmp2 = tmp1 << 4;
	       tmp2 >>= 4;
	       putPixel(i, j, tmp2, flag);
	       break;
      case 1 : for (k = 0; k < 8; k++)       // for 1-bit BMP.
		{
		 if (height == bmih.biHeight) break;     // if BMP ends in middle of byte.
		 tmp2 = tmp1 & 128;
		 tmp1 <<= 1;
		 if (tmp2 == 0) ;
		  else tmp2 = 1;
		 putPixel(i, j, tmp2, flag);
		}
	       break;
     }
   }
finish :
  fclose(ptr);
  getch();
  closegraph();
  goto start;
 }