/* VIEWBMP.C
this file opens 16 color images and not 256 color images as
TURBO C supports only 16 colors only.
email:	chingpongin@yahoo.co.in	
PLEASE VOTE ME !!!!
*/
#include <stdio.h>
#include <graphics.h>
#define BYTE unsigned char
#define WORD unsigned int
#define DWORD unsigned long
	 /*STRUCTURE OF BITMAP FILE HEADER*/
/* FILE HEADER */
struct fileheader


    {
    	 char bftype[2];
    	 DWORD bfsize;
    	 WORD bfreserved1;
    	 WORD bfreserved2;
    	 DWORD bfoffbits;
};
/* IMAGE INFORMATION HEADER */
struct bitmapinfoheader


    {
    	DWORD bisize;
    	DWORD biwidth;
    	DWORD biheight;
    	WORD biplanes;
    	WORD bibitcount;
    	DWORD bicompression;
    	DWORD bisizeimage;
    	DWORD bixpelspermeter;
    	DWORD biypelspermeter;
    	DWORD biclrused;
    	DWORD biclrimportant;
};
/* PALETTE HEADER*/
struct colortable


    {
    	 BYTE rgbblue;
    	 BYTE rgbgreen;
    	 BYTE rgbred;
    	 BYTE rgbreserved;
};
/* COMMAND LINE ARGUMENTS */
void main(int argc,char *argv[ ])


    {
    int gd=DETECT,gm;
    int i=0,colorno,loop,x,y,higher,lower,color;
    unsigned long size;
    unsigned char *ptr;
    FILE *fp;
    struct fileheader header;
    struct bitmapinfoheader info;
    struct colortable table;
    struct palettetype pal;
    /*TO CHECK THE EXISTENCE OF FILE */
    if((fp=fopen(argv[1],"rb"))==NULL)


        {
        	clrscr( );
        	gotoxy(10,10);
        	printf("bmp file %s does not exist",argv[1]);
        	gotoxy(10,20);
        	printf("press ENTER to continue....");
        	getchar( );
        	clrscr( );
        	exit(0);
    }
    	 fseek(fp,0,SEEK_END);
    	 size=ftell(fp);
    	 fseek(fp,0,SEEK_SET);
    	 fread(&header,1,sizeof(header),fp);
    	 clrscr( );
    /* TO CHECK THE SIGNATURE OF THE BITMAP FILE "BM" */
    		 if(header.bftype[0]!='B' || header.bftype[1]!='M')


        		 {
        			 gotoxy(10,10);
        			 printf("%s is not a BMP file",argv[1]);
        			 gotoxy(10,20);
        			 printf("press ENTER to continue....");
        			 getchar();
        			 clrscr();
        			 exit(1);
        		 }
        	fread(&info,1,sizeof(info),fp);
        	/*if required the following BMP header informations can be displayed */
        	printf("\n\t\t\tBITMAP FILE HEADER");
        	printf("\nBMPFILE's SIGNATURE= %c",header.bftype[0]);
        	printf("%c",header.bftype[1]);
        	printf("\nSIZE OF BITMAPFILE= %ld",header.bfsize);
        	printf("\nRESERVED1 = %d",header.bfreserved1);
        	printf("\nRESERVED2 = %d",header.bfreserved2);
        	printf("\nOFFSET TO THE IMAGE DATA = %ld",header.bfoffbits);
        	printf("\n\n\t\t\tBITMAP INFO HEADER");
        	printf("\n\nBITMAPINFO HEADER SIZE\t\t\t= %ld",info.bisize);
        	printf("\nIMAGE WIDTH\t\t\t\t= %ld",info.biwidth);
        	printf("\nIMAGE HEIGHT\t\t\t\t= %ld",info.biheight);
        	printf("\nNo. OF PLANES IN THE IMAGE\t\t= %d (usually '1')",info.biplanes);
        	printf("\nBITS REQUIRED TO REPRESENT A PIXEL\t= %d",info.bibitcount);
        	printf("\nCOMPRESSION BIT\t\t\t\t= %ld (0 -if no Compression used)",info.bicompression);
        	printf("\nBYTES REQUIRED for IMAGE DATA ALONE\t= %ld",info.bisizeimage);
        	printf("\nbixpelspermeter\t\t\t\t= %ld",info.bixpelspermeter);
        	printf("\nbiypelspermeter\t\t\t\t= %ld",info.biypelspermeter);
        	printf("\nNo. OF COLORS USED\t\t\t= %ld",info.biclrused);
        	printf("\nCOLOR IMPORTANT\t\t\t\t= %ld",info.biclrimportant);
        	getch( );
        	if(info.bibitcount==1)
        		colorno=2;
        	if(info.bibitcount==4)
        		colorno=16;
        	if(info.bibitcount==8)
        		colorno=256;
        	if(info.bibitcount==0)
        		colorno=0;
        	if(info.biclrused!=0)
        		colorno=info.biclrused;
        	initgraph(&gd,&gm,"");
        	 /*TO SET THE PALETTE */
        	getpalette(&pal);
        	for(loop=0;loop<colorno;loop++)


            	{
            	 fread(&table,1,sizeof(table),fp);
            /*	 printf("\n\tPalette %3d",loop+1);
            	 printf("\tBLUE=%3d",table.rgbblue);
            	 printf("\tGREEN=%3d",table.rgbgreen);
            	 printf("\tRED=%3d",table.rgbred);
            	 printf("\tRESERVED=%3d",table.rgbreserved);*/
            	 setrgbpalette(pal.colors[loop],table.rgbred,table.rgbgreen,table.rgbblue);
            	 }
            	 cleardevice( );
            			 if(colorno==256)


                			 {
                					for(i=0;i<16;i++)
                					 setrgbpalette(pal.colors[i],i*4,i*4,i*4);
                			 }
                	 if(info.bibitcount==4) 	 /*FOR 16 COLOR IMAGE */


                    	 {
                    		for(y=info.biheight;y>=1;y--)


                        		 {
                        			for(x=1;x<=info.biwidth;x++)


                            			 {
                            				fread(ptr,1,1,fp);
                            				color=*ptr; /* Each byte contains two 4-bit data */
                            				lower=color&15;
                            				higher=color&240; higher=higher>>4;
                            				putpixel(x,y,higher);x++;
                            				putpixel(x,y,lower);
                            			 }
                            		 }
                            	 }
                            	 if(info.bibitcount==8) 	 /*FOR 256 COLOR IMAGE */


                                	 {
                                		for(y=info.biheight;y>=1;y--)


                                    		 {
                                    			for(x=1;x<=info.biwidth;x++)


                                        			 {
                                        					fread(ptr,1,1,fp);
                                        					color=*ptr;
                                        					putpixel(x,y,color/16-1);
                                        			 }
                                        		 }
                                        	 }
                                        	 getchar( );
                                        	 closegraph( );
                                        	 fclose(fp);
                                    }