/******************************************************
** 
** Sample Code ICON Displayer
** 
** Please check this file before downloading to determine what will you need
** for this file to work.
** Please read the disclaimer before using this code.
**
** This file has to be compiled with SVGALIB System from a project file.
** SVGALIB.LIB is contained SVGACC25.ZIP
** Please check these files in the C MS-DOS archives in SimTelnet or Garbo.
**
** if you want to use another VGA system. Please change
** all the function referal to SVGALIB system to your own.
**
** Ahmad Hafiz:
** http://www.geocities.com/SiliconValley/Vista/2459
** cobra_ayaq@hotmail.com
** 
** ps:// The difference from Bitmap displayer is, the program
**       save the icon image into memory. Displayed to screen from
**       memory allocated.
** ps:// Please set TAB to 2
**
*******************************************************/

#include <dos.h>
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <svga\svgacc.h>
#include <svga\svgademo.h>

typedef unsigned char BYTE;
typedef unsigned int UINT;
typedef unsigned long DWORD;
typedef unsigned int WORD;
typedef signed long LONG;

typedef struct tagBITMAPINFOHEADER {    /* bmih */
    DWORD   biSize;
		LONG    biWidth;
		LONG    biHeight;
    WORD    biPlanes;
    WORD    biBitCount;
    DWORD   biCompression;
    DWORD   biSizeImage;
    LONG    biXPelsPerMeter;
    LONG    biYPelsPerMeter;
    DWORD   biClrUsed;
    DWORD   biClrImportant;
} BITMAPINFOHEADER;

typedef struct ICONDIR {
	WORD idReserved;
	WORD idType;
	WORD idCount;
} ICONHEADER;

typedef struct IconDirectoryEntry {
	BYTE bWidth;
	BYTE bHeight;
	BYTE bColorCount;
	BYTE bReserved;
	WORD wPlanes;
	WORD wBitCount;
	DWORD dwBytesInRes;
	DWORD dwImageOffset;
} ICONDIRENTRY;

typedef struct tagICONS{
	WORD	x;
	WORD	y;
	BYTE	bWidth;
	BYTE	bHeight;
	DWORD biClrUsed;
	BYTE	*palette;
	BYTE	*icXOR;
	BYTE	*icAND;
}ICONS;

unsigned getbits(unsigned x, int p, int n)
{ return(x>>(p+1-n)) & ~(~0<<n); }

/************************* START ***********************/
int main(int argc, char **argv)
{
FILE *fp={0};
BITMAPINFOHEADER hbmp={0};
ICONHEADER hico={0};
ICONDIRENTRY dico={0};
ICONS icon={0};
int startvmode;       /* initial video mode */
PaletteData pal3={0}; /* svgalib system */
int i,x,y,z;
BYTE ch;

	clrscr();

	if ((fp=fopen(argv[1],"rb"))==NULL)
	{
	printf("error opening icon file \n terminating");
	getch();
	exit(1);
	}

  /* reading b.width, b.height and number of Colour*/
	fread(&hico,sizeof(ICONHEADER),1,fp);

	printf("This icon file has %d number(s) of icon file\n",hico.idCount);
	printf("Press numbers to view each file",hico.idCount);

	/*** move to desired icon directory entry and read */

	fseek(fp,sizeof(ICONDIRENTRY)*(getch()-'1'),SEEK_CUR);
	fread(&dico,sizeof(ICONDIRENTRY),1,fp);

	/* move to the start of desired Image base on Directory Entry info */

	fseek(fp,dico.dwImageOffset,SEEK_SET);
	fread(&hbmp,sizeof(BITMAPINFOHEADER),1,fp);

	icon.x=0;icon.y=0;  /* place icon at the top of screen 0,0 */
	icon.bWidth=dico.bWidth; 			/* set icon width */
	icon.bHeight=dico.bHeight; 		/* set icon height */
	if(hbmp.biBitCount==8) (icon.biClrUsed=256);
	else if (hbmp.biBitCount==4) (icon.biClrUsed=16);

	/** allocate mem space for icons pallete, XOR, pixel, AND pixel **/

	if((icon.palette=(BYTE*)malloc((DWORD)icon.biClrUsed*3+1))==NULL) exit(1);
	if((icon.icXOR=(BYTE*)malloc((BYTE)icon.bWidth*icon.bHeight+1))==NULL) exit(1);
	if((icon.icAND=(BYTE*)malloc((BYTE)(icon.bWidth/8)*icon.bHeight+1))==NULL) exit(1);

	/** read palettes from file to icon palette ****/

	for(i=0;i<(icon.biClrUsed);i++)
		{
		icon.palette[i*3+2]=fgetc(fp)>>2;
		icon.palette[i*3+1]=fgetc(fp)>>2;
		icon.palette[i*3+0]=fgetc(fp)>>2;
		x=fgetc(fp);
		}

	/** refering from icons palette to system pallete **/

	for(i=0;i<icon.biClrUsed;i++)
	{
		pal3[i].b=*(icon.palette+i*3+2);
		pal3[i].g=*(icon.palette+i*3+1);
		pal3[i].r=*(icon.palette+i*3+0);
	}

  /********** read the real Image - if 256 Color */
	if(icon.biClrUsed==256){
		for(i=0;i<icon.bWidth*icon.bHeight;i++)
			*(icon.icXOR+i)=fgetc(fp);
	}

  /********** read the real Image - if 16 Color */
	if(icon.biClrUsed==16){
		for(i=0;i<icon.bWidth*icon.bHeight;i+=2){
			ch=fgetc(fp);
			*(icon.icXOR+i)=getbits(ch,7,4);   /* read the first 4 bits */
			*(icon.icXOR+i+1)=getbits(ch,3,4); /* read the last 4 bits  */
		}
	}

  /****** read the solid background */
	for(i=0;i<(icon.bWidth/8)*icon.bHeight;i++)
		*(icon.icAND+i)=getc(fp);

  fclose(fp);  /* close file pointer finished reading */

  startvmode=videomodeget(); /* save initial video mode - svgalib system */
	whichvga(); /* determine which vga - svgalib system */
	res320();   /* set resolution - svgalib system      */

		palset(pal3,0,icon.biClrUsed-1); /* setting palette for VGA 256 colour - svgalib system */

		/** DRAWing to the screen **/

		/* ANDing the display location using ANDmask to preserved the location */
		for(i=0,y=(icon.bHeight)-1;y>-1;y--)
			for(x=0;x<icon.bWidth;x+=8,i++){
				for(z=0;z<8;z++){
					if(!(getbits(icon.icAND[i],z,1)))
						drwpoint(AND,0x00,x+z+icon.x,y+icon.y); /* svgalib system */
				}
			}

		/* XORing with the pixel on the display surface */
		for(i=0,y=(icon.bHeight)-1;y>-1;y--)
			for(x=0;x<icon.bWidth;x++){
				drwpoint(XOR,icon.icXOR[i++],x+icon.x,y+icon.y);
			}


	getch(); /* pause for a while to see the result */

	videomodeset(startvmode); /* set to original video mode - svgalib system*/

	/* freeing memory space previously allocated by malloc */

	free(icon.palette);
	free(icon.icXOR);
	free(icon.icAND);
}