/* settup graphics mode */	registerbgidriver(CGA_driver);	registerbgidriver(EGAVGA_driver);	initgraph(&GraphDriver, &GraphMode, "");	if (graphresult() != grOk)  {		fprintf(stderr, "fft: %s\n", grapherrormsg(graphresult()));		exit(1);	}	if ((i_size = getgraphmode()) != CGAHI)		setbkcolor(BLACK);	switch (i_size)  {	case CGAHI:		Primary = WHITE;		Cursor  = WHITE;		Length  = 100.0;		Bottom  = 150;		break;	case EGAHI:		Primary = LIGHTGRAY;		Cursor  = LIGHTGREEN;		Length  = 250.0;		Bottom  = 300;		break;	case VGAHI:		Primary = LIGHTGRAY;		Cursor  = LIGHTGREEN;		Length  = 380.0;		Bottom  = 430;	}	setcolor(Primary);	setfillstyle(SOLID_FILL, Primary);	settextjustify(LEFT_TEXT, TOP_TEXT);	settextstyle(DEFAULT_FONT, HORIZ_DIR, 2);	cleardevice();	outtextxy(TEXTX, TEXTY, "Computing FFT");	/* Draw ruler line */	line(LEFT, Bottom + 5, RIGHT, Bottom + 5);	for (i_size = LEFT; i_size <= RIGHT ; i_size += 10)  {		line(i_size, Bottom + 5, i_size, Bottom + 10);		line(i_size + 1, Bottom + 5, i_size + 1, Bottom + 10);	}	/* create under-cursor memory */	i_size = imagesize(LEFT, TOP, LEFT + 1, Bottom);	Save   = malloc(i_size);}void commands(){	int	key, filter;	char	string[4];	setcolor(BLACK);	/* erase text */	outtextxy(TEXTX, TEXTY, "Computing FFT");	setcolor(Primary);	Left   = 320;	filter = 128;	strcpy(string, "128");	outtextxy(TEXTX, TEXTY, "Filter # 128");	getimage(Left, TOP, Left + 1, Bottom, Save);	setfillstyle(SOLID_FILL, Cursor);	bar(Left, TOP, Left + 1, Bottom);	for (;;)  {		while (bioskey(1) == 0)		/* wait for key press */			;		key = getkey();		switch(key)  {		/* find out which key was pressed */		case HOMEKEY:j1:			putimage(Left, TOP, Save, COPY_PUT);			filter = 0;			Left = LEFT;			getimage(Left, TOP, Left + 1, Bottom, Save);			bar(Left, TOP, Left + 1, Bottom);			setcolor(BLACK);	/* erase old text */			outtextxy(TEXTXN, TEXTY, string);			setcolor(Primary);			sprintf(string, "%d", filter);			outtextxy(TEXTXN, TEXTY, string);			break;		case ENDKEY:j2:			putimage(Left, TOP, Save, COPY_PUT);			filter = 255;			Left = RIGHT - 1;			getimage(Left, TOP, Left + 1, Bottom, Save);			bar(Left, TOP, Left + 1, Bottom);			setcolor(BLACK);	/* erase old text */			outtextxy(TEXTXN, TEXTY, string);			setcolor(Primary);			sprintf(string, "%d", filter);			outtextxy(TEXTXN, TEXTY, string);			break;		case CTRLLEFTKEY:			if (filter <= 9)				goto j1;			putimage(Left, TOP, Save, COPY_PUT);			Left -= 20;			filter -= 10;			getimage(Left, TOP, Left + 1, Bottom, Save);			bar(Left, TOP, Left + 1, Bottom);			setcolor(BLACK);	/* erase old text */			outtextxy(TEXTXN, TEXTY, string);			setcolor(Primary);			sprintf(string, "%d", filter);			outtextxy(TEXTXN, TEXTY, string);			break;		case LEFTKEY:			if (filter <= 0)  {				beep();				break;			}			putimage(Left, TOP, Save, COPY_PUT);			Left -= 2;			filter--;			getimage(Left, TOP, Left + 1, Bottom, Save);			bar(Left, TOP, Left + 1, Bottom);			setcolor(BLACK);	/* erase old text */			outtextxy(TEXTXN, TEXTY, string);			setcolor(Primary);			sprintf(string, "%d", filter);			outtextxy(TEXTXN, TEXTY, string);			break;		case CTRLRIGHTKEY:			if (filter >= 245)				goto j2;			putimage(Left, TOP, Save, COPY_PUT);			Left += 20;			filter += 10;			getimage(Left, TOP, Left + 1, Bottom, Save);			bar(Left, TOP, Left + 1, Bottom);			setcolor(BLACK);	/* erase old text */			outtextxy(TEXTXN, TEXTY, string);			setcolor(Primary);			sprintf(string, "%d", filter);			outtextxy(TEXTXN, TEXTY, string);			break;		case RIGHTKEY:			if (filter >= 255)  {				beep();				break;			}			putimage(Left, TOP, Save, COPY_PUT);			Left += 2;			filter++;			getimage(Left, TOP, Left + 1, Bottom, Save);			bar(Left, TOP, Left + 1, Bottom);			setcolor(BLACK);	/* erase old text */			outtextxy(TEXTXN, TEXTY, string);			setcolor(Primary);			sprintf(string, "%d", filter);			outtextxy(TEXTXN, TEXTY, string);			break;		case F1:			if (PrintScreen())				bee_bop();			break;		case ESC:			quit();		default:			beep();		}	}}void beep(){	sound(200);	delay(125);	nosound();}void bee_bop(){	sound(1000);	delay(80);	sound(200);	delay(160);	sound(1000);	nosound();}/* *	Return to MS-DOS operating system */void quit(){	sound(1000);	delay(250);	nosound();	closegraph();	free((char *)Save);	exit(0);}/* *	Dumps a screen to printer in Double Density landscape format. *	This routine is from the Borland Programming Forum on CompuServe. * *	returns TRUE on error */int PrintScreen(){	int			X,Y,YOfs;	int			BitData,MaxBits;	unsigned int		Height,Width;	struct viewporttype 	Vport;	getviewsettings(&Vport);	Width  = Vport.bottom - Vport.top;	Height = (Vport.right + 1) - Vport.left;	if (PrintChar(27))		return (1);	if (PrintChar('3'))		return (1);	if (PrintChar(24))	/* 24/216 inch line spacing */		return (1);	Y = 0;	while (Y < Height)  {		if (PrintChar(27))			return (1);		if (PrintChar('L'))	/* Double Density */			return (1);		if (PrintChar(Width & 0xff))			return (1);		if (PrintChar(Width >> 8))			return (1);		for (X = Width - 1; X >= 0; X--)  {			BitData = 0;			if ((Y + 7) <= Height)				MaxBits = 7;			else				MaxBits = Height - Y;			for (YOfs = 0; YOfs <= MaxBits; YOfs++)  {				BitData = BitData << 1;				if (getpixel(YOfs + Y, X) > 0)					BitData++;			}			if (PrintChar(BitData))				return (1);		}		if (PrintChar('\r'))			return (1);		if (PrintChar('\n'))			return (1);		Y += 8;	}	PrintChar(12);		/* formfeed */	return (0);}/* *	returns TRUE on error */int PrintChar(out)int	out;{	unsigned char	ret;	ret = biosprint(0, out, 0);	if ((ret & 0x29) || !(ret & 0x10))		return 1;	else		return 0;}int getkey(){	int	key, lo, hi;	key = bioskey(0);	lo = key & 0x00FF;	hi = (key & 0xFF00) >> 8;	return((lo == 0) ? hi + 256 : lo);}/* EOF */