/* 
 *	wacom -
 *		This is a temporary WACOM tablet driver process, it sould 
 *	be run in the background after system startup by adding it to 
 *	/etc/inittab.  This driver is made to work with a 9x6 Wacom
 *	SD-510C while using the pressure sensitive pen.  Feel free to 
 *	modify and distribute this source as you like.
 *
 *				Paul Haeberli - 1990
 *
 *	1. Your cable should look like this:
 *		
 *		WACOM 			IRIS
 *	-----------------------------------------
 *		TX Pin 2		RX Pin 3
 *		RX Pin 3		TX Pin 2
 *		RTS Pin 4		CTS Pin 5
 *		CTS Pin 5		RTS Pin 4
 *		DSR Pin 6		DTR Pin 9
 *		GND Pin 7		GND Pin 7
 *
 *
 *	2. Plug the tablet into /dev/tty1.
 *	3. make sure there isn't a getty running on /dev/ttyd1.
 *	4. vi /etc/inittab, and make sure any lines with "ttyd1"
 *		in them have "off" in them as well.
 *	5. su and chmod +wr /dev/ttyd1
 *	6. compile the driver with a command like: 
 *		cc -I/usr/include/ wacom.c -o wacom -lgl_s
 *	7. run the driver in the background ./wacom & to try it out.
 *
 *	8. This driver is set up to generate mouse position events
 *	and to make the left mouse button appear to go down when
 *	the pressure sensitive pen in pressed.  The actual pressure 
 *	value is available by reading the valuator "DIAL0". 
 *
 *	9. when things are working well, copy wacom /etc/gl and add 
 *		a line to /etc/inittab like the line for "tabletd".
 *
 */
#include "stdio.h"
#include "sys/types.h"
#include "sys/stat.h"
#include "fcntl.h"
#include "termio.h"
#include "gl.h" 
#include "device.h"
#include "dials.h"

/* #ifdef DEBUG */

#define PENBUTTON	LEFTMOUSE
#define PENX		MOUSEX
#define PENY		MOUSEY
#define PENPRESSURE	DIAL0

#define MINPRESS 	(5)
#define PSCALE		(0.40)

#define TTYDEV		"/dev/ttyd1"

struct termio term, sterm;
int f, n;
int os1, os2, os3, os4;
int s1, s2, s3, s4;
int oxpos, oypos, opval;
int xpos, ypos, pval;

main()
{
    f = open(TTYDEV,O_RDWR);
    if(f < 0) {
	fprintf(stderr,"penmouse: error opening %s\n",TTYDEV);
	exit(1);
    }
    serialinit();
    os1 = -1;
    os2 = -1;
    os3 = -1;
    os4 = -1;
    oxpos = -1;
    oypos = -1;
    wacominit();
    readbinary();
}

wacominit()
{
    int n;

    /* n = write(f,"DE1\r",4);	/* relative mode */
    /* n = write(f,"IT50\r",5);	/* transmit rate 4 per sec */
    /* n = write(f,"SU03\r",5);	/* suppressed mode DON'T WORK RIGHT */
    /* n = write(f,"IT02\r",5);	/* transmit rate 100 per sec */
    /* n = write(f,"IT99\r",5);	/* transmit rate 5 per sec */

    n = write(f,"DE0\r",4);	/* absolute mode */
    n = write(f,"PH1\r",4);	/* pressure mode */
    n = write(f,"IT02\r",5);	/* transmit rate 100 per sec */
    n = write(f,"SR\r",3);	/* continous stream mode */
    n = write(f,"IN003\r",6);   /* increment mode */
    n = write(f,"AS1\r",4);	/* binary mode */
}

readbinary()
{
    int c, phase;
    int xsign, ysign, psign, inside;

    while(1) {
	c = getwchar();
	if(c&0x80)
	    break;
    }
    phase = 1;
    while(1) {
	switch(phase) {
	    case 1:
		inside = (c>>6)&1;
		if(inside) {
		    if(c&0x04)
			xsign = -1;
		    else
			xsign = 1;
		    xpos = c&0x03;
		}
		break;
	    case 2:
		if(inside) 
		    xpos = (xpos<<7) + (c&0x7f);
		break;
	    case 3:
		if(inside) 
		    xpos = (xpos<<7) + (c&0x7f);
		break;
	    case 4:
		if(inside) {
		    if(c&0x04)
			ysign = -1;
		    else
			ysign = 1;
		    ypos = c&0x03;
		}
		break;
	    case 5:
		if(inside) 
		    ypos = (ypos<<7) + (c&0x7f);
		break;
	    case 6:
		if(inside) 
		    ypos = (ypos<<7) + (c&0x7f);
		break;
	    case 7:
		if(inside) {
		    pval = c&0x3f;
		    if(c&0x40)
			pval = pval | 0xffffffc0;
		    pval += 32;
		    xpos = PSCALE*(xsign*xpos);
		    ypos = PSCALE*(3000-(ysign*ypos));
		    if(xpos != oxpos) {
			mygl_changedevice(PENX,xpos);
			oxpos = xpos;
		    }
		    if(ypos != oypos) {
			mygl_changedevice(PENY,ypos);
			oypos = ypos;
		    }
		} else 
		    pval = 0;
		if(pval != opval) {
		    if(pval > MINPRESS+2) 
			s1 = 1;
		    if(pval < MINPRESS-2) 
			s1 = 0;
		    if(s1 != os1) {
			mygl_changedevice(PENBUTTON,s1);
			os1 = s1;
		    }
		    mygl_changedevice(PENPRESSURE,(4*pval)-639);
		    opval = pval;
		}
		break;
	}
	phase++;
	c = getwchar();
	if(c&0x80) {
	    if(phase != 8)
	        fprintf(stderr,"lost char");
	    phase = 1;
	}
    }
}

int cleft;
unsigned char *bptr;
unsigned char buf[512];

getwchar()
{
    while(cleft == 0) {
        n = read(f,buf,512);
	if(n<0) {
	    fprintf(stderr,"penmouse: bad read\n");
	    exit(1);
	}
	cleft = n;
	bptr = buf;
    }
    cleft--;
    return (*bptr++); 
}

serialinit()
{
    if (ioctl(f, TCGETA, &term) == -1) {
	fprintf(stderr,"ioctl(TCGETA) failed\n");
	perror("init");
	return(0);
    }
    sterm = term;

    /* change the modes */
    term.c_iflag = 0; 
    term.c_oflag = 0;
    term.c_lflag = 0;
    term.c_cflag = B9600 | CS8 | CREAD ;
    term.c_cc[VMIN] = 1;
    term.c_cc[VTIME] = 0;

    if (ioctl(f, TCSETA, &term) == -1) {
	fprintf(stderr,"ioctl(TCSETA) failed\n");
	perror("init");
	return(0);
    }
}

mygl_changedevice(dev,val)
int dev, val;
{
#ifdef DEBUG
    printf("%d %d\n",dev,val);
#else 
    gl_changedevice(dev,val);
#endif
}