harvey/sys/src/cmd/bitsy/pencal.c

#include <u.h>
#include <libc.h>
#include <draw.h>

int debug = 0;

struct Cal {
	double scalex;
	double transx;
	double scaley;
	double transy;
} cal;

/* Calibrate the pen */

Point pts[5];

Point pens[5];

Point up	= {  0, -10};
Point down	= {  0,  10};
Point left	= {-10,   0};
Point right	= { 10,   0};

Point
pen2scr(Point p)
{
	return Pt(p.x * cal.scalex / 65536.0 + cal.transx,
			  p.y * cal.scaley / 65536.0 + cal.transy);
}

Point
scr2pen(Point p)
{
	return Pt((p.x - cal.transx) * 65536.0 / cal.scalex,
			  (p.y + cal.transy) * 65536.0 / cal.scaley);
}

void
cross(Point p) {
	draw(screen, screen->r, display->white, nil, ZP);
	line(screen, addpt(p, up), addpt(p, down), Endsquare, Endsquare, 0, display->black, ZP);
	line(screen, addpt(p, left), addpt(p, right), Endsquare, Endsquare, 0, display->black, ZP);
	flushimage(display, 1);
}

Point
getmouse(int mouse) {
	static char buf[50];
	int x, y, b, n;
	Point p;

	n = 0;
	p.x = p.y = 0;
	do {
		if (read(mouse, buf, 48) != 48)
			sysfatal("read: %r");
		if (debug > 1) fprint(2, "%s\n", buf);
		if (buf[0] == 'r') {
			b = 1;
			continue;
		}
		if (buf[0] != 'm')
			sysfatal("mouse message: %s", buf);
		x = strtol(buf+1, nil, 10);
		y = strtol(buf+13, nil, 10);
		b = strtol(buf+25, nil, 10);
		p.x = (n * p.x + x)/(n+1);
		p.y = (n * p.y + y)/(n+1);
		n++;
	} while (b & 0x7);
	return p;
}

void
main(int argc, char **argv) {
	int i, mouse, mousectl, wctl;
	Rectangle r, oldsize;

	ARGBEGIN{
	case 'd':
		debug = 1;
		break;
	}ARGEND;
	
	if ((mouse = open("/dev/mouse", OREAD)) < 0
	 && (mouse = open("#m/mouse", OREAD)) < 0)
		sysfatal("#m/mouse: %r");

	mousectl = open("#m/mousectl", ORDWR);
	if (mousectl < 0)
		sysfatal("#m/mousectl: %r");

	if(initdraw(nil, nil, "calibrate") < 0)
		sysfatal("initdraw: %r\n");

again:

	r = insetrect(display->image->r, 2);

	wctl = open("/dev/wctl", ORDWR);
	if (wctl >= 0) {
		char buf[4*12+1];

		buf[48] = 0;
		oldsize = screen->r;
		if (fprint(wctl, "resize -r %R", r) <= 0)
			sysfatal("write /dev/wctl, %r");
		if (getwindow(display, Refbackup) < 0)
			sysfatal("getwindow");
		if (debug) fprint(2, "resize: %R\n", screen->r);

		if (read(mousectl, buf, 48) != 48)
			sysfatal("read mousectl: %r");
		if (debug > 1) fprint(2, "mousectl %s\n", buf);
		if (buf[0] != 'c')
			sysfatal("mousectl message: %s", buf);
		cal.scalex = strtol(buf+ 1, nil, 10);
		cal.scaley = strtol(buf+13, nil, 10);
		cal.transx = strtol(buf+25, nil, 10);
		cal.transy = strtol(buf+37, nil, 10);
	} else {
		fprint(mousectl, "calibrate");
		cal.scalex = 1<<16;
		cal.scaley = 1<<16;
		cal.transx = 0;
		cal.transy = 0;
	}

	fprint(2, "calibrate %ld %ld %ld %ld (old)\n",
		(long)cal.scalex, (long)cal.scaley, (long)cal.transx, (long)cal.transy);

	if (debug) fprint(2, "screen coords %R\n", screen->r);
	pts[0] = addpt(Pt( 16,  16), screen->r.min);
	pts[1] = addpt(Pt( 16, -16), Pt(screen->r.min.x, screen->r.max.y));
	pts[2] = addpt(Pt(-16,  16), Pt(screen->r.max.x, screen->r.min.y));
	pts[3] = addpt(Pt(-16, -16), screen->r.max);
	pts[4] = Pt((screen->r.max.x + screen->r.min.x)/2,
				(screen->r.max.y + screen->r.min.y)/2);;

	for (i = 0; i < 4; i++) {
		cross(pts[i]);
		pens[i] = scr2pen(getmouse(mouse));
		if (debug) fprint(2, "%P\n", pens[i]);
	}

	cal.scalex = (pts[2].x + pts[3].x - pts[0].x - pts[1].x) * 65536.0 /
			  (pens[2].x + pens[3].x - pens[0].x - pens[1].x);
	cal.scaley = (pts[1].y + pts[3].y - pts[0].y - pts[2].y) * 65536.0 /
			  (pens[1].y + pens[3].y - pens[0].y - pens[2].y);
	cal.transx = pts[0].x - (pens[0].x*cal.scalex) / 65536.0;
	cal.transy = pts[0].y - (pens[0].y*cal.scaley) / 65536.0;

	if (debug) fprint(2, "scale [%f, %f], trans [%f, %f]\n",
		cal.scalex, cal.scaley, cal.transx, cal.transy);

	fprint(mousectl, "calibrate %ld %ld %ld %ld",
		(long)cal.scalex, (long)cal.scaley, (long)cal.transx, (long)cal.transy);

	cross(pts[4]);
	pens[4] = getmouse(mouse);

	draw(screen, screen->r, display->white, nil, ZP);
	flushimage(display, 1);

	if (abs(pts[4].x-pens[4].x) > 4 || abs(pts[4].y-pens[4].y) > 4) {
		fprint(2, "Calibration inaccurate: %P -> %P\n", pts[4], pens[4]);
		goto again;
	} else {
		fprint(2, "Calibration ok: %P -> %P\n", pts[4], pens[4]);
	}

	print("calibrate='%ld %ld %ld %ld'\n",
		(long)cal.scalex, (long)cal.scaley, (long)cal.transx, (long)cal.transy);

	if (debug)
		for (i = 0; i < 4; i++) {
			cross(pts[i]);
			pens[i] = getmouse(mouse);
			if (debug) fprint(2, "%P\n", pens[i]);
		}

	if (wctl >= 0)
		fprint(wctl, "resize -r %R", oldsize);

}