implement Dividers; include "sys.m";	sys: Sys;include "draw.m";	draw: Draw;	Point, Rect: import draw;include "tk.m";	tk: Tk;include "dividers.m"; Lay: adt {	d: int;	x: fn(l: self Lay, p: Point): int;	y: fn(l: self Lay, p: Point): int;	mkr: fn(l: self Lay, r: Rect): Rect;	mkpt: fn(l: self Lay, p: Point): Point;}; DIVHEIGHT: con 6; init(){	sys = load Sys Sys->PATH;	draw = load Draw Draw->PATH;	tk = load Tk Tk->PATH;} # dir is direction in which to stack widgets (NS or EW)Divider.new(win: ref Tk->Toplevel, w: string, wl: list of string, dir: int): (ref Divider, chan of string){	lay := Lay(dir);	n := len wl;	d := ref Divider(win, w, nil, dir, array[n] of {* => ref DWidget}, (0, 0));	p := Point(0, 0);	for (i := 0; wl != nil; (wl, i) = (tl wl, i+1)) {		sz := lay.mkpt(wsize(win, hd wl));		*d.widgets[i] = (hd wl, (p, p.add(sz)), sz);		if (sz.x > d.canvsize.x)			d.canvsize.x = sz.x;		p.y += sz.y + DIVHEIGHT;	}	d.canvsize.y = p.y - DIVHEIGHT;	cmd(win, "canvas " + d.w + " -width " + string lay.x(d.canvsize) +			" -height " + string lay.y(d.canvsize));	ech := chan of string;	echname := "dw" + d.w;	tk->namechan(win, ech, echname);	for (i = 0; i < n; i++) {		dw := d.widgets[i];		dw.r.max.x = d.canvsize.x + dw.r.min.x;		sz := dxy(dw.r);		cmd(win, d.w + " create window " + p2s(lay.mkpt(dw.r.min)) +			" -window " + dw.w +			" -tags w" + string i + " -anchor nw" +			" -width " + string lay.x(sz) +			" -height " + string lay.y(sz));		cmd(win, "pack propagate " + dw.w + " 0");		if (i < n - 1) {			r := lay.mkr(((dw.r.min.x, dw.r.max.y),					(dw.r.max.x, dw.r.max.y + DIVHEIGHT)));			cmd(win, d.w + " create rectangle " + r2s(r) +				" -fill red" +				" -tags d" + string i);			cmd(win, d.w + " bind d" + string i + " <Button-1>" +				" {send " + echname + " but " + string i + " %x %y}");			cmd(win, d.w + " bind d" + string i + " <Motion-Button-1> {}");			cmd(win, d.w + " bind d" + string i + " <ButtonRelease-1>" +				" {send " + echname + " up x %x %y}");		}	}	cmd(win, d.w + " create rectangle -2 -2 -1 -1 -tags grab");	cmd(win, d.w + " bind grab <Button-1> {send " + echname + " drag x %x %y}");	cmd(win, d.w + " bind grab <ButtonRelease-1> {send " + echname + " up x %x %y}");	cmd(win, "bind " + d.w + " <Configure> {send " + echname + " config x x x}");	return (d, ech);} Divider.event(d: self ref Divider, e: string){	(n, toks) := sys->tokenize(e, " ");	if (n != 4) {		sys->print("dividers: invalid event %s\n", e);		return;	}	lay := Lay(d.dir);	p := lay.mkpt((int hd tl tl toks, int hd tl tl tl toks));	t := hd toks;	if (t == "but" && d.state != nil)		t = "drag";	case t {	"but" =>		if (d.state != nil) {			sys->print("dividers: event '%s' received in drag mode\n", e);			return;		}		div := int hd tl toks;		d.state = ref DState;		d.state.dragdiv = div;		d.state.dy = p.y - d.widgets[div].r.max.y;		d.state.maxy = d.widgets[div+1].r.max.y - DIVHEIGHT;		d.state.miny = d.widgets[div].r.min.y;		cmd(d.win, d.w + " itemconfigure d" + string div + " -fill orange");		cmd(d.win, d.w + " raise d" + string div);		cmd(d.win, d.w + " coords grab -10000 -10000 10000 10000");		cmd(d.win, "grab set " + d.w);		cmd(d.win, "update");	"drag" =>		if (d.state == nil) {			sys->print("dividers: event '%s' received in non-drag mode\n", e);			return;		}		div := d.state.dragdiv;		ypos := p.y - d.state.dy;		if (ypos > d.state.maxy)			ypos = d.state.maxy;		else if (ypos < d.state.miny)			ypos = d.state.miny;		r := Rect((0, ypos), (d.canvsize.x, ypos + DIVHEIGHT));		cmd(d.win, d.w + " coords d" + string div + " " + r2s(lay.mkr(r)));		d.widgets[div].r.max.y = ypos;		d.widgets[div+1].r.min.y = ypos + DIVHEIGHT;		relayout(d);		cmd(d.win, "update");	"up" =>		if (d.state == nil) {			sys->print("dividers: event '%s' received in non-drag mode\n", e);			return;		}		div := d.state.dragdiv;		cmd(d.win, d.w + " itemconfigure d" + string div + " -fill red");		cmd(d.win, d.w + " coords grab -2 -2 -1 -1");		cmd(d.win, "grab release " + d.w);		cmd(d.win, "update");		d.state = nil;	"config" =>		resize(d);		cmd(d.win, "update");	}} # lay out widgets according to rectangles that have been already specified.relayout(d: ref Divider){	lay := Lay(d.dir);	for (i := 0; i < len d.widgets; i++) {		dw := d.widgets[i];		sz := dxy(dw.r);		szs := " -width " + string lay.x(sz) + " -height " + string lay.y(sz);		cmd(d.win, d.w + " coords w" + string i + " " + p2s(lay.mkpt(dw.r.min)));		cmd(d.win, d.w + " itemconfigure w" + string i + szs);		cmd(d.win, dw.w + " configure" + szs);		if (i < len d.widgets - 1) {			r := lay.mkr(((dw.r.min.x, dw.r.max.y),					(dw.r.max.x, dw.r.max.y + DIVHEIGHT)));			cmd(d.win, d.w + " coords d" + string i + " " + r2s(r));		}	}} # resize based on current actual size of canvas;# sections resize proportionate to their previously occupied space.# strange things will happen if we're resizing in the middle of a drag...resize(d: ref Divider){	lay := Lay(d.dir);	sz := lay.mkpt((int cmd(d.win, d.w + " cget -actwidth"), 			int cmd(d.win, d.w + " cget -actheight"))); 	wspace := (len d.widgets - 1) * DIVHEIGHT;	y := 0;	for (i := 0; i < len d.widgets; i++) {		dw := d.widgets[i];		prop := real dw.r.dy() / real (d.canvsize.y - wspace);		dw.r = ((0, y), (sz.x, y + int (prop * real (sz.y - wspace))));		y = dw.r.max.y + DIVHEIGHT;	}	y -= DIVHEIGHT;	# compensate for rounding errors	d.widgets[i - 1].r.max.y -= y - sz.y;	d.canvsize = sz;	relayout(d);} wsize(win: ref Tk->Toplevel, w: string): Point{	bw := int cmd(win, w + " cget -borderwidth");	return Point(int cmd(win, w + " cget -width") + bw*2,			int cmd(win, w + " cget -height") + bw*2);} dxy(r: Rect): Point{	return r.max.sub(r.min);} p2s(p: Point): string{	return string p.x + " " + string p.y;} r2s(r: Rect): string{	return string r.min.x + " " + string r.min.y + " " +			string r.max.x + " " + string r.max.y;} Lay.x(l: self Lay, p: Point): int{	if (l.d == NS)		return p.x;	return p.y;} Lay.y(l: self Lay, p: Point): int{	if (l.d == NS)		return p.y;	return p.x;} Lay.mkr(l: self Lay, r: Rect): Rect{	if (l.d == NS)		return r;	return ((r.min.y, r.min.x), (r.max.y, r.max.x));} Lay.mkpt(l: self Lay, p: Point): Point{	if (l.d == NS)		return p;	return (p.y, p.x);} cmd(top: ref Tk->Toplevel, s: string): string{	e := tk->cmd(top, s);	if (e != nil && e[0] == '!')		sys->print("dividers: tk error %s on '%s'\n", e, s);	return e;}