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Subject: Re: [9front] Patch for libframe and acme to eliminate redrawing body of documents when typing in the tagline.
Reply-To: 9front@9front.org
Precedence: bulk

I haven't looked at the patch closely, but would this also fix the
redrawing of body when other windows in acme are hidden?  For example
when 'Mail' running and its window is hidden, the body text of the top
acme window has artefacts shown when a new message is received.

Quoth David Leimbach <leimy2k@icloud.com>:
> diff -r aa49706ca881 sys/include/frame.h
> --- a/sys/include/frame.h	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/include/frame.h	Thu May 20 11:58:46 2021 -0400
> @@ -49,6 +49,7 @@
> 	Image		*tick;	/* typing tick */
> 	Image		*tickback;	/* saved image under tick */
> 	int			ticked;	/* flag: is tick onscreen? */
> +	int			noredraw; 	/* don't draw on the screen */
> };
> 
> ulong	frcharofpt(Frame*, Point);
> diff -r aa49706ca881 sys/src/cmd/acme/acme.c
> --- a/sys/src/cmd/acme/acme.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/acme.c	Thu May 20 11:58:46 2021 -0400
> @@ -256,6 +256,7 @@
> 	w->body.file->mod = FALSE;
> 	w->dirty = FALSE;
> 	winsettag(w);
> +	winresize(w, w->r, FALSE, TRUE);
> 	textscrdraw(&w->body);
> 	textsetselect(&w->tag, w->tag.file->nc, w->tag.file->nc);
> 	xfidlog(w, "new");
> @@ -464,6 +465,7 @@
> 		case MResize:
> 			if(getwindow(display, Refnone) < 0)
> 				error("attach to window");
> +			draw(screen, screen->r, display->white, nil, ZP);
> 			scrlresize();
> 			rowresize(&row, screen->clipr);
> 			break;
> diff -r aa49706ca881 sys/src/cmd/acme/cols.c
> --- a/sys/src/cmd/acme/cols.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/cols.c	Thu May 20 11:58:46 2021 -0400
> @@ -77,7 +77,7 @@
> 		r1 = r;
> 		y = min(y, t-(v->tag.font->height+v->body.font->height+Border+1));
> 		r1.max.y = min(y, v->body.r.min.y+v->body.nlines*v->body.font->height);
> -		r1.min.y = winresize(v, r1, FALSE);
> +		r1.min.y = winresize(v, r1, FALSE, FALSE);
> 		r1.max.y = r1.min.y+Border;
> 		draw(screen, r1, display->black, nil, ZP);
> 		r.min.y = r1.max.y;
> @@ -90,7 +90,7 @@
> 		wininit(w, clone, r);
> 	}else{
> 		w->col = c;
> -		winresize(w, r, FALSE);
> +		winresize(w, r, FALSE, TRUE);
> 	}
> 	w->tag.col = c;
> 	w->tag.row = c->row;
> @@ -152,7 +152,7 @@
> 	if(c->safe) {
> 		if(!didmouse && up)
> 			w->showdel = TRUE;
> -		winresize(w, r, FALSE);
> +		winresize(w, r, FALSE, TRUE);
> 		if(!didmouse && up)
> 			movetodel(w);
> 	}
> @@ -193,7 +193,7 @@
> 	clearmouse();
> 	r1 = r;
> 	r1.max.y = r1.min.y + c->tag.font->height;
> -	textresize(&c->tag, r1);
> +	textresize(&c->tag, r1, TRUE);
> 	draw(screen, c->tag.scrollr, colbutton, nil, colbutton->r.min);
> 	r1.min.y = r1.max.y;
> 	r1.max.y += Border;
> @@ -215,7 +215,7 @@
> 		r2.max.y = r2.min.y+Border;
> 		draw(screen, r2, display->black, nil, ZP);
> 		r1.min.y = r2.max.y;
> -		r1.min.y = winresize(w, r1, FALSE);
> +		r1.min.y = winresize(w, r1, FALSE, i==c->nw-1);
> 	}
> 	c->r = r;
> }
> @@ -271,7 +271,7 @@
> 		r1.max.y = r1.min.y+Border;
> 		draw(screen, r1, display->black, nil, ZP);
> 		r.min.y = r1.max.y;
> -		y = winresize(w, r, FALSE);
> +		y = winresize(w, r, FALSE, i==c->nw-1);
> 	}
> 	free(rp);
> 	free(c->w);
> @@ -298,7 +298,7 @@
> 			r.max.y = cr.max.y;
> 		else
> 			r.max.y = c->w[i+1]->r.min.y;
> -		winresize(w, r, FALSE);
> +		winresize(w, r, FALSE, TRUE);
> 		return;
> 	}
> 	cr.min.y = c->w[0]->r.min.y;
> @@ -309,7 +309,7 @@
> 			c->w[i] = v;
> 		}
> 		draw(screen, cr, textcols[BACK], nil, ZP);
> -		winresize(w, cr, FALSE);
> +		winresize(w, cr, FALSE, TRUE);
> 		for(i=1; i<c->nw; i++)
> 			c->w[i]->body.maxlines = 0;
> 		c->safe = FALSE;
> @@ -367,7 +367,7 @@
> 			r.max.y += 1 + nl[j]*v->body.font->height;
> 		if(!c->safe || !eqrect(v->r, r)){
> 			draw(screen, r, textcols[BACK], nil, ZP);
> -			winresize(v, r, c->safe);
> +			winresize(v, r, c->safe, FALSE);
> 		}
> 		r.min.y = v->r.max.y;
> 		r.max.y += Border;
> @@ -389,17 +389,12 @@
> 	/* compute new size of window */
> 	r = w->r;
> 	r.min.y = y1;
> -	r.max.y = r.min.y+Dy(w->tag.all);
> +	r.max.y = y2;
> 	h = w->body.font->height;
> -	if(y2-r.max.y >= 1+h+Border){
> -		r.max.y += 1;
> -		r.max.y += h*((y2-r.max.y)/h);
> -	}
> +	if(Dy(r) < Dy(w->tagtop)+1+h+Border)
> +		r.max.y = r.min.y + Dy(w->tagtop)+1+h+Border;
> 	/* draw window */
> -	if(!c->safe || !eqrect(w->r, r)){
> -		draw(screen, r, textcols[BACK], nil, ZP);
> -		winresize(w, r, c->safe);
> -	}
> +	r.max.y = winresize(w, r, c->safe, TRUE);
> 	if(i < c->nw-1){
> 		r.min.y = r.max.y;
> 		r.max.y += Border;
> @@ -413,24 +408,18 @@
> 		v = c->w[j];
> 		r = v->r;
> 		r.min.y = y1;
> -		r.max.y = y1+Dy(v->tag.all);
> +		//r.max.y = y1+Dy(v->tag.all);
> +		r.max.y = y1+Dy(v->tagtop);
> 		if(nl[j])
> 			r.max.y += 1 + nl[j]*v->body.font->height;
> -		if(!c->safe || !eqrect(v->r, r)){
> -			draw(screen, r, textcols[BACK], nil, ZP);
> -			winresize(v, r, c->safe);
> -		}
> +		y1 = winresize(v, r, c->safe, j==c->nw-1);
> 		if(j < c->nw-1){	/* no border on last window */
> 			r.min.y = v->r.max.y;
> 			r.max.y = r.min.y + Border;
> 			draw(screen, r, display->black, nil, ZP);
> +			y1 = r.max.y;
> 		}
> -		y1 = r.max.y;
> 	}
> -	r = w->r;
> -	r.min.y = y1;
> -	r.max.y = c->r.max.y;
> -	draw(screen, r, textcols[BACK], nil, ZP);
> 	free(nl);
> 	free(ny);
> 	c->safe = TRUE;
> @@ -465,6 +454,8 @@
> 	error("can't find window");
> 
>   Found:
> +	if(w->tagexpand)	/* force recomputation of window tag size */
> +		w->taglines = 1;
> 	p = mouse->xy;
> 	if(abs(p.x-op.x)<5 && abs(p.y-op.y)<5){
> 		colgrow(c, w, but);
> @@ -494,10 +485,10 @@
> 	if(i == 0)
> 		return;
> 	v = c->w[i-1];
> -	if(p.y < v->tag.all.max.y)
> -		p.y = v->tag.all.max.y;
> -	if(p.y > w->r.max.y-Dy(w->tag.all)-Border)
> -		p.y = w->r.max.y-Dy(w->tag.all)-Border;
> +	if(p.y < v->tagtop.max.y)
> +		p.y = v->tagtop.max.y;
> +	if(p.y > w->r.max.y-Dy(w->tagtop)-Border)
> +		p.y = w->r.max.y-Dy(w->tagtop)-Border;
> 	r = v->r;
> 	r.max.y = p.y;
> 	if(r.max.y > v->body.r.min.y){
> @@ -505,11 +496,7 @@
> 		if(v->body.r.min.y == v->body.r.max.y)
> 			r.max.y++;
> 	}
> -	if(!eqrect(v->r, r)){
> -		draw(screen, r, textcols[BACK], nil, ZP);
> -		winresize(v, r, c->safe);
> -	}
> -	r.min.y = v->r.max.y;
> +	r.min.y = winresize(v, r, c->safe, FALSE);
> 	r.max.y = r.min.y+Border;
> 	draw(screen, r, display->black, nil, ZP);
> 	r.min.y = r.max.y;
> @@ -517,10 +504,7 @@
> 		r.max.y = c->r.max.y;
> 	else
> 		r.max.y = c->w[i+1]->r.min.y-Border;
> -	if(!eqrect(w->r, r)){
> -		draw(screen, r, textcols[BACK], nil, ZP);
> -		winresize(w, r, c->safe);
> -	}
> +	winresize(w, r, c->safe, TRUE);
> 	c->safe = TRUE;
>     	winmousebut(w);
> }
> diff -r aa49706ca881 sys/src/cmd/acme/dat.h
> --- a/sys/src/cmd/acme/dat.h	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/dat.h	Thu May 20 11:58:46 2021 -0400
> @@ -185,7 +185,7 @@
> 	Rectangle all;
> 	Row		*row;
> 	Column	*col;
> -
> +	uint	iq1;	/* last input position */
> 	uint	eq0;	/* start of typing for ESC */
> 	uint	cq0;	/* cache position */
> 	int		ncache;	/* storage for insert */
> @@ -213,7 +213,7 @@
> Rune		textreadc(Text*, uint);
> void		textredraw(Text*, Rectangle, Font*, Image*, int);
> void		textreset(Text*);
> -int		textresize(Text*, Rectangle);
> +int		textresize(Text*, Rectangle, int);
> void		textscrdraw(Text*);
> void		textscroll(Text*, int);
> void		textselect(Text*);
> @@ -290,7 +290,7 @@
> void	winsettag(Window*);
> void	winsettag1(Window*);
> void	wincommit(Window*, Text*);
> -int	winresize(Window*, Rectangle, int);
> +int	winresize(Window*, Rectangle, int, int);
> void	winclose(Window*);
> void	windelete(Window*);
> int	winclean(Window*, int);
> diff -r aa49706ca881 sys/src/cmd/acme/exec.c
> --- a/sys/src/cmd/acme/exec.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/exec.c	Thu May 20 11:58:46 2021 -0400
> @@ -908,6 +908,8 @@
> 		textinsert(t, t->file->nc, L"\n", 1, TRUE);
> 		textsetselect(t, t->file->nc, t->file->nc);
> 	}
> +	t->iq1 = t->q1;
> +	textshow(t, t->q1, t->q1, 1);
> }
> 
> void
> @@ -1219,7 +1221,7 @@
> 	if(tab > 0){
> 		if(w->body.tabstop != tab){
> 			w->body.tabstop = tab;
> -			winresize(w, w->r, 1);
> +			winresize(w, w->r, FALSE, TRUE);
> 		}
> 	}else
> 		warning(nil, "%.*S: Tab %d\n", w->body.file->nname, w->body.file->name, w->body.tabstop);
> diff -r aa49706ca881 sys/src/cmd/acme/rows.c
> --- a/sys/src/cmd/acme/rows.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/rows.c	Thu May 20 11:58:46 2021 -0400
> @@ -102,7 +102,7 @@
> 	row->r = r;
> 	r1 = r;
> 	r1.max.y = r1.min.y + font->height;
> -	textresize(&row->tag, r1);
> +	textresize(&row->tag, r1, TRUE);
> 	r1.min.y = r1.max.y;
> 	r1.max.y += Border;
> 	draw(screen, r1, display->black, nil, ZP);
> @@ -258,6 +258,9 @@
> 	Window *w;
> 	Text *t;
> 
> +	if (r == 0)
> +		r = Runeerror;
> +
> 	clearmouse();
> 	qlock(row);
> 	if(bartflag)
> @@ -271,6 +274,13 @@
> 		else{
> 			winlock(w, 'K');
> 			wintype(w, t, r);
> +			/* Expand tag if necessary */
> +			if(t->what == Tag) {
> +				//t->w->tagsafe = FALSE;
> +				if(r == '\n')
> +					t->w->tagexpand = TRUE;
> +				winresize(w, w->r, TRUE, TRUE);
> +			}
> 			winunlock(w);
> 		}
> 	}
> diff -r aa49706ca881 sys/src/cmd/acme/text.c
> --- a/sys/src/cmd/acme/text.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/text.c	Thu May 20 11:58:46 2021 -0400
> @@ -45,7 +45,8 @@
> 	frinit(t, r, f, b, t->Frame.cols);
> 	rr = t->r;
> 	rr.min.x -= Scrollwid+Scrollgap;	/* back fill to scroll bar */
> -	draw(t->b, rr, t->cols[BACK], nil, ZP);
> +	if(!t->noredraw)
> +		draw(t->b, rr, t->cols[BACK], nil, ZP);
> 	/* use no wider than 3-space tabs in a directory */
> 	maxt = maxtab;
> 	if(t->what == Body){
> @@ -68,14 +69,14 @@
> }
> 
> int
> -textresize(Text *t, Rectangle r)
> +textresize(Text *t, Rectangle r, int keepextra)
> {
> 	int odx;
> 
> -	if(Dy(r) > 0)
> +	if(Dy(r) <= 0)
> +		r.max.y = r.min.y;
> +	else if(!keepextra)
> 		r.max.y -= Dy(r)%t->font->height;
> -	else
> -		r.max.y = r.min.y;
> 	odx = Dx(t->all);
> 	t->all = r;
> 	t->scrollr = r;
> @@ -84,9 +85,17 @@
> 	r.min.x += Scrollwid+Scrollgap;
> 	frclear(t, 0);
> 	textredraw(t, r, t->font, t->b, odx);
> -	return r.max.y;
> +	if(keepextra && t->r.max.y < t->all.max.y && !t->noredraw){
> +		/* draw background in bottom fringe of window */
> +		r.min.x -= Scrollgap;
> +		r.min.y = t->r.max.y;
> +		r.max.y = t->all.max.y;
> +		draw(screen, r, t->cols[BACK], nil, ZP);
> +	}
> +	return t->all.max.y;
> }
> 
> +
> void
> textclose(Text *t)
> {
> @@ -276,7 +285,7 @@
> 		if(u != t){
> 			if(u->org > u->file->nc)	/* will be 0 because of reset(), but safety first */
> 				u->org = 0;
> -			textresize(u, u->all);
> +			textresize(u, u->all, TRUE);
> 			textbacknl(u, u->org, 0);	/* go to beginning of line */
> 		}
> 		textsetselect(u, q0, q0);
> @@ -364,6 +373,8 @@
> 			}
> 					
> 	}
> +	if(q0 < t->iq1)
> +		t->iq1 += n;
> 	if(q0 < t->q1)
> 		t->q1 += n;
> 	if(q0 < t->q0)
> @@ -457,6 +468,8 @@
> 				}
> 			}
> 	}
> +	if(q0 < t->iq1)
> +		t->iq1 -= min(n, t->iq1-q0);
> 	if(q0 < t->q0)
> 		t->q0 -= min(n, t->q0-q0);
> 	if(q0 < t->q1)
> @@ -668,6 +681,11 @@
> 	Rune *rp;
> 	Text *u;
> 
> +	if(t->what!=Body && t->what!=Tag && r=='\n')
> +		return;
> +	if(t->what == Tag)
> +		t->w->tagsafe = FALSE;
> +
> 	nr = 1;
> 	rp = &r;
> 	switch(r){
> @@ -682,9 +700,13 @@
> 			textshow(t, t->q1+1, t->q1+1, TRUE);
> 		return;
> 	case Kdown:
> +		if(t->what == Tag)
> +			goto Tagdown;
> 		n = t->maxlines/3;
> 		goto case_Down;
> 	case Kscrollonedown:
> +		if(t->what == Tag)
> +			goto Tagdown;
> 		n = mousescrollsize(t->maxlines);
> 		if(n <= 0)
> 			n = 1;
> @@ -693,29 +715,43 @@
> 		n = 2*t->maxlines/3;
> 	case_Down:
> 		q0 = t->org+frcharofpt(t, Pt(t->r.min.x, t->r.min.y+n*t->font->height));
> -		if(t->what == Body)
> -			textsetorigin(t, q0, TRUE);
> +		textsetorigin(t, q0, TRUE);
> 		return;
> 	case Kup:
> +		if(t->what == Tag)
> +			goto Tagup;
> 		n = t->maxlines/3;
> 		goto case_Up;
> 	case Kscrolloneup:
> +		if(t->what == Tag)
> +			goto Tagup;
> 		n = mousescrollsize(t->maxlines);
> 		goto case_Up;
> 	case Kpgup:
> 		n = 2*t->maxlines/3;
> 	case_Up:
> 		q0 = textbacknl(t, t->org, n);
> -		if(t->what == Body)
> -			textsetorigin(t, q0, TRUE);
> +		textsetorigin(t, q0, TRUE);
> 		return;
> 	case Khome:
> 		typecommit(t);
> -		textshow(t, 0, 0, FALSE);
> +		if(t->org > t->iq1) {
> +			q0 = textbacknl(t, t->iq1, 1);
> +			textsetorigin(t, q0, TRUE);
> +		} else
> +			textshow(t, 0, 0, FALSE);
> 		return;
> 	case Kend:
> 		typecommit(t);
> -		textshow(t, t->file->nc, t->file->nc, FALSE);
> +		if(t->iq1 > t->org+t->nchars) {
> +			if(t->iq1 > t->file->nc) {
> +				// should not happen, but does. and it will crash textbacknl.
> +				t->iq1 = t->file->nc;
> +			}
> +			q0 = textbacknl(t, t->iq1, 1);
> +			textsetorigin(t, q0, TRUE);
> +		} else
> +			textshow(t, t->file->nc, t->file->nc, FALSE);
> 		return;
> 	case 0x01:	/* ^A: beginning of line */
> 		typecommit(t);
> @@ -732,7 +768,24 @@
> 			q0++;
> 		textshow(t, q0, q0, TRUE);
> 		return;
> +
> +	Tagdown:
> +		/* expand tag to show all text */
> +		if(!t->w->tagexpand){
> +			t->w->tagexpand = TRUE;
> +			winresize(t->w, t->w->r, FALSE, TRUE);
> +		}
> +		return;
> +
> +	Tagup:
> +		/* shrink tag to single line */
> +		if(t->w->tagexpand){
> +			t->w->tagexpand = FALSE;
> +			winresize(t->w, t->w->r, FALSE, TRUE);
> +		}
> +		return;
> 	}
> +
> 	if(t->what == Body){
> 		seq++;
> 		filemark(t->file);
> @@ -812,7 +865,7 @@
> 		}
> 		break;
> 	case '\n':
> -		if(t->what == Body && t->w->indent[AUTOINDENT]){
> +		if(t->w->indent[AUTOINDENT]){
> 			/* find beginning of previous line using backspace code */
> 			nnb = textbswidth(t, 0x15); /* ^U case */
> 			rp = runemalloc(nnb + 1);
> @@ -825,6 +878,7 @@
> 				rp[nr++] = rr;
> 			}
> 		}
> +
> 		break; /* fall through to normal code */
> 	}
> 	/* otherwise ordinary character; just insert, typically in caches of all texts */
> @@ -836,6 +890,16 @@
> 			u->cq0 = t->q0;
> 		else if(t->q0 != u->cq0+u->ncache)
> 			error("text.type cq1");
> +		/*
> +		 * Change the tag before we add to ncache,
> +		 * so that if the window body is resized the
> +		 * commit will not find anything in ncache
> +		 */
> +		if(u->what==Body && u->ncache==0) {
> +			u->needundo = TRUE;
> +			winsettag(t->w);
> +			u->needundo = FALSE;
> +		}
> 		textinsert(u, t->q0, rp, nr, FALSE);
> 		if(u != t)
> 			textsetselect(u, u->q0, u->q1);
> @@ -851,6 +915,7 @@
> 	textsetselect(t, t->q0+nr, t->q0+nr);
> 	if(r=='\n' && t->w!=nil)
> 		wincommit(t->w, t);
> +	t->iq1 = t->q0;
> }
> 
> void
> diff -r aa49706ca881 sys/src/cmd/acme/wind.c
> --- a/sys/src/cmd/acme/wind.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/cmd/acme/wind.c	Thu May 20 11:58:46 2021 -0400
> @@ -13,6 +13,24 @@
> 
> int	winid;
> 
> +/*
> + * Draw the appropriate button.
> + */
> +void
> +windrawbutton(Window *w)
> +{
> +	Image *b;
> +	Rectangle br;
> +
> +	b = button;
> +	if(!w->isdir && !w->isscratch && (w->body.file->mod || w->body.ncache))
> +		b = modbutton;
> +	br.min = w->tag.scrollr.min;
> +	br.max.x = br.min.x + Dx(b->r);
> +	br.max.y = br.min.y + Dy(b->r);
> +	draw(screen, br, b, nil, b->r.min);
> +}
> +
> void
> wininit(Window *w, Window *clone, Rectangle r)
> {
> @@ -33,9 +51,11 @@
> 	w->ctlfid = ~0;
> 	w->utflastqid = -1;
> 	r1 = r;
> -	r1.max.y = r1.min.y + font->height;
> +
> 	w->tagtop = r;
> 	w->tagtop.max.y = r.min.y + font->height;
> +	r1.max.y = r1.min.y + w->taglines * font->height;
> +
> 	incref(&reffont);
> 	f = fileaddtext(nil, &w->tag);
> 	textinit(&w->tag, f, r1, &reffont, tagcols);
> @@ -71,7 +91,6 @@
> 	draw(screen, r1, tagcols[BORD], nil, ZP);
> 	textscrdraw(&w->body);
> 	w->r = r;
> -	w->r.max.y = w->body.r.max.y;
> 	br.min = w->tag.scrollr.min;
> 	br.max.x = br.min.x + Dx(button->r);
> 	br.max.y = br.min.y + Dy(button->r);
> @@ -136,9 +155,9 @@
> 	if(!w->tagexpand && !w->showdel)
> 		return 1;
> 	w->showdel = FALSE;
> -	w->noredraw = 1;
> -	textresize(&w->tag, r);
> -	w->noredraw = 0;
> +	w->tag.noredraw = 1;
> +	textresize(&w->tag, r, TRUE);
> +	w->tag.noredraw = 0;
> 	w->tagsafe = FALSE;
> 	
> 	if(!w->tagexpand) {
> @@ -167,43 +186,34 @@
> }
> 
> int
> -winresize(Window *w, Rectangle r, int safe)
> +winresize(Window *w, Rectangle r, int safe, int keepextra)
> {
> -	int oy, mouseintag, mouseinbody;
> +	int oy, y, mouseintag, mouseinbody;
> 	Point p;
> 	Rectangle r1;
> -	int y;
> -	Image *b;
> -	Rectangle br;
> 
> 	mouseintag = ptinrect(mouse->xy, w->tag.all);
> 	mouseinbody = ptinrect(mouse->xy, w->body.all);
> 
> +	/* tagtop is the first line of the tag */
> 	w->tagtop = r;
> 	w->tagtop.max.y = r.min.y+font->height;
> 
> 	r1 = r;
> -	r1.max.y = r1.min.y + font->height;
> 	r1.max.y = min(r.max.y, r1.min.y + w->taglines*font->height);
> 
> +	/* If needed, recompute the number of lies in the tag. */
> 	if(!safe || !w->tagsafe || !eqrect(w->tag.all, r1)){
> 		w->taglines = wintaglines(w, r);
> 		r1.max.y = min(r.max.y, r1.min.y + w->taglines*font->height);
> 	}
> -	if(Dy(r1) < font->height)
> -		r1.max.y = r1.min.y+font->height;
> +
> +	/* If needed, resize & redraw tag. */
> 	y = r1.max.y;
> -	if(!safe || !eqrect(w->tag.r, r1)){
> -		textresize(&w->tag, r1);
> +	if(!safe || !w->tagsafe || !eqrect(w->tag.r, r1)){
> +		textresize(&w->tag, r1, TRUE);
> 		y = w->tag.r.max.y;
> -		b = button;
> -		if(w->body.file->mod && !w->isdir && !w->isscratch)
> -			b = modbutton;
> -		br.min = w->tag.scrollr.min;
> -		br.max.x = br.min.x + Dx(b->r);
> -		br.max.y = br.min.y + Dy(b->r);
> -		draw(screen, br, b, nil, b->r.min);
> -
> +		windrawbutton(w);
> 		w->tagsafe = TRUE;
> 
> 		/* If mouse is in tag, pull up as tag closes. */
> @@ -221,7 +231,11 @@
> 		}
> 
> 	}
> -	if(!safe || !eqrect(w->body.r, r1)){
> +
> +	/* If needed, resize & redraw body. */
> +	r1 = r;
> +	r1.min.y = y;
> +	if(!safe || !eqrect(w->body.all, r1)){
> 		oy = y;
> 		if(y+1+w->body.font->height <= r.max.y){	/* room for one line */
>   			r1.min.y = y;
> @@ -234,7 +248,7 @@
> 			r1.min.y = y;
> 			r1.max.y = y;
> 		}
> -		y = textresize(&w->body, r1);
> +		y = textresize(&w->body, r1, keepextra);
> 		w->r = r;
> 		w->r.max.y = y;
> 		textscrdraw(&w->body);
> @@ -395,8 +409,6 @@
> 	int i;
> 
> 	texttype(t, r);
> -	if(t->what == Tag)
> -		w->tagsafe = FALSE;
> 	if(t->what == Body)
> 		for(i=0; i<t->file->ntext; i++)
> 			textscrdraw(t->file->text[i]);
> @@ -435,11 +447,9 @@
> void
> winsettag1(Window *w)
> {
> -	int i, j, k, n, bar, dirty;
> +	int i, j, k, n, bar, dirty, resize;
> 	Rune *new, *old, *r;
> -	Image *b;
> 	uint q0, q1;
> -	Rectangle br;
> 
> 	/* there are races that get us here with stuff in the tag cache, so we take extra care to sync it */
> 	if(w->tag.ncache!=0 || w->tag.file->mod)
> @@ -457,16 +467,17 @@
> 		old = runemalloc(w->tag.file->nc+1);
> 		bufread(w->tag.file, 0, old, w->tag.file->nc);
> 		old[w->tag.file->nc] = '\0';
> -		w->tagsafe = FALSE;
> 	}
> +	/* compute the text for the whole tag, replacing current only if it differs */
> 	new = runemalloc(w->body.file->nname+100);
> 	i = 0;
> -	runemove(new+i, w->body.file->name, w->body.file->nname);
> +	if(w->body.file->nname != 0)
> +		runemove(new, w->body.file->name, w->body.file->nname);
> 	i += w->body.file->nname;
> 	runemove(new+i, L" Del Snarf", 10);
> 	i += 10;
> 	if(w->filemenu){
> -		if(w->body.file->delta.nc>0 || w->body.ncache){
> +		if(w->body.needundo || w->body.file->delta.nc>0 || w->body.ncache){
> 			runemove(new+i, L" Undo", 5);
> 			i += 5;
> 		}
> @@ -496,10 +507,12 @@
> 			i += 6;
> 		}
> 	}
> +	new[i] = 0;
> 
> -	new[i] = 0;
> 	/* replace tag if the new one is different */
> +	resize = 0;
> 	if(runeeq(new, i, old, k) == FALSE){
> +		resize = 1;
> 		n = k;
> 		if(n > i)
> 			n = i;
> @@ -520,7 +533,6 @@
> 				w->tag.q1 = q1+bar;
> 			}
> 		}
> -		w->tagsafe = FALSE;
> 	}
> 	free(old);
> 	free(new);
> @@ -531,15 +543,11 @@
> 	if(w->tag.q1 > n)
> 		w->tag.q1 = n;
> 	textsetselect(&w->tag, w->tag.q0, w->tag.q1);
> -	b = button;
> -	if(!w->isdir && !w->isscratch && (w->body.file->mod || w->body.ncache))
> -		b = modbutton;
> -	br.min = w->tag.scrollr.min;
> -	br.max.x = br.min.x + Dx(b->r);
> -	br.max.y = br.min.y + Dy(b->r);
> -	draw(screen, br, b, nil, b->r.min);
> -	if(w->tagsafe == FALSE)
> -		winresize(w, w->r, TRUE);
> +	windrawbutton(w);
> +	if(resize){
> +		w->tagsafe = 0;
> +		winresize(w, w->r, TRUE, TRUE);
> +	}
> }
> 
> void
> diff -r aa49706ca881 sys/src/libframe/frdraw.c
> --- a/sys/src/libframe/frdraw.c	Wed May 12 22:40:51 2021 +0200
> +++ b/sys/src/libframe/frdraw.c	Thu May 20 11:58:46 2021 -0400
> @@ -13,7 +13,7 @@
> 
> 	for(nb=0,b=f->box; nb<f->nbox; nb++, b++){
> 		_frcklinewrap(f, &pt, b);
> -		if(b->nrune >= 0){
> +		if(!f->noredraw && b->nrune >= 0){
> 			stringbg(f->b, pt, text, ZP, f->font, (char*)b->ptr, back, ZP);
> 		}
> 		pt.x += b->wid;
>