unsticky scrollbars

scrollbars used to put the mouse on the scrollbar while scrolling. if latency
is high, this often results to the cursor jumping back. instead, make button 2
srolling work without needing the mouse to be inside the scrollbar and leave
the mouse position alone.

sys/src/cmd/abaco/scrl.c

@@ -108,11 +108,10 @@ textscroll(Text *t, int but)
 {
 	uint p0, oldp0;
 	Rectangle s;
-	int x, y, my, h, first;
+	int y, my, h, first;
 
 	s = insetrect(t->scrollr, 1);
 	h = s.max.y-s.min.y;
-	x = (s.min.x+s.max.x)/2;
 	oldp0 = ~0;
 	first = TRUE;
 	do{
@@ -122,10 +121,6 @@ textscroll(Text *t, int but)
 			my = s.min.y;
 		if(my >= s.max.y)
 			my = s.max.y;
-		if(!eqpt(mouse->xy, Pt(x, my))){
-			moveto(mousectl, Pt(x, my));
-			readmouse(mousectl);		/* absorb event generated by moveto() */
-		}
 		if(but == 2){
 			y = my;
 			p0 = (vlong)t->rs.nr*(y-s.min.y)/h;
@@ -240,10 +235,12 @@ pagescroll(Page *p, int but, int horizontal)
 		else
 			m = mouse->xy.y;
 
-		if(m > om)
+		if(but != 2){
-			m += (m-om)*Panspeed;
+			if(m > om)
-		else if(m < om)
+				m += (m-om)*Panspeed;
-			m -= (om-m)*Panspeed;
+			else if(m < om)
+				m -= (om-m)*Panspeed;
+		}
 
 		if(m < smin)
 			m = smin;
@@ -255,10 +252,6 @@ pagescroll(Page *p, int but, int horizontal)
 			mxy = Pt(m, i);
 		else
 			mxy = Pt(i, m);
-		if(!eqpt(mouse->xy, mxy)){
-			moveto(mousectl, mxy);
-			readmouse(mousectl);	/* absorb event generated by moveto() */
-		}
 		if(but == 2){
 			p0 = muldiv(m-smin, size, ss);
 			p0 = max(p0, 0);

sys/src/cmd/acme/scrl.c

@@ -108,11 +108,10 @@ textscroll(Text *t, int but)
 {
 	uint p0, oldp0;
 	Rectangle s;
-	int x, y, my, h, first;
+	int y, my, h, first;
 
 	s = insetrect(t->scrollr, 1);
 	h = s.max.y-s.min.y;
-	x = (s.min.x+s.max.x)/2;
 	oldp0 = ~0;
 	first = TRUE;
 	do{
@@ -122,10 +121,6 @@ textscroll(Text *t, int but)
 			my = s.min.y;
 		if(my >= s.max.y)
 			my = s.max.y;
-		if(!eqpt(mouse->xy, Pt(x, my))){
-			moveto(mousectl, Pt(x, my));
-			readmouse(mousectl);		/* absorb event generated by moveto() */
-		}
 		if(but == 2){
 			y = my;
 			p0 = (vlong)t->file->nc*(y-s.min.y)/h;

sys/src/cmd/rio/scrl.c

@@ -135,48 +135,40 @@ wscroll(Window *w, int but)
 	first = TRUE;
 	do{
 		flushimage(display, 1);
-		if(w->mc.xy.x<s.min.x || s.max.x<=w->mc.xy.x){
+		my = w->mc.xy.y;
-			readmouse(&w->mc);
+		if(my < s.min.y)
-		}else{
+			my = s.min.y;
-			my = w->mc.xy.y;
+		if(my >= s.max.y)
-			if(my < s.min.y)
+			my = s.max.y;
-				my = s.min.y;
+		if(but == 2){
-			if(my >= s.max.y)
+			y = my;
-				my = s.max.y;
+			if(y > s.max.y-2)
-			if(!eqpt(w->mc.xy, Pt(x, my))){
+				y = s.max.y-2;
-				wmovemouse(w, Pt(x, my));
+			if(w->nr > 1024*1024)
-				readmouse(&w->mc);		/* absorb event generated by moveto() */
+				p0 = ((w->nr>>10)*(y-s.min.y)/h)<<10;
-			}
-			if(but == 2){
-				y = my;
-				if(y > s.max.y-2)
-					y = s.max.y-2;
-				if(w->nr > 1024*1024)
-					p0 = ((w->nr>>10)*(y-s.min.y)/h)<<10;
-				else
-					p0 = w->nr*(y-s.min.y)/h;
-				if(oldp0 != p0)
-					wsetorigin(w, p0, FALSE);
-				oldp0 = p0;
-				readmouse(&w->mc);
-				continue;
-			}
-			if(but == 1)
-				p0 = wbacknl(w, w->org, (my-s.min.y)/w->font->height);
 			else
-				p0 = w->org+frcharofpt(w, Pt(s.max.x, my));
+				p0 = w->nr*(y-s.min.y)/h;
 			if(oldp0 != p0)
-				wsetorigin(w, p0, TRUE);
+				wsetorigin(w, p0, FALSE);
 			oldp0 = p0;
-			/* debounce */
+			readmouse(&w->mc);
-			if(first){
+			continue;
-				flushimage(display, 1);
-				sleep(200);
-				nbrecv(w->mc.c, &w->mc.Mouse);
-				first = FALSE;
-			}
-			wscrsleep(w, 100);
 		}
+		if(but == 1)
+			p0 = wbacknl(w, w->org, (my-s.min.y)/w->font->height);
+		else
+			p0 = w->org+frcharofpt(w, Pt(s.max.x, my));
+		if(oldp0 != p0)
+			wsetorigin(w, p0, TRUE);
+		oldp0 = p0;
+		/* debounce */
+		if(first){
+			flushimage(display, 1);
+			sleep(200);
+			nbrecv(w->mc.c, &w->mc.Mouse);
+			first = FALSE;
+		}
+		wscrsleep(w, 100);
 	}while(w->mc.buttons & (1<<(but-1)));
 	while(w->mc.buttons)
 		readmouse(&w->mc);

sys/src/cmd/samterm/scroll.c

@@ -120,10 +120,10 @@ scroll(Flayer *l, int but)
 	draw(scrback, Rect(0,0,Dx(l->scroll), Dy(l->scroll)), l->f.b, nil, l->scroll.min);
 	do{
 		oin = in;
-		in = abs(x-mousep->xy.x)<=FLSCROLLWID/2;
+		in = (but > 3) || (but == 2) || abs(x-mousep->xy.x)<=FLSCROLLWID/2;
 		if(oin && !in)
 			scrunmark(l, r);
-		if(but > 3 || in){
+		if(in){
 			scrmark(l, r);
 			oy = y;
 			my = mousep->xy.y;
@@ -131,8 +131,6 @@ scroll(Flayer *l, int but)
 				my = s.min.y;
 			if(my >= s.max.y)
 				my = s.max.y;
-			if(in && !eqpt(mousep->xy, Pt(x, my)))
-				moveto(mousectl, Pt(x, my));
 			if(but == 1 || but == 4){
 				p0 = l->origin-frcharofpt(&l->f, Pt(s.max.x, my));
 				rt = scrpos(l->scroll, p0, p0+l->f.nchars, tot);
@@ -153,7 +151,7 @@ scroll(Flayer *l, int but)
 			}
 		}
 	}while(but <= 3 && button(but));
-	if(but > 3 || in){
+	if(in){
 		h = s.max.y-s.min.y;
 		scrunmark(l, r);
 		p0 = 0;