Instead of working out which pane to resize with the mouse by walking

the panes list, look through the layout cells for the nearest border and
resize that cell. From Dan Aloni in GitHub issue 1374.

3 files changed, 86 insertions, 59 deletions

diff --git a/usr.bin/tmux/cmd-resize-pane.c b/usr.bin/tmux/cmd-resize-pane.c
index b235863edd0..c0508183953 100644
--- a/usr.bin/tmux/cmd-resize-pane.c
+++ b/usr.bin/tmux/cmd-resize-pane.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-resize-pane.c,v 1.31 2017/05/11 07:24:42 nicm Exp $ */
+/* $OpenBSD: cmd-resize-pane.c,v 1.32 2018/06/08 20:54:22 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -129,14 +129,16 @@ static void
 cmd_resize_pane_mouse_update(struct client *c, struct mouse_event *m)
 {
 	struct winlink		*wl;
-	struct window_pane	*loop, *wp_x, *wp_y;
-	u_int			 y, ly, x, lx, sx, sy, ex, ey;
+	struct window		*w;
+	u_int			 y, ly, x, lx;
+	struct layout_cell	*lc;
 
 	wl = cmd_mouse_window(m, NULL);
 	if (wl == NULL) {
 		c->tty.mouse_drag_update = NULL;
 		return;
 	}
+	w = wl->window;
 
 	y = m->y; x = m->x;
 	if (m->statusat == 0 && y > 0)
@@ -149,37 +151,16 @@ cmd_resize_pane_mouse_update(struct client *c, struct mouse_event *m)
 	else if (m->statusat > 0 && ly >= (u_int)m->statusat)
 		ly = m->statusat - 1;
 
-	wp_x = wp_y = NULL;
-	TAILQ_FOREACH(loop, &wl->window->panes, entry) {
-		if (!window_pane_visible(loop))
-			continue;
-
-		sx = loop->xoff;
-		if (sx != 0)
-			sx--;
-		ex = loop->xoff + loop->sx;
-
-		sy = loop->yoff;
-		if (sy != 0)
-			sy--;
-		ey = loop->yoff + loop->sy;
-
-		if ((lx == sx || lx == ex) &&
-		    (ly >= sy && ly <= ey) &&
-		    (wp_x == NULL || loop->sy > wp_x->sy))
-			wp_x = loop;
-		if ((ly == sy || ly == ey) &&
-		    (lx >= sx && lx <= ex) &&
-		    (wp_y == NULL || loop->sx > wp_y->sx))
-			wp_y = loop;
-	}
-	if (wp_x == NULL && wp_y == NULL) {
-		c->tty.mouse_drag_update = NULL;
+	lc = layout_search_by_border(w->layout_root, lx, ly);
+	if (lc == NULL)
 		return;
-	}
-	if (wp_x != NULL)
-		layout_resize_pane(wp_x, LAYOUT_LEFTRIGHT, x - lx, 0);
-	if (wp_y != NULL)
-		layout_resize_pane(wp_y, LAYOUT_TOPBOTTOM, y - ly, 0);
-	server_redraw_window(wl->window);
+
+	if (y != ly && lc->parent->type == LAYOUT_TOPBOTTOM)
+		layout_resize_layout(w, lc, LAYOUT_TOPBOTTOM, y - ly, 0);
+	else if (x != lx && lc->parent->type == LAYOUT_LEFTRIGHT)
+		layout_resize_layout(w, lc, LAYOUT_LEFTRIGHT, x - lx, 0);
+	else
+		return;
+
+	server_redraw_window(w);
 }
diff --git a/usr.bin/tmux/layout.c b/usr.bin/tmux/layout.c
index 1b04215ab63..a0b81b52f83 100644
--- a/usr.bin/tmux/layout.c
+++ b/usr.bin/tmux/layout.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: layout.c,v 1.35 2018/03/23 07:44:44 nicm Exp $ */
+/* $OpenBSD: layout.c,v 1.36 2018/06/08 20:54:22 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -127,6 +127,42 @@ layout_print_cell(struct layout_cell *lc, const char *hdr, u_int n)
 	}
 }
 
+struct layout_cell *
+layout_search_by_border(struct layout_cell *lc, u_int x, u_int y)
+{
+	struct layout_cell	*lcchild, *last = NULL;
+
+	TAILQ_FOREACH(lcchild, &lc->cells, entry) {
+		if (x >= lcchild->xoff && x < lcchild->xoff + lcchild->sx &&
+		    y >= lcchild->yoff && y < lcchild->yoff + lcchild->sy) {
+			/* Inside the cell - recurse. */
+			return (layout_search_by_border(lcchild, x, y));
+		}
+
+		if (last == NULL) {
+			last = lcchild;
+			continue;
+		}
+
+		switch (lc->type) {
+		case LAYOUT_LEFTRIGHT:
+			if (x < lcchild->xoff && x >= last->xoff + last->sx)
+				return (last);
+			break;
+		case LAYOUT_TOPBOTTOM:
+			if (y < lcchild->yoff && y >= last->yoff + last->sy)
+				return (last);
+			break;
+		case LAYOUT_WINDOWPANE:
+			break;
+		}
+
+		last = lcchild;
+	}
+
+	return (NULL);
+}
+
 void
 layout_set_size(struct layout_cell *lc, u_int sx, u_int sy, u_int xoff,
     u_int yoff)
@@ -550,14 +586,40 @@ layout_resize_pane_to(struct window_pane *wp, enum layout_type type,
 	layout_resize_pane(wp, type, change, 1);
 }
 
+void
+layout_resize_layout(struct window *w, struct layout_cell *lc,
+    enum layout_type type, int change, int opposite)
+{
+	int	needed, size;
+
+	/* Grow or shrink the cell. */
+	needed = change;
+	while (needed != 0) {
+		if (change > 0) {
+			size = layout_resize_pane_grow(w, lc, type, needed,
+			    opposite);
+			needed -= size;
+		} else {
+			size = layout_resize_pane_shrink(w, lc, type, needed);
+			needed += size;
+		}
+
+		if (size == 0)	/* no more change possible */
+			break;
+	}
+
+	/* Fix cell offsets. */
+	layout_fix_offsets(w->layout_root);
+	layout_fix_panes(w, w->sx, w->sy);
+	notify_window("window-layout-changed", w);
+}
+
 /* Resize a single pane within the layout. */
 void
 layout_resize_pane(struct window_pane *wp, enum layout_type type, int change,
     int opposite)
 {
-	struct window		*w = wp->window;
 	struct layout_cell	*lc, *lcparent;
-	int			 needed, size;
 
 	lc = wp->layout_cell;
 
@@ -574,26 +636,7 @@ layout_resize_pane(struct window_pane *wp, enum layout_type type, int change,
 	if (lc == TAILQ_LAST(&lcparent->cells, layout_cells))
 		lc = TAILQ_PREV(lc, layout_cells, entry);
 
-	/* Grow or shrink the cell. */
-	needed = change;
-	while (needed != 0) {
-		if (change > 0) {
-			size = layout_resize_pane_grow(w, lc, type, needed,
-			    opposite);
-			needed -= size;
-		} else {
-			size = layout_resize_pane_shrink(w, lc, type, needed);
-			needed += size;
-		}
-
-		if (size == 0)	/* no more change possible */
-			break;
-	}
-
-	/* Fix cell offsets. */
-	layout_fix_offsets(wp->window->layout_root);
-	layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
-	notify_window("window-layout-changed", wp->window);
+	layout_resize_layout(wp->window, lc, type, change, opposite);
 }
 
 /* Helper function to grow pane. */
diff --git a/usr.bin/tmux/tmux.h b/usr.bin/tmux/tmux.h
index 180cf10e332..82971931723 100644
--- a/usr.bin/tmux/tmux.h
+++ b/usr.bin/tmux/tmux.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.825 2018/05/24 09:42:49 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.826 2018/06/08 20:54:22 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -2203,6 +2203,9 @@ void		 layout_free_cell(struct layout_cell *);
 void		 layout_print_cell(struct layout_cell *, const char *, u_int);
 void		 layout_destroy_cell(struct window *, struct layout_cell *,
 		     struct layout_cell **);
+void		 layout_resize_layout(struct window *, struct layout_cell *,
+		     enum layout_type, int, int);
+struct layout_cell *layout_search_by_border(struct layout_cell *, u_int, u_int);
 void		 layout_set_size(struct layout_cell *, u_int, u_int, u_int,
 		     u_int);
 void		 layout_make_leaf(struct layout_cell *, struct window_pane *);