===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/tmux/screen.c,v
retrieving revision 1.3
retrieving revision 1.4
diff -c -r1.3 -r1.4
*** src/usr.bin/tmux/screen.c	2009/06/04 18:48:24	1.3
--- src/usr.bin/tmux/screen.c	2009/06/24 19:12:44	1.4
***************
*** 1,4 ****
! /* $OpenBSD: screen.c,v 1.3 2009/06/04 18:48:24 nicm Exp $ */
  
  /*
   * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
--- 1,4 ----
! /* $OpenBSD: screen.c,v 1.4 2009/06/24 19:12:44 nicm Exp $ */
  
  /*
   * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
***************
*** 169,206 ****
  screen_resize_y(struct screen *s, u_int sy)
  {
  	struct grid	*gd = s->grid;
! 	u_int		 oy, yy, ny;
  
  	if (sy == 0)
  		fatalx("zero size");
  
  	/* Size decreasing. */
! 	if (sy < screen_size_y(s)) {
! 		oy = screen_size_y(s);
  
! 		if (s->cy != 0) {
! 			/*
! 			 * The cursor is not at the start. Try to remove as
! 			 * many lines as possible from the top. (Up to the
! 			 * cursor line.)
! 			 */
! 			ny = s->cy;
! 			if (ny > oy - sy)
! 				ny = oy - sy;
! 
! 			grid_view_delete_lines(gd, 0, ny);
! 
!  			s->cy -= ny;
! 			oy -= ny;
  		}
  
! 		if (sy < oy) {
! 			/* Remove any remaining lines from the bottom. */
! 			grid_view_delete_lines(gd, sy, oy - sy);
! 			if (s->cy >= sy)
! 				s->cy = sy - 1;
! 		}
! 	}
  
  	/* Resize line arrays. */
  	gd->size = xrealloc(gd->size, gd->hsize + sy, sizeof *gd->size);
--- 169,210 ----
  screen_resize_y(struct screen *s, u_int sy)
  {
  	struct grid	*gd = s->grid;
! 	u_int		 needed, available, oldy, i;
  
  	if (sy == 0)
  		fatalx("zero size");
+ 	oldy = screen_size_y(s);
  
+ 	/* 
+ 	 * When resizing:
+ 	 *
+ 	 * If the height is decreasing, delete lines from the bottom until
+ 	 * hitting the cursor, then push lines from the top into the history.
+ 	 * 
+ 	 * When increasing, pull as many lines as possible from the history to
+ 	 * the top, then fill the remaining with blanks at the bottom.
+ 	 */
+ 
  	/* Size decreasing. */
! 	if (sy < oldy) {
! 		needed = oldy - sy;
  
! 		/* Delete as many lines as possible from the bottom. */
! 		available = oldy - 1 - s->cy;
! 		if (available > 0) {
! 			if (available > needed)
! 				available = needed;
! 			grid_view_delete_lines(gd, oldy - available, available);
  		}
+ 		needed -= available;
  
! 		/*
! 		 * Now just increase the history size to take over the lines
! 		 * which are left. XXX Should apply history limit?
! 		 */
! 		gd->hsize += needed;
! 		s->cy -= needed;
!  	}
  
  	/* Resize line arrays. */
  	gd->size = xrealloc(gd->size, gd->hsize + sy, sizeof *gd->size);
***************
*** 209,226 ****
  	gd->udata = xrealloc(gd->udata, gd->hsize + sy, sizeof *gd->udata);
  
  	/* Size increasing. */
! 	if (sy > screen_size_y(s)) {
! 		oy = screen_size_y(s);
! 		for (yy = gd->hsize + oy; yy < gd->hsize + sy; yy++) {
! 			gd->size[yy] = 0;
! 			gd->data[yy] = NULL;
! 			gd->usize[yy] = 0;
! 			gd->udata[yy] = NULL;
  		}
  	}
  
  	gd->sy = sy;
- 
  	s->rupper = 0;
  	s->rlower = screen_size_y(s) - 1;
  }
--- 213,240 ----
  	gd->udata = xrealloc(gd->udata, gd->hsize + sy, sizeof *gd->udata);
  
  	/* Size increasing. */
! 	if (sy > oldy) {
! 		needed = sy - oldy;
! 
! 		/* Try to pull as much as possible out of the history. */
! 		available = gd->hsize;
! 		if (available > 0) {
! 			if (available > needed)
! 				available = needed;
! 			gd->hsize -= available;
! 			s->cy += available;
  		}
+ 		needed -= available;
+ 
+ 		/* Then fill the rest in with blanks. */
+ 		for (i = gd->hsize + sy - needed; i < gd->hsize + sy; i++) {
+ 			gd->size[i] = gd->usize[i] = 0;
+ 			gd->data[i] = gd->udata[i] = NULL;
+ 		}
  	}
  
+ 	/* Set the new size, and reset the scroll region. */
  	gd->sy = sy;
  	s->rupper = 0;
  	s->rlower = screen_size_y(s) - 1;
  }