mutter/src/place.c

/* Metacity window placement */

/* 
 * Copyright (C) 2001 Havoc Pennington
 * Copyright (C) 2002, 2003 Red Hat, Inc.
 * Copyright (C) 2003 Rob Adams
 * Copyright (C) 2005 Elijah Newren
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <config.h>

#include "place.h"
#include "workspace.h"
#include "prefs.h"
#include <gdk/gdkregion.h>
#include <math.h>
#include <stdlib.h>

typedef enum
{
  META_LEFT,
  META_RIGHT,
  META_TOP,
  META_BOTTOM
} MetaWindowDirection;

static gint
northwestcmp (gconstpointer a, gconstpointer b)
{
  MetaWindow *aw = (gpointer) a;
  MetaWindow *bw = (gpointer) b;
  int from_origin_a;
  int from_origin_b;
  int ax, ay, bx, by;

  /* we're interested in the frame position for cascading,
   * not meta_window_get_position()
   */
  if (aw->frame)
    {
      ax = aw->frame->rect.x;
      ay = aw->frame->rect.y;
    }
  else
    {
      ax = aw->rect.x;
      ay = aw->rect.y;
    }

  if (bw->frame)
    {
      bx = bw->frame->rect.x;
      by = bw->frame->rect.y;
    }
  else
    {
      bx = bw->rect.x;
      by = bw->rect.y;
    }
  
  /* probably there's a fast good-enough-guess we could use here. */
  from_origin_a = sqrt (ax * ax + ay * ay);
  from_origin_b = sqrt (bx * bx + by * by);
    
  if (from_origin_a < from_origin_b)
    return -1;
  else if (from_origin_a > from_origin_b)
    return 1;
  else
    return 0;
}
     
static void
find_next_cascade (MetaWindow *window,
                   MetaFrameGeometry *fgeom,
                   /* visible windows on relevant workspaces */
                   GList      *windows,
                   int         x,
                   int         y,
                   int        *new_x,
                   int        *new_y)
{
  GList *tmp;
  GList *sorted;
  int cascade_x, cascade_y;
  int x_threshold, y_threshold;
  int window_width, window_height;
  int cascade_stage;
  MetaRectangle work_area;
  const MetaXineramaScreenInfo* current;
  
  sorted = g_list_copy (windows);
  sorted = g_list_sort (sorted, northwestcmp);

  /* This is a "fuzzy" cascade algorithm. 
   * For each window in the list, we find where we'd cascade a
   * new window after it. If a window is already nearly at that
   * position, we move on.
   */
  
  /* arbitrary-ish threshold, honors user attempts to
   * manually cascade.
   */
#define CASCADE_FUZZ 15
  if (fgeom)
    {
      x_threshold = MAX (fgeom->left_width, CASCADE_FUZZ);
      y_threshold = MAX (fgeom->top_height, CASCADE_FUZZ);
    }
  else
    {
      x_threshold = CASCADE_FUZZ;
      y_threshold = CASCADE_FUZZ;
    }
  
  /* Find furthest-SE origin of all workspaces.
   * cascade_x, cascade_y are the target position
   * of NW corner of window frame.
   */

  current = meta_screen_get_current_xinerama (window->screen);
  meta_window_get_work_area_for_xinerama (window, current->number, &work_area);

  cascade_x = MAX (0, work_area.x);
  cascade_y = MAX (0, work_area.y);
  
  /* Find first cascade position that's not used. */
  
  window_width = window->frame ? window->frame->rect.width : window->rect.width;
  window_height = window->frame ? window->frame->rect.height : window->rect.height;
  
  cascade_stage = 0;
  tmp = sorted;
  while (tmp != NULL)
    {
      MetaWindow *w;
      int wx, wy;
      
      w = tmp->data;

      /* we want frame position, not window position */
      if (w->frame)
        {
          wx = w->frame->rect.x;
          wy = w->frame->rect.y;
        }
      else
        {
          wx = w->rect.x;
          wy = w->rect.y;
        }
      
      if (ABS (wx - cascade_x) < x_threshold &&
          ABS (wy - cascade_y) < y_threshold)
        {
          /* This window is "in the way", move to next cascade
           * point. The new window frame should go at the origin
           * of the client window we're stacking above.
           */
          meta_window_get_position (w, &wx, &wy);
          cascade_x = wx;
          cascade_y = wy;
          
          /* If we go off the screen, start over with a new cascade */
	  if (((cascade_x + window_width) >
               (work_area.x + work_area.width)) ||
              ((cascade_y + window_height) >
	       (work_area.y + work_area.height)))
	    {
	      cascade_x = MAX (0, work_area.x);
	      cascade_y = MAX (0, work_area.y);
              
#define CASCADE_INTERVAL 50 /* space between top-left corners of cascades */
              cascade_stage += 1;
	      cascade_x += CASCADE_INTERVAL * cascade_stage;
              
	      /* start over with a new cascade translated to the right, unless
               * we are out of space
               */
              if ((cascade_x + window_width) <
                  (work_area.x + work_area.width))
                {
                  tmp = sorted;
                  continue;
                }
              else
                {
                  /* All out of space, this cascade_x won't work */
                  cascade_x = MAX (0, work_area.x);
                  break;
                }
	    }
        }
      else
        {
          /* Keep searching for a further-down-the-diagonal window. */
        }
        
      tmp = tmp->next;
    }

  /* cascade_x and cascade_y will match the last window in the list
   * that was "in the way" (in the approximate cascade diagonal)
   */
  
  g_list_free (sorted);

  /* Convert coords to position of window, not position of frame. */
  if (fgeom == NULL)
    {
      *new_x = cascade_x;
      *new_y = cascade_y;
    }
  else
    {
      *new_x = cascade_x + fgeom->left_width;
      *new_y = cascade_y + fgeom->top_height;
    }
}

static void
find_most_freespace (MetaWindow *window,
                     MetaFrameGeometry *fgeom,
                     /* visible windows on relevant workspaces */
                     MetaWindow *focus_window,
                     int         x,
                     int         y,
                     int        *new_x,
                     int        *new_y)
{
  MetaWindowDirection side;
  int max_area;
  int max_width, max_height, left, right, top, bottom;
  int left_space, right_space, top_space, bottom_space;
  int frame_size_left, frame_size_top;
  MetaRectangle work_area;
  MetaRectangle avoid;
  MetaRectangle outer;

  frame_size_left = fgeom ? fgeom->left_width : 0;
  frame_size_top  = fgeom ? fgeom->top_height : 0;

  meta_window_get_work_area_current_xinerama (focus_window, &work_area);
  meta_window_get_outer_rect (focus_window, &avoid);
  meta_window_get_outer_rect (window, &outer);

  /* Find the areas of choosing the various sides of the focus window */
  max_width  = MIN (avoid.width, outer.width);
  max_height = MIN (avoid.height, outer.height);
  left_space   = avoid.x - work_area.x;
  right_space  = work_area.width - (avoid.x + avoid.width - work_area.x);
  top_space    = avoid.y - work_area.y;
  bottom_space = work_area.height - (avoid.y + avoid.height - work_area.y);
  left   = MIN (left_space,   outer.width);
  right  = MIN (right_space,  outer.width);
  top    = MIN (top_space,    outer.height);
  bottom = MIN (bottom_space, outer.height);

  /* Find out which side of the focus_window can show the most of the window */
  side = META_LEFT;
  max_area = left*max_height;
  if (right*max_height > max_area)
    {
      side = META_RIGHT;
      max_area = right*max_height;
    }
  if (top*max_width > max_area)
    {
      side = META_TOP;
      max_area = top*max_width;
    }
  if (bottom*max_width > max_area)
    {
      side = META_BOTTOM;
      max_area = bottom*max_width;
    }

  /* Give up if there's no where to put it (i.e. focus window is maximized) */
  if (max_area == 0)
    return;

  /* Place the window on the relevant side; if the whole window fits,
   * make it adjacent to the focus window; if not, make sure the
   * window doesn't go off the edge of the screen.
   */
  switch (side)
    {
    case META_LEFT:
      *new_y = avoid.y + frame_size_top;
      if (left_space > outer.width)
        *new_x = avoid.x - outer.width + frame_size_left;
      else
        *new_x = work_area.x + frame_size_left;
      break;
    case META_RIGHT:
      *new_y = avoid.y + frame_size_top;
      if (right_space > outer.width)
        *new_x = avoid.x + avoid.width + frame_size_left;
      else
        *new_x = work_area.x + work_area.width - outer.width + frame_size_left;
      break;
    case META_TOP:
      *new_x = avoid.x + frame_size_left;
      if (top_space > outer.height)
        *new_y = avoid.y - outer.height + frame_size_top;
      else
        *new_y = work_area.y + frame_size_top;
      break;
    case META_BOTTOM:
      *new_x = avoid.x + frame_size_left;
      if (bottom_space > outer.height)
        *new_y = avoid.y + avoid.height + frame_size_top;
      else
        *new_y = work_area.y + work_area.height - outer.height + frame_size_top;
      break;
    }
}

static void
avoid_being_obscured_as_second_modal_dialog (MetaWindow *window,
                                             MetaFrameGeometry *fgeom,
                                             int        *x,
                                             int        *y)
{
  /* We can't center this dialog if it was denied focus and it
   * overlaps with the focus window and this dialog is modal and this
   * dialog is in the same app as the focus window (*phew*...please
   * don't make me say that ten times fast). See bug 307875 comment 11
   * and 12 for details, but basically it means this is probably a
   * second modal dialog for some app while the focus window is the
   * first modal dialog.  We should probably make them simultaneously
   * visible in general, but it becomes mandatory to do so due to
   * buggy apps (e.g. those using gtk+ *sigh*) because in those cases
   * this second modal dialog also happens to be modal to the first
   * dialog in addition to the main window, while it has only let us
   * know about the modal-to-the-main-window part.
   */

  MetaWindow *focus_window;
  MetaRectangle overlap;

  focus_window = window->display->focus_window;

  if (window->denied_focus_and_not_transient &&
      window->wm_state_modal && /* FIXME: Maybe do this for all transients? */
      meta_window_same_application (window, focus_window) &&
      meta_rectangle_intersect (&window->rect,
                                &focus_window->rect,
                                &overlap))
    {
      find_most_freespace (window, fgeom, focus_window, *x, *y, x, y);
      meta_topic (META_DEBUG_PLACEMENT,
                  "Dialog window %s was denied focus but may be modal "
                  "to the focus window; had to move it to avoid the "
                  "focus window\n",
                  window->desc);
    }
}

static int
intcmp (const void* a, const void* b)
{
  const int *ai = a;
  const int *bi = b;

  if (*ai < *bi)
    return -1;
  else if (*ai > *bi)
    return 1;
  else
    return 0;
}

static void
window_get_edges (MetaWindow *w,
                  int        *left,
                  int        *right,
                  int        *top,
                  int        *bottom)
{
  int left_edge;
  int right_edge;
  int top_edge;
  int bottom_edge;
  MetaRectangle rect;

  meta_window_get_outer_rect (w, &rect);
  
  left_edge = rect.x;
  right_edge = rect.x + rect.width;
  top_edge = rect.y;
  bottom_edge = rect.y + rect.height;
  
  if (left)
    *left = left_edge;
  if (right)
    *right = right_edge;
  if (top)
    *top = top_edge;
  if (bottom)
    *bottom = bottom_edge;
}

static gboolean
rectangle_overlaps_some_window (MetaRectangle *rect,
                                GList         *windows)
{
  GList *tmp;
  MetaRectangle dest;
  
  tmp = windows;
  while (tmp != NULL)
    {
      MetaWindow *other = tmp->data;
      MetaRectangle other_rect;      

      switch (other->type)
        {
        case META_WINDOW_DOCK:
        case META_WINDOW_SPLASHSCREEN:
        case META_WINDOW_DESKTOP:
        case META_WINDOW_DIALOG:
        case META_WINDOW_MODAL_DIALOG:
          break;

        case META_WINDOW_NORMAL:
        case META_WINDOW_UTILITY:
        case META_WINDOW_TOOLBAR:
        case META_WINDOW_MENU:
          meta_window_get_outer_rect (other, &other_rect);
          
          if (meta_rectangle_intersect (rect, &other_rect, &dest))
            return TRUE;
          break;
        }
      
      tmp = tmp->next;
    }

  return FALSE;
}

static gint
leftmost_cmp (gconstpointer a, gconstpointer b)
{
  MetaWindow *aw = (gpointer) a;
  MetaWindow *bw = (gpointer) b;
  int ax, bx;

  /* we're interested in the frame position for cascading,
   * not meta_window_get_position()
   */
  if (aw->frame)
    ax = aw->frame->rect.x;
  else
    ax = aw->rect.x;

  if (bw->frame)
    bx = bw->frame->rect.x;
  else
    bx = bw->rect.x;

  if (ax < bx)
    return -1;
  else if (ax > bx)
    return 1;
  else
    return 0;
}

static gint
topmost_cmp (gconstpointer a, gconstpointer b)
{
  MetaWindow *aw = (gpointer) a;
  MetaWindow *bw = (gpointer) b;
  int ay, by;

  /* we're interested in the frame position for cascading,
   * not meta_window_get_position()
   */
  if (aw->frame)
    ay = aw->frame->rect.y;
  else
    ay = aw->rect.y;

  if (bw->frame)
    by = bw->frame->rect.y;
  else
    by = bw->rect.y;

  if (ay < by)
    return -1;
  else if (ay > by)
    return 1;
  else
    return 0;
}

static void
center_tile_rect_in_area (MetaRectangle *rect,
                          MetaRectangle *work_area)
{
  int fluff;

  /* The point here is to tile a window such that "extra"
   * space is equal on either side (i.e. so a full screen
   * of windows tiled this way would center the windows
   * as a group)
   */

  fluff = (work_area->width % (rect->width+1)) / 2;
  rect->x = work_area->x + fluff;
  fluff = (work_area->height % (rect->height+1)) / 3;
  rect->y = work_area->y + fluff;
}

/* Find the leftmost, then topmost, empty area on the workspace
 * that can contain the new window.
 *
 * Cool feature to have: if we can't fit the current window size,
 * try shrinking the window (within geometry constraints). But
 * beware windows such as Emacs with no sane minimum size, we
 * don't want to create a 1x1 Emacs.
 */
static gboolean
find_first_fit (MetaWindow *window,
                MetaFrameGeometry *fgeom,
                /* visible windows on relevant workspaces */
                GList      *windows,
		int*        xineramas_list,
		int         n_xineramas,
                int         x,
                int         y,
                int        *new_x,
                int        *new_y)
{
  /* This algorithm is limited - it just brute-force tries
   * to fit the window in a small number of locations that are aligned
   * with existing windows. It tries to place the window on
   * the bottom of each existing window, and then to the right
   * of each existing window, aligned with the left/top of the
   * existing window in each of those cases.
   */  
  int retval;
  GList *below_sorted;
  GList *right_sorted;
  GList *tmp;
  MetaRectangle rect;
  MetaRectangle work_area;
  int i;
  
  retval = FALSE;

  /* Below each window */
  below_sorted = g_list_copy (windows);
  below_sorted = g_list_sort (below_sorted, leftmost_cmp);
  below_sorted = g_list_sort (below_sorted, topmost_cmp);  

  /* To the right of each window */
  right_sorted = g_list_copy (windows);
  right_sorted = g_list_sort (right_sorted, topmost_cmp);
  right_sorted = g_list_sort (right_sorted, leftmost_cmp);
  
  rect.width = window->rect.width;
  rect.height = window->rect.height;
  
  if (fgeom)
    {
      rect.width += fgeom->left_width + fgeom->right_width;
      rect.height += fgeom->top_height + fgeom->bottom_height;
    }

  for (i = 0; i < n_xineramas; i++)
    {
#ifdef WITH_VERBOSE_MODE
      char xinerama_location_string[RECT_LENGTH];
      meta_rectangle_to_string (&window->screen->xinerama_infos[xineramas_list[i]].rect,
                                xinerama_location_string);
      meta_topic (META_DEBUG_XINERAMA,
		  "Natural xinerama %d is %s\n",
		  i,
		  xinerama_location_string);
#endif
    }

  /* try each xinerama in the natural ordering in turn */
  i = 0;
  while (i < n_xineramas)
    {
      meta_window_get_work_area_for_xinerama (window, xineramas_list[i], &work_area);

      center_tile_rect_in_area (&rect, &work_area);

      if (meta_rectangle_contains_rect (&work_area, &rect) &&
          !rectangle_overlaps_some_window (&rect, windows))
        {
          *new_x = rect.x;
          *new_y = rect.y;
          if (fgeom)
            {
              *new_x += fgeom->left_width;
              *new_y += fgeom->top_height;
            }
      
          retval = TRUE;
          
          goto out;
        }

      /* try below each window */
      tmp = below_sorted;
      while (tmp != NULL)
        {
          MetaWindow *w = tmp->data;
          MetaRectangle outer_rect;

          meta_window_get_outer_rect (w, &outer_rect);
      
          rect.x = outer_rect.x;
          rect.y = outer_rect.y + outer_rect.height;
      
          if (meta_rectangle_contains_rect (&work_area, &rect) &&
              !rectangle_overlaps_some_window (&rect, below_sorted))
            {
              *new_x = rect.x;
              *new_y = rect.y;
              if (fgeom)
                {
                  *new_x += fgeom->left_width;
                  *new_y += fgeom->top_height;
                }
          
              retval = TRUE;
          
              goto out;
            }

          tmp = tmp->next;
        }

      /* try to the right of each window */
      tmp = right_sorted;
      while (tmp != NULL)
        {
          MetaWindow *w = tmp->data;
          MetaRectangle outer_rect;
     
          meta_window_get_outer_rect (w, &outer_rect);
     
          rect.x = outer_rect.x + outer_rect.width;
          rect.y = outer_rect.y;
     
          if (meta_rectangle_contains_rect (&work_area, &rect) &&
              !rectangle_overlaps_some_window (&rect, right_sorted))
            {
              *new_x = rect.x;
              *new_y = rect.y;
              if (fgeom)
                {
                  *new_x += fgeom->left_width;
                  *new_y += fgeom->top_height;
                }
         
              retval = TRUE;
         
              goto out;
            }

          tmp = tmp->next;
        }
      
      ++i;
    }
  
 out:

  g_list_free (below_sorted);
  g_list_free (right_sorted);
  return retval;
}

void
meta_window_place (MetaWindow        *window,
                   MetaFrameGeometry *fgeom,
                   int                x,
                   int                y,
                   int               *new_x,
                   int               *new_y)
{
  GList *windows;
  const MetaXineramaScreenInfo *xi;
  int* xineramas_list = NULL;
  int  n_xineramas;
  int  i;
  int placed_on = -1;
  
  /* frame member variables should NEVER be used in here, only
   * MetaFrameGeometry. But remember fgeom == NULL
   * for undecorated windows. Also, this function should
   * NEVER have side effects other than computing the
   * placement coordinates.
   */
  
  meta_topic (META_DEBUG_PLACEMENT, "Placing window %s\n", window->desc);

  windows = NULL;
  
  switch (window->type)
    {
      /* Run placement algorithm on these. */
    case META_WINDOW_NORMAL:
    case META_WINDOW_DIALOG:
    case META_WINDOW_MODAL_DIALOG:
    case META_WINDOW_SPLASHSCREEN:
      break;
          
      /* Assume the app knows best how to place these, no placement
       * algorithm ever (other than "leave them as-is")
       */
    case META_WINDOW_DESKTOP:
    case META_WINDOW_DOCK:
    case META_WINDOW_TOOLBAR:
    case META_WINDOW_MENU:
    case META_WINDOW_UTILITY:
      goto done_no_constraints;
      break;
    }
  
  if (meta_prefs_get_disable_workarounds ())
    {
      switch (window->type)
        {
          /* Only accept USPosition on normal windows because the app is full
           * of shit claiming the user set -geometry for a dialog or dock
           */
        case META_WINDOW_NORMAL:
          if (window->size_hints.flags & USPosition)
            {
              /* don't constrain with placement algorithm */
              meta_topic (META_DEBUG_PLACEMENT,
                          "Honoring USPosition for %s instead of using placement algorithm\n", window->desc);

              goto done;
            }
          break;

          /* Ignore even USPosition on dialogs, splashscreen */
        case META_WINDOW_DIALOG:
        case META_WINDOW_MODAL_DIALOG:
        case META_WINDOW_SPLASHSCREEN:
          break;
          
          /* Assume the app knows best how to place these. */
        case META_WINDOW_DESKTOP:
        case META_WINDOW_DOCK:
        case META_WINDOW_TOOLBAR:
        case META_WINDOW_MENU:
        case META_WINDOW_UTILITY:
          if (window->size_hints.flags & PPosition)
            {
              meta_topic (META_DEBUG_PLACEMENT,
                          "Not placing non-normal non-dialog window with PPosition set\n");
              goto done_no_constraints;
            }
          break;
        }
    }
  else
    {
      /* workarounds enabled */
      
      if ((window->size_hints.flags & PPosition) ||
          (window->size_hints.flags & USPosition))
        {
          meta_topic (META_DEBUG_PLACEMENT,
                      "Not placing window with PPosition or USPosition set\n");
          avoid_being_obscured_as_second_modal_dialog (window, fgeom, &x, &y);
          goto done_no_constraints;
        }
    }
  
  if ((window->type == META_WINDOW_DIALOG ||
       window->type == META_WINDOW_MODAL_DIALOG) &&
      window->xtransient_for != None)
    {
      /* Center horizontally, at top of parent vertically */

      MetaWindow *parent;
          
      parent =
        meta_display_lookup_x_window (window->display,
                                      window->xtransient_for);

      if (parent)
        {
          int w;

          meta_window_get_position (parent, &x, &y);
          w = parent->rect.width;

          /* center of parent */
          x = x + w / 2;
          /* center of child over center of parent */
          x -= window->rect.width / 2;

          /* "visually" center window over parent, leaving twice as
           * much space below as on top.
           */
          y += (parent->rect.height - window->rect.height)/3;

          /* put top of child's frame, not top of child's client */
          if (fgeom)
            y += fgeom->top_height;

#if 0
          /* FIXME: If no one has complained about this within a couple
           * months, it means that the constraints.c rewrite fixed this
           * correctly and this hack is no longer necessary.  Feel free to
           * submit a patch removing this #ifdef'd out code.  (Comment
           * written on 2005-10-28).
           */

          MetaRectangle area;

          /* clip to xinerama of parent*/
          meta_window_get_work_area_current_xinerama (parent, &area);

          if (x + window->rect.width > area.x + area.width) 
            x = area.x + area.width - window->rect.width;
          if (y + window->rect.height > area.y + area.height) 
            y = area.y + area.height - window->rect.height;
          if (x < area.x) x = area.x;
          if (y < area.y) y = area.y;     
#endif

          meta_topic (META_DEBUG_PLACEMENT, "Centered window %s over transient parent\n",
                      window->desc);
          
          avoid_being_obscured_as_second_modal_dialog (window, fgeom, &x, &y);

          goto done;
        }
    }
  
  meta_screen_get_natural_xinerama_list (window->screen,
					 &xineramas_list,
					 &n_xineramas);

  /* FIXME UTILITY with transient set should be stacked up
   * on the sides of the parent window or something.
   */
  
  if (window->type == META_WINDOW_DIALOG ||
      window->type == META_WINDOW_MODAL_DIALOG ||
      window->type == META_WINDOW_SPLASHSCREEN)
    {
      /* Center on current xinerama (i.e. on current monitor) */
      int w, h;

      /* Warning, this function is a round trip! */
      xi = meta_screen_get_current_xinerama (window->screen);

      w = xi->rect.width;
      h = xi->rect.height;

      x = (w - window->rect.width) / 2;
      y = (h - window->rect.height) / 2;

      x += xi->rect.x;
      y += xi->rect.y;
      
      meta_topic (META_DEBUG_PLACEMENT, "Centered window %s on screen %d xinerama %d\n",
                  window->desc, window->screen->number, xi->number);

      goto done_check_denied_focus;
    }
  
  /* Find windows that matter (not minimized, on same workspace
   * as placed window, may be shaded - if shaded we pretend it isn't
   * for placement purposes)
   */
  {
    GSList *all_windows;
    GSList *tmp;
    
    all_windows = meta_display_list_windows (window->display);

    tmp = all_windows;
    while (tmp != NULL)
      {
        MetaWindow *w = tmp->data;

        if (meta_window_showing_on_its_workspace (w) &&
            w != window && 
            (window->workspace == w->workspace ||
             window->on_all_workspaces || w->on_all_workspaces))
          windows = g_list_prepend (windows, w);

        tmp = tmp->next;
      }

    g_slist_free (all_windows);
  }

  /* Warning, this is a round trip! */
  xi = meta_screen_get_current_xinerama (window->screen);
  
  /* "Origin" placement algorithm */
  x = xi->rect.x;
  y = xi->rect.y;

  if (find_first_fit (window, fgeom, windows,
                      xineramas_list, n_xineramas,
                      x, y, &x, &y))
    goto done_check_denied_focus;

  /* This is a special-case origin-cascade so that windows that are
   * too large to fit onto a workspace (and which will be
   * automaximized later) will go onto an empty xinerama if one is
   * available.
   */
  if (window->has_maximize_func && window->decorated &&
      !window->fullscreen)
    {
      if (window->frame)
        {
          x = fgeom->left_width;
          y = fgeom->top_height;
        }
      else
        {
          x = 0;
          y = 0;
        }

      for (i = 0; i < n_xineramas; i++)
        {
          MetaRectangle work_area;
          
          meta_window_get_work_area_for_xinerama (window, xineramas_list[i], &work_area);
          
          if (!rectangle_overlaps_some_window (&work_area, windows))
            {
              x += work_area.x;
              y += work_area.y;
              placed_on = i;
              break;
            }
        }
    }

  /* if the window wasn't placed at the origin of an empty xinerama,
   * cascade it onto the current xinerama
   */
  if (placed_on == -1)
    {
      find_next_cascade (window, fgeom, windows, x, y, &x, &y);
      placed_on = window->screen->last_xinerama_index;
    }

  /* Maximize windows if they are too big for their work area (bit of
   * a hack here). Assume undecorated windows probably don't intend to
   * be maximized.  
   */
  if (window->has_maximize_func && window->decorated &&
      !window->fullscreen)
    {
      MetaRectangle workarea;
      MetaRectangle outer;

      meta_window_get_work_area_for_xinerama (window,
                                              xineramas_list[placed_on],
                                              &workarea);      
      meta_window_get_outer_rect (window, &outer);
      
      if (outer.width >= workarea.width)
        window->maximize_horizontally_after_placement = TRUE;

      if (outer.height >= workarea.height)
        window->maximize_vertically_after_placement = TRUE;
    }

 done_check_denied_focus:
  /* If the window is being denied focus and isn't a transient of the
   * focus window, we do NOT want it to overlap with the focus window
   * if at all possible.  This is guaranteed to only be called if the
   * focus_window is non-NULL, and we try to avoid that window.
   */
  if (window->denied_focus_and_not_transient)
    {
      gboolean       found_fit;
      MetaWindow    *focus_window;
      MetaRectangle  overlap;

      focus_window = window->display->focus_window;
      g_assert (focus_window != NULL);

      /* No need to do anything if the window doesn't overlap at all */
      found_fit = !meta_rectangle_intersect (&window->rect,
                                             &focus_window->rect,
                                             &overlap);

      /* Try to do a first fit again, this time only taking into account the
       * focus window.
       */
      if (!found_fit)
        {
          GList *focus_window_list;
          focus_window_list = g_list_prepend (NULL, focus_window);

          /* Reset x and y ("origin" placement algorithm) */
          x = xi->rect.x;
          y = xi->rect.y;

          found_fit = find_first_fit (window, fgeom, focus_window_list,
                                      xineramas_list, n_xineramas,
                                      x, y, &x, &y);
          g_list_free (focus_window_list);
	}

      /* If that still didn't work, just place it where we can see as much
       * as possible.
       */
      if (!found_fit)
        find_most_freespace (window, fgeom, focus_window, x, y, &x, &y);
    }
  
 done:
  g_free (xineramas_list);
  g_list_free (windows);
  
 done_no_constraints:

  *new_x = x;
  *new_y = y;
}


/* These are used while moving or resizing to "snap" to useful
 * places; the return value is the x/y position of the window to
 * be snapped to the given edge.
 *
 * They only use edges on the current workspace, since things
 * would be weird otherwise.
 */
static GSList*
get_windows_showing_on_same_screen (MetaWindow *window,
                                    int        *n_windows)
{
  GSList *windows;
  GSList *all_windows;
  GSList *tmp;
  int i;
  
  windows = NULL;

  i = 0;
  all_windows = meta_display_list_windows (window->display);
  
  tmp = all_windows;
  while (tmp != NULL)
    {
      MetaWindow *w = tmp->data;
      
      if (meta_window_should_be_showing (w) &&
          w->screen == window->screen       &&
          w != window)
        {            
          windows = g_slist_prepend (windows, w);
          ++i;
        }
      
      tmp = tmp->next;
    }

  if (n_windows)
    *n_windows = i;
  
  g_slist_free (all_windows);

  return windows;
}

static void
get_vertical_edges (MetaWindow *window,
                    int       **edges_p,
                    int        *n_edges_p)
{
  GSList *windows;
  GSList *tmp;
  int n_windows;
  GArray *edges;
  int edge, i;
  MetaRectangle rect;
  MetaRectangle work_area;
  
  windows = get_windows_showing_on_same_screen (window, &n_windows);

  edges = g_array_sized_new (FALSE, FALSE, sizeof (int), 
                             n_windows * 2 + 4 /* 4 = workspace/screen edges */
                             + window->screen->n_xinerama_infos - 1
                             + 2 /* active window edges when in wireframe mode */); 

  /* workspace/screen edges */
  meta_window_get_work_area_current_xinerama (window, &work_area);
  
  g_array_append_val (edges, work_area.x);
  edge = work_area.x + work_area.width;
  g_array_append_val (edges, edge);
  edge = 0;
  g_array_append_val (edges, edge);
  g_array_append_val (edges, window->screen->rect.width);

  /* Now get the xinerama screen edges */
  for (i = 0; i < window->screen->n_xinerama_infos - 1; i++)
    {
      edge = window->screen->xinerama_infos[i].rect.x +
             window->screen->xinerama_infos[i].rect.width;

      g_array_append_val (edges, edge);
    }

  if (window->display->grab_wireframe_active)
    {
      int left_edge, right_edge, top_edge, bottom_edge;

      meta_window_get_xor_rect (window, &window->display->grab_wireframe_rect,
                                &rect);

      window_get_edges (window, &left_edge, &right_edge, 
                        &top_edge, &bottom_edge);

      g_array_append_val (edges, left_edge);
      g_array_append_val (edges, right_edge);
    }
  else
    meta_window_get_outer_rect (window, &rect);

  /* get window edges */
  tmp = windows;
  while (tmp != NULL)
    {
      MetaWindow *w = tmp->data;
      MetaRectangle w_rect;

      meta_window_get_outer_rect (w, &w_rect);
      
      if (meta_rectangle_vert_overlap (&rect, &w_rect))
        {
          g_array_append_val (edges, w_rect.x);
          edge = w_rect.x + w_rect.width;
          g_array_append_val (edges, edge);
        }

      tmp = tmp->next;
    }
  g_slist_free (windows);

  /* Sort */
  qsort (edges->data, edges->len, sizeof (int), intcmp);

  *n_edges_p = edges->len;  
  *edges_p = (int *) g_array_free (edges, FALSE);
}

static void
get_horizontal_edges (MetaWindow *window,
                      int       **edges_p,
                      int        *n_edges_p)
{
  GSList *windows;
  GSList *tmp;
  int n_windows;
  GArray *edges;
  int edge, i;
  MetaRectangle rect;
  MetaRectangle work_area;
  
  windows = get_windows_showing_on_same_screen (window, &n_windows);

  edges = g_array_sized_new (FALSE, FALSE, sizeof (int), 
                             n_windows * 2 + 4 /* 4 = workspace/screen edges */
                             + window->screen->n_xinerama_infos - 1
                             + 2 /* active window edges when in wireframe mode */); 

  /* workspace/screen edges */
  meta_window_get_work_area_current_xinerama (window, &work_area);
  
  g_array_append_val (edges, work_area.y);
  edge = work_area.y + work_area.height;
  g_array_append_val (edges, edge);
  edge = 0;
  g_array_append_val (edges, edge);
  g_array_append_val (edges, window->screen->rect.height);

  /* Now get the xinerama screen edges */
  for (i = 0; i < window->screen->n_xinerama_infos - 1; i++) 
    {
      edge = window->screen->xinerama_infos[i].rect.y +
             window->screen->xinerama_infos[i].rect.height;
      g_array_append_val (edges, edge);
    }

  if (window->display->grab_wireframe_active)
    {
      int left_edge, right_edge, top_edge, bottom_edge;

      meta_window_get_xor_rect (window, &window->display->grab_wireframe_rect,
                                &rect);

      window_get_edges (window, &left_edge, &right_edge, 
                        &top_edge, &bottom_edge);

      g_array_append_val (edges, top_edge);
      g_array_append_val (edges, bottom_edge);
    }
  else
    meta_window_get_outer_rect (window, &rect);
 
  /* get window edges */
  tmp = windows;
  while (tmp != NULL)
    {
      MetaWindow *w = tmp->data;
      MetaRectangle w_rect;

      meta_window_get_outer_rect (w, &w_rect);
      
      if (meta_rectangle_horiz_overlap (&rect, &w_rect))
        {
          g_array_append_val (edges, w_rect.y);
          edge = w_rect.y + w_rect.height;
          g_array_append_val (edges, edge);
        }

      tmp = tmp->next;
    }
  g_slist_free (windows);

  /* Sort */
  qsort (edges->data, edges->len, sizeof (int), intcmp);

  *n_edges_p = edges->len;  
  *edges_p = (int *) g_array_free (edges, FALSE);
}

int
meta_window_find_next_vertical_edge (MetaWindow *window,
                                     MetaWindowEdgePosition source_edge_position,
                                     gboolean    right)
{
  int left_edge, right_edge, source_edge;
  int *edges;
  int i;
  int n_edges;
  int retval;

  get_vertical_edges (window, &edges, &n_edges);

  /* Find next */
  if (window->display->grab_wireframe_active)
    {
      MetaRectangle rect;

      meta_window_get_xor_rect (window, &window->display->grab_wireframe_rect,
                                &rect);

      left_edge = rect.x;
      right_edge = left_edge + rect.width;
    }
  else
    window_get_edges (window, &left_edge, &right_edge, NULL, NULL);

  switch (source_edge_position)
    {
      case META_WINDOW_EDGE_LEFT:
        source_edge = left_edge;
        break;

      case META_WINDOW_EDGE_RIGHT:
        source_edge = right_edge;
        break;

      case META_WINDOW_EDGE_TOP:
      case META_WINDOW_EDGE_BOTTOM:
      default:
        g_assert_not_reached ();
    }

  retval = source_edge;

  if (right)
    {
      i = 0;
      while (i < n_edges)
        {
          if (edges[i] > source_edge)
            {
              retval = edges[i];
              break;
            }
          
          ++i;
        }
    }
  else
    {
      i = n_edges;
      do
        {
          --i;
          
          if (edges[i] < source_edge)
            {
              retval = edges[i];
              break;
            }
        }
      while (i > 0);
    }

  g_free (edges);
  
  return retval;
}

int
meta_window_find_next_horizontal_edge (MetaWindow *window,
                                       MetaWindowEdgePosition source_edge_position,
                                       gboolean    down)
{
  int top_edge, bottom_edge, source_edge;
  int *edges;
  int i;
  int n_edges;
  int retval;

  get_horizontal_edges (window, &edges, &n_edges);
  
  /* Find next */
  if (window->display->grab_wireframe_active)
    {
      MetaRectangle rect;

      meta_window_get_xor_rect (window, &window->display->grab_wireframe_rect,
                                &rect);

      top_edge = rect.y;
      bottom_edge = top_edge + rect.height;
    }
  else
    window_get_edges (window, NULL, NULL, &top_edge, &bottom_edge);

  switch (source_edge_position)
    {
      case META_WINDOW_EDGE_TOP:
        source_edge = top_edge;
        break;

      case META_WINDOW_EDGE_BOTTOM:
        source_edge = bottom_edge;
        break;

      case META_WINDOW_EDGE_LEFT:
      case META_WINDOW_EDGE_RIGHT:
      default:
        g_assert_not_reached ();
    }

  retval = source_edge;

  if (down)
    {
      i = 0;
      while (i < n_edges)
        {
          if (edges[i] > source_edge)
            {
              retval = edges[i];
              break;
            }
          
          ++i;
        }
    }
  else
    {
      i = n_edges;
      do
        {
          --i;
          
          if (edges[i] < source_edge)
            {
              retval = edges[i];
              break;
            }
        }
      while (i > 0);
    }

  g_free (edges);
  
  return retval;
}

int
meta_window_find_nearest_vertical_edge (MetaWindow *window,
                                        int         x_pos)
{
  int *edges;
  int i;
  int n_edges;
  int *positions;
  int n_positions;
  int retval;
  
  get_vertical_edges (window, &edges, &n_edges);

  /* Create an array of all snapped positions our window could have */
  n_positions = n_edges * 2;
  positions = g_new (int, n_positions);
  
  i = 0;
  while (i < n_edges)
    {
      int left_pos, right_pos;

      left_pos = edges[i];

      if (window->frame)
        {
          left_pos += window->frame->child_x;
          right_pos = edges[i] - window->frame->rect.width;
          right_pos += window->frame->child_x;
        }
      else
        {
          right_pos = edges[i] - window->rect.width;
        }

      positions[i * 2] = left_pos;
      positions[i * 2 + 1] = right_pos;
      
      ++i;
    }

  g_free (edges);

  /* Sort */
  qsort (positions, n_positions, sizeof (int), intcmp);
  
  /* Find nearest */

  retval = positions[0];
    
  i = 1;
  while (i < n_positions)
    {
      int delta;
      int best_delta;

      delta = ABS (x_pos - positions[i]);
      best_delta = ABS (x_pos - retval);

      if (delta < best_delta)
        retval = positions[i];
      
      ++i;
    }
  
  g_free (positions);
  
  return retval;
}

int
meta_window_find_nearest_horizontal_edge (MetaWindow *window,
                                          int         y_pos)
{
  int *edges;
  int i;
  int n_edges;
  int *positions;
  int n_positions;
  int retval;
  
  get_horizontal_edges (window, &edges, &n_edges);

  /* Create an array of all snapped positions our window could have */
  n_positions = n_edges * 2;
  positions = g_new (int, n_positions);
  
  i = 0;
  while (i < n_edges)
    {
      int top_pos, bottom_pos;

      top_pos = edges[i];

      if (window->frame)
        {
          top_pos += window->frame->child_y;
          bottom_pos = edges[i] - window->frame->rect.height;
          bottom_pos += window->frame->child_y;
        }
      else
        {
          bottom_pos = edges[i] - window->rect.height;
        }

      positions[i * 2] = top_pos;
      positions[i * 2 + 1] = bottom_pos;
      
      ++i;
    }

  g_free (edges);

  /* Sort */
  qsort (positions, n_positions, sizeof (int), intcmp);
  
  /* Find nearest */

  retval = positions[0];
    
  i = 1;
  while (i < n_positions)
    {
      int delta;
      int best_delta;

      delta = ABS (y_pos - positions[i]);
      best_delta = ABS (y_pos - retval);

      if (delta < best_delta)
        retval = positions[i];
      
      ++i;
    }
  
  g_free (positions);
  
  return retval;
}