[gtk+] Support arbitrary screen layouts

[Kristian Rietveld <kristian src gnome org>]

commit 959a9437e61b803ba9234d7a4e71a96910dbbc69
Author: Kristian Rietveld <kris gtk org>
Date:   Mon Oct 26 08:42:15 2009 +0100

    Support arbitrary screen layouts
    
    The Quartz port now supports arbitrary multiple monitor layouts instead
    of only monitors are were laid out horizontally.  This builds on the
    reworked coordinate translation done in a previous commit.

 gdk/quartz/gdkscreen-quartz.c |   41 ++++++++++++++---------------------------
 1 files changed, 14 insertions(+), 27 deletions(-)
---
diff --git a/gdk/quartz/gdkscreen-quartz.c b/gdk/quartz/gdkscreen-quartz.c
index 4afeb51..54577ed 100644
--- a/gdk/quartz/gdkscreen-quartz.c
+++ b/gdk/quartz/gdkscreen-quartz.c
@@ -112,8 +112,8 @@ static void
 gdk_screen_quartz_calculate_layout (GdkScreenQuartz *screen)
 {
   NSArray *array;
-  NSRect largest_rect;
   int i;
+  int max_x, max_y;
 
   GDK_QUARTZ_ALLOC_POOL;
 
@@ -121,43 +121,33 @@ gdk_screen_quartz_calculate_layout (GdkScreenQuartz *screen)
 
   array = [NSScreen screens];
 
-  /* FIXME: For now we only support screen layouts where the screens are laid
-   * out horizontally.  Mac OS X also supports laying out the screens vertically
-   * and the screens having "non-standard" offsets from eachother.  In the
-   * future we need a much more sophiscated algorithm to translate these
-   * layouts to GDK coordinate space and GDK screen layout.
-   */
   screen->width = 0;
   screen->height = 0;
   screen->min_x = 0;
   screen->min_y = 0;
+  max_x = max_y = 0;
 
+  /* We determine the minimum and maximum x and y coordinates
+   * covered by the monitors.  From this we can deduce the width
+   * and height of the root screen.
+   */
   for (i = 0; i < [array count]; i++)
     {
       NSRect rect = [[array objectAtIndex:i] frame];
 
-      screen->width += rect.size.width;
-      screen->height = MAX (screen->height, rect.size.height);
       screen->min_x = MIN (screen->min_x, rect.origin.x);
+      max_x = MAX (max_x, rect.origin.x + rect.size.width);
+
       screen->min_y = MIN (screen->min_y, rect.origin.y);
+      max_y = MAX (max_y, rect.origin.y + rect.size.height);
     }
 
+  screen->width = max_x - screen->min_x;
+  screen->height = max_y - screen->min_y;
+
   screen->n_screens = [array count];
   screen->screen_rects = g_new0 (GdkRectangle, screen->n_screens);
 
-  /* Find the monitor with the largest height.  All monitors should be
-   * offset to this one in the GDK screen space instead of offset to
-   * the screen with the menu bar.
-   */
-  largest_rect = [[array objectAtIndex:0] frame];
-  for (i = 1; i < [array count]; i++)
-    {
-      NSRect rect = [[array objectAtIndex:i] frame];
-
-      if (rect.size.height > largest_rect.size.height)
-        largest_rect = [[array objectAtIndex:i] frame];
-    }
-
   for (i = 0; i < screen->n_screens; i++)
     {
       NSScreen *nsscreen;
@@ -167,13 +157,10 @@ gdk_screen_quartz_calculate_layout (GdkScreenQuartz *screen)
       rect = [nsscreen frame];
 
       screen->screen_rects[i].x = rect.origin.x - screen->min_x;
+      screen->screen_rects[i].y
+          = screen->height - (rect.origin.y + rect.size.height) + screen->min_y;
       screen->screen_rects[i].width = rect.size.width;
       screen->screen_rects[i].height = rect.size.height;
-
-      if (largest_rect.size.height - rect.size.height == 0)
-        screen->screen_rects[i].y = 0;
-      else
-        screen->screen_rects[i].y = largest_rect.size.height - rect.size.height + largest_rect.origin.y;
     }
 
   GDK_QUARTZ_RELEASE_POOL;