[gnome-shell] Use a grid pattern in overlay if more than 6 windows

[Owen Taylor <otaylor src gnome org>]

commit a074ef5d7c840e5ea95cae43001034cfee09772a
Author: Dave Jordan <dmj726 sbcglobal net>
Date:   Tue Mar 31 16:40:18 2009 -0500

    Use a grid pattern in overlay if more than 6 windows
    
    The diagonal arrangement currently used in the overlay when there are
    more than 6 windows is hard to read and hides most of the previews.
    Both of these issues are fixed by arranging the windows in a grid pattern.
    
    http://bugzilla.gnome.org/show_bug.cgi?id=576269
---
 js/ui/workspaces.js |   18 ++++++++----------
 1 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/js/ui/workspaces.js b/js/ui/workspaces.js
index f0eefb7..37a9c1d 100644
--- a/js/ui/workspaces.js
+++ b/js/ui/workspaces.js
@@ -696,16 +696,14 @@ Workspace.prototype = {
             return POSITIONS[numberOfWindows][windowIndex];
 
         // If we don't have a predefined scheme for this window count,
-        // overlap the windows along the diagonal of the workspace
-        // (improve this!)
-        let fraction = Math.sqrt(1/numberOfWindows);
-
-        // The top window goes at the lower right - this is different from the
-        // fixed position schemes where the windows are in "reading order"
-        // and the top window goes at the upper left.
-        let pos = (numberOfWindows - windowIndex - 1) / (numberOfWindows - 1);
-        let xCenter = (fraction / 2) + (1 - fraction) * pos;
-        let yCenter = xCenter;
+        // arrange the windows in a grid pattern.
+        let gridWidth = Math.ceil(Math.sqrt(numberOfWindows));
+        let gridHeight = Math.ceil(numberOfWindows / gridWidth);
+
+        let fraction = Math.sqrt(.5/(gridWidth * gridHeight));
+
+        let xCenter = (.5 / gridWidth) + ((windowIndex) % gridWidth) / gridWidth;
+        let yCenter = (.5 / gridHeight) + Math.floor((windowIndex / gridWidth)) / gridHeight;
 
         return [xCenter, yCenter, fraction];
     },