From 47c190a1b732225a9c26bfd492f8c392f5adc931 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Sun, 4 Mar 2012 17:19:16 -0500
Subject: [PATCH] grid: Work harder for tight homogeneous allocation

When doing homogeneous allocation in the presence of
overlapping spanning children, we need to avoid uneven
line allocations, otherwise, the final homogenization
will blow up the size request of the grid.

https://bugzilla.gnome.org/show_bug.cgi?id=671170
---
 gtk/gtkgrid.c | 71 ++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 53 insertions(+), 18 deletions(-)

diff --git a/gtk/gtkgrid.c b/gtk/gtkgrid.c
index 3b75219259..fdbdf7c147 100644
--- a/gtk/gtkgrid.c
+++ b/gtk/gtkgrid.c
@@ -770,37 +770,72 @@ gtk_grid_request_spanning (GtkGridRequest *request,
       /* If we need to request more space for this child to fill
        * its requisition, then divide up the needed space amongst the
        * lines it spans, favoring expandable lines if any.
+       *
+       * When doing homogeneous allocation though, try to keep the
+       * line allocations even, since we're going to force them to
+       * be the same anyway, and we don't want to introduce unnecessary
+       * extra space.
        */
       if (span_minimum < minimum)
         {
-          extra = minimum - span_minimum;
-          expand = span_expand;
-          for (i = 0; i < attach->span; i++)
+          if (linedata->homogeneous)
             {
-              line = &lines->lines[attach->pos - lines->min + i];
-              if (force_expand || line->expand)
+              gint total, m;
+
+              total = minimum - (attach->span - 1) * linedata->spacing;
+              m = total / attach->span + (total % attach->span ? 1 : 0);
+              for (i = 0; i < attach->span; i++)
+                {
+                  line = &lines->lines[attach->pos - lines->min + i];
+                  line->minimum = MAX(line->minimum, m);
+                }
+            }
+          else
+            {
+              extra = minimum - span_minimum;
+              expand = span_expand;
+              for (i = 0; i < attach->span; i++)
                 {
-                  line_extra = extra / expand;
-                  line->minimum += line_extra;
-                  extra -= line_extra;
-                  expand -= 1;
+                  line = &lines->lines[attach->pos - lines->min + i];
+                  if (force_expand || line->expand)
+                    {
+                      line_extra = extra / expand;
+                      line->minimum += line_extra;
+                      extra -= line_extra;
+                      expand -= 1;
+                    }
                 }
             }
         }
 
       if (span_natural < natural)
         {
-          extra = natural - span_natural;
-          expand = span_expand;
-          for (i = 0; i < attach->span; i++)
+          if (linedata->homogeneous)
             {
-              line = &lines->lines[attach->pos - lines->min + i];
-              if (force_expand || line->expand)
+              gint total, n;
+
+              total = natural - (attach->span - 1) * linedata->spacing;
+              n = total / attach->span + (total % attach->span ? 1 : 0);
+              for (i = 0; i < attach->span; i++)
+                {
+                  line = &lines->lines[attach->pos - lines->min + i];
+                  line->natural = MAX(line->natural, n);
+                }
+            }
+          else
+            {
+              extra = natural - span_natural;
+              expand = span_expand;
+              for (i = 0; i < attach->span; i++)
                 {
-                  line_extra = extra / expand;
-                  line->natural += line_extra;
-                  extra -= line_extra;
-                  expand -= 1;
+                  line = &lines->lines[attach->pos - lines->min + i];
+                  if (force_expand || line->expand)
+                    {
+                      line_extra = extra / expand;
+                      line->natural += line_extra;
+                      extra -= line_extra;
+                      expand -= 1;
+                    }
                 }
             }
         }
-- 
2.30.2