[hyena] support ToplevelBorderCollapse

[Gabriel Burt <gburt src gnome org>]

commit 09e68adaa42b4ac5fc40fe069327618007623f93
Author: Aaron Bockover <abockover novell com>
Date:   Sun May 2 16:21:42 2010 -0400

    support ToplevelBorderCollapse
    
    When this property is set on the context, do not render borders of the
    frame that are flush against an edge of the toplevel window of the
    widget. This ensures widgets can be visually flush against a
    window/screen edge.

 src/Hyena.Gui/Hyena.Gui.Theming/GtkTheme.cs |   45 +++++++++++++++++++++++---
 1 files changed, 39 insertions(+), 6 deletions(-)
---
diff --git a/src/Hyena.Gui/Hyena.Gui.Theming/GtkTheme.cs b/src/Hyena.Gui/Hyena.Gui.Theming/GtkTheme.cs
index e67768a..a898f62 100644
--- a/src/Hyena.Gui/Hyena.Gui.Theming/GtkTheme.cs
+++ b/src/Hyena.Gui/Hyena.Gui.Theming/GtkTheme.cs
@@ -141,11 +141,47 @@ namespace Hyena.Gui.Theming
 
         public override void DrawFrameBorder (Cairo.Context cr, Gdk.Rectangle alloc)
         {
+            var corners = CairoCorners.All;
+            double top_extend = 0;
+            double bottom_extend = 0;
+            double left_extend = 0;
+            double right_extend = 0;
+
+            if (Context.ToplevelBorderCollapse) {
+                if (Widget.Allocation.Top <= Widget.Toplevel.Allocation.Top) {
+                    corners &= ~(CairoCorners.TopLeft | CairoCorners.TopRight);
+                    top_extend = cr.LineWidth;
+                }
+
+                if (Widget.Allocation.Bottom >= Widget.Toplevel.Allocation.Bottom) {
+                    corners &= ~(CairoCorners.BottomLeft | CairoCorners.BottomRight);
+                    bottom_extend = cr.LineWidth;
+                }
+
+                if (Widget.Allocation.Left <= Widget.Toplevel.Allocation.Left) {
+                    corners &= ~(CairoCorners.BottomLeft | CairoCorners.TopLeft);
+                    left_extend = cr.LineWidth;
+                }
+
+                if (Widget.Allocation.Right >= Widget.Toplevel.Allocation.Right) {
+                    corners &= ~(CairoCorners.BottomRight | CairoCorners.TopRight);
+                    right_extend = cr.LineWidth;
+                }
+            }
+
             cr.LineWidth = BorderWidth;
             cr.Color = border_color;
+
             double offset = (double)cr.LineWidth / 2.0;
-            CairoExtensions.RoundedRectangle (cr, alloc.X + offset, alloc.Y + offset,
-                alloc.Width - cr.LineWidth, alloc.Height - cr.LineWidth, Context.Radius, CairoCorners.All);
+
+            CairoExtensions.RoundedRectangle (cr,
+                alloc.X + offset - left_extend,
+                alloc.Y + offset - top_extend,
+                alloc.Width - cr.LineWidth + left_extend + right_extend,
+                alloc.Height - cr.LineWidth - top_extend + bottom_extend,
+                Context.Radius,
+                corners);
+
             cr.Stroke ();
         }
 
@@ -153,10 +189,7 @@ namespace Hyena.Gui.Theming
         {
             cr.LineWidth = BorderWidth * 1.5;
             cr.Color = CairoExtensions.ColorShade (border_color, 0.8);
-            double offset = (double)cr.LineWidth / 2.0;
-            CairoExtensions.RoundedRectangle (cr, alloc.X + offset, alloc.Y + offset,
-                alloc.Width - cr.LineWidth, alloc.Height - cr.LineWidth, Context.Radius, CairoCorners.All);
-            cr.Stroke ();
+            DrawFrameBorder (cr, alloc);
         }
 
         public override void DrawColumnHighlight (Cairo.Context cr, Gdk.Rectangle alloc, Cairo.Color color)