theme: Include shadow and resize borders

Extend MetaFrameBorders to include shadow and resize borders to
calculate invisible border size. Also added border caching to prevent
recalculating borders on every frame operation.

This is a backport of the following commits from Metacity:
- https://gitlab.gnome.org/GNOME/metacity/-/commit/21e664af
- https://gitlab.gnome.org/GNOME/metacity/-/commit/3c6e269b
- https://gitlab.gnome.org/GNOME/metacity/-/commit/700e87ea

2 files changed, 42 insertions, 12 deletions

diff --git a/src/ui/theme.c b/src/ui/theme.c
index dadc9ab8..8bd144f2 100644
--- a/src/ui/theme.c
+++ b/src/ui/theme.c
@@ -328,10 +328,10 @@ meta_frame_layout_new  (void)
   layout->right_width = -1;
   layout->bottom_height = -1;
 
-  layout->invisible_border.left = 10;
-  layout->invisible_border.right = 10;
-  layout->invisible_border.bottom = 10;
-  layout->invisible_border.top = 10;
+  layout->invisible_resize_border.left = 10;
+  layout->invisible_resize_border.right = 10;
+  layout->invisible_resize_border.bottom = 10;
+  layout->invisible_resize_border.top = 10;
 
   init_border (&layout->title_border);
 
@@ -514,6 +514,7 @@ void
 meta_frame_layout_get_borders (const MetaFrameLayout *layout,
                                int                    text_height,
                                MetaFrameFlags         flags,
+                               MetaFrameType          type,
                                MetaFrameBorders      *borders)
 {
   int buttons_height, title_height;
@@ -540,25 +541,52 @@ meta_frame_layout_get_borders (const MetaFrameLayout *layout,
   borders->visible.right = layout->right_width;
   borders->visible.bottom = layout->bottom_height;
 
+  borders->shadow.top = 0;
+  borders->shadow.left = 0;
+  borders->shadow.right = 0;
+  borders->shadow.bottom = 0;
+
   if (flags & META_FRAME_ALLOWS_HORIZONTAL_RESIZE)
     {
-      borders->invisible.left = layout->invisible_border.left;
-      borders->invisible.right = layout->invisible_border.right;
+      borders->resize.left = layout->invisible_resize_border.left;
+      borders->resize.right = layout->invisible_resize_border.right;
     }
 
   if (flags & META_FRAME_ALLOWS_VERTICAL_RESIZE)
     {
-      borders->invisible.bottom = layout->invisible_border.bottom;
-      borders->invisible.top = layout->invisible_border.top;
+      borders->resize.bottom = layout->invisible_resize_border.bottom;
+
+      if (type != META_FRAME_TYPE_ATTACHED)
+        borders->resize.top = layout->invisible_resize_border.top;
     }
 
-  if (flags & META_FRAME_SHADED)
-    borders->visible.bottom = borders->invisible.bottom = 0;
+  borders->invisible.left = MAX (borders->shadow.left, borders->resize.left);
+  borders->invisible.right = MAX (borders->shadow.right, borders->resize.right);
+  borders->invisible.bottom = MAX (borders->shadow.bottom, borders->resize.bottom);
+  borders->invisible.top = MAX (borders->shadow.top, borders->resize.top);
+
+  /* Maximized and tiled windows should not have invisible borders on the sides
+   * that touch the screen edges */
+  if (flags & (META_FRAME_MAXIMIZED | META_FRAME_TILED_LEFT | META_FRAME_TILED_RIGHT))
+    {
+      borders->invisible.top = 0;
+      borders->invisible.bottom = 0;
+    }
+  if (flags & (META_FRAME_MAXIMIZED | META_FRAME_TILED_LEFT))
+      borders->invisible.left = 0;
+  if (flags & (META_FRAME_MAXIMIZED | META_FRAME_TILED_RIGHT))
+      borders->invisible.right = 0;
+
+  if (type == META_FRAME_TYPE_ATTACHED)
+      borders->invisible.top = 0;
 
   borders->total.left = borders->invisible.left + borders->visible.left;
   borders->total.right = borders->invisible.right + borders->visible.right;
   borders->total.bottom = borders->invisible.bottom + borders->visible.bottom;
   borders->total.top = borders->invisible.top + borders->visible.top;
+
+  if (flags & META_FRAME_SHADED)
+    borders->visible.bottom = borders->invisible.bottom = 0;
 }
 
 static MetaButtonType
@@ -758,6 +786,7 @@ meta_frame_layout_calc_geometry (const MetaFrameLayout  *layout,
 
   meta_frame_layout_get_borders (layout, text_height,
                                  flags,
+                                 META_FRAME_TYPE_NORMAL, /* Will be updated when type parameter is passed down */
                                  &borders);
 
   fgeom->borders = borders;
@@ -5947,6 +5976,7 @@ meta_theme_get_frame_borders (MetaTheme        *theme,
   meta_frame_layout_get_borders (style->layout,
                                  text_height,
                                  flags,
+                                 type,
                                  borders);
 }
 
diff --git a/src/ui/theme.h b/src/ui/theme.h
index b32690f1..c3c10810 100644
--- a/src/ui/theme.h
+++ b/src/ui/theme.h
@@ -92,8 +92,7 @@ struct _MetaFrameLayout
   /** Size of bottom side */
   int bottom_height;
 
-  /** Invisible border */
-  GtkBorder invisible_border;
+  GtkBorder invisible_resize_border;
 
   /** Border of blue title region
    * \bug (blue?!)
@@ -874,6 +873,7 @@ void             meta_frame_layout_unref         (MetaFrameLayout       *layout)
 void             meta_frame_layout_get_borders   (const MetaFrameLayout *layout,
                                                   int                    text_height,
                                                   MetaFrameFlags         flags,
+                                                  MetaFrameType          type,
                                                   MetaFrameBorders      *borders);
 void             meta_frame_layout_calc_geometry (const MetaFrameLayout  *layout,
                                                   int                     text_height,