[gtk+] wayland: Restore size when configure size is 0x0

[Olivier Fourdan <ofourdan src gnome org>]

commit 3607b9aa2e4b2c57489947efa5dcf47877d68e69
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Fri Feb 26 13:35:35 2016 +0100

    wayland: Restore size when configure size is 0x0
    
    According to xdg_shell, an xdg_surface.configure with size 0x0 should
    be interpreted as that it is up to the client to set a size.
    
    When transitioning from maximize or fullscreen state, this means the
    client should configure its size back to what it was before being
    maximize or fullscreen.
    
    This problem currently only occurs on weston because weston sends a
    configure with size 0x0 when transitioning back from maximize or
    fullscreen.
    
    bugzilla: https://bugzilla.gnome.org/show_bug.cgi?id=762713

 gdk/wayland/gdkwindow-wayland.c |   58 +++++++++++++++++++++++++++++++++++++-
 1 files changed, 56 insertions(+), 2 deletions(-)
---
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 168c1a3..34c6805 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -152,12 +152,15 @@ struct _GdkWindowImplWayland
   int margin_right;
   int margin_top;
   int margin_bottom;
-  
+
   int initial_fullscreen_monitor;
 
   cairo_region_t *opaque_region;
   cairo_region_t *input_region;
   cairo_region_t *staged_updates_region;
+
+  int saved_width;
+  int saved_height;
 };
 
 struct _GdkWindowImplWaylandClass
@@ -184,6 +187,8 @@ _gdk_window_impl_wayland_init (GdkWindowImplWayland *impl)
 {
   impl->scale = 1;
   impl->initial_fullscreen_monitor = -1;
+  impl->saved_width = -1;
+  impl->saved_height = -1;
 }
 
 /* Keep a list of orphaned dialogs (i.e. without parent) */
@@ -210,6 +215,30 @@ drop_cairo_surfaces (GdkWindow *window)
   impl->committed_cairo_surface = NULL;
 }
 
+static void
+_gdk_wayland_window_save_size (GdkWindow *window)
+{
+  GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
+
+  if (window->state & (GDK_WINDOW_STATE_FULLSCREEN | GDK_WINDOW_STATE_MAXIMIZED))
+    return;
+
+  impl->saved_width = window->width - impl->margin_left - impl->margin_right;
+  impl->saved_height = window->height - impl->margin_top - impl->margin_bottom;
+}
+
+static void
+_gdk_wayland_window_clear_saved_size (GdkWindow *window)
+{
+  GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
+
+  if (window->state & (GDK_WINDOW_STATE_FULLSCREEN | GDK_WINDOW_STATE_MAXIMIZED))
+    return;
+
+  impl->saved_width = -1;
+  impl->saved_height = -1;
+}
+
 /*
  * gdk_wayland_window_update_size:
  * @drawable: a #GdkDrawableImplWayland.
@@ -1132,6 +1161,7 @@ xdg_surface_configure (void               *data,
   GdkWindow *window = GDK_WINDOW (data);
   GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
   GdkWindowState new_state = 0;
+  gboolean maximized_or_fullscreen;
   uint32_t *p;
 
   wl_array_for_each (p, states)
@@ -1156,12 +1186,29 @@ xdg_surface_configure (void               *data,
         }
     }
 
+   maximized_or_fullscreen =
+       new_state & (GDK_WINDOW_STATE_MAXIMIZED | GDK_WINDOW_STATE_FULLSCREEN);
+
+    /* According to xdg_shell, an xdg_surface.configure with size 0x0
+     * should be interpreted as that it is up to the client to set a
+     * size.
+     *
+     * When transitioning from maximize or fullscreen state, this means
+     * the client should configure its size back to what it was before
+     * being maximize or fullscreen.
+     */
+   if (width == 0 && height == 0 && !maximized_or_fullscreen)
+    {
+      width = impl->saved_width;
+      height = impl->saved_height;
+    }
+
    if (width > 0 && height > 0)
     {
       GdkWindowHints geometry_mask = impl->geometry_mask;
 
       /* Ignore size increments for maximized/fullscreen windows */
-      if (new_state & (GDK_WINDOW_STATE_MAXIMIZED | GDK_WINDOW_STATE_FULLSCREEN))
+      if (maximized_or_fullscreen)
         geometry_mask &= ~GDK_HINT_RESIZE_INC;
 
       gdk_window_constrain_size (&impl->geometry_hints,
@@ -1171,6 +1218,9 @@ xdg_surface_configure (void               *data,
                                  &width,
                                  &height);
 
+      /* Save size for next time we get 0x0 */
+      _gdk_wayland_window_save_size (window);
+
       gdk_wayland_window_configure (window, width, height, impl->scale);
     }
 
@@ -1739,6 +1789,7 @@ gdk_wayland_window_hide_surface (GdkWindow *window)
         orphan_dialogs = g_list_remove (orphan_dialogs, window);
     }
 
+  _gdk_wayland_window_clear_saved_size (window);
   impl->pending_commit = FALSE;
   impl->mapped = FALSE;
 }
@@ -2293,6 +2344,7 @@ gdk_wayland_window_maximize (GdkWindow *window)
   if (GDK_WINDOW_DESTROYED (window))
     return;
 
+  _gdk_wayland_window_save_size (window);
   if (impl->display_server.xdg_surface)
     xdg_surface_set_maximized (impl->display_server.xdg_surface);
   else
@@ -2324,6 +2376,7 @@ gdk_wayland_window_fullscreen_on_monitor (GdkWindow *window, gint monitor)
   if (GDK_WINDOW_DESTROYED (window))
     return;
 
+  _gdk_wayland_window_save_size (window);
   if (impl->display_server.xdg_surface)
     xdg_surface_set_fullscreen (impl->display_server.xdg_surface, fullscreen_output);
   else {
@@ -2342,6 +2395,7 @@ gdk_wayland_window_fullscreen (GdkWindow *window)
 
   impl->initial_fullscreen_monitor = -1;
 
+  _gdk_wayland_window_save_size (window);
   if (impl->display_server.xdg_surface)
     xdg_surface_set_fullscreen (impl->display_server.xdg_surface, NULL);
   else