From 3607b9aa2e4b2c57489947efa5dcf47877d68e69 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Fri, 26 Feb 2016 13:35:35 +0100
Subject: [PATCH] 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 file changed, 56 insertions(+), 2 deletions(-)

diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 168c1a3d88..34c6805ce8 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