[gtk/gtk-3-24: 2/5] wayland: Respect fixed size when resizing

[Matthias Clasen <matthiasc src gnome org>]

commit 04b7853a38a3b2ee830502499427f6cedbe2bb01
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Apr 2 16:41:21 2020 +0200

    wayland: Respect fixed size when resizing
    
    If a window is configured with a fixed size (it's tiled, maximized, or
    fullscreen), ignore any resize call that doesn't respect this. The set
    size will instead be saved, when appropriate, so that the new size is
    used when e.g. unmaximizing.
    
    This makes it possible to call 'gtk_window_resize()' while the window is
    maximized, without the window actually changing size until it's
    unmaximized. Changing size to a non-maximized size is a violation of the
    xdg-shell protocol.

 gdk/wayland/gdkwindow-wayland.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)
---
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index ca91e78adc..e0fc4010df 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -206,6 +206,9 @@ struct _GdkWindowImplWayland
   int unconfigured_width;
   int unconfigured_height;
 
+  int fixed_size_width;
+  int fixed_size_height;
+
   gulong parent_surface_committed_handler;
 
   struct {
@@ -1511,6 +1514,14 @@ gdk_wayland_window_create_surface (GdkWindow *window)
   wl_surface_add_listener (impl->display_server.wl_surface, &surface_listener, window);
 }
 
+static gboolean
+should_use_fixed_size (GdkWindowState state)
+{
+  return state & (GDK_WINDOW_STATE_MAXIMIZED |
+                  GDK_WINDOW_STATE_FULLSCREEN |
+                  GDK_WINDOW_STATE_TILED);
+}
+
 static void
 gdk_wayland_window_handle_configure (GdkWindow *window,
                                      uint32_t   serial)
@@ -1545,10 +1556,7 @@ gdk_wayland_window_handle_configure (GdkWindow *window,
   new_state = impl->pending.state;
   impl->pending.state = 0;
 
-  fixed_size =
-    new_state & (GDK_WINDOW_STATE_MAXIMIZED |
-                 GDK_WINDOW_STATE_FULLSCREEN |
-                 GDK_WINDOW_STATE_TILED);
+  fixed_size = should_use_fixed_size (new_state);
 
   saved_size = (width == 0 && height == 0);
   /* According to xdg_shell, an xdg_surface.configure with size 0x0
@@ -1596,6 +1604,11 @@ gdk_wayland_window_handle_configure (GdkWindow *window,
                                     impl->scale);
     }
 
+  if (fixed_size)
+    {
+      impl->fixed_size_width = width;
+      impl->fixed_size_height = height;
+    }
 
   GDK_NOTE (EVENTS,
             g_message ("configure, window %p %dx%d,%s%s%s%s",
@@ -3345,7 +3358,12 @@ gdk_window_wayland_move_resize (GdkWindow *window,
    * just move the window - don't update its size
    */
   if (width > 0 && height > 0)
-    gdk_wayland_window_maybe_configure (window, width, height, impl->scale);
+    {
+      if (!should_use_fixed_size (window->state) ||
+          (width == impl->fixed_size_width &&
+           height == impl->fixed_size_height))
+        gdk_wayland_window_maybe_configure (window, width, height, impl->scale);
+    }
 }
 
 /* Avoid zero width/height as this is a protocol error */