fdo: Support maximizing the Wayland surface

Maximizing the surface asks the compositor to let it occupy as much as
it would allow, e.g. without covering other important UI elements. This
is toggled with the COG_PLATFORM_FDO_VIEW_MAXIMIZE environment variable.
Note if both fullscreening *and* maximization are requested (using their
respective environment variables) then fullscreening is preferred.

platform/cog-platform-fdo.c

@@ -104,7 +104,15 @@ static struct {
     uint32_t height;
 
     bool is_fullscreen;
-} win_data;
+    bool is_maximized;
+} win_data = {
+    .egl_surface = EGL_NO_SURFACE,
+    .width = DEFAULT_WIDTH,
+    .height = DEFAULT_HEIGHT,
+    .is_fullscreen = false,
+    .is_maximized = false,
+};
+
 
 static struct {
     struct xkb_context* context;
@@ -1245,46 +1253,39 @@ create_window (GError **error)
         configure_surface_geometry (0, 0);
     }
 
-    win_data.egl_window = wl_egl_window_create (win_data.wl_surface,
-                                                DEFAULT_WIDTH,
-                                                DEFAULT_HEIGHT);
-    g_assert_nonnull (win_data.egl_window);
-
-    win_data.egl_surface =
-        eglCreateWindowSurface (egl_data.display,
-                                egl_data.egl_config,
-                                (EGLNativeWindowType) win_data.egl_window,
-                                NULL);
-    if (win_data.egl_surface == EGL_NO_SURFACE) {
-        ERR_EGL (error, "Cannot create EGL window surface for Wayland-EGL window");
-        destroy_window ();
-        return FALSE;
-    }
-
-    wl_surface_commit (win_data.wl_surface);
-    wl_display_flush (wl_data.display);
-
-    /* Activate window */
-    if (!eglMakeCurrent (egl_data.display,
-                         win_data.egl_surface,
-                         win_data.egl_surface,
-                         egl_data.context)) {
-        ERR_EGL (error, "Cannot activate EGL context");
-        destroy_window ();
-        return FALSE;
-    }
+    const char* env_var;
+    if ((env_var = g_getenv ("COG_PLATFORM_FDO_VIEW_FULLSCREEN")) &&
+        g_ascii_strtoll (env_var, NULL, 10) > 0)
+    {
+        win_data.is_maximized = false;
+        win_data.is_fullscreen = true;
 
-    const char* env_var = g_getenv("COG_PLATFORM_FDO_VIEW_FULLSCREEN");
-    if (env_var != NULL && g_ascii_strtod(env_var, NULL) >= 1.0) {
         if (wl_data.xdg_shell != NULL) {
-            zxdg_toplevel_v6_set_fullscreen(win_data.xdg_toplevel, NULL);
+            zxdg_toplevel_v6_set_fullscreen (win_data.xdg_toplevel, NULL);
         } else if (wl_data.shell != NULL) {
             wl_shell_surface_set_fullscreen (win_data.shell_surface,
                                              WL_SHELL_SURFACE_FULLSCREEN_METHOD_SCALE,
                                              0,
                                              NULL);
+        } else {
+            g_warning ("No available shell capable of fullscreening.");
+            win_data.is_fullscreen = false;
+        }
+    }
+    else if ((env_var = g_getenv ("COG_PLATFORM_FDO_VIEW_MAXIMIZE")) &&
+             g_ascii_strtoll (env_var, NULL, 10) > 0)
+    {
+        win_data.is_maximized = true;
+        win_data.is_fullscreen = false;
+
+        if (wl_data.xdg_shell != NULL) {
+            zxdg_toplevel_v6_set_maximized (win_data.xdg_toplevel);
+        } else if (wl_data.shell != NULL) {
+            wl_shell_surface_set_maximized (win_data.shell_surface, NULL);
+        } else {
+            g_warning ("No available shell capable of maximizing.");
+            win_data.is_maximized = false;
         }
-        win_data.is_fullscreen = TRUE;
     }
 
     return TRUE;