stage-x11: Move view management to renderer

In the native backend, the MetaRenderer manages the view by creating one
per CRTC, but until now the MetaStageX11 managed the view for the X11
backend. This caused some issues as it meant meta_renderer_get_views()
not returning anything, and that the view of the X11 screen not being a
MetaRendererView, while in the other backends, all views are.

Fix this by moving the view management responsibility to
MetaRendererX11Cm, and have MetaStageX11 only operate on it via
meta_renderer_x11_cm_*() API. The MetaRendererX11Cm takes care of making
sure the view is always added to the list in the renderer, and turning
X11 screen sizes into "layouts" etc.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1251

src/backends/x11/cm/meta-renderer-x11-cm.c

@@ -24,14 +24,75 @@
 
 #include "backends/x11/cm/meta-renderer-x11-cm.h"
 
+#include "backends/meta-renderer-view.h"
+
 struct _MetaRendererX11Cm
 {
   MetaRendererX11 parent;
+
+  MetaRendererView *screen_view;
 };
 
 G_DEFINE_TYPE (MetaRendererX11Cm, meta_renderer_x11_cm,
                META_TYPE_RENDERER_X11)
 
+void
+meta_renderer_x11_cm_ensure_screen_view (MetaRendererX11Cm *renderer_x11_cm,
+                                         int                width,
+                                         int                height)
+{
+  cairo_rectangle_int_t view_layout;
+
+  if (renderer_x11_cm->screen_view)
+    return;
+
+  view_layout = (cairo_rectangle_int_t) {
+    .width = width,
+    .height = height,
+  };
+  renderer_x11_cm->screen_view = g_object_new (META_TYPE_RENDERER_VIEW,
+                                               "layout", &view_layout,
+                                               NULL);
+  meta_renderer_add_view (META_RENDERER (renderer_x11_cm),
+                          renderer_x11_cm->screen_view);
+}
+
+void
+meta_renderer_x11_cm_resize (MetaRendererX11Cm *renderer_x11_cm,
+                             int                width,
+                             int                height)
+{
+  cairo_rectangle_int_t view_layout;
+
+  view_layout = (cairo_rectangle_int_t) {
+    .width = width,
+    .height = height,
+  };
+
+  g_object_set (G_OBJECT (renderer_x11_cm->screen_view),
+                "layout", &view_layout,
+                NULL);
+}
+
+void
+meta_renderer_x11_cm_set_onscreen (MetaRendererX11Cm *renderer_x11_cm,
+                                   CoglOnscreen      *onscreen)
+{
+  g_object_set (G_OBJECT (renderer_x11_cm->screen_view),
+                "framebuffer", onscreen,
+                NULL);
+}
+
+static void
+meta_renderer_x11_cm_rebuild_views (MetaRenderer *renderer)
+{
+  MetaRendererX11Cm *renderer_x11_cm = META_RENDERER_X11_CM (renderer);
+
+  g_return_if_fail (!meta_renderer_get_views (renderer));
+
+  meta_renderer_add_view (renderer, renderer_x11_cm->screen_view);
+}
+
 static void
 meta_renderer_x11_cm_init (MetaRendererX11Cm *renderer_x11_cm)
 {
@@ -40,4 +101,7 @@ meta_renderer_x11_cm_init (MetaRendererX11Cm *renderer_x11_cm)
 static void
 meta_renderer_x11_cm_class_init (MetaRendererX11CmClass *klass)
 {
+  MetaRendererClass *renderer_class = META_RENDERER_CLASS (klass);
+
+  renderer_class->rebuild_views = meta_renderer_x11_cm_rebuild_views;
 }

src/backends/x11/cm/meta-renderer-x11-cm.h

@@ -30,4 +30,15 @@ G_DECLARE_FINAL_TYPE (MetaRendererX11Cm, meta_renderer_x11_cm,
                       META, RENDERER_X11_CM,
                       MetaRendererX11)
 
+void meta_renderer_x11_cm_ensure_screen_view (MetaRendererX11Cm *renderer_x11_cm,
+                                              int                width,
+                                              int                height);
+
+void meta_renderer_x11_cm_resize (MetaRendererX11Cm *renderer_x11_cm,
+                                  int                width,
+                                  int                height);
+
+void meta_renderer_x11_cm_set_onscreen (MetaRendererX11Cm *renderer_x11_cm,
+                                        CoglOnscreen      *onscreen);
+
 #endif /* META_RENDERER_X11_CM_H */

src/backends/x11/meta-stage-x11.c

@@ -26,6 +26,8 @@
 #include <unistd.h>
 #endif
 
+#include "backends/x11/cm/meta-backend-x11-cm.h"
+#include "backends/x11/cm/meta-renderer-x11-cm.h"
 #include "backends/x11/meta-backend-x11.h"
 #include "backends/x11/meta-seat-x11.h"
 #include "backends/x11/meta-stage-x11.h"
@@ -254,8 +256,6 @@ meta_stage_x11_unrealize (ClutterStageWindow *stage_window)
 
   clutter_stage_window_parent_iface->unrealize (stage_window);
 
-  g_list_free (stage_x11->legacy_views);
-  g_clear_object (&stage_x11->legacy_view);
   g_clear_pointer (&stage_x11->onscreen, cogl_object_unref);
 }
 
@@ -297,10 +297,13 @@ meta_stage_x11_realize (ClutterStageWindow *stage_window)
                                       stage_cogl,
                                       NULL);
 
-  if (stage_x11->legacy_view)
-    g_object_set (G_OBJECT (stage_x11->legacy_view),
-                  "framebuffer", stage_x11->onscreen,
-                  NULL);
+  if (META_IS_BACKEND_X11_CM (stage_x11->backend))
+    {
+      MetaRenderer *renderer = meta_backend_get_renderer (stage_x11->backend);
+      MetaRendererX11Cm *renderer_x11_cm = META_RENDERER_X11_CM (renderer);
+
+      meta_renderer_x11_cm_set_onscreen (renderer_x11_cm, stage_x11->onscreen);
+    }
 
   /* We just created a window of the size of the actor. No need to fix
      the size of the stage, just update it. */
@@ -468,34 +471,13 @@ meta_stage_x11_can_clip_redraws (ClutterStageWindow *stage_window)
   return stage_x11->clipped_redraws_cool_off == 0;
 }
 
-static void
-ensure_legacy_view (ClutterStageWindow *stage_window)
-{
-  MetaStageX11 *stage_x11 = META_STAGE_X11 (stage_window);
-  cairo_rectangle_int_t view_layout;
-  CoglFramebuffer *framebuffer;
-
-  if (stage_x11->legacy_view)
-    return;
-
-  _clutter_stage_window_get_geometry (stage_window, &view_layout);
-  framebuffer = COGL_FRAMEBUFFER (stage_x11->onscreen);
-  stage_x11->legacy_view = g_object_new (CLUTTER_TYPE_STAGE_VIEW_COGL,
-                                         "layout", &view_layout,
-                                         "framebuffer", framebuffer,
-                                         NULL);
-  stage_x11->legacy_views = g_list_append (stage_x11->legacy_views,
-                                           stage_x11->legacy_view);
-}
-
 static GList *
 meta_stage_x11_get_views (ClutterStageWindow *stage_window)
 {
   MetaStageX11 *stage_x11 = META_STAGE_X11 (stage_window);
+  MetaRenderer *renderer = meta_backend_get_renderer (stage_x11->backend);
 
-  ensure_legacy_view (stage_window);
-
-  return stage_x11->legacy_views;
+  return meta_renderer_get_views (renderer);
 }
 
 static int64_t
@@ -527,6 +509,9 @@ meta_stage_x11_class_init (MetaStageX11Class *klass)
 static void
 meta_stage_x11_init (MetaStageX11 *stage)
 {
+  MetaRenderer *renderer;
+  MetaRendererX11Cm *renderer_x11_cm;
+
   stage->xwin = None;
   stage->xwin_width = 640;
   stage->xwin_height = 480;
@@ -534,6 +519,19 @@ meta_stage_x11_init (MetaStageX11 *stage)
   stage->wm_state = STAGE_X11_WITHDRAWN;
 
   stage->title = NULL;
+
+  stage->backend = meta_get_backend ();
+  g_assert (stage->backend);
+
+  if (META_IS_BACKEND_X11_CM (stage->backend))
+    {
+      renderer = meta_backend_get_renderer (stage->backend);
+      renderer_x11_cm = META_RENDERER_X11_CM (renderer);
+
+      meta_renderer_x11_cm_ensure_screen_view (renderer_x11_cm,
+                                               stage->xwin_width,
+                                               stage->xwin_height);
+    }
 }
 
 static void
@@ -719,16 +717,16 @@ meta_stage_x11_translate_event (MetaStageX11 *stage_x11,
                * X11 compositing manager, we need to reset the legacy
                * stage view, now that it has a new size.
                */
-              if (stage_x11->legacy_view)
+              if (META_IS_BACKEND_X11_CM (stage_x11->backend))
                 {
-                  cairo_rectangle_int_t view_layout = {
-                    .width = stage_width,
-                    .height = stage_height
-                  };
+                  MetaBackend *backend = stage_x11->backend;
+                  MetaRenderer *renderer = meta_backend_get_renderer (backend);
+                  MetaRendererX11Cm *renderer_x11_cm =
+                    META_RENDERER_X11_CM (renderer);
 
-                  g_object_set (G_OBJECT (stage_x11->legacy_view),
-                                "layout", &view_layout,
-                                NULL);
+                  meta_renderer_x11_cm_resize (renderer_x11_cm,
+                                               stage_width,
+                                               stage_height);
                 }
             }
         }

src/backends/x11/meta-stage-x11.h

@@ -25,6 +25,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>
 
+#include "backends/meta-backend-private.h"
 #include "clutter/clutter-mutter.h"
 #include "clutter/x11/clutter-x11.h"
 
@@ -51,14 +52,13 @@ struct _MetaStageX11
 {
   ClutterStageCogl parent_instance;
 
+  MetaBackend *backend;
+
   CoglOnscreen *onscreen;
   Window xwin;
   gint xwin_width;
   gint xwin_height; /* FIXME target_width / height */
 
-  ClutterStageView *legacy_view;
-  GList *legacy_views;
-
   CoglFrameClosure *frame_closure;
 
   gchar *title;