gsk: Add GskLayerwip/ebassi/gsk-layer

After GskRenderer and GskRenderNode, this commit adds the higher level
scene graph API of GSK.

GskLayer is a 2D layer in 3D space, which can be manipulated like a
widget would, but without the history; unlike GskRenderNode, a scene
graph of GskLayer instances is meant to be kept around.

4 files changed, 133 insertions, 2 deletions

diff --git a/gsk/Makefile.am b/gsk/Makefile.am
index 7edabe3f5e..a8596858ca 100644
--- a/gsk/Makefile.am
+++ b/gsk/Makefile.am
@@ -29,6 +29,7 @@ lib_LTLIBRARIES =
 
 gsk_public_source_h = \
 	gskenums.h \
+	gsklayer.h \
 	gskrenderer.h \
 	gskrendernode.h \
 	gskrendernodeiter.h \
@@ -53,6 +54,7 @@ gsk_source_c = \
 	gskcairorenderer.c \
 	gskdebug.c \
 	gskglrenderer.c \
+	gsklayer.c \
 	gskrenderer.c \
 	gskrendernode.c \
 	gskrendernodeiter.c \
diff --git a/gsk/gsk.h b/gsk/gsk.h
index 01c45693f5..cab9ac82f8 100644
--- a/gsk/gsk.h
+++ b/gsk/gsk.h
@@ -20,13 +20,15 @@
 
 #define __GSK_H_INSIDE__
 
+#include <gsk/gsktypes.h>
 #include <gsk/gskenums.h>
+#include <gsk/gskenumtypes.h>
+
 #include <gsk/gskrenderer.h>
 #include <gsk/gskrendernode.h>
 #include <gsk/gskrendernodeiter.h>
 
-#include <gsk/gsktypes.h>
-#include <gsk/gskenumtypes.h>
+#include <gsk/gsklayer.h>
 
 #undef __GSK_H_INSIDE__
 
diff --git a/gsk/gsklayer.c b/gsk/gsklayer.c
new file mode 100644
index 0000000000..ffc9fb09e7
--- /dev/null
+++ b/gsk/gsklayer.c
@@ -0,0 +1,59 @@
+#include "config.h"
+
+#include "gsklayer.h"
+
+#include <gdk/gdk.h>
+
+#include "gskenumtypes.h"
+#include "gskdebugprivate.h"
+
+typedef struct {
+  GskLayer *parent;
+
+  GskLayer *first_child;
+  GskLayer *last_child;
+  GskLayer *prev_sibling;
+  GskLayer *next_sibling;
+
+  int n_children;
+
+  gint64 age;
+
+  graphene_rect_t bounds;
+  graphene_point_t anchor;
+
+  graphene_matrix_t transform;
+  graphene_matrix_t child_transform;
+
+  gboolean transform_set : 1;
+  gboolean child_transform_set : 1;
+  gboolean is_hidden : 1;
+  gboolean is_opaque : 1;
+} GskLayerPrivate;
+
+G_DEFINE_TYPE_WITH_PRIVATE (GskLayer, gsk_layer, G_TYPE_INITIALLY_UNOWNED)
+
+static void
+gsk_layer_class_init (GskLayerClass *klass)
+{
+}
+
+static void
+gsk_layer_init (GskLayer *self)
+{
+}
+
+/**
+ * gsk_layer_new:
+ *
+ * Creates a new #GskLayer.
+ *
+ * Returns: (transfer full): the newly created #GskLayer
+ *
+ * Since: 3.22
+ */
+GskLayer *
+gsk_layer_new (void)
+{
+  return g_object_new (GSK_TYPE_LAYER, NULL);
+}
diff --git a/gsk/gsklayer.h b/gsk/gsklayer.h
new file mode 100644
index 0000000000..839a8405a6
--- /dev/null
+++ b/gsk/gsklayer.h
@@ -0,0 +1,68 @@
+/* GSK - The GTK Scene Kit
+ *
+ * Copyright 2016  Endless
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __GSK_LAYER_H__
+#define __GSK_LAYER_H__
+
+#if !defined (__GSK_H_INSIDE__) && !defined (GSK_COMPILATION)
+#error "Only <gsk/gsk.h> can be included directly."
+#endif
+
+#include <gsk/gsktypes.h>
+#include <gsk/gskrenderer.h>
+
+G_BEGIN_DECLS
+
+#define GSK_TYPE_LAYER gsk_layer_get_type()
+
+GDK_AVAILABLE_IN_3_22
+G_DECLARE_DERIVABLE_TYPE (GskLayer, gsk_layer, GSK, LAYER, GInitiallyUnowned)
+
+struct _GskLayerClass
+{
+  /*< private >*/
+  GInitiallyUnowned parent_instance;
+
+  /*< public >*/
+
+  /* vfuncs */
+  GskRenderNode *(* get_render_node)     (GskLayer         *layer,
+                                          GskRenderer      *renderer);
+
+  void           (* queue_resize)        (GskLayer         *layer,
+                                          GskLayer         *origin);
+  void           (* queue_redraw)        (GskLayer         *layer,
+                                          GskLayer         *origin);
+
+  /* signals */
+  void           (* child_added)         (GskLayer         *layer,
+                                          GskLayer         *child);
+  void           (* child_removed)       (GskLayer         *layer,
+                                          GskLayer         *child);
+  void           (* destroy)             (GskLayer         *layer);
+
+
+  /*< private >*/
+  gpointer _padding[16];
+};
+
+GskLayer *              gsk_layer_new           (void);
+
+G_END_DECLS
+
+#endif /* __GSK_LAYER_H__ */