[gtk] snapshot: Add _push_collect() and _pop_collect()

[Matthias Clasen <matthiasc src gnome org>]

commit bf8fb2c1a522fa46fbe1b86e5da16158d7c691fe
Author: Timm Bäder <mail baedert org>
Date:   Fri Jan 31 08:05:34 2020 +0100

    snapshot: Add _push_collect() and _pop_collect()
    
    These will replace the previous gtk_snapshot_new_with_parent(), which
    allocated an entirely new GObject just to push()/pop() some state. This
    is already a problem but will be more important in the future as we
    start using this more.

 gtk/gtksnapshot.c        | 24 ++++++++++++++++++++++++
 gtk/gtksnapshotprivate.h |  4 ++++
 2 files changed, 28 insertions(+)
---
diff --git a/gtk/gtksnapshot.c b/gtk/gtksnapshot.c
index 5654e0abbc..1804ffb9c2 100644
--- a/gtk/gtksnapshot.c
+++ b/gtk/gtksnapshot.c
@@ -1138,6 +1138,30 @@ gtk_snapshot_pop_internal (GtkSnapshot *snapshot)
   return gtk_snapshot_pop_one (snapshot);
 }
 
+/**
+ * gtk_snapshot_push_collect:
+ *
+ * PRIVATE.
+ *
+ * Puhses state so a later pop_collect call can collect all nodes
+ * appended until that point.
+ */
+void
+gtk_snapshot_push_collect (GtkSnapshot *snapshot)
+{
+  gtk_snapshot_push_state (snapshot,
+                           NULL,
+                           gtk_snapshot_collect_default);
+}
+
+GskRenderNode *
+gtk_snapshot_pop_collect (GtkSnapshot *snapshot)
+{
+  GskRenderNode *result = gtk_snapshot_pop_internal (snapshot);
+
+  return result;
+}
+
 /**
  * gtk_snapshot_to_node:
  * @snapshot: a #GtkSnapshot
diff --git a/gtk/gtksnapshotprivate.h b/gtk/gtksnapshotprivate.h
index e02531e1a5..7317b4ad59 100644
--- a/gtk/gtksnapshotprivate.h
+++ b/gtk/gtksnapshotprivate.h
@@ -104,6 +104,10 @@ void                    gtk_snapshot_append_text                (GtkSnapshot
                                                                  const GdkRGBA          *color,
                                                                  float                   x,
                                                                  float                   y);
+
+void                    gtk_snapshot_push_collect               (GtkSnapshot            *snapshot);
+GskRenderNode *         gtk_snapshot_pop_collect                (GtkSnapshot            *snapshot);
+
 G_END_DECLS
 
 #endif /* __GTK_SNAPSHOT_PRIVATE_H__ */