[gimp] app: add a canvas group item which keeps around sub-items

[Michael Natterer <mitch src gnome org>]

commit 349c1500c94067ec52575ae0ab088a0b31ec8cae
Author: Michael Natterer <mitch gimp org>
Date:   Sat Sep 25 17:14:57 2010 +0200

    app: add a canvas group item which keeps around sub-items
    
    It can draw them all with one call to draw() and returns a union of
    their extents via get_extents().

 app/display/Makefile.am       |    2 +
 app/display/gimpcanvasgroup.c |  209 +++++++++++++++++++++++++++++++++++++++++
 app/display/gimpcanvasgroup.h |   58 +++++++++++
 3 files changed, 269 insertions(+), 0 deletions(-)
---
diff --git a/app/display/Makefile.am b/app/display/Makefile.am
index 7b16694..3b82f4a 100644
--- a/app/display/Makefile.am
+++ b/app/display/Makefile.am
@@ -25,6 +25,8 @@ libappdisplay_a_sources = \
 	gimpcanvasboundary.h			\
 	gimpcanvascorner.c			\
 	gimpcanvascorner.h			\
+	gimpcanvasgroup.c			\
+	gimpcanvasgroup.h			\
 	gimpcanvasguide.c			\
 	gimpcanvasguide.h			\
 	gimpcanvashandle.c			\
diff --git a/app/display/gimpcanvasgroup.c b/app/display/gimpcanvasgroup.c
new file mode 100644
index 0000000..6b4d465
--- /dev/null
+++ b/app/display/gimpcanvasgroup.c
@@ -0,0 +1,209 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpcanvasgroup.c
+ * Copyright (C) 2010 Michael Natterer <mitch gimp org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gegl.h>
+#include <gtk/gtk.h>
+
+#include "libgimpbase/gimpbase.h"
+#include "libgimpmath/gimpmath.h"
+
+#include "display-types.h"
+
+#include "gimpcanvasgroup.h"
+#include "gimpdisplayshell.h"
+#include "gimpdisplayshell-transform.h"
+
+
+enum
+{
+  PROP_0
+};
+
+
+typedef struct _GimpCanvasGroupPrivate GimpCanvasGroupPrivate;
+
+struct _GimpCanvasGroupPrivate
+{
+  GList *items;
+};
+
+#define GET_PRIVATE(group) \
+        G_TYPE_INSTANCE_GET_PRIVATE (group, \
+                                     GIMP_TYPE_CANVAS_GROUP, \
+                                     GimpCanvasGroupPrivate)
+
+
+/*  local function prototypes  */
+
+static void        gimp_canvas_group_dispose      (GObject          *object);
+static void        gimp_canvas_group_set_property (GObject          *object,
+                                                   guint             property_id,
+                                                   const GValue     *value,
+                                                   GParamSpec       *pspec);
+static void        gimp_canvas_group_get_property (GObject          *object,
+                                                   guint             property_id,
+                                                   GValue           *value,
+                                                   GParamSpec       *pspec);
+static void        gimp_canvas_group_draw         (GimpCanvasItem   *item,
+                                                   GimpDisplayShell *shell,
+                                                   cairo_t          *cr);
+static GdkRegion * gimp_canvas_group_get_extents  (GimpCanvasItem   *item,
+                                                   GimpDisplayShell *shell);
+
+
+G_DEFINE_TYPE (GimpCanvasGroup, gimp_canvas_group, GIMP_TYPE_CANVAS_ITEM)
+
+#define parent_class gimp_canvas_group_parent_class
+
+
+static void
+gimp_canvas_group_class_init (GimpCanvasGroupClass *klass)
+{
+  GObjectClass        *object_class = G_OBJECT_CLASS (klass);
+  GimpCanvasItemClass *item_class   = GIMP_CANVAS_ITEM_CLASS (klass);
+
+  object_class->dispose      = gimp_canvas_group_dispose;
+  object_class->set_property = gimp_canvas_group_set_property;
+  object_class->get_property = gimp_canvas_group_get_property;
+
+  item_class->draw           = gimp_canvas_group_draw;
+  item_class->get_extents    = gimp_canvas_group_get_extents;
+
+  g_type_class_add_private (klass, sizeof (GimpCanvasGroupPrivate));
+}
+
+static void
+gimp_canvas_group_init (GimpCanvasGroup *group)
+{
+}
+
+static void
+gimp_canvas_group_dispose (GObject *object)
+{
+  GimpCanvasGroupPrivate *private = GET_PRIVATE (object);
+
+  if (private->items)
+    {
+      g_list_foreach (private->items, (GFunc) g_object_unref, NULL);
+      g_list_free (private->items);
+      private->items = NULL;
+    }
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+gimp_canvas_group_set_property (GObject      *object,
+                                guint         property_id,
+                                const GValue *value,
+                                GParamSpec   *pspec)
+{
+  /* GimpCanvasGroupPrivate *private = GET_PRIVATE (object); */
+
+  switch (property_id)
+    {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_canvas_group_get_property (GObject    *object,
+                                guint       property_id,
+                                GValue     *value,
+                                GParamSpec *pspec)
+{
+  /* GimpCanvasGroupPrivate *private = GET_PRIVATE (object); */
+
+  switch (property_id)
+    {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_canvas_group_draw (GimpCanvasItem   *item,
+                        GimpDisplayShell *shell,
+                        cairo_t          *cr)
+{
+  GimpCanvasGroupPrivate *private = GET_PRIVATE (item);
+  GList                  *list;
+
+  for (list = private->items; list; list = g_list_next (list))
+    {
+      GimpCanvasItem *sub_item = list->data;
+
+      gimp_canvas_item_draw (sub_item, shell, cr);
+    }
+}
+
+static GdkRegion *
+gimp_canvas_group_get_extents (GimpCanvasItem   *item,
+                               GimpDisplayShell *shell)
+{
+  GimpCanvasGroupPrivate *private = GET_PRIVATE (item);
+  GdkRegion              *region  = NULL;
+  GList                  *list;
+
+  for (list = private->items; list; list = g_list_next (list))
+    {
+      GimpCanvasItem *sub_item   = list->data;
+      GdkRegion      *sub_region = gimp_canvas_item_get_extents (sub_item,
+                                                                 shell);
+
+      if (region)
+        {
+          gdk_region_union (region, sub_region);
+          gdk_region_destroy (sub_region);
+        }
+      else
+        {
+          region = sub_region;
+        }
+    }
+
+  return region;
+}
+
+GimpCanvasItem *
+gimp_canvas_group_new (void)
+{
+  return g_object_new (GIMP_TYPE_CANVAS_GROUP, NULL);
+}
+
+void
+gimp_canvas_group_add_item (GimpCanvasGroup *group,
+                            GimpCanvasItem  *item)
+{
+  GimpCanvasGroupPrivate *private;
+
+  g_return_if_fail (GIMP_IS_CANVAS_GROUP (group));
+  g_return_if_fail (GIMP_IS_CANVAS_ITEM (item));
+  g_return_if_fail (GIMP_CANVAS_ITEM (group) != item);
+
+  private = GET_PRIVATE (group);
+
+  private->items = g_list_append (private->items, g_object_ref (item));
+}
diff --git a/app/display/gimpcanvasgroup.h b/app/display/gimpcanvasgroup.h
new file mode 100644
index 0000000..150bb54
--- /dev/null
+++ b/app/display/gimpcanvasgroup.h
@@ -0,0 +1,58 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpcanvasgroup.h
+ * Copyright (C) 2010 Michael Natterer <mitch gimp org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __GIMP_CANVAS_GROUP_H__
+#define __GIMP_CANVAS_GROUP_H__
+
+
+#include "gimpcanvasitem.h"
+
+
+#define GIMP_TYPE_CANVAS_GROUP            (gimp_canvas_group_get_type ())
+#define GIMP_CANVAS_GROUP(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GIMP_TYPE_CANVAS_GROUP, GimpCanvasGroup))
+#define GIMP_CANVAS_GROUP_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), GIMP_TYPE_CANVAS_GROUP, GimpCanvasGroupClass))
+#define GIMP_IS_CANVAS_GROUP(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GIMP_TYPE_CANVAS_GROUP))
+#define GIMP_IS_CANVAS_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GIMP_TYPE_CANVAS_GROUP))
+#define GIMP_CANVAS_GROUP_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), GIMP_TYPE_CANVAS_GROUP, GimpCanvasGroupClass))
+
+
+typedef struct _GimpCanvasGroup      GimpCanvasGroup;
+typedef struct _GimpCanvasGroupClass GimpCanvasGroupClass;
+
+struct _GimpCanvasGroup
+{
+  GimpCanvasItem  parent_instance;
+};
+
+struct _GimpCanvasGroupClass
+{
+  GimpCanvasItemClass  parent_class;
+};
+
+
+GType            gimp_canvas_group_get_type (void) G_GNUC_CONST;
+
+GimpCanvasItem * gimp_canvas_group_new      (void);
+
+void             gimp_canvas_group_add_item (GimpCanvasGroup *group,
+                                             GimpCanvasItem  *item);
+
+
+#endif /* __GIMP_CANVAS_GROUP_H__ */