Drag&Drop clean up.

Added private _GladeDrag interface. (only used internaly in gladeui)

Implemented _GladeDrag in GladePlaceholder GladeWidget GladeDesignView and GladeDesignLayout

Added drag-dest property to GladeWidget to enable/disable drag support
(used in GtkFixed GtkLayout and GtkOverlay containers)

Made GladeInspector a drag source by implementing GtkTreeDragSource interface in GladeProject

1 files changed, 174 insertions, 0 deletions

diff --git a/gladeui/glade-dnd.c b/gladeui/glade-dnd.c
new file mode 100644
index 00000000..122d74d4
--- /dev/null
+++ b/gladeui/glade-dnd.c
@@ -0,0 +1,174 @@
+/*
+ * glade-dnd.c
+ *
+ * Copyright (C) 2013  Juan Pablo Ugarte
+ *
+ * Authors:
+ *   Juan Pablo Ugarte <juanpablougarte@gmail.com>
+ *
+ * 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 2.1 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 program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "glade.h"
+#include "glade-dnd.h"
+
+GtkTargetEntry *
+_glade_dnd_get_target (void)
+{
+  static GtkTargetEntry target = {GLADE_DND_TARGET_DATA, GTK_TARGET_SAME_APP, GLADE_DND_INFO_DATA};
+  return &target;
+}
+
+void
+_glade_dnd_dest_set (GtkWidget *target)
+{
+  GtkTargetEntry targets[1];
+
+  targets[0] = *_glade_dnd_get_target ();
+
+  gtk_drag_dest_set (target, 0, targets, 2, GDK_ACTION_COPY);
+}
+
+GObject *
+_glade_dnd_get_data (GdkDragContext   *context,
+                     GtkSelectionData *selection,
+                     guint             info)
+{
+  GdkAtom target = gtk_selection_data_get_target (selection);
+
+  if (info == GLADE_DND_INFO_DATA &&
+      g_strcmp0 (gdk_atom_name (target), GLADE_DND_TARGET_DATA) == 0)
+    {
+      const guchar *data = gtk_selection_data_get_data (selection);
+      if (data)
+        return *((GObject **)data);
+    }
+  return NULL;
+}
+
+
+void
+_glade_dnd_set_data (GtkSelectionData *selection, GObject *data)
+{
+  static GdkAtom type = 0;
+
+  if (!type)
+    type = gdk_atom_intern_static_string (GLADE_DND_TARGET_DATA);
+
+  gtk_selection_data_set (selection, type, sizeof (gpointer),
+                          (const guchar *)&data,
+                          sizeof (gpointer));
+}
+
+static gboolean
+on_drag_icon_draw (GtkWidget *widget, cairo_t *cr)
+{
+  GtkStyleContext *context = gtk_widget_get_style_context (widget);
+  cairo_pattern_t *gradient;
+  GtkAllocation alloc;
+  gint x, y, w, h;
+  gdouble h2;
+  GdkRGBA bg;
+
+  /* Not needed acording to GtkWidget:draw documentation
+   * But seems like there is a bug when used as a drag_icon that makes the
+   * cairo translation used here persist when drawing children.
+   */
+  cairo_save (cr);
+
+  /* Clear BG */
+  cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
+  cairo_paint (cr);
+  cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
+
+  gtk_widget_get_allocation (widget, &alloc);
+  x = alloc.x;
+  y = alloc.y;
+  w = alloc.width;
+  h = alloc.height;
+  h2 = h/2.0;
+
+  gtk_style_context_get_background_color (context, GTK_STATE_NORMAL, &bg);
+
+  gradient = cairo_pattern_create_linear (x, y, x, y+h);
+  cairo_pattern_add_color_stop_rgba (gradient, 0, bg.red, bg.green, bg.blue, 0);
+  cairo_pattern_add_color_stop_rgba (gradient, .5, bg.red, bg.green, bg.blue, .8);
+  cairo_pattern_add_color_stop_rgba (gradient, 1, bg.red, bg.green, bg.blue, 0);
+
+  cairo_set_source (cr, gradient);
+  cairo_rectangle (cr, x+h2, y, w-h, h);
+  cairo_fill (cr);
+  cairo_pattern_destroy (gradient);
+
+  gradient = cairo_pattern_create_radial (x+h2, y+h2, 0, x+h2, y+h2, h2);
+  cairo_pattern_add_color_stop_rgba (gradient, 0, bg.red, bg.green, bg.blue, .8);
+  cairo_pattern_add_color_stop_rgba (gradient, 1, bg.red, bg.green, bg.blue, 0);
+
+  cairo_set_source (cr, gradient);
+  cairo_rectangle (cr, x, y, h2, h);
+  cairo_fill (cr);
+
+  cairo_translate (cr, w-h, 0);
+  cairo_set_source (cr, gradient);
+  cairo_rectangle (cr, x+h2, y, h2, h);
+  cairo_fill (cr);
+
+  cairo_pattern_destroy (gradient);
+  cairo_restore (cr);
+
+  return FALSE;
+}
+
+void
+_glade_dnd_set_icon_widget (GdkDragContext *context,
+                            const gchar *icon_name,
+                            const gchar *description)
+{
+  GtkWidget *window, *box, *label, *icon;
+  GdkScreen *screen;
+  GdkVisual *visual;
+
+  screen = gdk_window_get_screen (gdk_drag_context_get_source_window (context));
+  window = gtk_window_new (GTK_WINDOW_POPUP);
+
+  gtk_window_set_type_hint (GTK_WINDOW (window), GDK_WINDOW_TYPE_HINT_DND);
+  gtk_window_set_screen (GTK_WINDOW (window), screen);
+
+  box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 4);
+  gtk_container_set_border_width (GTK_CONTAINER (box), 12);
+
+  icon = gtk_image_new_from_icon_name (icon_name, GTK_ICON_SIZE_BUTTON);
+  gtk_widget_set_opacity (icon, .8);
+
+  label = gtk_label_new (description);
+
+  gtk_box_pack_start (GTK_BOX (box), icon, FALSE, TRUE, 0);
+  gtk_box_pack_start (GTK_BOX (box), label, FALSE, TRUE, 0);
+
+  gtk_widget_show_all (box);
+  gtk_container_add (GTK_CONTAINER (window), box);
+
+  if ((visual = gdk_screen_get_rgba_visual (screen)))
+    {
+      gtk_widget_set_visual (window, visual);
+      gtk_widget_set_app_paintable (window, TRUE);
+      g_signal_connect (window, "draw", G_CALLBACK (on_drag_icon_draw), NULL);
+    }
+
+  g_object_ref_sink (window);
+  gtk_drag_set_icon_widget (context, window, 0, 0);
+  g_object_unref (window);
+}