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-rw-r--r--widgets/misc/e-canvas.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/widgets/misc/e-canvas.c b/widgets/misc/e-canvas.c
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--- /dev/null
+++ b/widgets/misc/e-canvas.c
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+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/*
+ * e-canvas.c
+ * Copyright (C) 2000 Helix Code, Inc.
+ * Author: Chris Lahey <clahey@helixcode.com>
+ *
+ * This library 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 2 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 library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <gnome.h>
+#include "e-canvas.h"
+static void e_canvas_init (ECanvas *card);
+static void e_canvas_class_init (ECanvasClass *klass);
+static gint e_canvas_key (GtkWidget *widget,
+ GdkEventKey *event);
+
+static int emit_event (GnomeCanvas *canvas, GdkEvent *event);
+
+static GnomeCanvasClass *parent_class = NULL;
+
+GtkType
+e_canvas_get_type (void)
+{
+ static GtkType canvas_type = 0;
+
+ if (!canvas_type)
+ {
+ static const GtkTypeInfo canvas_info =
+ {
+ "ECanvas",
+ sizeof (ECanvas),
+ sizeof (ECanvasClass),
+ (GtkClassInitFunc) e_canvas_class_init,
+ (GtkObjectInitFunc) e_canvas_init,
+ /* reserved_1 */ NULL,
+ /* reserved_2 */ NULL,
+ (GtkClassInitFunc) NULL,
+ };
+
+ canvas_type = gtk_type_unique (gnome_canvas_get_type (), &canvas_info);
+ }
+
+ return canvas_type;
+}
+
+static void
+e_canvas_class_init (ECanvasClass *klass)
+{
+ GtkObjectClass *object_class;
+ GnomeCanvasClass *canvas_class;
+ GtkWidgetClass *widget_class;
+
+ object_class = (GtkObjectClass*) klass;
+ canvas_class = (GnomeCanvasClass *) klass;
+ widget_class = (GtkWidgetClass *) klass;
+
+ parent_class = gtk_type_class (gnome_canvas_get_type ());
+
+ widget_class->key_press_event = e_canvas_key;
+ widget_class->key_release_event = e_canvas_key;
+}
+
+static void
+e_canvas_init (ECanvas *canvas)
+{
+}
+
+GtkWidget *
+e_canvas_new()
+{
+ return GTK_WIDGET (gtk_type_new (e_canvas_get_type ()));
+}
+
+
+/* Returns whether the item is an inferior of or is equal to the parent. */
+static int
+is_descendant (GnomeCanvasItem *item, GnomeCanvasItem *parent)
+{
+ for (; item; item = item->parent)
+ if (item == parent)
+ return TRUE;
+
+ return FALSE;
+}
+
+/* Emits an event for an item in the canvas, be it the current item, grabbed
+ * item, or focused item, as appropriate.
+ */
+static int
+emit_event (GnomeCanvas *canvas, GdkEvent *event)
+{
+ GdkEvent ev;
+ gint finished;
+ GnomeCanvasItem *item;
+ GnomeCanvasItem *parent;
+ guint mask;
+
+ /* Perform checks for grabbed items */
+
+ if (canvas->grabbed_item && !is_descendant (canvas->current_item, canvas->grabbed_item))
+ return FALSE;
+
+ if (canvas->grabbed_item) {
+ switch (event->type) {
+ case GDK_ENTER_NOTIFY:
+ mask = GDK_ENTER_NOTIFY_MASK;
+ break;
+
+ case GDK_LEAVE_NOTIFY:
+ mask = GDK_LEAVE_NOTIFY_MASK;
+ break;
+
+ case GDK_MOTION_NOTIFY:
+ mask = GDK_POINTER_MOTION_MASK;
+ break;
+
+ case GDK_BUTTON_PRESS:
+ case GDK_2BUTTON_PRESS:
+ case GDK_3BUTTON_PRESS:
+ mask = GDK_BUTTON_PRESS_MASK;
+ break;
+
+ case GDK_BUTTON_RELEASE:
+ mask = GDK_BUTTON_RELEASE_MASK;
+ break;
+
+ case GDK_KEY_PRESS:
+ mask = GDK_KEY_PRESS_MASK;
+ break;
+
+ case GDK_KEY_RELEASE:
+ mask = GDK_KEY_RELEASE_MASK;
+ break;
+
+ default:
+ mask = 0;
+ break;
+ }
+
+ if (!(mask & canvas->grabbed_event_mask))
+ return FALSE;
+ }
+
+ /* Convert to world coordinates -- we have two cases because of diferent
+ * offsets of the fields in the event structures.
+ */
+
+ ev = *event;
+
+ switch (ev.type) {
+ case GDK_ENTER_NOTIFY:
+ case GDK_LEAVE_NOTIFY:
+ gnome_canvas_window_to_world (canvas,
+ ev.crossing.x, ev.crossing.y,
+ &ev.crossing.x, &ev.crossing.y);
+ break;
+
+ case GDK_MOTION_NOTIFY:
+ case GDK_BUTTON_PRESS:
+ case GDK_2BUTTON_PRESS:
+ case GDK_3BUTTON_PRESS:
+ case GDK_BUTTON_RELEASE:
+ gnome_canvas_window_to_world (canvas,
+ ev.motion.x, ev.motion.y,
+ &ev.motion.x, &ev.motion.y);
+ break;
+
+ default:
+ break;
+ }
+
+ /* Choose where we send the event */
+
+ item = canvas->current_item;
+
+ if (canvas->focused_item
+ && ((event->type == GDK_KEY_PRESS) || (event->type == GDK_KEY_RELEASE) || (event->type == GDK_FOCUS_CHANGE)))
+ item = canvas->focused_item;
+
+ /* The event is propagated up the hierarchy (for if someone connected to
+ * a group instead of a leaf event), and emission is stopped if a
+ * handler returns TRUE, just like for GtkWidget events.
+ */
+
+ finished = FALSE;
+
+ while (item && !finished) {
+ gtk_object_ref (GTK_OBJECT (item));
+
+ gtk_signal_emit_by_name (GTK_OBJECT (item), "event",
+ &ev,
+ &finished);
+
+ if (GTK_OBJECT_DESTROYED (item))
+ finished = TRUE;
+
+ parent = item->parent;
+ gtk_object_unref (GTK_OBJECT (item));
+
+ item = parent;
+ }
+
+ return finished;
+}
+
+/* Key event handler for the canvas */
+static gint
+e_canvas_key (GtkWidget *widget, GdkEventKey *event)
+{
+ GnomeCanvas *canvas;
+
+ g_return_val_if_fail (widget != NULL, FALSE);
+ g_return_val_if_fail (GNOME_IS_CANVAS (widget), FALSE);
+ g_return_val_if_fail (event != NULL, FALSE);
+
+ canvas = GNOME_CANVAS (widget);
+
+ return emit_event (canvas, (GdkEvent *) event);
+}
+