2012-08-31 13:57:06 +02:00
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/*
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* Copyright (C) 2012, One Laptop Per Child.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Author(s): Carlos Garnacho <carlos@lanedo.com>
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*/
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#include <math.h>
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#include "sugar-zoom-controller.h"
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typedef struct _SugarZoomControllerPriv SugarZoomControllerPriv;
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typedef struct _SugarTouch SugarTouch;
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enum {
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ZOOM_CHANGED,
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LAST_SIGNAL
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};
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struct _SugarTouch
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{
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GdkEventSequence *sequence;
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gint x;
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gint y;
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guint set : 1;
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};
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struct _SugarZoomControllerPriv
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{
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GdkDevice *device;
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SugarTouch touches[2];
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gdouble initial_distance;
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};
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static guint signals[LAST_SIGNAL] = { 0 };
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G_DEFINE_TYPE (SugarZoomController,
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sugar_zoom_controller,
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SUGAR_TYPE_EVENT_CONTROLLER)
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static void
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sugar_zoom_controller_init (SugarZoomController *controller)
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{
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controller->_priv = G_TYPE_INSTANCE_GET_PRIVATE (controller,
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SUGAR_TYPE_ZOOM_CONTROLLER,
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SugarZoomControllerPriv);
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}
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static void
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sugar_zoom_controller_finalize (GObject *object)
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{
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G_OBJECT_CLASS (sugar_zoom_controller_parent_class)->finalize (object);
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}
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static SugarTouch *
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_sugar_zoom_controller_find_touch (SugarZoomController *controller,
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GdkEventSequence *sequence)
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{
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SugarZoomControllerPriv *priv;
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gint unset = -1, i;
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priv = controller->_priv;
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for (i = 0; i < 2; i++)
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{
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if (priv->touches[i].sequence == sequence)
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return &priv->touches[i];
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else if (!priv->touches[i].set && unset < 0)
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unset = i;
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}
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if (unset < 0)
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return NULL;
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priv->touches[unset].sequence = sequence;
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priv->touches[unset].set = TRUE;
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return &priv->touches[unset];
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}
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static gboolean
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_sugar_zoom_controller_get_distance (SugarZoomController *controller,
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gdouble *distance)
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{
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SugarZoomControllerPriv *priv;
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gdouble dx, dy;
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priv = controller->_priv;
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if (!priv->touches[0].set || !priv->touches[1].set)
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return FALSE;
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dx = priv->touches[0].x - priv->touches[1].x;
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dy = priv->touches[0].y - priv->touches[1].y;
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*distance = sqrt ((dx * dx) + (dy * dy));
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return TRUE;
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}
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static gboolean
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_sugar_zoom_controller_check_emit (SugarZoomController *controller)
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{
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SugarZoomControllerPriv *priv;
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gdouble distance, zoom;
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if (!_sugar_zoom_controller_get_distance (controller, &distance))
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return FALSE;
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priv = controller->_priv;
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if (distance == 0 || priv->initial_distance == 0)
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return FALSE;
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zoom = distance / priv->initial_distance;
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g_signal_emit (controller, signals[ZOOM_CHANGED], 0, zoom);
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return TRUE;
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}
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static gboolean
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sugar_zoom_controller_handle_event (SugarEventController *controller,
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GdkEvent *event)
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{
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SugarZoomControllerPriv *priv;
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GdkEventSequence *sequence;
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gboolean handled = TRUE;
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GdkDevice *device;
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SugarTouch *touch;
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priv = SUGAR_ZOOM_CONTROLLER (controller)->_priv;
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device = gdk_event_get_device (event);
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sequence = gdk_event_get_event_sequence (event);
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if (priv->device && priv->device != device)
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return FALSE;
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touch = _sugar_zoom_controller_find_touch (SUGAR_ZOOM_CONTROLLER (controller),
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sequence);
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if (!touch)
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return FALSE;
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switch (event->type)
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{
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case GDK_TOUCH_BEGIN:
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touch->x = event->touch.x;
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touch->y = event->touch.y;
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if (!priv->device)
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priv->device = g_object_ref (device);
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if (priv->touches[0].set && priv->touches[1].set)
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{
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_sugar_zoom_controller_get_distance (SUGAR_ZOOM_CONTROLLER (controller),
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&priv->initial_distance);
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2012-09-13 14:29:32 +02:00
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g_signal_emit_by_name (G_OBJECT (controller), "began");
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2012-08-31 13:57:06 +02:00
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g_object_notify (G_OBJECT (controller), "state");
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}
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break;
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case GDK_TOUCH_END:
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touch->sequence = NULL;
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touch->set = FALSE;
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if (!priv->touches[0].set && !priv->touches[1].set)
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{
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g_object_unref (priv->device);
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priv->device = NULL;
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}
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else if (!priv->touches[0].set || priv->touches[1].set)
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{
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2012-09-13 14:29:32 +02:00
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g_signal_emit_by_name (G_OBJECT (controller), "ended");
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2012-08-31 13:57:06 +02:00
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g_object_notify (G_OBJECT (controller), "state");
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}
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break;
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case GDK_TOUCH_UPDATE:
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touch->x = event->touch.x;
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touch->y = event->touch.y;
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_sugar_zoom_controller_check_emit (SUGAR_ZOOM_CONTROLLER (controller));
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break;
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default:
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handled = FALSE;
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break;
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}
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return handled;
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}
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SugarEventControllerState
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sugar_zoom_controller_get_state (SugarEventController *controller)
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{
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SugarZoomControllerPriv *priv;
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priv = SUGAR_ZOOM_CONTROLLER (controller)->_priv;
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if (priv->device)
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{
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if (priv->touches[0].set && priv->touches[1].set)
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return SUGAR_EVENT_CONTROLLER_STATE_RECOGNIZED;
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else if (priv->touches[0].set || priv->touches[1].set)
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return SUGAR_EVENT_CONTROLLER_STATE_COLLECTING;
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}
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return SUGAR_EVENT_CONTROLLER_STATE_NONE;
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}
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void
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sugar_zoom_controller_reset (SugarEventController *controller)
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{
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SugarZoomControllerPriv *priv;
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priv = SUGAR_ZOOM_CONTROLLER (controller)->_priv;
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if (priv->touches[0].set && priv->touches[1].set)
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2012-09-13 14:29:32 +02:00
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g_signal_emit_by_name (G_OBJECT (controller), "ended");
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2012-08-31 13:57:06 +02:00
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priv->touches[0].sequence = NULL;
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priv->touches[0].set = FALSE;
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priv->touches[1].sequence = NULL;
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priv->touches[1].set = FALSE;
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if (priv->device)
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{
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g_object_unref (priv->device);
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priv->device = NULL;
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}
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g_object_notify (G_OBJECT (controller), "state");
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}
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static void
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sugar_zoom_controller_class_init (SugarZoomControllerClass *klass)
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{
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SugarEventControllerClass *controller_class;
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GObjectClass *object_class;
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object_class = G_OBJECT_CLASS (klass);
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object_class->finalize = sugar_zoom_controller_finalize;
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controller_class = SUGAR_EVENT_CONTROLLER_CLASS (klass);
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controller_class->handle_event = sugar_zoom_controller_handle_event;
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controller_class->get_state = sugar_zoom_controller_get_state;
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controller_class->reset = sugar_zoom_controller_reset;
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2012-08-31 14:23:35 +02:00
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/**
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* SugarZoomController::zoom-changed:
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* @controller: the object on which the signal is emitted
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* @delta: Difference with the starting zooming state
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*/
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2012-08-31 13:57:06 +02:00
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signals[ZOOM_CHANGED] =
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g_signal_new ("zoom-changed",
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SUGAR_TYPE_ZOOM_CONTROLLER,
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G_SIGNAL_RUN_FIRST,
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G_STRUCT_OFFSET (SugarZoomControllerClass, zoom_changed),
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NULL, NULL,
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g_cclosure_marshal_VOID__DOUBLE,
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G_TYPE_NONE, 1,
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G_TYPE_DOUBLE);
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g_type_class_add_private (klass, sizeof (SugarZoomControllerPriv));
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}
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SugarEventController *
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sugar_zoom_controller_new (void)
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{
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return g_object_new (SUGAR_TYPE_ZOOM_CONTROLLER, NULL);
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}
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2012-08-31 14:23:35 +02:00
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/**
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* sugar_zoom_controller_get_zoom_delta:
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* @controller: a #SugarZoomController
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* @delta: (out) (transfer none): zoom delta
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*
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* If @controller is on state %SUGAR_EVENT_CONTROLLER_STATE_RECOGNIZED,
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* this function returns %TRUE and fills in @delta with the zooming
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* difference since the gesture was recognized (hence the starting point
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* is considered 1x).
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*
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* Returns: %TRUE if @controller is recognizing a zoom gesture
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**/
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2012-08-31 13:57:06 +02:00
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gboolean
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sugar_zoom_controller_get_zoom_delta (SugarZoomController *controller,
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gdouble *delta)
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{
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SugarZoomControllerPriv *priv;
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gdouble distance;
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g_return_val_if_fail (SUGAR_IS_ZOOM_CONTROLLER (controller), FALSE);
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if (!_sugar_zoom_controller_get_distance (controller, &distance))
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return FALSE;
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priv = controller->_priv;
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if (delta)
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*delta = distance / priv->initial_distance;
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return TRUE;
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}
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