add a multitouch example that shows how to handle multitouch events in QGraphicsItems

1 files changed, 93 insertions, 0 deletions

diff --git a/examples/multitouch/knobs/knob.cpp b/examples/multitouch/knobs/knob.cpp
new file mode 100644
index 0000000..4622f69
--- /dev/null
+++ b/examples/multitouch/knobs/knob.cpp
@@ -0,0 +1,93 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the $MODULE$ of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Commercial License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Nokia.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "knob.h"
+
+#include <QBrush>
+#include <QGraphicsSceneTouchEvent>
+
+Knob::Knob()
+    : QGraphicsEllipseItem(-50, -50, 100, 100)
+{
+    setAcceptTouchEvents(true);
+    setBrush(Qt::lightGray);
+
+    QGraphicsEllipseItem *leftItem = new QGraphicsEllipseItem(0, 0, 10, 10, this);
+    leftItem->setPos(-45, -5);
+    leftItem->setBrush(Qt::darkGreen);
+
+    QGraphicsEllipseItem *rightItem = new QGraphicsEllipseItem(0, 0, 10, 10, this);
+    rightItem->setPos(35, -5);
+    rightItem->setBrush(Qt::darkRed);
+}
+
+bool Knob::sceneEvent(QEvent *event)
+{
+    switch (event->type()) {
+    case QEvent::GraphicsSceneTouchBegin:
+        event->accept();
+        break;
+
+    case QEvent::GraphicsSceneTouchUpdate:
+    case QEvent::GraphicsSceneTouchEnd:
+    {
+        QGraphicsSceneTouchEvent *touchEvent = static_cast<QGraphicsSceneTouchEvent *>(event);
+
+        if (touchEvent->touchPoints().count() == 2) {
+            QGraphicsSceneTouchEvent::TouchPoint *touchPoint1 = touchEvent->touchPoints().first();
+            QGraphicsSceneTouchEvent::TouchPoint *touchPoint2 = touchEvent->touchPoints().last();
+
+            QLineF line1(touchPoint1->lastScenePos(), touchPoint2->lastScenePos());
+            QLineF line2(touchPoint1->scenePos(), touchPoint2->scenePos());
+
+            rotate(line2.angleTo(line1));
+        }
+
+        touchEvent->accept();
+        break;
+    }
+
+    default:
+        return QGraphicsItem::sceneEvent(event);
+    }
+
+    return true;
+}