First example using QGraphicsEffect class: drop shadows on items.

The shadow is casted from a moving light source. The shadow
offset for each item is different, depending on the relative
position of the item to the light source. The same goes for the
shadow opacity.

7 files changed, 403 insertions, 0 deletions

diff --git a/examples/graphicsview/graphicsview.pro b/examples/graphicsview/graphicsview.pro
index 66eb0b4..7e372fa 100644
--- a/examples/graphicsview/graphicsview.pro
+++ b/examples/graphicsview/graphicsview.pro
@@ -6,6 +6,7 @@ SUBDIRS       = \
               diagramscene \
               dragdroprobot \
               padnavigator \
+              lighting \
               basicgraphicslayouts
 
 contains(QT_CONFIG, qt3support):SUBDIRS += portedcanvas portedasteroids
diff --git a/examples/graphicsview/lighting/lighting.cpp b/examples/graphicsview/lighting/lighting.cpp
new file mode 100644
index 0000000..f92e428
--- /dev/null
+++ b/examples/graphicsview/lighting/lighting.cpp
@@ -0,0 +1,126 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 "lighting.h"
+
+#include <QtGui>
+
+#include "shadoweffect.h"
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+Lighting::Lighting(QWidget *parent): QGraphicsView(parent), angle(0.0)
+{
+    setScene(&m_scene);
+
+    setupScene();
+
+    QTimer *timer = new QTimer(this);
+    connect(timer, SIGNAL(timeout()), SLOT(animate()));
+    timer->setInterval(30);
+    timer->start();
+
+    setRenderHint(QPainter::Antialiasing, true);
+    setFrameStyle(QFrame::NoFrame);
+}
+
+Lighting::~Lighting()
+{
+    delete m_shadowEffect;
+}
+
+void Lighting::setupScene()
+{
+    m_scene.setSceneRect(-300, -200, 600, 460);
+
+    QLinearGradient linearGrad(QPointF(-100, -100), QPointF(100, 100));
+    linearGrad.setColorAt(0, QColor(255, 255, 255));
+    linearGrad.setColorAt(1, QColor(192, 192, 255));
+    setBackgroundBrush(linearGrad);
+
+    QRadialGradient radialGrad(30, 30, 30);
+    radialGrad.setColorAt(0, Qt::yellow);
+    radialGrad.setColorAt(0.2, Qt::yellow);
+    radialGrad.setColorAt(1, Qt::transparent);
+    QPixmap pixmap(60, 60);
+    pixmap.fill(Qt::transparent);
+    QPainter painter(&pixmap);
+    painter.setPen(Qt::NoPen);
+    painter.setBrush(radialGrad);
+    painter.drawEllipse(0, 0, 60, 60);
+    painter.end();
+
+    m_lightSource = m_scene.addPixmap(pixmap);
+    m_lightSource->setZValue(2);
+
+    m_shadowEffect = new ShadowEffect(m_lightSource);
+
+    for (int i = -2; i < 3; ++i)
+        for (int j = -2; j < 3; ++j) {
+            QAbstractGraphicsShapeItem *item;
+            if ((i + j) & 1)
+                item = new QGraphicsEllipseItem(0, 0, 50, 50);
+            else
+                item = new QGraphicsRectItem(0, 0, 50, 50);
+
+            item->setPen(QPen(Qt::black));
+            item->setBrush(QBrush(Qt::white));
+            item->setEffect(m_shadowEffect);
+            item->setZValue(1);
+            item->setPos(i * 80, j * 80);
+            m_scene.addItem(item);
+            m_items << item;
+        }
+
+
+}
+
+void Lighting::animate()
+{
+    angle += (M_PI / 30);
+    qreal xs = 200 * sin(angle) - 40 + 25;
+    qreal ys = 200 * cos(angle) - 40 + 25;
+    m_lightSource->setPos(xs, ys);
+    m_scene.update();
+}
+
diff --git a/examples/graphicsview/lighting/lighting.h b/examples/graphicsview/lighting/lighting.h
new file mode 100644
index 0000000..0334d10
--- /dev/null
+++ b/examples/graphicsview/lighting/lighting.h
@@ -0,0 +1,72 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef LIGHTING_H
+#define LIGHTING_H
+
+#include <QGraphicsEffect>
+#include <QGraphicsView>
+
+#include "shadoweffect.h"
+
+class Lighting: public QGraphicsView
+{
+    Q_OBJECT
+
+public:
+    Lighting(QWidget *parent = 0);
+    ~Lighting();
+
+private slots:
+    void animate();
+
+private:
+    void setupScene();
+
+private:
+    qreal angle;
+    QGraphicsScene m_scene;
+    QGraphicsItem *m_lightSource;
+    ShadowEffect *m_shadowEffect;
+    QList<QGraphicsItem*> m_items;
+};
+
+#endif // LIGHTING_H
diff --git a/examples/graphicsview/lighting/lighting.pro b/examples/graphicsview/lighting/lighting.pro
new file mode 100644
index 0000000..440bb53
--- /dev/null
+++ b/examples/graphicsview/lighting/lighting.pro
@@ -0,0 +1,8 @@
+SOURCES += main.cpp lighting.cpp shadoweffect.cpp
+HEADERS += lighting.h shadoweffect.h
+
+# install
+target.path = $$[QT_INSTALL_EXAMPLES]/graphicsview/lighting
+sources.files = $$SOURCES $$HEADERS $$RESOURCES $$FORMS lighting.pro
+sources.path = $$[QT_INSTALL_EXAMPLES]/graphicsview/lighting
+INSTALLS += target sources
diff --git a/examples/graphicsview/lighting/main.cpp b/examples/graphicsview/lighting/main.cpp
new file mode 100644
index 0000000..07415f6
--- /dev/null
+++ b/examples/graphicsview/lighting/main.cpp
@@ -0,0 +1,55 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 "lighting.h"
+#include <QApplication>
+
+int main(int argc, char **argv)
+{
+    QApplication app(argc, argv);
+
+    Lighting lighting;
+    lighting.setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Lighting and Shadows"));
+    lighting.resize(640, 480);
+    lighting.show();
+
+    return app.exec();
+}
diff --git a/examples/graphicsview/lighting/shadoweffect.cpp b/examples/graphicsview/lighting/shadoweffect.cpp
new file mode 100644
index 0000000..c1d384a
--- /dev/null
+++ b/examples/graphicsview/lighting/shadoweffect.cpp
@@ -0,0 +1,75 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 "shadoweffect.h"
+
+#include <math.h>
+
+ShadowEffect::ShadowEffect(QGraphicsItem *source)
+    : QGraphicsShadowEffect()
+    , m_lightSource(source)
+{
+    setBlurRadius(8);
+}
+
+void ShadowEffect::adjustForItem(const QGraphicsItem *item)
+{
+    QPointF delta = item->pos() - m_lightSource->pos();
+    setShadowOffset(delta.toPoint() / 30);
+
+    qreal dx = delta.x();
+    qreal dy = delta.y();
+    qreal dd = sqrt(dx * dx + dy * dy);
+    setOpacity(qBound(0.4, 1 - dd / 200.0, 0.7));
+}
+
+QRectF ShadowEffect::boundingRectFor(const QGraphicsItem *item)
+{
+    adjustForItem(item);
+    return QGraphicsShadowEffect::boundingRectFor(item);
+}
+
+void ShadowEffect::drawItem(QGraphicsItem *item, QPainter *painter,
+                                       const QStyleOptionGraphicsItem *option, QWidget *widget)
+{
+    adjustForItem(item);
+    QGraphicsShadowEffect::drawItem(item, painter, option, widget);
+}
diff --git a/examples/graphicsview/lighting/shadoweffect.h b/examples/graphicsview/lighting/shadoweffect.h
new file mode 100644
index 0000000..09b63e3
--- /dev/null
+++ b/examples/graphicsview/lighting/shadoweffect.h
@@ -0,0 +1,66 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef SHADOWEFFECT_H
+#define SHADOWEFFECT_H
+
+#include <QGraphicsEffect>
+#include <QGraphicsItem>
+
+class ShadowEffect: public QGraphicsShadowEffect
+{
+public:
+    ShadowEffect(QGraphicsItem *source);
+
+    QRectF boundingRectFor(const QGraphicsItem *item);
+
+    void drawItem(QGraphicsItem *item, QPainter *painter,
+                  const QStyleOptionGraphicsItem *option = 0,
+                  QWidget *widget = 0);
+
+private:
+    void adjustForItem(const QGraphicsItem *item);
+
+private:
+    QGraphicsItem *m_lightSource;
+};
+
+#endif // SHADOWEFFECT_H