Doc: Moving the Image Gestures example.

Reviewed-by: Trust Me

1 files changed, 268 insertions, 0 deletions

diff --git a/examples/gestures/imagegestures/imagewidget.cpp b/examples/gestures/imagegestures/imagewidget.cpp
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+++ b/examples/gestures/imagegestures/imagewidget.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (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 Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "imagewidget.h"
+
+#include <QtGui>
+
+ImageWidget::ImageWidget(QWidget *parent)
+    : QWidget(parent),
+    position(0),
+    horizontalOffset(0),
+    verticalOffset(0),
+    rotationAngle(0),
+    scaleFactor(1)
+
+{
+    setObjectName("ImageWidget");
+    setMinimumSize(QSize(100,100));
+
+    setAttribute(Qt::WA_PaintOnScreen);
+    setAttribute(Qt::WA_OpaquePaintEvent);
+    setAttribute(Qt::WA_NoSystemBackground);
+
+//! [enable gestures]
+    grabGesture(Qt::PanGesture);
+    grabGesture(Qt::PinchGesture);
+    grabGesture(Qt::SwipeGesture);
+//! [enable gestures]
+}
+
+//! [event handler]
+bool ImageWidget::event(QEvent *event)
+{
+    if (event->type() == QEvent::Gesture)
+        return gestureEvent(static_cast<QGestureEvent*>(event));
+    return QWidget::event(event);
+}
+//! [event handler]
+
+void ImageWidget::paintEvent(QPaintEvent*)
+{
+    QPainter p(this);
+    p.fillRect(rect(), Qt::white);
+
+    float iw = currentImage.width();
+    float ih = currentImage.height();
+    float wh = height();
+    float ww = width();
+
+    p.translate(ww/2, wh/2);
+    p.translate(horizontalOffset, verticalOffset);
+    p.rotate(rotationAngle);
+    p.scale(scaleFactor, scaleFactor);
+    p.translate(-iw/2, -ih/2);
+    p.drawImage(0, 0, currentImage);
+}
+
+void ImageWidget::mouseDoubleClickEvent(QMouseEvent *)
+{
+    rotationAngle = 0;
+    scaleFactor = 1;
+    verticalOffset = 0;
+    horizontalOffset = 0;
+    update();
+}
+
+//! [gesture event handler]
+bool ImageWidget::gestureEvent(QGestureEvent *event)
+{
+    if (QGesture *pan = event->gesture(Qt::PanGesture)) {
+        panTriggered(static_cast<QPanGesture*>(pan));
+        return true;
+    } else if (QGesture *pinch = event->gesture(Qt::PinchGesture)) {
+        pinchTriggered(static_cast<QPinchGesture*>(pinch));
+        return true;
+    } else if (QGesture *swipe = event->gesture(Qt::SwipeGesture)) {
+        swipeTriggered(static_cast<QSwipeGesture*>(swipe));
+        return true;
+    }
+    return false;
+}
+//! [gesture event handler]
+
+void ImageWidget::panTriggered(QPanGesture *gesture)
+{
+#ifndef QT_NO_CURSOR
+    switch (gesture->state()) {
+        case Qt::GestureStarted:
+        case Qt::GestureUpdated:
+            setCursor(Qt::SizeAllCursor);
+            break;
+        default:
+            setCursor(Qt::ArrowCursor);
+    }
+#endif
+    QSizeF lastOffset = gesture->offset();
+    horizontalOffset += lastOffset.width();
+    verticalOffset += lastOffset.height();
+    update();
+}
+
+void ImageWidget::pinchTriggered(QPinchGesture *gesture)
+{
+    QPinchGesture::WhatChanged whatChanged = gesture->whatChanged();
+    if (whatChanged & QPinchGesture::RotationAngleChanged) {
+        qreal value = gesture->property("rotationAngle").toReal();
+        qreal lastValue = gesture->property("lastRotationAngle").toReal();
+        rotationAngle += value - lastValue;
+    }
+    if (whatChanged & QPinchGesture::ScaleFactorChanged) {
+        qreal value = gesture->property("scaleFactor").toReal();
+        qreal lastValue = gesture->property("lastScaleFactor").toReal();
+        scaleFactor += value - lastValue;
+    }
+    update();
+}
+
+//! [swipe function]
+void ImageWidget::swipeTriggered(QSwipeGesture *gesture)
+{
+    if (gesture->horizontalDirection() == QSwipeGesture::Left
+            || gesture->verticalDirection() == QSwipeGesture::Up)
+        goPrevImage();
+    else
+        goNextImage();
+    update();
+}
+//! [swipe function]
+
+void ImageWidget::resizeEvent(QResizeEvent*)
+{
+    update();
+}
+
+void ImageWidget::openDirectory(const QString &path)
+{
+    this->path = path;
+    QDir dir(path);
+    QStringList nameFilters;
+    nameFilters << "*.jpg" << "*.png";
+    files = dir.entryList(nameFilters, QDir::Files|QDir::Readable, QDir::Name);
+
+    position = 0;
+    goToImage(0);
+    update();
+}
+
+QImage ImageWidget::loadImage(const QString &fileName)
+{
+    QImageReader reader(fileName);
+    if (!reader.canRead()) {
+        qDebug() << fileName << ": can't load image";
+        return QImage();
+    }
+
+    QImage image;
+    if (!reader.read(&image)) {
+        qDebug() << fileName << ": corrupted image";
+        return QImage();
+    }
+    return image;
+}
+
+void ImageWidget::goNextImage()
+{
+    if (files.isEmpty())
+        return;
+
+    if (position < files.size()-1) {
+        ++position;
+        prevImage = currentImage;
+        currentImage = nextImage;
+        if (position+1 < files.size())
+            nextImage = loadImage(path+QLatin1String("/")+files.at(position+1));
+        else
+            nextImage = QImage();
+    }
+    update();
+}
+
+void ImageWidget::goPrevImage()
+{
+    if (files.isEmpty())
+        return;
+
+    if (position > 0) {
+        --position;
+        nextImage = currentImage;
+        currentImage = prevImage;
+        if (position > 0)
+            prevImage = loadImage(path+QLatin1String("/")+files.at(position-1));
+        else
+            prevImage = QImage();
+    }
+    update();
+}
+
+void ImageWidget::goToImage(int index)
+{
+    if (files.isEmpty())
+        return;
+
+    if (index < 0 || index >= files.size()) {
+        qDebug() << "goToImage: invalid index: " << index;
+        return;
+    }
+
+    if (index == position+1) {
+        goNextImage();
+        return;
+    }
+
+    if (position > 0 && index == position-1) {
+        goPrevImage();
+        return;
+    }
+
+    position = index;
+
+    if (index > 0)
+        prevImage = loadImage(path+QLatin1String("/")+files.at(position-1));
+    else
+        prevImage = QImage();
+    currentImage = loadImage(path+QLatin1String("/")+files.at(position));
+    if (position+1 < files.size())
+        nextImage = loadImage(path+QLatin1String("/")+files.at(position+1));
+    else
+        nextImage = QImage();
+    update();
+}