embeddedsvgviewer.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see http://www.qt.io/terms-conditions. For further
 ** information use the contact form at http://www.qt.io/contact-us.
 **
 ** 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 or version 3 as published by the Free
 ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
 ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
 ** following information to ensure the GNU Lesser General Public License
 ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** As a special exception, The Qt Company gives you certain additional
 ** rights. These rights are described in The Qt Company LGPL Exception
 ** version 1.1, 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.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QPainter>
 #include <QApplication>

 #include "embeddedsvgviewer.h"

 EmbeddedSvgViewer::EmbeddedSvgViewer(const QString &filePath)
 {
     qApp->setStyleSheet(" QSlider:vertical { width: 50px; } \
                           QSlider::groove:vertical { border: 1px solid black; border-radius: 3px; width: 6px; } \
                           QSlider::handle:vertical { height: 25px; margin: 0 -22px; image: url(':/files/v-slider-handle.svg'); } \
                        ");

     m_renderer = new QSvgRenderer(filePath);
     m_imageSize = m_renderer->viewBox().size();

     m_viewBoxCenter = (QPointF(m_imageSize.width() / qreal(2.0), m_imageSize.height() / qreal(2.0)));

     m_zoomSlider = new QSlider(Qt::Vertical, this);
     m_zoomSlider->setMaximum(150);
     m_zoomSlider->setMinimum(1);

     connect(m_zoomSlider, SIGNAL(valueChanged(int)), this, SLOT(setZoom(int)));
     m_zoomSlider->setValue(100);

     m_quitButton = new QPushButton("Quit", this);

     connect(m_quitButton, SIGNAL(pressed()), QApplication::instance(), SLOT(quit()));

     if (m_renderer->animated())
         connect(m_renderer, SIGNAL(repaintNeeded()), this, SLOT(update()));

 }

 void EmbeddedSvgViewer::paintEvent(QPaintEvent *event)
 {
     Q_UNUSED(event)
     QPainter painter(this);
     m_renderer->setViewBox(m_viewBox);
     m_renderer->render(&painter);
 }

 void EmbeddedSvgViewer::mouseMoveEvent ( QMouseEvent * event )
 {
     int incX = int((event->globalX() - m_mousePress.x()) * m_imageScale);
     int incY = int((event->globalY() - m_mousePress.y()) * m_imageScale);

     QPointF newCenter;
     newCenter.setX(m_viewBoxCenterOnMousePress.x() - incX);
     newCenter.setY(m_viewBoxCenterOnMousePress.y() - incY);

     QRectF newViewBox = getViewBox(newCenter);

     // Do a bounded move on the horizontal:
     if ( (newViewBox.left() >= m_viewBoxBounds.left()) &&
          (newViewBox.right() <= m_viewBoxBounds.right()) )
     {
         m_viewBoxCenter.setX(newCenter.x());
         m_viewBox.setLeft(newViewBox.left());
         m_viewBox.setRight(newViewBox.right());
     }

     // do a bounded move on the vertical:
     if (  (newViewBox.top() >= m_viewBoxBounds.top()) &&
           (newViewBox.bottom() <= m_viewBoxBounds.bottom()) )
     {
         m_viewBoxCenter.setY(newCenter.y());
         m_viewBox.setTop(newViewBox.top());
         m_viewBox.setBottom(newViewBox.bottom());
     }

     update();
 }

 void EmbeddedSvgViewer::mousePressEvent ( QMouseEvent * event )
 {
     m_viewBoxCenterOnMousePress = m_viewBoxCenter;
     m_mousePress = event->globalPos();
 }

 QRectF EmbeddedSvgViewer::getViewBox(QPointF viewBoxCenter)
 {
     QRectF result;
     result.setLeft(viewBoxCenter.x() - (m_viewBoxSize.width() / 2));
     result.setTop(viewBoxCenter.y() - (m_viewBoxSize.height() / 2));
     result.setRight(viewBoxCenter.x() + (m_viewBoxSize.width() / 2));
     result.setBottom(viewBoxCenter.y() + (m_viewBoxSize.height() / 2));
     return result;
 }

 void EmbeddedSvgViewer::updateImageScale()
 {
     m_imageScale = qMax( (qreal)m_imageSize.width() / (qreal)width(),
                                (qreal)m_imageSize.height() / (qreal)height())*m_zoomLevel;

     m_viewBoxSize.setWidth((qreal)width() * m_imageScale);
     m_viewBoxSize.setHeight((qreal)height() * m_imageScale);
 }

 void EmbeddedSvgViewer::resizeEvent ( QResizeEvent * /* event */ )
 {
     qreal origZoom = m_zoomLevel;

     // Get the new bounds:
     m_zoomLevel = 1.0;
     updateImageScale();
     m_viewBoxBounds = getViewBox(QPointF(m_imageSize.width() / 2.0, m_imageSize.height() / 2.0));

     m_zoomLevel = origZoom;
     updateImageScale();
     m_viewBox = getViewBox(m_viewBoxCenter);

     QRect sliderRect;
     sliderRect.setLeft(width() - m_zoomSlider->sizeHint().width());
     sliderRect.setRight(width());
     sliderRect.setTop(height()/4);
     sliderRect.setBottom(height() - (height()/4));
     m_zoomSlider->setGeometry(sliderRect);
 }

 void EmbeddedSvgViewer::setZoom(int newZoom)
 {
     m_zoomLevel = qreal(newZoom) / qreal(100);

     updateImageScale();
     m_viewBox = getViewBox(m_viewBoxCenter);

     update();
 }