Qt Reference Documentation

# embeddedsvgviewer.cpp Example File

demos/embedded/embeddedsvgviewer/embeddedsvgviewer.cpp

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     ** This file is part of the demonstration applications of the Qt Toolkit.
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     #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();
     }