svgview.cpp Example File | Qt SVG 5.4

- Qt 5.4
- Qt SVG
- SVG Viewer Example
- svgview.cpp Example File
- Qt 5.4.2 Reference Documentation

# svgview.cpp Example File

svgviewer/svgview.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
    ** Contact: http://www.qt-project.org/legal
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
    ** met:
    **   * Redistributions of source code must retain the above copyright
    **     notice, this list of conditions and the following disclaimer.
    **   * Redistributions in binary form must reproduce the above copyright
    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
    **     of its contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
    **
    **
    ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
    **
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/
    #include "svgview.h"

    #include <QFile>
    #include <QWheelEvent>
    #include <QMouseEvent>
    #include <QGraphicsRectItem>
    #include <QGraphicsSvgItem>
    #include <QPaintEvent>
    #include <qmath.h>

    #ifndef QT_NO_OPENGL
    #include <QGLWidget>
    #endif

    SvgView::SvgView(QWidget *parent)
        : QGraphicsView(parent)
        , m_renderer(Native)
        , m_svgItem(0)
        , m_backgroundItem(0)
        , m_outlineItem(0)
    {
        setScene(new QGraphicsScene(this));
        setTransformationAnchor(AnchorUnderMouse);
        setDragMode(ScrollHandDrag);
        setViewportUpdateMode(FullViewportUpdate);

        // Prepare background check-board pattern
        QPixmap tilePixmap(64, 64);
        tilePixmap.fill(Qt::white);
        QPainter tilePainter(&tilePixmap);
        QColor color(220, 220, 220);
        tilePainter.fillRect(0, 0, 32, 32, color);
        tilePainter.fillRect(32, 32, 32, 32, color);
        tilePainter.end();

        setBackgroundBrush(tilePixmap);
    }

    void SvgView::drawBackground(QPainter *p, const QRectF &)
    {
        p->save();
        p->resetTransform();
        p->drawTiledPixmap(viewport()->rect(), backgroundBrush().texture());
        p->restore();
    }

    void SvgView::openFile(const QFile &file)
    {
        if (!file.exists())
            return;

        QGraphicsScene *s = scene();

        bool drawBackground = (m_backgroundItem ? m_backgroundItem->isVisible() : false);
        bool drawOutline = (m_outlineItem ? m_outlineItem->isVisible() : true);

        s->clear();
        resetTransform();

        m_svgItem = new QGraphicsSvgItem(file.fileName());
        m_svgItem->setFlags(QGraphicsItem::ItemClipsToShape);
        m_svgItem->setCacheMode(QGraphicsItem::NoCache);
        m_svgItem->setZValue(0);

        m_backgroundItem = new QGraphicsRectItem(m_svgItem->boundingRect());
        m_backgroundItem->setBrush(Qt::white);
        m_backgroundItem->setPen(Qt::NoPen);
        m_backgroundItem->setVisible(drawBackground);
        m_backgroundItem->setZValue(-1);

        m_outlineItem = new QGraphicsRectItem(m_svgItem->boundingRect());
        QPen outline(Qt::black, 2, Qt::DashLine);
        outline.setCosmetic(true);
        m_outlineItem->setPen(outline);
        m_outlineItem->setBrush(Qt::NoBrush);
        m_outlineItem->setVisible(drawOutline);
        m_outlineItem->setZValue(1);

        s->addItem(m_backgroundItem);
        s->addItem(m_svgItem);
        s->addItem(m_outlineItem);

        s->setSceneRect(m_outlineItem->boundingRect().adjusted(-10, -10, 10, 10));
    }

    void SvgView::setRenderer(RendererType type)
    {
        m_renderer = type;

        if (m_renderer == OpenGL) {
    #ifndef QT_NO_OPENGL
            setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers)));
    #endif
        } else {
            setViewport(new QWidget);
        }
    }

    void SvgView::setHighQualityAntialiasing(bool highQualityAntialiasing)
    {
    #ifndef QT_NO_OPENGL
        setRenderHint(QPainter::HighQualityAntialiasing, highQualityAntialiasing);
    #else
        Q_UNUSED(highQualityAntialiasing);
    #endif
    }

    void SvgView::setViewBackground(bool enable)
    {
        if (!m_backgroundItem)
              return;

        m_backgroundItem->setVisible(enable);
    }

    void SvgView::setViewOutline(bool enable)
    {
        if (!m_outlineItem)
            return;

        m_outlineItem->setVisible(enable);
    }

    void SvgView::paintEvent(QPaintEvent *event)
    {
        if (m_renderer == Image) {
            if (m_image.size() != viewport()->size()) {
                m_image = QImage(viewport()->size(), QImage::Format_ARGB32_Premultiplied);
            }

            QPainter imagePainter(&m_image);
            QGraphicsView::render(&imagePainter);
            imagePainter.end();

            QPainter p(viewport());
            p.drawImage(0, 0, m_image);

        } else {
            QGraphicsView::paintEvent(event);
        }
    }

    void SvgView::wheelEvent(QWheelEvent *event)
    {
        qreal factor = qPow(1.2, event->delta() / 240.0);
        scale(factor, factor);
        event->accept();
    }