svgview.cpp Example File

svgviewer/svgview.cpp
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** Copyright (C) 2015 The Qt Company Ltd.
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** This file is part of the examples of the Qt Toolkit.
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#include "svgview.h"

#include <QSvgRenderer>

#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(nullptr)
    , m_backgroundItem(nullptr)
    , m_outlineItem(nullptr)
{
    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();
}

QSize SvgView::svgSize() const
{
    return m_svgItem ? m_svgItem->boundingRect().size().toSize() : QSize();
}

bool SvgView::openFile(const QString &fileName)
{
    QGraphicsScene *s = scene();

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

    QScopedPointer<QGraphicsSvgItem> svgItem(new QGraphicsSvgItem(fileName));
    if (!svgItem->renderer()->isValid())
        return false;

    s->clear();
    resetTransform();

    m_svgItem = svgItem.take();
    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));
    return true;
}

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();
}

QSvgRenderer *SvgView::renderer() const
{
    if (m_svgItem)
        return m_svgItem->renderer();
    return nullptr;
}

© 2017 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.