svgview.cpp Example File

/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** 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 https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, 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 The Qt Company Ltd 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 <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;
}