svgview.cpp Example File
svgviewer/svgview.cpp
#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);
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);
}
qreal SvgView::zoomFactor() const
{
return transform().m11();
}
void SvgView::zoomIn()
{
zoomBy(2);
}
void SvgView::zoomOut()
{
zoomBy(0.5);
}
void SvgView::resetZoom()
{
if (!qFuzzyCompare(zoomFactor(), qreal(1))) {
resetTransform();
emit zoomChanged();
}
}
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)
{
zoomBy(qPow(1.2, event->delta() / 240.0));
}
void SvgView::zoomBy(qreal factor)
{
const qreal currentZoom = zoomFactor();
if ((factor < 1 && currentZoom < 0.1) || (factor > 1 && currentZoom > 10))
return;
scale(factor, factor);
emit zoomChanged();
}
QSvgRenderer *SvgView::renderer() const
{
if (m_svgItem)
return m_svgItem->renderer();
return nullptr;
}