svgview.cpp Example File | Qt SVG 5.6

Qt 5.6 | Qt SVG | SVG Viewer Example | svgview.cpp Example File

Qt 5.6.2 Reference Documentation

# svgview.cpp Example File

svgviewer/svgview.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** 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.
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      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
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      #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();
      }