svgviewer.cpp

   1 #include "svgviewer.h"
   2
   3 SVGViewer::SVGViewer(QWidget *parent) : QGraphicsView(parent) {
   4     /* Init scene */
   5     setScene(new QGraphicsScene(this));
   6     setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
   7     setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);
   8     setOptimizationFlag(QGraphicsView::DontSavePainterState, true);
   9 }
  10
  11 void SVGViewer::paintEvent(QPaintEvent *event) {
  12     QGraphicsView::paintEvent(event);
  13 }
  14
  15 QString SVGViewer::SVGRemoveWhitespace(QString text) {
  16     /* Remove whitespace according to SVG spec.
  17         (xml:space="default")
  18     */
  19
  20     /* Remove newlines */
  21     text = text.remove('\n');
  22     /* Replace tabs by spaces */
  23     text.replace("\t", " ");
  24     text.replace("\v", " ");
  25     /* Remove leading and traling spaces */
  26     int i;
  27     for(i=0; i<text.length(); i++) {
  28         if(!(text[i] == ' ')) {
  29             break;
  30         }
  31     }
  32     text.remove(0, i);
  33     for(i=text.length()-1; i>=0; i--) {
  34         if(!(text[i] == ' ')) {
  35             break;
  36         }
  37     }
  38     text.truncate(i+1);
  39     /* Squash consecutive spaces into a single space */
  40     int len = text.length();
  41     int newlen;
  42     while(len!=newlen) {
  43         len = text.length();
  44         text.replace("  ", " ");
  45         newlen = text.length();
  46     }
  47
  48     return text;
  49 }
  50 QString SVGViewer::SVGPreserveWhitespace(QString text) {
  51     /* Preserve whitespace according to SVG spec.
  52         (xml:space="preserve") */
  53
  54     /* Replace newlines and tabs by spaces */
  55     text.replace("\n", " ");
  56     text.replace("\t", " ");
  57     text.replace("\v", " ");
  58
  59     return text;
  60 }
  61
  62 QString SVGViewer::SVGReadText(QXmlStreamReader* reader, bool keepWhitespace) {
  63     if(keepWhitespace) {
  64         return SVGPreserveWhitespace(reader->text().toString());
  65     } else {
  66         return SVGRemoveWhitespace(reader->text().toString());
  67     }
  68 }
  69
  70 bool SVGViewer::openFile(QString fileName) {
  71     /* Read SVG's XML to gather some metadata and settings. */
  72     /* FIXME: Only works for non-compressed SVGs */
  73     QFile xmlFile(fileName);
  74     if (!xmlFile.open(QFile::ReadOnly)) {
  75         QMessageBox::critical(this, tr("Error"), tr("The file could not be opened."));
  76         return false;
  77     }
  78     QByteArray bytes = xmlFile.readAll();
  79     xmlFile.close();
  80     QXmlStreamReader* xmlReader = new QXmlStreamReader();
  81     xmlReader->addData(bytes);
  82
  83     /* Default values for various settings according to SVG spec. */
  84     zoomAndPan = true;
  85     title = QString();
  86     desc = QString();
  87
  88     /* Waiter variables remember element names */
  89     bool waiterTitle = false;
  90     bool waiterDesc = false;
  91     bool keepWhitespace = false;
  92
  93     while(!xmlReader->atEnd()) {
  94         if(xmlReader->readNext()) {
  95             if(xmlReader->tokenType() == QXmlStreamReader::StartElement) {
  96                 if(xmlReader->namespaceUri() == "http://www.w3.org/2000/svg") {
  97                     if(xmlReader->name() == "svg") {
  98                         QString s(xmlReader->attributes().value("zoomAndPan").toString());
  99                         /* Check if zooming and pan in XML is disabled */
 100                         if(s == "disable") {
 101                             zoomAndPan = false;
 102                         }
 103                     } else if(xmlReader->name() == "title") {
 104                         waiterTitle = true;
 105                     } else if(xmlReader->name() == "desc") {
 106                         waiterDesc = true;
 107                     }
 108                     if(xmlReader->attributes().value("xml:space").toString() == "preserve") {
 109                         keepWhitespace = true;
 110                     } else {
 111                         keepWhitespace = false;
 112                     }
 113                 }
 114             } else if(xmlReader->tokenType() == QXmlStreamReader::Characters) {
 115                 if(waiterTitle && title.isNull()) {
 116                     title = SVGReadText(xmlReader, keepWhitespace);
 117                     waiterTitle = false;
 118                 } else if(waiterDesc && desc.isNull()) {
 119                     desc = SVGReadText(xmlReader, keepWhitespace);
 120                     waiterDesc = false;
 121                 }
 122             }
 123         }
 124     }
 125
 126     /* Create SVG item and load the file */
 127     svgItem = new QGraphicsSvgItem(fileName);
 128     svgRenderer = svgItem->renderer();
 129
 130     /* Reject invalid SVG documents */
 131     if (!svgRenderer->isValid()) {
 132         /* TODO: Also show details in error message */
 133         QMessageBox::critical(this, tr("Invalid SVG document"),
 134                               tr("The selected file is not a valid SVG document and could not be opened."));
 135         return false;
 136     }
 137
 138     /* Set up scene */
 139     if(zoomAndPan) {
 140         setDragMode(ScrollHandDrag);
 141     } else {
 142         setDragMode(NoDrag);
 143     }
 144
 145     scene()->clear();
 146     resetTransform();
 147
 148     svgItem->setFlags(QGraphicsItem::ItemClipsToShape);
 149     svgItem->setCacheMode(QGraphicsItem::NoCache);
 150
 151     /* Show image */
 152     scene()->addItem(svgItem);
 153     return true;
 154 }
 155
 156 void SVGViewer::closeFile() {
 157     delete svgItem;
 158     svgItem = NULL;
 159     /* Reset view parameters */
 160     scene()->clear();
 161     resetTransform();
 162     setDragMode(NoDrag);
 163 }
 164
 165 void SVGViewer::zoomIn() {
 166     if(zoomAndPan && svgItem != NULL) {
 167         zoomChange(1.25);
 168     }
 169 }
 170 void SVGViewer::zoomOut() {
 171     if(zoomAndPan && svgItem != NULL) {
 172         zoomChange(0.8);
 173     }
 174 }
 175 void SVGViewer::zoomReset() {
 176     if(zoomAndPan && svgItem != NULL) {
 177         resetTransform();
 178     }
 179 }
 180
 181 void SVGViewer::zoomSet(qreal factor) {
 182     if(zoomAndPan && svgItem != NULL) {
 183         zoomReset();
 184         zoomChange(factor);
 185     }
 186 }
 187
 188 void SVGViewer::zoomChange(qreal factor) {
 189     if(zoomAndPan && svgItem != NULL) {
 190         scale(factor, factor);
 191     }
 192 }
 193
 194 #ifndef QT_NO_WHEELEVENT
 195 void SVGViewer::wheelEvent(QWheelEvent *event) {
 196     /* Change zoom on using the mouse wheel */
 197     qreal factor = qPow(1.2, event->delta() / 240.0);
 198     zoomChange(factor);
 199     event->accept();
 200 }
 201 #endif
 202
 203 bool SVGViewer::getZoomAndPan() {
 204     return zoomAndPan;
 205 }
 206
 207 bool SVGViewer::getAnim() {
 208     if(svgItem != NULL) {
 209         return svgRenderer->animated();
 210     } else {
 211         return false;
 212     }
 213 }
 214
 215 QString SVGViewer::getTitle() {
 216     return title;
 217 }
 218
 219 QString SVGViewer::getDesc() {
 220     return desc;
 221 }
 222
 223 QSize SVGViewer::getImageSize() {
 224     if(svgItem != NULL) {
 225         return svgRenderer->defaultSize();
 226     } else {
 227         return QSize();
 228     }
 229 }