How to add SVG widget to MainWindow?

SPlatten

I have a class derived from QMainWindow, so far I'm adding widgets to the window by simply adding the window as the parent of the widget. I haven't had to implement a paintEvent yet.

How can I use the same technique to render the SVG in the window? This is what I have so far:

I read the SVG in as part of the XML, the SVG is:

<svg id="svgLED" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <linearGradient id="svg_6" x1="0" y1="0" x2="1" y2="0">
      <stop stop-color="#bfbfbf" offset="0"/>
      <stop stop-color="#404040" offset="1"/>
    </linearGradient>
    <linearGradient id="svg_11" x1="0" y1="0" x2="1" y2="1" spreadMethod="pad">
      <stop stop-color="#dd0000" stop-opacity="0.992188" offset="0"/>
     <stop stop-color="#820101" stop-opacity="0.988281" offset="1"/>
    </linearGradient>
    <linearGradient id="svg_14" x1="0" y1="0" x2="1" y2="1" spreadMethod="pad">
      <stop stop-color="#ffffff" stop-opacity="0.996094" offset="0"/>
      <stop stop-color="#d30606" stop-opacity="0.984375" offset="0.703125"/>
    </linearGradient>
  </defs>
  <g>
    <circle id="svgLED@[id]_c1" fill="url(#svg_6)" 
		stroke-width="17.5" stroke-linecap="round" 
		cx="320" cy="240" r="196.125" id="svg_3" 
		fill-opacity="0.77" transform="rotate(90, 320, 240)"/>
    <circle id="svgLED@[id]_c2" fill="url(#svg_6)" 
		stroke-width="17.5" stroke-linecap="round" 
		fill-opacity="0.64" cx="319.252837" cy="239.999045" 
		r="160" id="svg_7"/>
    <circle id="svgLED@[id]_c3" fill="url(#svg_11)" stroke-width="17.5" 
		stroke-linecap="round" cx="320.000535" cy="240.001698" r="150"/>
    <ellipse id="svgLED@[id]_e1" fill="url(#svg_14)" stroke-width="17.5" 
		 stroke-linecap="round" cx="250.179609" cy="170.124194" 
		 rx="75.675959" ry="44.402987" id="svg_20" 
		 transform="rotate(-47.7626, 250.18, 170.125)"/>
  </g>
</svg>

Once this is in my application along with the rest of the XML which isn't shown above I then use the following function to recreate a QByteArray containing only the SVG:

/**
 * @brief clsXMLnode::bytArrDocument
 * @param pobjNode : Optional, default is nullptr
 * @return Byte Array containing document
 */
QByteArray clsXMLnode::bytArrDocument(clsXMLnode* pobjNode) {
    QByteArray bytArrDoc;

    if ( pobjNode == nullptr ) {
    //Start off with the document header
        bytArrDoc.append(QString("<?xml version='1.0'?>").toLocal8Bit());
    //No node passed so use 'this'
        pobjNode = this;
    }
    QString strNode(clsXMLnode::msccTokenOpen), strName(pobjNode->strGetNodeName());
    strNode += strName;

    foreach( const prAttr &attrPr, pobjNode->mlstAttrPrs ) {
        strNode += clsXMLnode::msccSpace + attrPr.first
                 + clsXMLnode::msccEquals + clsXMLnode::msccQuoteSingle
                 + attrPr.second + clsXMLnode::msccQuoteSingle;
    }
    if ( pobjNode->blnHasChildren() == true ) {
        strNode += clsXMLnode::msccTokenClose;
        bytArrDoc.append(strNode.toLocal8Bit());        

        foreach( clsXMLnode* pobjChild, pobjNode->mlstChildren ) {
            bytArrDoc.append(bytArrDocument(pobjChild));
        }
        strNode = clsXMLnode::mscszXMLcloseToken2 + strName + clsXMLnode::msccTokenClose;
        bytArrDoc.append(strNode.toLocal8Bit());
    } else {
        strNode += clsXMLnode::mscszXMLcloseToken;
        bytArrDoc.append(strNode.toLocal8Bit());
    }
    return bytArrDoc;
}

This is what I do so far with the SVG:

if ( pobjNode->strGetNodeName().compare(clsXMLnode::mscszNodeSVGroot) == 0 ) {
  QString strID = pobjNode->strGetAttribute(clsXMLnode::mscszAttrID);

  if ( strID.isEmpty() != true ) {
    clsXMLnode* pobjWinNode = pobjNode->pobjGetWindow();

    if ( pobjWinNode != nullptr ) {
      QWidget* pobjPWidget = pobjWinNode->pobjGetWidget();

      if ( pobjPWidget != nullptr ) {
        QByteArray bytArrSVG = pobjNode->bytArrDocument();
        pobjNode->mpobjSVGrender = new QSvgRenderer(bytArrSVG, pobjPWidget);
      }
    }
  }
}

I see everything else in my window except the SVG, can you see anything missing?

jsulm

@SPlatten said in How to add SVG widget to MainWindow?:

QSvgWidget* pobjSVGwidget = new QSvgWidget(pobjPWidget);
pobjSVGwidget->load(bytArrSVG);

You never call show() on the widget, so why should it be visible?

Bonnie

You need a QSvgWidget...A "renderer" won't show automatically...

SPlatten

@Bonnie , thank you, how to I put that together with what I have as the QSvgWidget doesn't take a QByteArray and I cannot see a method to set the renderer?

Bonnie

@SPlatten
QSvgWidget can take a QByteArray, just create one and use QSvgWidget::load(const QByteArray &contents)

SPlatten

I've edited my source:

if ( pobjNode->strGetNodeName().compare(clsXMLnode::mscszNodeSVGroot) == 0 ) {
  QString strID = pobjNode->strGetAttribute(clsXMLnode::mscszAttrID);

  if ( strID.isEmpty() != true ) {
    clsXMLnode* pobjWinNode = pobjNode->pobjGetWindow();

    if ( pobjWinNode != nullptr ) {
      QWidget* pobjPWidget = pobjWinNode->pobjGetWidget();

      if ( pobjPWidget != nullptr ) {
        QByteArray bytArrSVG = pobjNode->bytArrDocument();
        QSvgWidget* pobjSVGwidget = new QSvgWidget(pobjPWidget);
        pobjSVGwidget->load(bytArrSVG);
      }
    }
  }
}

I've single stepped all the way to load, but I don't see anything in the window. I thought I may need to apply a position to the SVG, however I've tried both:

<svg id="svgLED" x="20" y="20" width="640" height="480" xmlns="http://www.w3.org/2000/svg">

No better, then tried:

<g transform="translate(20,20)">

Again, no better.

jsulm

@SPlatten said in How to add SVG widget to MainWindow?:

QSvgWidget* pobjSVGwidget = new QSvgWidget(pobjPWidget);
pobjSVGwidget->load(bytArrSVG);

You never call show() on the widget, so why should it be visible?

SPlatten

@jsulm , Excellent, thank you, thats done the trick!