title: How to resize a QLabel with pixmap inside a QScrollArea?
body: <p>I have a designer form (Dialog without Buttons template) containing <code>QScrollArea</code> and 2 <code>QPushButton</code> objects inside a vertical layout. I want to set <code>QLabel</code> with a pixmap inside the <code>QScrollArea</code>.</p>
  
  <p>Here is my code:</p>
  
  <p><em>In the constructor of <code>Viewer</code></em></p>
  
  <pre><code>m_imageLabel = new QLabel;
  m_imageLabel-&gt;setPixmap(image);
  m_imageLabel-&gt;setScaledContents(true);
  
  ui-&gt;scrollArea-&gt;setBackgroundRole(QPalette::Dark);
  ui-&gt;scrollArea-&gt;setWidget(m_imageLabel);
  ui-&gt;scrollArea-&gt;setWidgetResizable(true);
  </code></pre>
  
  <p><em>the slot</em></p>
  
  <pre><code>void Viewer::on_zoomInButton_clicked()
  {
      m_imageLabel-&gt;resize(m_scaleFactor * m_imageLabel-&gt;pixmap()-&gt;size());
      ...
  }
  </code></pre>
  
  <p>The problem is that when the <code>zoomInButton</code> is clicked, nothing happens.</p>
  
  <p>How to achieve this?</p>