How to add Icon into QHeaderView

karlheinzreichel

I would like to add an Icon right beside the text in the QHeaderView.
If the Icon will be added the text in the QHeaderView-Section should be elided if necessary.

To solve this problem I do the following:

In MyHeaderView::paintSection(painter rect , index)

QRect iconRect = iconPixmap.rect();
QRect textRect = rect;
textRect.setWidth(textRect.width() - iconRect.width());
// textRect will contain the available space for the text

QFont theFont = ... // get actual QHeaderView text font
QFontMetrics fontMetrics(theFont);         
QString elidedText = fontMetrics.elidedText(text, Qt::ElideRight, textRect.width());
// so I get the elidedText if necessary
model() -> setHorizontalHeaderText(index, elidedText)
// setting the text in the model, but without emitting a dataChanged
QHeaderView::paintSection(painter, textRect, logicalIndex);

This is a little bit complicated, but seems to be working (at least when the alignment for the text is Qt::AlignLeft)
but is not working for text which is aligned Qt::AlignRight.

Is there another (maybe much easier) solution for icons in QHeaderViews ?

karlheinzreichel

Got a solution for that question by myself.

The solution works also for right aligned text.

void MyHeaderView::paintSection(QPainter* painter, const QRect& rect, int logicalIndex) const
{
// The Icon to draw on right of the header text is in iconPixmap
QRect iconRect = iconPixmap.rect();
QRect textRect = rect;
textRect.setWidth(textRect.width() - iconRect.width());

  QFont myFont = getFont();  // delivers the font for for the header text
  QFontMetrics fontMetrics(myFont);
  
  // determine the elided text which will be printed for the available width
  // m_header_padding is the padding of the headerview section
  QString elidedText = fontMetrics.elidedText(text, Qt::ElideRight, textRect.width() - m_header_padding * 2);
  
  // Drawing procedure
  // First draw without text over the complete header section size
  // this will draw the background and the borders etc. for the complete header section         
  model() -> setHorizontalHeaderText(index, QString());  // set text in model without emitting datachanged
  QHeaderView::paintSection(painter, rect, logicalIndex);
  
  // now draw the (possibly elided) text into the header section
  model() -> setHorizontalHeaderText(logicalIndex, elidedText);
  QHeaderView::paintSection(painter, textRect, logicalIndex);
  
  // Now restore the header section text in the model 
  model() -> setHorizontalHeaderText(logicalIndex, text);
  
  // Draw the icon
  // center icon vertical
  int iconHeight = iconRect.height();
  int headerHeight = rect.height();
  int offset = 0;
  if (iconHeight < headerHeight) {
     offset = (headerHeight - iconHeight) / 2;
  }    
  painter -> setClipRect(rect);
  painter -> drawPixmap(textRect.right()-1, rect.top() + offset, iconRect.width(), iconRect.height(), iconPixmap);
  painter -> setClipRect(rect);

}