QTreeWidget minimum height

[wysota]

+2 comes from the frame size. You should use QStyle::styleHint() to ask the style for the proper frame size of your style.

[Alundra]

I have found an easy way to handle my problem, I have a SetFixedHeightToShowAllItems() and I set the size policy to fixed when needed.
About the frame width I only found this one, all other are for specific widget but not the tree :

const int FrameWidth = m_TreeWidget->style()->styleHint( QStyle::StyleHint::SH_WindowFrame_Mask );

const int FrameWidth = m_TreeWidget->style()->styleHint( QStyle::StyleHint::SH_WindowFrame_Mask );

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That return the value 1, I guess it's normal because there is one border on top and one on bottom so that's (2*FrameWidth).
Is it the correct styleHint or that can cause problems ?

[wysota]

Hmm... actually I think I told you wrong. You should use pixelMetric() with PM_DefaultFrameWidth or alike.

[Alundra]

ok Thanks, I have changed like that :

void CPropertyEditorWidget::SetFixedHeightToShowAllProperties()
{
  // Iterator of all items.
  QTreeWidgetItemIterator AllIterator( m_TreeWidget, QTreeWidgetItemIterator::All );
 
  // Initialize the SpinBox style option.
  const int FrameWidth = m_TreeWidget->style()->pixelMetric( QStyle::PM_DefaultFrameWidth );
 
  // Height of all item and header.
  int Height = m_TreeWidget->header()->height() + (2 * FrameWidth);
 
  // While iterator is valid.
  while( *AllIterator )
  {
    // Update the height.
    QTreeWidgetItem* Item = *AllIterator;
    Height += m_TreeWidget->visualItemRect( Item ).height();
 
    // Next iterator.
    ++AllIterator;
  }
 
  // Set the fixed height.
  setFixedHeight( Height );
}

void CPropertyEditorWidget::SetFixedHeightToShowAllProperties()
{
  // Iterator of all items.
  QTreeWidgetItemIterator AllIterator( m_TreeWidget, QTreeWidgetItemIterator::All );

  // Initialize the SpinBox style option.
  const int FrameWidth = m_TreeWidget->style()->pixelMetric( QStyle::PM_DefaultFrameWidth );

  // Height of all item and header.
  int Height = m_TreeWidget->header()->height() + (2 * FrameWidth);

  // While iterator is valid.
  while( *AllIterator )
  {
    // Update the height.
    QTreeWidgetItem* Item = *AllIterator;
    Height += m_TreeWidget->visualItemRect( Item ).height();

    // Next iterator.
    ++AllIterator;
  }

  // Set the fixed height.
  setFixedHeight( Height );
}

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[wysota]

Wouldn't it be easier to query for the visual rect of the last item only? You could then take its bottom() value.

[Alundra]

I have tried :

void CPropertyEditorWidget::SetFixedHeightToShowAllProperties()
{
  const int FrameWidth = m_TreeWidget->style()->pixelMetric( QStyle::PM_DefaultFrameWidth );
  const int LastItemBottom = m_TreeWidget->visualItemRect( m_TreeWidget->topLevelItem( m_TreeWidget->topLevelItemCount() - 1 ) ).bottom();
  setFixedHeight( m_TreeWidget->header()->height() + ( 2 * FrameWidth ) + LastItemBottom );
}

void CPropertyEditorWidget::SetFixedHeightToShowAllProperties()
{
  const int FrameWidth = m_TreeWidget->style()->pixelMetric( QStyle::PM_DefaultFrameWidth );
  const int LastItemBottom = m_TreeWidget->visualItemRect( m_TreeWidget->topLevelItem( m_TreeWidget->topLevelItemCount() - 1 ) ).bottom();
  setFixedHeight( m_TreeWidget->header()->height() + ( 2 * FrameWidth ) + LastItemBottom );
}

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But that doesn't work, I have the scrollbar on the right, using the iterator version the scrollbar is not visible.

[wysota]

Due to how bottom() is interpreted (see the docs) you should add 1 to it.

[Alundra]

Note that for historical reasons this function returns top() + height() - 1; use y() + height() to retrieve the true y-coordinate.

I have added the +1 on the "bottom()" version and that works good, thanks for the comment on bottom(), this version is faster surely.

[wysota]

Just keep in mind your code will not work for trees where items have children. You'd have to recursively descend to the deep-most visible child of the last item.