This question is further development of this post and is different, though may seem similar as this one.
I am trying to reimplement QHeaderView::paintSection
, so that the background returned from the model would be honored. I tried to do this
void Header::paintSection(QPainter * painter, const QRect & rect, int logicalIndex) const
{
QVariant bg = model()->headerData(logicalIndex, Qt::Horizontal, Qt::BackgroundRole);
// try before
if(bg.isValid()) // workaround for Qt bug https://bugreports.qt.io/browse/QTBUG-46216
painter->fillRect(rect, bg.value<QBrush>());
QHeaderView::paintSection(painter, rect, logicalIndex);
// try after
if(bg.isValid()) // workaround for Qt bug https://bugreports.qt.io/browse/QTBUG-46216
painter->fillRect(rect, bg.value<QBrush>());
}
However, it didn't work - if I make QHeaderView::paintSection
call, nothing I draw with the painter is visible (I also tried drawing a diagonal line). If I remove QHeaderView::paintSection
call, the line and the background will be visible.
Making the fillRect
call before vs. after the QHeaderView::paintSection
doesn't make any difference.
I wonder, what is it that QHeaderView::paintSection
does that makes it impossible for me to draw something on top of it.
And whether there is a way to overcome it without reimplementing everythning what QHeaderView::paintSection
does?
All I need to do is to add a certain shade to a certain cell - I still want everything in the cell (text, icons, gradient background etc.) to be painted as it is now...
It is obvious why the first
fillRect
doesn't work. Everything that you paint beforepaintSection
is overridden by base painting.The second call is more interesting.
Usually all paint methods preserves
painter
state. It means that when you callpaint
it looks like the painter state hasn't been changed.Nevertheless
QHeaderView::paintSection
spoils the painter state.To bypass the issue you need to save and restore the state by yourself: