tablewidget and pixmap

[magoo]

Hi, using Qt 4.2.1, I'd like to display images on one of the fourth column of my tablewidget. Anyone could give me hints on how I can do this ? it's a display-only table.

thanks

[wysota]

Set the icon of the item to the pixmap you wish to display (using QTableWidgetItem::setIcon().

[magoo]

yes, but i'd like to display the pixmap at a fixed size and not a tiny icon... how can I do this ?

many thanks

[wysota]

Provide a new item delegate which will render your pixmap and return a proper size for the item so that the pixmap can fit it. See QAbstractItemDelegate for more info.

[magoo]

that's cool and I was able to make it works. Another problem I have, why do I have to call resizeColumnsToContents() and resizeRowsToContents() if I add more than one rows to my TableWidget ? The cells size seems to reset after I add new TableWidgetItem to the table... There's probably a way for the table to remember the size of the cells that are already in the table...

Also, calling scrollToBottom() doesn't actually scroll anything...

as an example :

mainwindow.cpp :

...
 
t = new QTableWidget();
t->setSelectionMode(QAbstractItemView::NoSelection);
t->setColumnCount(2);
t->setHorizontalHeaderLabels(labels);
t->setItemDelegateForColumn(1, new ImageDelegate(this));
 
QTableWidgetItem *item[100][2];
 
for(int i=0;i < 100; i++)
{
   t->insertRow(i);
 
   item[i][0] = new QTableWidgetItem(s.arg(i));
   item[i][0]->setFlags(item[i][0]->flags() & ~Qt::ItemIsEditable);
   t->setItem(i, 0, item[i][0]);
 
   item[i][1] = new QTableWidgetItem(":/icons/unknown.png");
   item[i][1]->setData(Qt::UserRole, ":/icons/unknown.png");
   item[i][1]->setFlags(item[i][1]->flags() & ~Qt::ItemIsEditable);
   t->setItem(i, 1, item[i][1]);
 
   //i tried a bunch of stuff... resizeColumnToContents() and resizeRowToContents() works, 
   //but only without any parameters and I guess it's not very good to recalculate everything
   //everytime I add something ? I'd like to just resize the inserted row AND that the already
   //inserted row keep their size.
 
   //t->resizeColumnToContents(0);
   //t->resizeColumnToContents(1);
   //t->resizeRowToContents(i);
   //t->resizeColumnsToContents();
   //t->resizeRowsToContents();
   //t->setColumnWidth(1,140);
   //t->setRowHeight(i,200);
 
   //t->scrollToBottom();
}

...

t = new QTableWidget();
t->setSelectionMode(QAbstractItemView::NoSelection);
t->setColumnCount(2);
t->setHorizontalHeaderLabels(labels);
t->setItemDelegateForColumn(1, new ImageDelegate(this));

QTableWidgetItem *item[100][2];

for(int i=0;i < 100; i++)
{
   t->insertRow(i);

   item[i][0] = new QTableWidgetItem(s.arg(i));
   item[i][0]->setFlags(item[i][0]->flags() & ~Qt::ItemIsEditable);
   t->setItem(i, 0, item[i][0]);

   item[i][1] = new QTableWidgetItem(":/icons/unknown.png");
   item[i][1]->setData(Qt::UserRole, ":/icons/unknown.png");
   item[i][1]->setFlags(item[i][1]->flags() & ~Qt::ItemIsEditable);
   t->setItem(i, 1, item[i][1]);

   //i tried a bunch of stuff... resizeColumnToContents() and resizeRowToContents() works, 
   //but only without any parameters and I guess it's not very good to recalculate everything
   //everytime I add something ? I'd like to just resize the inserted row AND that the already
   //inserted row keep their size.

   //t->resizeColumnToContents(0);
   //t->resizeColumnToContents(1);
   //t->resizeRowToContents(i);
   //t->resizeColumnsToContents();
   //t->resizeRowsToContents();
   //t->setColumnWidth(1,140);
   //t->setRowHeight(i,200);

   //t->scrollToBottom();
}

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imagedelegate.cpp:

#include <QtGui>
 
#include "imagedelegate.h"
 
 ImageDelegate::ImageDelegate(QObject *parent)
     : QAbstractItemDelegate(parent)
 {
 }
 
void ImageDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                           const QModelIndex &index) const
{
   QPixmap pixmap(index.model()->data(index).toString());
   painter->save();
   painter->drawPixmap(option.rect, pixmap);
   painter->restore();
}
 
QSize ImageDelegate::sizeHint(const QStyleOptionViewItem & /* option */,
                               const QModelIndex & /* index */) const
{
   return(QSize(140,200));
}

#include <QtGui>

#include "imagedelegate.h"

 ImageDelegate::ImageDelegate(QObject *parent)
     : QAbstractItemDelegate(parent)
 {
 }

void ImageDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                           const QModelIndex &index) const
{
   QPixmap pixmap(index.model()->data(index).toString());
   painter->save();
   painter->drawPixmap(option.rect, pixmap);
   painter->restore();
}

QSize ImageDelegate::sizeHint(const QStyleOptionViewItem & /* option */,
                               const QModelIndex & /* index */) const
{
   return(QSize(140,200));
}

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[wysota]

Another problem I have, why do I have to call resizeColumnsToContents() and resizeRowsToContents() if I add more than one rows to my TableWidget ? The cells size seems to reset after I add new TableWidgetItem to the table... There's probably a way for the table to remember the size of the cells that are already in the table...

Provide a correct size hint in the delegate. For example:

QSize myDelegate::sizeHint(const QStyleOptionViewItem & /* option */, 
                           const QModelIndex & index) const {
    return index.data(Qt::DecorationRole).toPixmap().size()+QSize(4,4);
}

QSize myDelegate::sizeHint(const QStyleOptionViewItem & /* option */, 
                           const QModelIndex & index) const {
    return index.data(Qt::DecorationRole).toPixmap().size()+QSize(4,4);
}

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[magoo]

I've put a qDebug() inside the sizeHint() method of the delegate and it's never actually called.

I've try adding

item[i][1]->setData(Qt::SizeHintRole, QSize(140,200));

item[i][1]->setData(Qt::SizeHintRole, QSize(140,200));

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in my mainwindow.cpp but the cells are still sizing incorrectly. if I call the sizeHint() method of the TableWidgetItem, it returns the correct value but the delegate sizeHint() is never call with or without adding the SizeHintRole data.

[wysota]

Try subclassing QItemDelegate instead of the abstract delegate.