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niklasf/title_and_description_delegate.cpp

Last active January 3, 2018 20:00
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A Qt QItemDelegate that shows a bold title above a description text. Could also be used to render more general rich text in QTableView and co.
Raw
title_and_description_delegate.cpp
#include "title_and_description_delegate.h"
void TitleAndDescriptionDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
m_paintingIndex = index;
QItemDelegate::paint(painter, option, index);
}
void TitleAndDescriptionDelegate::drawDisplay(QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect, const QString &text) const
{
Q_UNUSED(option);
Q_UNUSED(text);
Q_ASSERT(m_paintingIndex.isValid());
QTextDocument *doc = document(option, m_paintingIndex);
doc->setTextWidth(rect.width());
painter->save();
painter->translate(rect.left(), rect.top());
doc->drawContents(painter, QRect(0, 0, rect.width(), rect.height()));
painter->restore();
delete doc;
}
QTextDocument *TitleAndDescriptionDelegate::document(const QStyleOptionViewItem &option, const QModelIndex& index) const
{
QFont fnt = qvariant_cast<QFont>(index.data(Qt::FontRole)).resolve(option.font);
QTextDocument *doc = new QTextDocument();
doc->setDefaultFont(fnt);
QVariant descriptionText = index.data(TitleAndDescriptionDelegate::DescriptionRole);
if (descriptionText.isValid()) {
doc->setHtml(QString("<html><strong>%1</strong><br>%2</html>")
.arg(Qt::escape(index.data(Qt::DisplayRole).toString()))
.arg(Qt::escape(descriptionText.toString())));
} else {
doc->setHtml(QString("<html><strong>%1</strong></html>")
.arg(Qt::escape(index.data(Qt::DisplayRole).toString())));
}
return doc;
}
QSize TitleAndDescriptionDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex& index) const
{
QVariant value = index.data(Qt::SizeHintRole);
if (value.isValid()) {
return qvariant_cast<QSize>(value);
}
QTextDocument *displayDocument = document(option, index);
displayDocument->adjustSize();
QRect decorationRect = rect(option, index, Qt::DecorationRole);
QRect displayRect = QRect(0, 0, displayDocument->size().width(), displayDocument->size().height());
QRect checkRect = rect(option, index, Qt::CheckStateRole);
doLayout(option, &checkRect, &decorationRect, &displayRect, true);
delete displayDocument;
return (decorationRect|displayRect|checkRect).size();
}
Raw
title_and_description_delegate.h
#ifndef TITLE_AND_DESCRIPTION_DELEGATE_H
#define TITLE_AND_DESCRIPTION_DELEGATE_H
#include <QtCore>
#include <QtGui>
class TitleAndDescriptionDelegate : public QItemDelegate
{
Q_OBJECT
public:
static const int DescriptionRole = Qt::UserRole + 1;
QSize sizeHint(const QStyleOptionViewItem& option, const QModelIndex& index) const;
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;
protected:
QTextDocument *document(const QStyleOptionViewItem &option, const QModelIndex& index) const;
void drawDisplay(QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect, const QString &text) const;
private:
mutable QModelIndex m_paintingIndex;
};
#endif
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