Implemented a custom delegate that does the samework as the BaseTableModel class did.

While this might seem to duplicate behaviour I believe having this code in a delegate
is a better solution.
- the logic in BaseTableModel is view logic not model logic
- letting the custom delegate determine the formatting is much more efficient
  then letting the default delegate do many virtual calls to detemine how the
  model wants it formatted.

pglab/PgLabItemDelegate.cpp

@@ -0,0 +1,129 @@
+#include "PgLabItemDelegate.h"
+#include <QApplication>
+
+#include "Pgsql_oids.h"
+#include "ResultTableModelUtil.h"
+
+PgLabItemDelegate::PgLabItemDelegate(QObject *parent)
+	: QStyledItemDelegate(parent)
+{
+
+}
+
+
+void PgLabItemDelegate::initStyleOption(QStyleOptionViewItem *option,
+										 const QModelIndex &index) const
+{
+	QVariant value;
+//	value = index.data(Qt::FontRole);
+//	if (value.isValid() && !value.isNull()) {
+//		option->font = qvariant_cast<QFont>(value).resolve(option->font);
+//		option->fontMetrics = QFontMetrics(option->font);
+//	}
+
+//	value = index.data(Qt::TextAlignmentRole);
+//	if (value.isValid() && !value.isNull())
+//		option->displayAlignment = Qt::Alignment(value.toInt());
+
+//	value = index.data(Qt::ForegroundRole);
+//	if (value.canConvert<QBrush>())
+//		option->palette.setBrush(QPalette::Text, qvariant_cast<QBrush>(value));
+
+
+	option->index = index;
+//	value = index.data(Qt::CheckStateRole);
+//	if (value.isValid() && !value.isNull()) {
+//		option->features |= QStyleOptionViewItem::HasCheckIndicator;
+//		option->checkState = static_cast<Qt::CheckState>(value.toInt());
+//	}
+
+//	value = index.data(Qt::DecorationRole);
+//	if (value.isValid() && !value.isNull()) {
+//		option->features |= QStyleOptionViewItem::HasDecoration;
+//		switch (value.type()) {
+//		case QVariant::Icon: {
+//			option->icon = qvariant_cast<QIcon>(value);
+//			QIcon::Mode mode;
+//			if (!(option->state & QStyle::State_Enabled))
+//				mode = QIcon::Disabled;
+//			else if (option->state & QStyle::State_Selected)
+//				mode = QIcon::Selected;
+//			else
+//				mode = QIcon::Normal;
+//			QIcon::State state = option->state & QStyle::State_Open ? QIcon::On : QIcon::Off;
+//			QSize actualSize = option->icon.actualSize(option->decorationSize, mode, state);
+//			// For highdpi icons actualSize might be larger than decorationSize, which we don't want. Clamp it to decorationSize.
+//			option->decorationSize = QSize(qMin(option->decorationSize.width(), actualSize.width()),
+//										   qMin(option->decorationSize.height(), actualSize.height()));
+//			break;
+//		}
+//		case QVariant::Color: {
+//			QPixmap pixmap(option->decorationSize);
+//			pixmap.fill(qvariant_cast<QColor>(value));
+//			option->icon = QIcon(pixmap);
+//			break;
+//		}
+//		case QVariant::Image: {
+//			QImage image = qvariant_cast<QImage>(value);
+//			option->icon = QIcon(QPixmap::fromImage(image));
+//			option->decorationSize = image.size() / image.devicePixelRatio();
+//			break;
+//		}
+//		case QVariant::Pixmap: {
+//			QPixmap pixmap = qvariant_cast<QPixmap>(value);
+//			option->icon = QIcon(pixmap);
+//			option->decorationSize = pixmap.size() / pixmap.devicePixelRatio();
+//			break;
+//		}
+//		default:
+//			break;
+//		}
+//	}
+
+	Oid oid = InvalidOid;
+	value = index.data(Qt::UserRole); // get OID
+	if (value.isValid())
+		oid = value.toInt(); //getType(index.column());
+
+	value = index.data(Qt::DisplayRole);
+
+	option->displayAlignment = GetDefaultAlignmentForType(oid);
+
+
+	if (value.isValid() && ! value.isNull()) {
+		QColor forground_color = oid == Pgsql::bool_oid
+				? GetDefaultBoolColor(value.toBool())
+				: GetDefaultColorForType(oid);
+		option->palette.setBrush(QPalette::Text, QBrush(forground_color));
+
+		option->features |= QStyleOptionViewItem::HasDisplay;
+		option->text = oid == Pgsql::bool_oid
+				? FormatBoolForDisplay(value.toBool())
+				: displayText(value, option->locale);
+	}
+	else {
+		option->palette.setBrush(QPalette::Text, QBrush(GetDefaultNullColor()));
+
+		option->features |= QStyleOptionViewItem::HasDisplay;
+		option->text = "null";
+	}
+
+
+//	option->backgroundBrush = qvariant_cast<QBrush>(index.data(Qt::BackgroundRole));
+
+	// disable style animations for checkboxes etc. within itemviews (QTBUG-30146)
+	option->styleObject = 0;
+}
+
+void PgLabItemDelegate::paint(QPainter *painter,
+		const QStyleOptionViewItem &option, const QModelIndex &index) const
+{
+	Q_ASSERT(index.isValid());
+
+	QStyleOptionViewItem opt = option;
+	initStyleOption(&opt, index);
+
+	const QWidget *widget = option.widget; // QStyledItemDelegatePrivate::widget(option);
+	QStyle *style = widget ? widget->style() : QApplication::style();
+	style->drawControl(QStyle::CE_ItemViewItem, &opt, painter, widget);
+}

pglab/PgLabItemDelegate.h

@@ -0,0 +1,18 @@
+#ifndef PGLABITEMDELEGATE_H
+#define PGLABITEMDELEGATE_H
+
+#include <QStyledItemDelegate>
+
+class PgLabItemDelegate : public QStyledItemDelegate
+{
+public:
+	PgLabItemDelegate(QObject *parent = nullptr);
+
+	virtual void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
+
+protected:
+	virtual void initStyleOption(QStyleOptionViewItem *option, const QModelIndex &index) const override;
+
+};
+
+#endif // PGLABITEMDELEGATE_H