Clear the data when the model resets.

This patch does a few things:
1 - reset the model when user closes the dive file
2 - connects the 'rowsAboutToBeRemoved' in a way that the graphics can
    remove their polygons too
3 - adds a 'clear' virtual method so items that don't follow the rules can
    clean themseves up.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/mainwindow.cpp

@@ -171,6 +171,7 @@ void MainWindow::on_actionClose_triggered()
 	if (unsaved_changes() && (askSaveChanges() == false))
 		return;
 
+	ui.graphicsView->setEmptyState();
 	/* free the dives and trips */
 	while (dive_table.nr)
 		delete_single_dive(0);

qt-ui/profile/diveplotdatamodel.cpp

@@ -99,6 +99,7 @@ void DivePlotDataModel::clear()
 {
 	if (rowCount() != 0) {
 		beginRemoveRows(QModelIndex(), 0, rowCount() - 1);
+		pInfo.nr = 0;
 		endRemoveRows();
 	}
 }

qt-ui/profile/diveprofileitem.cpp

@@ -44,9 +44,17 @@ void AbstractProfilePolygonItem::setModel(DivePlotDataModel* model)
 {
 	dataModel = model;
 	connect(dataModel, SIGNAL(dataChanged(QModelIndex,QModelIndex)), this, SLOT(modelDataChanged(QModelIndex, QModelIndex)));
+	connect(dataModel, SIGNAL(rowsAboutToBeRemoved(QModelIndex,int,int)), this, SLOT(modelDataRemoved(QModelIndex, int, int)));
 	modelDataChanged();
 }
 
+void AbstractProfilePolygonItem::modelDataRemoved(const QModelIndex& parent, int from, int to)
+{
+	setPolygon(QPolygonF());
+	qDeleteAll(texts);
+	texts.clear();
+}
+
 void AbstractProfilePolygonItem::setVerticalAxis(DiveCartesianAxis* vertical)
 {
 	vAxis = vertical;
@@ -107,6 +115,8 @@ DiveProfileItem::DiveProfileItem() : show_reported_ceiling(0), reported_ceiling_
 
 void DiveProfileItem::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget) {
 	Q_UNUSED(widget);
+	if(polygon().isEmpty())
+		return;
 
 	// This paints the Polygon + Background. I'm setting the pen to QPen() so we don't get a black line here,
 	// after all we need to plot the correct velocities colors later.
@@ -277,6 +287,8 @@ void DiveTemperatureItem::createTextItem(int sec, int mkelvin)
 
 void DiveTemperatureItem::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 {
+	if(polygon().isEmpty())
+		return;
 	painter->setPen(pen());
 	painter->drawPolyline(polygon());
 }
@@ -374,6 +386,8 @@ void DiveGasPressureItem::plot_gas_value(int mbar, int sec, QFlags<Qt::Alignment
 
 void DiveGasPressureItem::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 {
+	if(polygon().isEmpty())
+		return;
 	QPen pen;
 	pen.setCosmetic(true);
 	pen.setWidth(2);
@@ -427,6 +441,8 @@ void DiveCalculatedCeiling::modelDataChanged(const QModelIndex& topLeft, const Q
 
 void DiveCalculatedCeiling::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 {
+	if(polygon().isEmpty())
+		return;
 	QGraphicsPolygonItem::paint(painter, option, widget);
 }
 
@@ -492,6 +508,8 @@ void DiveReportedCeiling::preferencesChanged()
 
 void DiveReportedCeiling::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 {
+	if(polygon().isEmpty())
+		return;
 	QGraphicsPolygonItem::paint(painter, option, widget);
 }
 

qt-ui/profile/diveprofileitem.h

@@ -41,9 +41,11 @@ public:
 	void setHorizontalDataColumn(int column);
 	void setVerticalDataColumn(int column);
 	virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0) = 0;
+	virtual void clear(){};
 public slots:
 	virtual void preferencesChanged();
 	virtual void modelDataChanged(const QModelIndex& topLeft = QModelIndex(), const QModelIndex& bottomRight = QModelIndex());
+	virtual void modelDataRemoved(const QModelIndex& parent, int from, int to);
 protected:
 	/* when the model emits a 'datachanged' signal, this method below should be used to check if the
 	 * modified data affects this particular item ( for example, when setting the '3m increment'

qt-ui/profile/profilewidget2.cpp

@@ -432,6 +432,7 @@ void ProfileWidget2::setEmptyState()
 	if (currentState == EMPTY)
 		return;
 
+	dataModel->clear();
 	backgroundFile = QString(":poster%1").arg( rand()%3 +1);
 	currentState = EMPTY;
 	fixBackgroundPos();