Show Active Position errors in X/26 triplet list

Attempts to move the Active Position upwards to a lesser numbered row,
or leftwards within the same row to a lesser numbered column, are now
highlighted red within the triplet list so the user can see which
triplets are being ignored due to these errors.

Detection for other triplet errors such as reserved bits/values or
object related errors will be added later on.

This is a part of moving the Active Position logic from the renderer
to the triplet list, so a renderer won't be needed if the ability to
editing (G)POP pages is added in the future.

x26model.cpp

@@ -64,6 +64,16 @@ QVariant X26Model::data(const QModelIndex &index, int role) const
 				return QVariant();
 		}
 
+	// Error colours from KDE Plasma Breeze (light) theme
+	if (role == Qt::ForegroundRole && triplet.error() != X26Triplet::NoError && index.column() == m_tripletErrors[triplet.error()].columnHighlight)
+		return QColor(252, 252, 252);
+
+	if (role == Qt::BackgroundRole && triplet.error() != X26Triplet::NoError && index.column() == m_tripletErrors[triplet.error()].columnHighlight)
+		return QColor(218, 68, 63);
+
+	if (role == Qt::ToolTipRole && triplet.error() != X26Triplet::NoError)
+		return m_tripletErrors[triplet.error()].message;
+
 	if (role == Qt::DisplayRole || role == Qt::EditRole)
 		switch (index.column()) {
 			case 0:
@@ -94,7 +104,7 @@ QVariant X26Model::data(const QModelIndex &index, int role) const
 
 	if (role == Qt::DisplayRole) {
 		if (index.column() == 2)
-			return (modeTripletName[triplet.modeExt()]);
+			return (m_modeTripletName[triplet.modeExt()]);
 		// Column 3 - describe effects of data/address triplet parameters in plain English
 		switch (triplet.modeExt()) {
 			case 0x01: // Full row colour

x26model.h

@@ -51,9 +51,8 @@ private:
 	TeletextWidget *m_parentMainWidget;
 	bool m_listLoaded;
 	TeletextFontBitmap m_fontBitmap;
-};
 
-static const QString modeTripletName[64] {
+	const QString m_modeTripletName[64] {
 		// Row triplet modes
 		"Full screen colour",
 		"Full row colour",
@@ -132,6 +131,18 @@ static const QString modeTripletName[64] {
 		"G0 character diacritical D",
 		"G0 character diacritical E",
 		"G0 character diacritical F"
+	};
+
+	struct tripletErrorShow {
+		QString message;
+		int columnHighlight;
+	};
+
+	const tripletErrorShow m_tripletErrors[3] {
+		{ "", 0 }, // No error
+		{ "Active Position can't move up", 0 },
+		{ "Active Position can't move left within row", 1 }
+	};
 };
 
 #endif

x26triplets.cpp

@@ -52,22 +52,117 @@ void X26Triplet::setAddressColumn(int addressColumn)
 }
 
 
+void X26TripletList::updateInternalData(int r)
+{
+	ActivePosition activePosition;
+	X26Triplet *triplet;
+
+	if (r != 0) {
+		activePosition.setRow(m_list[r-1].m_activePositionRow);
+		activePosition.setColumn(m_list[r-1].m_activePositionColumn);
+	}
+
+	for (int i = r; i < m_list.size(); i++) {
+		triplet = &m_list[i];
+		triplet->m_error = X26Triplet::NoError;
+		if (triplet->isRowTriplet()) {
+			switch (m_list.at(i).modeExt()) {
+				case 0x00: // Full screen colour
+					if (activePosition.isDeployed())
+						// TODO more specific error needed
+						triplet->m_error = X26Triplet::ActivePositionMovedUp;
+					break;
+				case 0x01: // Full row colour
+					if (!activePosition.setRow(triplet->addressRow()))
+						triplet->m_error = X26Triplet::ActivePositionMovedUp;
+					break;
+				case 0x04: // Set Active Position;
+					if (!activePosition.setRow(triplet->addressRow()))
+						triplet->m_error = X26Triplet::ActivePositionMovedUp;
+					else if (triplet->data() >= 40 || !activePosition.setColumn(triplet->data()))
+						triplet->m_error = X26Triplet::ActivePositionMovedLeft;
+					break;
+				case 0x07: // Address row 0
+					if (activePosition.isDeployed())
+						triplet->m_error = X26Triplet::ActivePositionMovedUp;
+					else {
+						activePosition.setRow(0);
+						activePosition.setColumn(8);
+					}
+					break;
+				case 0x15 ... 0x17: // Define Object
+					activePosition.reset();
+			};
+		// Column triplet: make sure that PDC and reserved triplets don't affect the Active Position
+		} else if (triplet->modeExt() != 0x24 && triplet->modeExt() != 0x25 && triplet->modeExt() != 0x26 && triplet->modeExt() != 0x2a)
+			if (!activePosition.setColumn(triplet->addressColumn()))
+				triplet->m_error = X26Triplet::ActivePositionMovedLeft;
+		triplet->m_activePositionRow = activePosition.row();
+		triplet->m_activePositionColumn = activePosition.column();
+	}
+}
+
 void X26TripletList::append(const X26Triplet &value)
 {
 	m_list.append(value);
+	updateInternalData(m_list.size()-1);
 }
 
 void X26TripletList::insert(int i, const X26Triplet &value)
 {
 	m_list.insert(i, value);
+	updateInternalData(i);
 }
 
 void X26TripletList::removeAt(int i)
 {
 	m_list.removeAt(i);
+	if (m_list.size() != 0 && i < m_list.size())
+		updateInternalData(i);
 }
 
 void X26TripletList::replace(int i, const X26Triplet &value)
 {
 	m_list.replace(i, value);
+	updateInternalData(i);
 }
+
+
+X26TripletList::ActivePosition::ActivePosition()
+{
+	m_row = m_column = -1;
+}
+
+void X26TripletList::ActivePosition::reset()
+{
+	m_row = m_column = -1;
+}
+
+bool X26TripletList::ActivePosition::setRow(int row)
+{
+	if (row < m_row)
+		return false;
+	if (row > m_row) {
+		m_row = row;
+		m_column = -1;
+	}
+	return true;
+}
+
+bool X26TripletList::ActivePosition::setColumn(int column)
+{
+	if (column < m_column)
+		return false;
+	if (m_row == -1 and column >= 0)
+		m_row = 0;
+	m_column = column;
+	return true;
+}
+/*
+bool X26TripletList::ActivePosition::setRowAndColumn(int newRow, int newColumn)
+{
+	if (!setRow(newRow))
+		return false;
+	return setColumn(newColumn);
+}
+*/

x26triplets.h

@@ -25,6 +25,8 @@
 class X26Triplet
 {
 public:
+	enum X26TripletError { NoError, ActivePositionMovedUp, ActivePositionMovedLeft };
+
 	X26Triplet() {}
 //	X26Triplet(const X26Triplet &other);
 
@@ -46,8 +48,17 @@ public:
 	void setAddressRow(int);
 	void setAddressColumn(int);
 
+	int activePositionRow() const { return m_activePositionRow; }
+	int activePositionColumn() const { return m_activePositionColumn; }
+	X26TripletError error() const { return m_error; }
+
+	friend class X26TripletList;
+
 private:
 	int m_address, m_mode, m_data;
+	int m_activePositionRow = -1;
+	int m_activePositionColumn = -1;
+	X26TripletError m_error = NoError;
 };
 
 class X26TripletList
@@ -66,7 +77,27 @@ public:
 	int size() const { return m_list.size(); }
 
 private:
+	void updateInternalData(int);
+
 	QList<X26Triplet> m_list;
+
+	class ActivePosition
+	{
+	public:
+		ActivePosition();
+		void reset();
+//		int row() const { return (m_row == -1) ? 0 : m_row; }
+//		int column() const { return (m_column == -1) ? 0 : m_column; }
+		int row() const { return m_row; }
+		int column() const { return m_column; }
+		bool isDeployed() const { return m_row != -1; }
+		bool setRow(int);
+		bool setColumn(int);
+//		bool setRowAndColumn(int, int);
+
+	private:
+		int m_row, m_column;
+	};
 };
 
 #endif