Tag version 0.7.2-beta

The saving code has been refactored into one class per format with common
methods for each part of the saving process. This should make it easier to
add further formats, and inheriting a format class can allow implementing a
different format that is largely based on an existing format.

The loading code is also in one class per format but is largely the same as
what it was before.

Both classes have the ability to warn the user if any issues or errors are
or will be encountered when loading or saving.

TTI files are now written with CR/LF line endings on all platforms as a
result of using binary file writing for all formats, previously Linux builds
would save TTI files with just LF line endings. TTI files are still loaded
with readLine() and trimmed() which can cope with either type of line ending.

Experimental support for loading and exporting EP1 and HMS SD-Teletext htt
formats has been added. The htt format inherits from the t42 format as the
format appears to be largely the same except for the bits being reversed
within each byte and the clock run-in and framing code added before each
packet.

README.md

@@ -4,17 +4,17 @@ QTeletextMaker is a teletext page editor with an emphasis on Level 2.5 enhanceme
 It is written in C++ using the Qt 6 widget libraries.
 
 Features
-- Load and save teletext pages in .tti format.
-- Rendering of teletext pages in Levels 1, 1.5, 2.5 and 3.5
-- Rendering of Local Objects and side panels.
-- Import and export of single pages in .t42 format.
-- Export PNG and animated GIF images of teletext pages.
+- Load and save pages in TTI format.
+- Rendering of pages in Levels 1, 1.5, 2.5 and 3.5 including Local Objects and side panels.
+- Import and export of single pages in t42, EP1 and HTT formats.
+- Export PNG and animated GIF images of pages.
 - Undo and redo of editing actions.
 - Interactive X/26 Local Enhancement Data triplet editor.
 - Editing of X/27/4 and X/27/5 compositional links to enhancement data pages.
 - Palette editor.
 - Configurable zoom.
-- View teletext pages in 4:3, 16:9 pillar-box and 16:9 stretch aspect ratios.
+- View pages in 4:3, 16:9 pillar-box and 16:9 stretch aspect ratios.
+- View pages in mix and attribute-less monochrome modes.
 
 Although designed on and developed for Linux, the Qt libraries are cross platform so a Windows executable can be built. A Windows executable can be found within the "Releases" link, compiled on a Linux host using [MXE](https://github.com/mxe/mxe) based on [these instructions](https://web.archive.org/web/20230606021352/https://blog.8bitbuddhism.com/2018/08/22/cross-compiling-windows-applications-with-mxe/). After MXE is installed `make qt6-qtbase` should build and install the required dependencies to build QTeletextMaker.
 

examples/Level3p5-Joseph.tti

@@ -0,0 +1,22 @@
+DE,The colours of Joseph's dreamcoat
+PN,19900
+SC,0000
+PS,8000
+CT,20,T
+OL,28,@@@|g`VrO@_r{kGFBooWk}M`ooGDsL`ORrs}c@@@
+OL,28,D@@|g@@pC@|p@@CH|O@pwp}]@@wAws]G@@
+OL,26,@lD@`CHnD@AcHTCI`cIpD@ACJJcEL`CTcJ`CKrD@
+OL,26,AhQRAcKTCL`cLtD@JCMTcM`cBvD@ACNTcN`cGxD@
+OL,26,BAcFTCO`cO_CpURJcDjD@ACElD@JCGBBB
+OL,2, It was...                              
+OL,4,A]GRed   C]DYellow B]DGreen  MLA]GBrown 
+OL,6,A]GScarlet\ Black  A]GOchre  MLC]DPeach 
+OL,8,E]GRuby  C]DOlive  E]GViolet MLC]DFawn  
+OL,10,E]DLilac C]DGold MLA]GChocolateE]DMauve 
+OL,12, ]DCream A]GCrimson ]DSilver MLE]GRose  
+OL,14,D]GAzure C]DLemon  A]GRusset ML \ Grey  
+OL,16,E]GPurple ]DWhite  E]DPink   MLA]GOrange
+OL,18,                            andD]GBlue!M
+OL,21,  FRose is CLUT 0:5. Gold, Cream and    
+OL,22,  FLemon are in CLUT 1 and applied with 
+OL,23,  Fa Level 3.5 only Object.             

src/qteletextdecoder/document.cpp

@@ -18,7 +18,7 @@
  */
 
 #include <QAbstractListModel>
-#include <vector>
+#include <QList>
 
 #include "document.h"
 
@@ -52,7 +52,7 @@ void ClutModel::setSubPage(LevelOnePage *subPage)
 {
 	if (subPage != m_subPage) {
 		m_subPage = subPage;
-		emit dataChanged(createIndex(0, 0), createIndex(31, 0), QVector<int>(Qt::DecorationRole));
+		emit dataChanged(createIndex(0, 0), createIndex(31, 0), QList<int>(Qt::DecorationRole));
 	}
 }
 
@@ -63,11 +63,12 @@ TeletextDocument::TeletextDocument()
 	m_description.clear();
 	m_pageFunction = PFLevelOnePage;
 	m_packetCoding = Coding7bit;
-	m_subPages.push_back(new LevelOnePage);
+	m_subPages.append(new LevelOnePage);
 	m_currentSubPageIndex = 0;
 	m_undoStack = new QUndoStack(this);
 	m_cursorRow = 1;
 	m_cursorColumn = 0;
+	m_rowZeroAllowed = false;
 	m_selectionCornerRow = m_selectionCornerColumn = -1;
 	m_selectionSubPage = nullptr;
 
@@ -96,9 +97,7 @@ bool TeletextDocument::isEmpty() const
 
 void TeletextDocument::clear()
 {
-	LevelOnePage *blankSubPage = new LevelOnePage;
-
-	m_subPages.insert(m_subPages.begin(), blankSubPage);
+	m_subPages.prepend(new LevelOnePage);
 
 	emit aboutToChangeSubPage();
 	m_currentSubPageIndex = 0;
@@ -109,7 +108,7 @@ void TeletextDocument::clear()
 
 	for (int i=m_subPages.size()-1; i>0; i--) {
 		delete(m_subPages[i]);
-		m_subPages.erase(m_subPages.begin()+i);
+		m_subPages.remove(i);
 	}
 }
 
@@ -176,9 +175,9 @@ void TeletextDocument::insertSubPage(int beforeSubPageIndex, bool copySubPage)
 		insertedSubPage = new LevelOnePage;
 
 	if (beforeSubPageIndex == m_subPages.size())
-		m_subPages.push_back(insertedSubPage);
+		m_subPages.append(insertedSubPage);
 	else
-		m_subPages.insert(m_subPages.begin()+beforeSubPageIndex, insertedSubPage);
+		m_subPages.insert(beforeSubPageIndex, insertedSubPage);
 }
 
 void TeletextDocument::deleteSubPage(int subPageToDelete)
@@ -186,19 +185,19 @@ void TeletextDocument::deleteSubPage(int subPageToDelete)
 	m_clutModel->setSubPage(nullptr);
 
 	delete(m_subPages[subPageToDelete]);
-	m_subPages.erase(m_subPages.begin()+subPageToDelete);
+	m_subPages.remove(subPageToDelete);
 }
 
 void TeletextDocument::deleteSubPageToRecycle(int subPageToRecycle)
 {
-	m_recycleSubPages.push_back(m_subPages[subPageToRecycle]);
-	m_subPages.erase(m_subPages.begin()+subPageToRecycle);
+	m_recycleSubPages.append(m_subPages[subPageToRecycle]);
+	m_subPages.remove(subPageToRecycle);
 }
 
 void TeletextDocument::unDeleteSubPageFromRecycle(int subPage)
 {
-	m_subPages.insert(m_subPages.begin()+subPage, m_recycleSubPages.back());
-	m_recycleSubPages.pop_back();
+	m_subPages.insert(subPage, m_recycleSubPages.last());
+	m_recycleSubPages.removeLast();
 }
 
 void TeletextDocument::setPageNumber(int pageNumber)
@@ -252,7 +251,7 @@ void TeletextDocument::cursorUp(bool shiftKey)
 	if (shiftKey && !selectionActive())
 		setSelectionCorner(m_cursorRow, m_cursorColumn);
 
-	if (--m_cursorRow == 0)
+	if (--m_cursorRow == 0 - (int)m_rowZeroAllowed)
 		m_cursorRow = 24;
 
 	if (shiftKey)
@@ -269,7 +268,7 @@ void TeletextDocument::cursorDown(bool shiftKey)
 		setSelectionCorner(m_cursorRow, m_cursorColumn);
 
 	if (++m_cursorRow == 25)
-		m_cursorRow = 1;
+		m_cursorRow = (int)!m_rowZeroAllowed;
 
 	if (shiftKey)
 		emit selectionMoved();
@@ -333,6 +332,13 @@ void TeletextDocument::moveCursor(int cursorRow, int cursorColumn, bool selectio
 	emit cursorMoved();
 }
 
+void TeletextDocument::setRowZeroAllowed(bool allowed)
+{
+	m_rowZeroAllowed = allowed;
+	if (m_cursorRow == 0 && !allowed)
+		cursorDown();
+}
+
 void TeletextDocument::setSelectionCorner(int row, int column)
 {
 	if (m_selectionCornerRow != row || m_selectionCornerColumn != column) {

src/qteletextdecoder/document.h

@@ -21,9 +21,9 @@
 #define DOCUMENT_H
 
 #include <QAbstractListModel>
+#include <QList>
 #include <QObject>
 #include <QUndoStack>
-#include <vector>
 
 #include "levelonepage.h"
 
@@ -89,6 +89,8 @@ public:
 	void cursorLeft(bool shiftKey=false);
 	void cursorRight(bool shiftKey=false);
 	void moveCursor(int cursorRow, int cursorColumn, bool selectionInProgress=false);
+	bool rowZeroAllowed() const { return m_rowZeroAllowed; };
+	void setRowZeroAllowed(bool allowed);
 	int selectionTopRow() const { return m_selectionCornerRow == -1 ? m_cursorRow : qMin(m_selectionCornerRow, m_cursorRow); }
 	int selectionBottomRow() const { return qMax(m_selectionCornerRow, m_cursorRow); }
 	int selectionLeftColumn() const { return m_selectionCornerColumn == -1 ? m_cursorColumn : qMin(m_selectionCornerColumn, m_cursorColumn); }
@@ -119,10 +121,11 @@ private:
 	int m_pageNumber, m_currentSubPageIndex;
 	PageFunctionEnum m_pageFunction;
 	PacketCodingEnum m_packetCoding;
-	std::vector<LevelOnePage *> m_subPages;
-	std::vector<LevelOnePage *> m_recycleSubPages;
+	QList<LevelOnePage *> m_subPages;
+	QList<LevelOnePage *> m_recycleSubPages;
 	QUndoStack *m_undoStack;
 	int m_cursorRow, m_cursorColumn, m_selectionCornerRow, m_selectionCornerColumn;
+	bool m_rowZeroAllowed;
 	LevelOnePage *m_selectionSubPage;
 	ClutModel *m_clutModel;
 };

src/qteletextdecoder/levelonepage.cpp

@@ -244,7 +244,7 @@ bool LevelOnePage::packetExists(int y, int d) const
 
 	if (y == 28) {
 		if (d == 0) {
-			if (m_leftSidePanelDisplayed || m_rightSidePanelDisplayed || m_defaultScreenColour !=0 || m_defaultRowColour !=0 || m_blackBackgroundSubst || m_colourTableRemap !=0 || m_defaultCharSet != 0 || m_secondCharSet != 0xf)
+			if (m_leftSidePanelDisplayed || m_rightSidePanelDisplayed || m_defaultScreenColour != 0 || m_defaultRowColour != 0 || m_blackBackgroundSubst || m_colourTableRemap != 0 || m_secondCharSet != 0xf)
 				return true;
 			return !isPaletteDefault(16, 31);
 		}

src/qteletextdecoder/render.cpp

@@ -161,7 +161,7 @@ inline void TeletextPageRender::drawCharacter(QPainter &painter, int r, int c, u
 	else if ((m_decoder->cellBold(r, c) || m_decoder->cellItalic(r, c)) && characterSet < 24)
 		drawBoldOrItalicCharacter(painter, r, c, characterCode, characterSet, characterFragment);
 	else {
-		m_fontBitmap.image()->setColorTable(QVector<QRgb>{m_backgroundQColor.rgba(), m_foregroundQColor.rgba()});
+		m_fontBitmap.image()->setColorTable(QList<QRgb>{m_backgroundQColor.rgba(), m_foregroundQColor.rgba()});
 		drawFromFontBitmap(painter, r, c, characterCode, characterSet, characterFragment);
 	}
 
@@ -185,7 +185,7 @@ inline void TeletextPageRender::drawCharacter(QPainter &painter, int r, int c, u
 
 	if (characterDiacritical != 0) {
 		painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
-		m_fontBitmap.image()->setColorTable(QVector<QRgb>{0x00000000, m_foregroundQColor.rgba()});
+		m_fontBitmap.image()->setColorTable(QList<QRgb>{0x00000000, m_foregroundQColor.rgba()});
 		drawFromFontBitmap(painter, r, c, characterDiacritical+64, 7, characterFragment);
 		painter.setCompositionMode(QPainter::CompositionMode_Source);
 	}
@@ -196,8 +196,8 @@ inline void TeletextPageRender::drawBoldOrItalicCharacter(QPainter &painter, int
 	QImage styledImage = QImage(12, 10, QImage::Format_Mono);
 	QPainter styledPainter;
 
-	m_fontBitmap.image()->setColorTable(QVector<QRgb>{m_backgroundQColor.rgba(), m_foregroundQColor.rgba()});
-	styledImage.setColorTable(QVector<QRgb>{m_backgroundQColor.rgba(), m_foregroundQColor.rgba()});
+	m_fontBitmap.image()->setColorTable(QList<QRgb>{m_backgroundQColor.rgba(), m_foregroundQColor.rgba()});
+	styledImage.setColorTable(QList<QRgb>{m_backgroundQColor.rgba(), m_foregroundQColor.rgba()});
 
 	if (m_decoder->cellItalic(r, c)) {
 		styledImage.fill(0);
@@ -217,7 +217,7 @@ inline void TeletextPageRender::drawBoldOrItalicCharacter(QPainter &painter, int
 		boldeningImage = styledImage.copy();
 		styledPainter.begin(&styledImage);
 		styledPainter.setCompositionMode(QPainter::CompositionMode_SourceOver);
-		boldeningImage.setColorTable(QVector<QRgb>{0x00000000, m_foregroundQColor.rgba()});
+		boldeningImage.setColorTable(QList<QRgb>{0x00000000, m_foregroundQColor.rgba()});
 		styledPainter.drawImage(1, 0, boldeningImage);
 		styledPainter.end();
 	}
@@ -324,7 +324,7 @@ void TeletextPageRender::renderRow(int r, int ph, bool force)
 
 			if (m_showControlCodes && c < 40 && m_decoder->teletextPage()->character(r, c) < 0x20) {
 				painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
-				m_fontBitmap.image()->setColorTable(QVector<QRgb>{0x7f000000, 0xe0ffffff});
+				m_fontBitmap.image()->setColorTable(QList<QRgb>{0x7f000000, 0xe0ffffff});
 				painter.drawImage(c*12, r*10, *m_fontBitmap.image(), (m_decoder->teletextPage()->character(r, c)+32)*12, 250, 12, 10);
 				painter.setCompositionMode(QPainter::CompositionMode_Source);
 			}

src/qteletextmaker/hashformats.cpp

@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2020-2025 Gavin MacGregor
+ *
+ * This file is part of QTeletextMaker.
+ *
+ * QTeletextMaker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QTeletextMaker is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "hashformats.h"
+
+#include <QByteArray>
+#include <QString>
+
+#include "levelonepage.h"
+#include "pagebase.h"
+
+QString exportHashStringPage(LevelOnePage *subPage)
+{
+	int hashDigits[1167]={0};
+	int totalBits, charBit;
+	const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+	QString hashString;
+	QByteArray rowPacket;
+
+	// TODO int editTFCharacterSet = 5;
+	bool blackForeground = false;
+
+	for (int r=0; r<25; r++) {
+		if (subPage->packetExists(r))
+			rowPacket = subPage->packet(r);
+		else
+			rowPacket = QByteArray(40, 0x20).constData();
+
+		for (int c=0; c<40; c++) {
+			if (rowPacket.at(c) == 0x00 || rowPacket.at(c) == 0x10)
+				blackForeground = true;
+			for (int b=0; b<7; b++) {
+				totalBits = (r * 40 + c) * 7 + b;
+				charBit = ((rowPacket.at(c)) >> (6 - b)) & 0x01;
+				hashDigits[totalBits / 6] |= charBit << (5 - (totalBits % 6));
+			}
+		}
+	}
+
+	hashString.append(QString("#%1:").arg(blackForeground ? 8 : 0, 1, 16));
+
+	for (int i=0; i<1167; i++)
+		hashString.append(base64[hashDigits[i]]);
+
+	return hashString;
+}
+
+QString exportHashStringPackets(LevelOnePage *subPage)
+{
+	auto colourToHexString=[&](int whichCLUT)
+	{
+		QString resultHexString;
+
+		for (int i=whichCLUT*8; i<whichCLUT*8+8; i++)
+			resultHexString.append(QString("%1").arg(subPage->CLUT(i), 3, 16, QChar('0')));
+		return resultHexString;
+	};
+
+	const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+	QString result;
+
+	if (subPage->packetExists(28,0) || subPage->packetExists(28,4)) {
+		// X/28/0 and X/28/4 are duplicates apart from the CLUT definitions
+		// Assemble the duplicate beginning and ending of both packets
+		QString x28StringBegin, x28StringEnd;
+
+		x28StringBegin.append(QString("00%1").arg((subPage->defaultCharSet() << 3) | subPage->defaultNOS(), 2, 16, QChar('0')).toUpper());
+		x28StringBegin.append(QString("%1").arg((subPage->secondCharSet() << 3) | subPage->secondNOS(), 2, 16, QChar('0')).toUpper());
+		x28StringBegin.append(QString("%1%2%3%4").arg(subPage->leftSidePanelDisplayed(), 1, 10).arg(subPage->rightSidePanelDisplayed(), 1, 10).arg(subPage->sidePanelStatusL25(), 1, 10).arg(subPage->sidePanelColumns(), 1, 16));
+
+		x28StringEnd = QString("%1%2%3%4").arg(subPage->defaultScreenColour(), 2, 16, QChar('0')).arg(subPage->defaultRowColour(), 2, 16, QChar('0')).arg(subPage->blackBackgroundSubst(), 1, 10).arg(subPage->colourTableRemap(), 1, 10);
+
+		if (subPage->packetExists(28,0))
+			result.append(":X280=" + x28StringBegin + colourToHexString(2) + colourToHexString(3) + x28StringEnd);
+		if (subPage->packetExists(28,4))
+			result.append(":X284=" + x28StringBegin + colourToHexString(0) + colourToHexString(1) + x28StringEnd);
+	}
+
+	if (!subPage->enhancements()->isEmpty()) {
+		result.append(":X26=");
+		for (int i=0; i<subPage->enhancements()->size(); i++) {
+			result.append(base64[subPage->enhancements()->at(i).data() >> 1]);
+			result.append(base64[subPage->enhancements()->at(i).mode() | ((subPage->enhancements()->at(i).data() & 1) << 5)]);
+			result.append(base64[subPage->enhancements()->at(i).address()]);
+		}
+	}
+
+	// Assemble PS
+	// C4 Erase page is stored in bit 14
+	int pageStatus = 0x8000 | (subPage->controlBit(PageBase::C4ErasePage) << 14);
+	// C5 to C11 stored in order from bits 1 to 6
+	for (int i=PageBase::C5Newsflash; i<=PageBase::C11SerialMagazine; i++)
+		pageStatus |= subPage->controlBit(i) << (i-1);
+	// Apparently the TTI format stores the NOS bits backwards
+	pageStatus |= subPage->controlBit(PageBase::C12NOS) << 9;
+	pageStatus |= subPage->controlBit(PageBase::C13NOS) << 8;
+	pageStatus |= subPage->controlBit(PageBase::C14NOS) << 7;
+
+	result.append(QString(":PS=%1").arg(0x8000 | pageStatus, 0, 16, QChar('0')));
+	return result;
+}

src/qteletextmaker/hashformats.h

@@ -17,30 +17,15 @@
  * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#ifndef LOADSAVE_H
-#define LOADSAVE_H
+#ifndef HASHFORMATS_H
+#define HASHFORMATS_H
 
 #include <QByteArray>
-#include <QFile>
-#include <QSaveFile>
 #include <QString>
-#include <QTextStream>
 
-#include "document.h"
 #include "levelonepage.h"
 #include "pagebase.h"
 
-void loadTTI(QFile *inFile, TeletextDocument *document);
-void importT42(QFile *inFile, TeletextDocument *document);
-
-int controlBitsToPS(PageBase *subPage);
-
-void saveTTI(QSaveFile &file, const TeletextDocument &document);
-void exportT42File(QSaveFile &file, const TeletextDocument &document);
-void exportM29File(QSaveFile &file, const TeletextDocument &document);
-
-QByteArray rowPacketAlways(PageBase *subPage, int packetNumber);
-
 QString exportHashStringPage(LevelOnePage *subPage);
 QString exportHashStringPackets(LevelOnePage *subPage);
 

src/qteletextmaker/levelonecommands.cpp

@@ -810,7 +810,7 @@ PasteCommand::PasteCommand(TeletextDocument *teletextDocument, int pageCharSet,
 			imageData.convertTo(QImage::Format_MonoLSB);
 		else
 			// Only pure black and white images convert reliably this way...
-			imageData = imageData.convertToFormat(QImage::Format_MonoLSB, QVector<QRgb>{0x000000ff, 0xffffffff});
+			imageData = imageData.convertToFormat(QImage::Format_MonoLSB, QList<QRgb>{0x000000ff, 0xffffffff});
 
 		for (int r=0; r<m_clipboardDataHeight; r++)
 			m_pastingCharacters.append(QByteArray(m_clipboardDataWidth, 0x00));

src/qteletextmaker/loadformats.cpp

@@ -0,0 +1,597 @@
+/*
+ * Copyright (C) 2020-2025 Gavin MacGregor
+ *
+ * This file is part of QTeletextMaker.
+ *
+ * QTeletextMaker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QTeletextMaker is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "loadformats.h"
+
+#include <QByteArray>
+#include <QDataStream>
+#include <QFile>
+#include <QString>
+#include <QStringList>
+#include <QTextStream>
+
+#include "document.h"
+#include "hamming.h"
+#include "levelonepage.h"
+#include "pagebase.h"
+
+bool LoadTTIFormat::load(QFile *inFile, TeletextDocument *document)
+{
+	m_warnings.clear();
+	m_error.clear();
+
+	QByteArray inLine;
+	bool firstSubPageAlreadyFound = false;
+	bool pageBodyPacketsFound = false;
+	int cycleCommandsFound = 0;
+	int mostRecentCycleValue = -1;
+	LevelOnePage::CycleTypeEnum mostRecentCycleType;
+
+	LevelOnePage* loadingPage = document->subPage(0);
+
+	for (;;) {
+		inLine = inFile->readLine(160).trimmed();
+		if (inLine.isEmpty())
+			break;
+		if (inLine.startsWith("DE,"))
+			document->setDescription(QString(inLine.remove(0, 3)));
+		if (inLine.startsWith("PN,")) {
+			// When second and subsequent PN commands are found, firstSubPageAlreadyFound==true at this point
+			// This assumes that PN is the first command of a new subpage...
+			if (firstSubPageAlreadyFound) {
+				document->insertSubPage(document->numberOfSubPages(), false);
+				loadingPage = document->subPage(document->numberOfSubPages()-1);
+			} else {
+				document->setPageNumberFromString(inLine.mid(3,3));
+				firstSubPageAlreadyFound = true;
+			}
+		}
+/*		if (lineType == "SC,") {
+			bool subPageNumberOk;
+			int subPageNumberRead = inLine.mid(3, 4).toInt(&subPageNumberOk, 16);
+			if ((!subPageNumberOk) || subPageNumberRead > 0x3f7f)
+				subPageNumberRead = 0;
+			loadingPage->setSubPageNumber(subPageNumberRead);
+		}*/
+		if (inLine.startsWith("PS,")) {
+			bool pageStatusOk;
+			int pageStatusRead = inLine.mid(3, 4).toInt(&pageStatusOk, 16);
+			if (pageStatusOk) {
+				loadingPage->setControlBit(PageBase::C4ErasePage, pageStatusRead & 0x4000);
+				for (int i=PageBase::C5Newsflash, pageStatusBit=0x0001; i<=PageBase::C11SerialMagazine; i++, pageStatusBit<<=1)
+					loadingPage->setControlBit(i, pageStatusRead & pageStatusBit);
+				loadingPage->setDefaultNOS(((pageStatusRead & 0x0200) >> 9) | ((pageStatusRead & 0x0100) >> 7) | ((pageStatusRead & 0x0080) >> 5));
+			}
+		}
+		if (inLine.startsWith("RE,")) {
+			bool regionValueOk;
+			int regionValueRead = inLine.remove(0, 3).toInt(&regionValueOk);
+			if (regionValueOk)
+				loadingPage->setDefaultCharSet(regionValueRead);
+		}
+		if (inLine.startsWith("CT,") && (inLine.endsWith(",C") || inLine.endsWith(",T"))) {
+			bool cycleValueOk;
+			int cycleValueRead = inLine.mid(3, inLine.size()-5).toInt(&cycleValueOk);
+			if (cycleValueOk) {
+				cycleCommandsFound++;
+				// House-keep CT command values, in case it's the only one within multiple subpages
+				mostRecentCycleValue = cycleValueRead;
+				loadingPage->setCycleValue(cycleValueRead);
+				mostRecentCycleType = inLine.endsWith("C") ? LevelOnePage::CTcycles : LevelOnePage::CTseconds;
+				loadingPage->setCycleType(mostRecentCycleType);
+			}
+		}
+		if (inLine.startsWith("FL,")) {
+			bool fastTextLinkOk;
+			int fastTextLinkRead;
+			QString flLine = QString(inLine.remove(0, 3));
+			if (flLine.count(',') == 5)
+				for (int i=0; i<6; i++) {
+					fastTextLinkRead = flLine.section(',', i, i).toInt(&fastTextLinkOk, 16);
+					if (fastTextLinkOk) {
+						if (fastTextLinkRead == 0)
+							fastTextLinkRead = 0x8ff;
+						// Stored as page link with relative magazine number, convert from absolute page number that was read
+						fastTextLinkRead ^= document->pageNumber() & 0x700;
+						fastTextLinkRead &= 0x7ff; // Fixes magazine 8 to 0
+						loadingPage->setFastTextLinkPageNumber(i, fastTextLinkRead);
+					}
+				}
+		}
+		if (inLine.startsWith("OL,")) {
+			bool lineNumberOk;
+			int lineNumber, secondCommaPosition;
+
+			secondCommaPosition = inLine.indexOf(",", 3);
+			if (secondCommaPosition != 4 && secondCommaPosition != 5)
+				continue;
+
+			lineNumber = inLine.mid(3, secondCommaPosition-3).toInt(&lineNumberOk, 10);
+			if (lineNumberOk && lineNumber >= 0 && lineNumber <= 29) {
+				pageBodyPacketsFound = true;
+
+				inLine.remove(0, secondCommaPosition+1);
+				if (lineNumber <= 25) {
+					for (int c=0; c<40; c++) {
+						// trimmed() helpfully removes CRLF line endings from the just-read line for us
+						// But it also (un)helpfully removes spaces at the end of a 40 character line, so put them back
+						if (c >= inLine.size())
+							inLine.append(' ');
+						if (inLine.at(c) & 0x80)
+							inLine[c] = inLine.at(c) & 0x7f;
+						else if (inLine.at(c) == 0x10)
+							inLine[c] = 0x0d;
+						else if (inLine.at(c) == 0x1b) {
+							inLine.remove(c, 1);
+							inLine[c] = inLine.at(c) & 0xbf;
+						}
+					}
+					loadingPage->setPacket(lineNumber, inLine);
+				} else {
+					int designationCode = inLine.at(0) & 0x3f;
+					if (inLine.size() < 40) {
+						// OL is too short!
+						if (lineNumber == 26) {
+							// For a too-short enhancement triplets OL, first trim the line down to nearest whole triplet
+							inLine.resize((inLine.size() / 3 * 3) + 1);
+							// Then use "dummy" enhancement triplets to extend the line to the proper length
+							for (int i=inLine.size(); i<40; i+=3)
+								inLine.append("i^@"); // Address 41, Mode 0x1e, Data 0
+						} else
+							// For other triplet OLs and Hamming 8/4 OLs, just pad with zero data
+							for (int i=inLine.size(); i<40; i++)
+								inLine.append("@");
+					}
+					for (int i=1; i<=39; i++)
+						inLine[i] = inLine.at(i) & 0x3f;
+					// Import M/29 whole-magazine packets as X/28 per-page packets
+					if (lineNumber == 29) {
+						if ((document->pageNumber() & 0xff) != 0xff)
+							m_warnings.append(QString("M/29/%1 packet found, but page number was not xFF.").arg(designationCode));
+						lineNumber = 28;
+					}
+					loadingPage->setPacket(lineNumber, designationCode, inLine);
+				}
+			}
+		}
+	}
+
+	if (!pageBodyPacketsFound) {
+		m_error = "No OL lines found";
+		return false;
+	}
+
+	// If there's more than one subpage but only one valid CT command was found, apply it to all subpages
+	// I don't know if this is correct
+	if (cycleCommandsFound == 1 && document->numberOfSubPages()>1)
+		for (int i=0; i<document->numberOfSubPages(); i++) {
+			document->subPage(i)->setCycleValue(mostRecentCycleValue);
+			document->subPage(i)->setCycleType(mostRecentCycleType);
+		}
+
+	return true;
+}
+
+
+bool LoadT42Format::readPacket()
+{
+	return m_inFile->read((char *)m_inLine, 42) == 42;
+}
+
+bool LoadT42Format::load(QFile *inFile, TeletextDocument *document)
+{
+	int readMagazineNumber, readPacketNumber;
+	int foundMagazineNumber = -1;
+	int foundPageNumber = -1;
+	bool firstPacket0Found = false;
+	bool pageBodyPacketsFound = false;
+
+	m_inFile = inFile;
+
+	m_warnings.clear();
+	m_error.clear();
+	m_reExportWarning = false;
+
+	for (;;) {
+		if (!readPacket())
+			// Reached end of .t42 file, or less than 42 bytes left
+			break;
+
+		// Magazine and packet numbers
+		m_inLine[0] = hamming_8_4_decode[m_inLine[0]];
+		m_inLine[1] = hamming_8_4_decode[m_inLine[1]];
+		if (m_inLine[0] == 0xff || m_inLine[1] == 0xff)
+			// Error decoding magazine or packet number
+			continue;
+		readMagazineNumber = m_inLine[0] & 0x07;
+		readPacketNumber = (m_inLine[0] >> 3) | (m_inLine[1] << 1);
+
+		if (readPacketNumber == 0) {
+			// Hamming decode page number, subcodes and control bits
+			for (int i=2; i<10; i++)
+				m_inLine[i] = hamming_8_4_decode[m_inLine[i]];
+			// See if the page number is valid
+			if (m_inLine[2] == 0xff || m_inLine[3] == 0xff)
+				// Error decoding page number
+				continue;
+
+			const int readPageNumber = (m_inLine[3] << 4) | m_inLine[2];
+
+			if (readPageNumber == 0xff)
+				// Time filling header
+				continue;
+
+			// A second or subsequent X/0 has been found
+			if (firstPacket0Found) {
+				if (readMagazineNumber != foundMagazineNumber)
+					// Packet from different magazine broadcast in parallel mode
+					continue;
+				if ((readPageNumber == foundPageNumber) && pageBodyPacketsFound)
+					// X/0 with same page number found after page body packets loaded - assume end of page
+					break;
+				if (readPageNumber != foundPageNumber) {
+					// More than one page in .t42 file - end of current page reached
+					m_warnings.append("More than one page in .t42 file, only first full page loaded.");
+					m_reExportWarning = true;
+					break;
+				}
+				// Could get here if X/0 with same page number was found with no body packets inbetween
+				continue;
+			} else {
+				// First X/0 found
+				foundMagazineNumber = readMagazineNumber;
+				foundPageNumber = readPageNumber;
+				firstPacket0Found = true;
+
+				if (foundMagazineNumber == 0)
+					document->setPageNumber(0x800 | foundPageNumber);
+				else
+					document->setPageNumber((foundMagazineNumber << 8) | foundPageNumber);
+
+				document->subPage(0)->setControlBit(PageBase::C4ErasePage, m_inLine[5] & 0x08);
+				document->subPage(0)->setControlBit(PageBase::C5Newsflash, m_inLine[7] & 0x04);
+				document->subPage(0)->setControlBit(PageBase::C6Subtitle, m_inLine[7] & 0x08);
+				for (int i=0; i<4; i++)
+					document->subPage(0)->setControlBit(PageBase::C7SuppressHeader+i, m_inLine[8] & (1 << i));
+				document->subPage(0)->setControlBit(PageBase::C11SerialMagazine, m_inLine[9] & 0x01);
+				document->subPage(0)->setControlBit(PageBase::C12NOS, m_inLine[9] & 0x08);
+				document->subPage(0)->setControlBit(PageBase::C13NOS, m_inLine[9] & 0x04);
+				document->subPage(0)->setControlBit(PageBase::C14NOS, m_inLine[9] & 0x02);
+
+				// See if there's text in the header row
+				bool headerText = false;
+
+				for (int i=10; i<42; i++)
+					if (m_inLine[i] != 0x20) {
+						// TODO - obey odd parity?
+						m_inLine[i] &= 0x7f;
+						headerText = true;
+					}
+				if (headerText) {
+					// Clear the page address and control bits to spaces before putting the row in
+					for (int i=0; i<10; i++)
+						m_inLine[i] = 0x20;
+
+					document->subPage(0)->setPacket(0, QByteArray((const char *)&m_inLine[2], 40));
+				}
+				continue;
+			}
+		}
+
+		// No X/0 has been found yet, keep looking for one
+		if (!firstPacket0Found)
+			continue;
+
+		// Disregard whole-magazine packets
+		if (readPacketNumber > 28)
+			continue;
+
+		// We get here when a page-body packet belonging to the found X/0 header was found
+		pageBodyPacketsFound = true;
+
+		// At the moment this only loads a Level One Page properly
+		// because it assumes X/1 to X/25 is odd partity
+		if (readPacketNumber < 25) {
+			for (int i=2; i<42; i++)
+				// TODO - obey odd parity?
+				m_inLine[i] &= 0x7f;
+			document->subPage(0)->setPacket(readPacketNumber, QByteArray((const char *)&m_inLine[2], 40));
+			continue;
+		}
+
+		// X/26, X/27 or X/28
+		int readDesignationCode = hamming_8_4_decode[m_inLine[2]];
+
+		if (readDesignationCode == 0xff)
+			// Error decoding designation code
+			continue;
+
+		if (readPacketNumber == 27 && readDesignationCode < 4) {
+			// X/27/0 to X/27/3 for Editorial Linking
+			// Decode Hamming 8/4 on each of the six links, checking for errors on the way
+			for (int i=0; i<6; i++) {
+				bool decodingError = false;
+				const int b = 3 + i*6; // First byte of this link
+
+				for (int j=0; j<6; j++) {
+					m_inLine[b+j] = hamming_8_4_decode[m_inLine[b+j]];
+					if (m_inLine[b+j] == 0xff) {
+						decodingError = true;
+						break;
+					}
+				}
+
+				if (decodingError) {
+					// Error found in at least one byte of the link
+					// Neutralise the whole link to same magazine, page FF, subcode 3F7F
+					qDebug("X/27/%d link %d decoding error", readDesignationCode, i);
+					m_inLine[b]   = 0xf;
+					m_inLine[b+1] = 0xf;
+					m_inLine[b+2] = 0xf;
+					m_inLine[b+3] = 0x7;
+					m_inLine[b+4] = 0xf;
+					m_inLine[b+5] = 0x3;
+				}
+			}
+			document->subPage(0)->setPacket(readPacketNumber, readDesignationCode, QByteArray((const char *)&m_inLine[2], 40));
+
+			continue;
+		}
+
+		// X/26, or X/27/4 to X/27/15, or X/28
+		// Decode Hamming 24/18
+		for (int i=0; i<13; i++) {
+			const int b = 3 + i*3; // First byte of triplet
+
+			const int p0 = m_inLine[b];
+			const int p1 = m_inLine[b+1];
+			const int p2 = m_inLine[b+2];
+
+			unsigned int D1_D4;
+			unsigned int D5_D11;
+			unsigned int D12_D18;
+			unsigned int ABCDEF;
+			int32_t d;
+
+			D1_D4 = hamming_24_18_decode_d1_d4[p0 >> 2];
+			D5_D11 = p1 & 0x7f;
+			D12_D18 = p2 & 0x7f;
+
+			d = D1_D4 | (D5_D11 << 4) | (D12_D18 << 11);
+
+			ABCDEF = (hamming_24_18_parities[0][p0] ^ hamming_24_18_parities[1][p1]  ^ hamming_24_18_parities[2][p2]);
+
+			d ^= (int)hamming_24_18_decode_correct[ABCDEF];
+
+			if ((d & 0x80000000) == 0x80000000) {
+				// Error decoding Hamming 24/18
+				qDebug("X/%d/%d triplet %d decoding error", readPacketNumber, readDesignationCode, i);
+				if (readPacketNumber == 26) {
+					// Enhancements packet, set to "dummy" Address 41, Mode 0x1e, Data 0
+					m_inLine[b]   = 41;
+					m_inLine[b+1] = 0x1e;
+					m_inLine[b+2] = 0;
+				} else {
+					// Zero out whole decoded triplet, bound to make things go wrong...
+					m_inLine[b]   = 0x00;
+					m_inLine[b+1] = 0x00;
+					m_inLine[b+2] = 0x00;
+				}
+			} else {
+				m_inLine[b]   = d & 0x0003f;
+				m_inLine[b+1] = (d & 0x00fc0) >> 6;
+				m_inLine[b+2] = d >> 12;
+			}
+		}
+		document->subPage(0)->setPacket(readPacketNumber, readDesignationCode, QByteArray((const char *)&m_inLine[2], 40));
+	}
+
+	if (!firstPacket0Found) {
+		m_error = "No X/0 found.";
+		return false;
+	} else if (!pageBodyPacketsFound) {
+		m_error = "X/0 found, but no page body packets were found.";
+		return false;
+	} else
+		return true;
+}
+
+
+bool LoadHTTFormat::readPacket()
+{
+	unsigned char httLine[45];
+
+	if (m_inFile->read((char *)httLine, 45) != 45)
+		return false;
+
+	if (httLine[0] != 0xaa || httLine[1] != 0xaa || httLine[2] != 0xe4)
+		return false;
+
+	for (int i=0; i<42; i++) {
+		unsigned char b = httLine[i+3];
+		b = (b & 0xf0) >> 4 | (b & 0x0f) << 4;
+		b = (b & 0xcc) >> 2 | (b & 0x33) << 2;
+		b = (b & 0xaa) >> 1 | (b & 0x55) << 1;
+		m_inLine[i] = b;
+	}
+
+	return true;
+}
+
+
+bool LoadEP1Format::load(QFile *inFile, TeletextDocument *document)
+{
+	m_warnings.clear();
+	m_error.clear();
+	m_reExportWarning = false;
+
+	unsigned char inLine[42];
+	unsigned char numOfSubPages = 1;
+
+	LevelOnePage* loadingPage = document->subPage(0);
+
+	for (;;) {
+		// Read six bytes, will either be a header for a (sub)page
+		// or a start header indicating multiple subpages are within
+		if (inFile->read((char *)inLine, 6) != 6)
+			return false;
+		if (inLine[0] == 'J' || inLine[1] == 'W' || inLine[2] == 'C') {
+			// Multiple subpages: get number of subpages then read
+			// next six bytes that really will be the header of the first subpage
+			numOfSubPages = inLine[3];
+			if (inFile->read((char *)inLine, 6) != 6)
+				return false;
+
+			m_warnings.append("More than one page in EP1/EPX file, only first full page loaded.");
+			m_reExportWarning = true;
+		}
+
+		// Check for header of a (sub)page
+		if (inLine[0] != 0xfe || inLine[1] != 0x01)
+			return false;
+
+		// Deal with language code unique to EP1 - unknown values are mapped to English
+		loadingPage->setDefaultCharSet(m_languageCode.key(inLine[2], 0x09) >> 3);
+		loadingPage->setDefaultNOS(m_languageCode.key(inLine[2], 0x09) & 0x7);
+
+		// If fourth byte is 0xca then "X/26 enhancements header" follows
+		// Otherwise Level 1 page data follows
+		if (inLine[3] == 0xca) {
+			// Read next four bytes that form the "X/26 enhancements header"
+			if (inFile->read((char *)inLine, 4) != 4)
+				return false;
+			// Third and fourth bytes are little-endian length of enhancement data
+			const int numOfX26Bytes = inLine[2] | (inLine[3] << 8);
+			const int numOfX26Packets = (numOfX26Bytes + 39) / 40;
+
+			QByteArray packet(40, 0x00);
+			packet[0] = 0;
+
+			for (int i=0; i<numOfX26Packets; i++) {
+				bool terminatorFound = false;
+				unsigned char terminatorTriplet[3];
+
+				if (inFile->read((char *)inLine, 40) != 40)
+					return false;
+
+				// Assumes that X/26 packets are saved with ascending designation codes...
+				for (int c=1; c<39; c+=3) {
+					if (!terminatorFound) {
+						// Shuffle triplet bits from 6 bit address, 5 bit mode, 7 bit data
+						packet[c] = inLine[c];
+						packet[c+1] = inLine[c+1] | ((inLine[c+2] & 1) << 5);
+						packet[c+2] = inLine[c+2] >> 1;
+						// Address of termination marker is 7f instead of 3f
+						if (inLine[c+1] == 0x1f && inLine[c] == 0x7f) {
+							packet[c] = 0x3f;
+
+							if (inLine[c+2] & 0x01) {
+								// If a termination marker was found, stop reading the packet
+								// and repeat the marker ourselves to the end
+								terminatorFound = true;
+								terminatorTriplet[0] = packet[c+1];
+								terminatorTriplet[1] = packet[c+2];
+							}
+						}
+					} else {
+						packet[c] = 0x3f;
+						packet[c+1] = terminatorTriplet[0];
+						packet[c+2] = terminatorTriplet[1];
+					}
+				}
+
+				loadingPage->setPacket(26, i, packet);
+			}
+		}
+
+		// Level 1 rows
+		for (int r=0; r<24; r++) {
+			if (inFile->read((char *)inLine, 40) != 40)
+				return false;
+
+			for (int c=0; c<40; c++)
+				if (inLine[c] != 0x20) {
+					loadingPage->setPacket(r, QByteArray((const char *)&inLine, 40));
+					break;
+				}
+		}
+
+		numOfSubPages--;
+
+		// FIXME uncomment "if" statement when we're ready to save multi-page EPX files
+		//if (numOfSubPages == 0)
+		break;
+
+		// There are more subpages coming up so skip over the 40 byte buffer and 2 byte terminator
+		if (inFile->read((char *)inLine, 42) != 42)
+			return false;
+
+		document->insertSubPage(document->numberOfSubPages(), false);
+		loadingPage = document->subPage(document->numberOfSubPages()-1);
+	}
+	return true;
+}
+
+
+int LoadFormats::s_instances = 0;
+
+LoadFormats::LoadFormats()
+{
+	if (s_instances == 0) {
+		s_fileFormat[0] = new LoadTTIFormat;
+		s_fileFormat[1] = new LoadT42Format;
+		s_fileFormat[2] = new LoadEP1Format;
+		s_fileFormat[3] = new LoadHTTFormat;
+
+		s_filters = "All Supported Files (*.";
+
+		for (int i=0; i<s_size; i++) {
+			if (i != 0)
+				s_filters.append(" *.");
+			s_filters.append(s_fileFormat[i]->extensions().join(" *."));
+		}
+		s_filters.append(");;");
+
+		for (int i=0; i<s_size; i++) {
+			if (i != 0)
+				s_filters.append(";;");
+			s_filters.append(s_fileFormat[i]->fileDialogFilter());
+		}
+	}
+
+	s_instances++;
+}
+
+LoadFormats::~LoadFormats()
+{
+	s_instances--;
+
+	if (s_instances == 0)
+		for (int i=s_size-1; i>=0; i--)
+			delete s_fileFormat[i];
+}
+
+LoadFormat *LoadFormats::findFormat(const QString &suffix) const
+{
+	for (int i=0; i<s_size; i++)
+		if (s_fileFormat[i]->extensions().contains(suffix, Qt::CaseInsensitive))
+			return s_fileFormat[i];
+
+	return nullptr;
+}

src/qteletextmaker/loadformats.h

@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2020-2025 Gavin MacGregor
+ *
+ * This file is part of QTeletextMaker.
+ *
+ * QTeletextMaker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QTeletextMaker is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef LOADFORMATS_H
+#define LOADFORMATS_H
+
+#include <QByteArray>
+#include <QDataStream>
+#include <QFile>
+#include <QString>
+#include <QStringList>
+#include <QTextStream>
+
+#include "document.h"
+#include "levelonepage.h"
+#include "pagebase.h"
+
+class LoadFormat
+{
+public:
+	virtual ~LoadFormat() {};
+
+	virtual bool load(QFile *inFile, TeletextDocument *document) =0;
+
+	virtual QString description() const =0;
+	virtual QStringList extensions() const =0;
+	QString fileDialogFilter() const { return QString(description() + " (*." + extensions().join(" *.") + ')'); };
+	QStringList warningStrings() const { return m_warnings; };
+	QString errorString() const { return m_error; };
+	bool reExportWarning() const { return m_reExportWarning; };
+
+protected:
+	TeletextDocument const *m_document;
+	QStringList m_warnings;
+	QString m_error;
+	bool m_reExportWarning = false;
+};
+
+class LoadTTIFormat : public LoadFormat
+{
+public:
+	bool load(QFile *inFile, TeletextDocument *document) override;
+
+	QString description() const override { return QString("MRG Systems TTI"); };
+	QStringList extensions() const override { return QStringList { "tti", "ttix" }; };
+};
+
+class LoadT42Format : public LoadFormat
+{
+public:
+	bool load(QFile *inFile, TeletextDocument *document) override;
+
+	QString description() const override { return QString("t42 packet stream"); };
+	QStringList extensions() const override { return QStringList { "t42" }; };
+
+protected:
+	virtual bool readPacket();
+
+	QFile *m_inFile;
+	unsigned char m_inLine[42];
+};
+
+class LoadHTTFormat : public LoadT42Format
+{
+public:
+	QString description() const override { return QString("HMS SD-Teletext HTT"); };
+	QStringList extensions() const override { return QStringList { "htt" }; };
+
+protected:
+	bool readPacket() override;
+};
+
+class LoadEP1Format : public LoadFormat
+{
+public:
+	bool load(QFile *inFile, TeletextDocument *document) override;
+
+	QString description() const override { return QString("Softel EP1"); };
+	QStringList extensions() const override { return QStringList { "ep1", "epx" }; };
+
+protected:
+	// Language codes unique to EP1
+	// FIXME duplicated in saveformats.h
+	const QMap<int, int> m_languageCode {
+		{ 0x00, 0x09 }, { 0x01, 0x0d }, { 0x02, 0x18 }, { 0x03, 0x11 }, { 0x04, 0x0b }, { 0x05, 0x17 }, { 0x06, 0x07 },
+		{ 0x08, 0x14 }, { 0x09, 0x0d }, { 0x0a, 0x18 }, { 0x0b, 0x11 }, { 0x0c, 0x0b }, { 0x0e, 0x07 },
+		{ 0x10, 0x09 }, { 0x11, 0x0d }, { 0x12, 0x18 }, { 0x13, 0x11 }, { 0x14, 0x0b }, { 0x15, 0x17 }, { 0x16, 0x1c },
+		{ 0x1d, 0x1e }, { 0x1f, 0x16 },
+		{ 0x21, 0x0d }, { 0x22, 0xff }, { 0x23, 0xff }, { 0x26, 0x07 },
+		{ 0x36, 0x1c }, { 0x37, 0x0e },
+		{ 0x40, 0x09 }, { 0x44, 0x0b }
+	};
+};
+
+
+class LoadFormats
+{
+public:
+	LoadFormats();
+	~LoadFormats();
+
+	LoadFormat *findFormat(const QString &suffix) const;
+	QString filters() const { return s_filters; };
+
+private:
+	static const inline int s_size = 4;
+	static int s_instances;
+	inline static LoadFormat *s_fileFormat[s_size];
+	inline static QString s_filters;
+};
+
+#endif

src/qteletextmaker/loadsave.cpp

@@ -1,811 +0,0 @@
-/*
- * Copyright (C) 2020-2025 Gavin MacGregor
- *
- * This file is part of QTeletextMaker.
- *
- * QTeletextMaker is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * QTeletextMaker is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-#include "loadsave.h"
-
-#include <QByteArray>
-#include <QDataStream>
-#include <QFile>
-#include <QSaveFile>
-#include <QString>
-#include <QTextStream>
-
-#include "document.h"
-#include "hamming.h"
-#include "levelonepage.h"
-#include "pagebase.h"
-
-void loadTTI(QFile *inFile, TeletextDocument *document)
-{
-	QByteArray inLine;
-	bool firstSubPageAlreadyFound = false;
-	int cycleCommandsFound = 0;
-	int mostRecentCycleValue = -1;
-	LevelOnePage::CycleTypeEnum mostRecentCycleType;
-
-	LevelOnePage* loadingPage = document->subPage(0);
-
-	for (;;) {
-		inLine = inFile->readLine(160).trimmed();
-		if (inLine.isEmpty())
-			break;
-		if (inLine.startsWith("DE,"))
-			document->setDescription(QString(inLine.remove(0, 3)));
-		if (inLine.startsWith("PN,")) {
-			// When second and subsequent PN commands are found, firstSubPageAlreadyFound==true at this point
-			// This assumes that PN is the first command of a new subpage...
-			if (firstSubPageAlreadyFound) {
-				document->insertSubPage(document->numberOfSubPages(), false);
-				loadingPage = document->subPage(document->numberOfSubPages()-1);
-			} else {
-				document->setPageNumberFromString(inLine.mid(3,3));
-				firstSubPageAlreadyFound = true;
-			}
-		}
-/*		if (lineType == "SC,") {
-			bool subPageNumberOk;
-			int subPageNumberRead = inLine.mid(3, 4).toInt(&subPageNumberOk, 16);
-			if ((!subPageNumberOk) || subPageNumberRead > 0x3f7f)
-				subPageNumberRead = 0;
-			loadingPage->setSubPageNumber(subPageNumberRead);
-		}*/
-		if (inLine.startsWith("PS,")) {
-			bool pageStatusOk;
-			int pageStatusRead = inLine.mid(3, 4).toInt(&pageStatusOk, 16);
-			if (pageStatusOk) {
-				loadingPage->setControlBit(PageBase::C4ErasePage, pageStatusRead & 0x4000);
-				for (int i=PageBase::C5Newsflash, pageStatusBit=0x0001; i<=PageBase::C11SerialMagazine; i++, pageStatusBit<<=1)
-					loadingPage->setControlBit(i, pageStatusRead & pageStatusBit);
-				loadingPage->setDefaultNOS(((pageStatusRead & 0x0200) >> 9) | ((pageStatusRead & 0x0100) >> 7) | ((pageStatusRead & 0x0080) >> 5));
-			}
-		}
-		if (inLine.startsWith("CT,") && (inLine.endsWith(",C") || inLine.endsWith(",T"))) {
-			bool cycleValueOk;
-			int cycleValueRead = inLine.mid(3, inLine.size()-5).toInt(&cycleValueOk);
-			if (cycleValueOk) {
-				cycleCommandsFound++;
-				// House-keep CT command values, in case it's the only one within multiple subpages
-				mostRecentCycleValue = cycleValueRead;
-				loadingPage->setCycleValue(cycleValueRead);
-				mostRecentCycleType = inLine.endsWith("C") ? LevelOnePage::CTcycles : LevelOnePage::CTseconds;
-				loadingPage->setCycleType(mostRecentCycleType);
-			}
-		}
-		if (inLine.startsWith("FL,")) {
-			bool fastTextLinkOk;
-			int fastTextLinkRead;
-			QString flLine = QString(inLine.remove(0, 3));
-			if (flLine.count(',') == 5)
-				for (int i=0; i<6; i++) {
-					fastTextLinkRead = flLine.section(',', i, i).toInt(&fastTextLinkOk, 16);
-					if (fastTextLinkOk) {
-						if (fastTextLinkRead == 0)
-							fastTextLinkRead = 0x8ff;
-						// Stored as page link with relative magazine number, convert from absolute page number that was read
-						fastTextLinkRead ^= document->pageNumber() & 0x700;
-						fastTextLinkRead &= 0x7ff; // Fixes magazine 8 to 0
-						loadingPage->setFastTextLinkPageNumber(i, fastTextLinkRead);
-					}
-				}
-		}
-		if (inLine.startsWith("OL,")) {
-			bool lineNumberOk;
-			int lineNumber, secondCommaPosition;
-
-			secondCommaPosition = inLine.indexOf(",", 3);
-			if (secondCommaPosition != 4 && secondCommaPosition != 5)
-				continue;
-
-			lineNumber = inLine.mid(3, secondCommaPosition-3).toInt(&lineNumberOk, 10);
-			if (lineNumberOk && lineNumber>=0 && lineNumber<=29) {
-				inLine.remove(0, secondCommaPosition+1);
-				if (lineNumber <= 25) {
-					for (int c=0; c<40; c++) {
-						// trimmed() helpfully removes CRLF line endings from the just-read line for us
-						// But it also (un)helpfully removes spaces at the end of a 40 character line, so put them back
-						if (c >= inLine.size())
-							inLine.append(' ');
-						if (inLine.at(c) & 0x80)
-							inLine[c] = inLine.at(c) & 0x7f;
-						else if (inLine.at(c) == 0x10)
-							inLine[c] = 0x0d;
-						else if (inLine.at(c) == 0x1b) {
-							inLine.remove(c, 1);
-							inLine[c] = inLine.at(c) & 0xbf;
-						}
-					}
-					loadingPage->setPacket(lineNumber, inLine);
-				} else {
-					int designationCode = inLine.at(0) & 0x3f;
-					if (inLine.size() < 40) {
-						// OL is too short!
-						if (lineNumber == 26) {
-							// For a too-short enhancement triplets OL, first trim the line down to nearest whole triplet
-							inLine.resize((inLine.size() / 3 * 3) + 1);
-							// Then use "dummy" enhancement triplets to extend the line to the proper length
-							for (int i=inLine.size(); i<40; i+=3)
-								inLine.append("i^@"); // Address 41, Mode 0x1e, Data 0
-						} else
-							// For other triplet OLs and Hamming 8/4 OLs, just pad with zero data
-							for (int i=inLine.size(); i<40; i++)
-								inLine.append("@");
-					}
-					for (int i=1; i<=39; i++)
-						inLine[i] = inLine.at(i) & 0x3f;
-					// Import M/29 whole-magazine packets as X/28 per-page packets
-					if (lineNumber == 29) {
-						if ((document->pageNumber() & 0xff) != 0xff)
-							qDebug("M/29/%d packet found, but page number is not xFF!", designationCode);
-						lineNumber = 28;
-					}
-					loadingPage->setPacket(lineNumber, designationCode, inLine);
-				}
-			}
-		}
-	}
-	// If there's more than one subpage but only one valid CT command was found, apply it to all subpages
-	// I don't know if this is correct
-	if (cycleCommandsFound == 1 && document->numberOfSubPages()>1)
-		for (int i=0; i<document->numberOfSubPages(); i++) {
-			document->subPage(i)->setCycleValue(mostRecentCycleValue);
-			document->subPage(i)->setCycleType(mostRecentCycleType);
-		}
-}
-
-void importT42(QFile *inFile, TeletextDocument *document)
-{
-	unsigned char inLine[42];
-	int readMagazineNumber, readPacketNumber;
-	int foundMagazineNumber = -1;
-	int foundPageNumber = -1;
-	bool firstPacket0Found = false;
-	bool pageBodyPacketsFound = false;
-
-	for (;;) {
-		if (inFile->read((char *)inLine, 42) != 42)
-			// Reached end of .t42 file, or less than 42 bytes left
-			break;
-
-		// Magazine and packet numbers
-		inLine[0] = hamming_8_4_decode[inLine[0]];
-		inLine[1] = hamming_8_4_decode[inLine[1]];
-		if (inLine[0] == 0xff || inLine[1] == 0xff)
-			// Error decoding magazine or packet number
-			continue;
-		readMagazineNumber = inLine[0] & 0x07;
-		readPacketNumber = (inLine[0] >> 3) | (inLine[1] << 1);
-
-		if (readPacketNumber == 0) {
-			// Hamming decode page number, subcodes and control bits
-			for (int i=2; i<10; i++)
-				inLine[i] = hamming_8_4_decode[inLine[i]];
-			// See if the page number is valid
-			if (inLine[2] == 0xff || inLine[3] == 0xff)
-				// Error decoding page number
-				continue;
-
-			const int readPageNumber = (inLine[3] << 4) | inLine[2];
-
-			if (readPageNumber == 0xff)
-				// Time filling header
-				continue;
-
-			// A second or subsequent X/0 has been found
-			if (firstPacket0Found) {
-				if (readMagazineNumber != foundMagazineNumber)
-					// Packet from different magazine broadcast in parallel mode
-					continue;
-				if ((readPageNumber == foundPageNumber) && pageBodyPacketsFound)
-					// X/0 with same page number found after page body packets loaded - assume end of page
-					break;
-				if (readPageNumber != foundPageNumber) {
-					// More than one page in .t42 file - end of current page reached
-					qDebug("More than one page in .t42 file");
-					break;
-				}
-				// Could get here if X/0 with same page number was found with no body packets inbetween
-				continue;
-			} else {
-				// First X/0 found
-				foundMagazineNumber = readMagazineNumber;
-				foundPageNumber = readPageNumber;
-				firstPacket0Found = true;
-
-				if (foundMagazineNumber == 0)
-					document->setPageNumber(0x800 | foundPageNumber);
-				else
-					document->setPageNumber((foundMagazineNumber << 8) | foundPageNumber);
-
-				document->subPage(0)->setControlBit(PageBase::C4ErasePage, inLine[5] & 0x08);
-				document->subPage(0)->setControlBit(PageBase::C5Newsflash, inLine[7] & 0x04);
-				document->subPage(0)->setControlBit(PageBase::C6Subtitle, inLine[7] & 0x08);
-				for (int i=0; i<4; i++)
-					document->subPage(0)->setControlBit(PageBase::C7SuppressHeader+i, inLine[8] & (1 << i));
-				document->subPage(0)->setControlBit(PageBase::C11SerialMagazine, inLine[9] & 0x01);
-				document->subPage(0)->setControlBit(PageBase::C12NOS, inLine[9] & 0x08);
-				document->subPage(0)->setControlBit(PageBase::C13NOS, inLine[9] & 0x04);
-				document->subPage(0)->setControlBit(PageBase::C14NOS, inLine[9] & 0x02);
-
-				continue;
-			}
-		}
-
-		// No X/0 has been found yet, keep looking for one
-		if (!firstPacket0Found)
-			continue;
-
-		// Disregard whole-magazine packets
-		if (readPacketNumber > 28)
-			continue;
-
-		// We get here when a page-body packet belonging to the found X/0 header was found
-		pageBodyPacketsFound = true;
-
-		// At the moment this only loads a Level One Page properly
-		// because it assumes X/1 to X/25 is odd partity
-		if (readPacketNumber < 25) {
-			for (int i=2; i<42; i++)
-				// TODO - obey odd parity?
-				inLine[i] &= 0x7f;
-			document->subPage(0)->setPacket(readPacketNumber, QByteArray((const char *)&inLine[2], 40));
-			continue;
-		}
-
-		// X/26, X/27 or X/28
-		int readDesignationCode = hamming_8_4_decode[inLine[2]];
-
-		if (readDesignationCode == 0xff)
-			// Error decoding designation code
-			continue;
-
-		if (readPacketNumber == 27 && readDesignationCode < 4) {
-			// X/27/0 to X/27/3 for Editorial Linking
-			// Decode Hamming 8/4 on each of the six links, checking for errors on the way
-			for (int i=0; i<6; i++) {
-				bool decodingError = false;
-				const int b = 3 + i*6; // First byte of this link
-
-				for (int j=0; j<6; j++) {
-					inLine[b+j] = hamming_8_4_decode[inLine[b+j]];
-					if (inLine[b+j] == 0xff) {
-						decodingError = true;
-						break;
-					}
-				}
-
-				if (decodingError) {
-					// Error found in at least one byte of the link
-					// Neutralise the whole link to same magazine, page FF, subcode 3F7F
-					qDebug("X/27/%d link %d decoding error", readDesignationCode, i);
-					inLine[b]   = 0xf;
-					inLine[b+1] = 0xf;
-					inLine[b+2] = 0xf;
-					inLine[b+3] = 0x7;
-					inLine[b+4] = 0xf;
-					inLine[b+5] = 0x3;
-				}
-			}
-			document->subPage(0)->setPacket(readPacketNumber, readDesignationCode, QByteArray((const char *)&inLine[2], 40));
-
-			continue;
-		}
-
-		// X/26, or X/27/4 to X/27/15, or X/28
-		// Decode Hamming 24/18
-		for (int i=0; i<13; i++) {
-			const int b = 3 + i*3; // First byte of triplet
-
-			const int p0 = inLine[b];
-			const int p1 = inLine[b+1];
-			const int p2 = inLine[b+2];
-
-			unsigned int D1_D4;
-			unsigned int D5_D11;
-			unsigned int D12_D18;
-			unsigned int ABCDEF;
-			int32_t d;
-
-			D1_D4 = hamming_24_18_decode_d1_d4[p0 >> 2];
-			D5_D11 = p1 & 0x7f;
-			D12_D18 = p2 & 0x7f;
-
-			d = D1_D4 | (D5_D11 << 4) | (D12_D18 << 11);
-
-			ABCDEF = (hamming_24_18_parities[0][p0] ^ hamming_24_18_parities[1][p1]  ^ hamming_24_18_parities[2][p2]);
-
-			d ^= (int)hamming_24_18_decode_correct[ABCDEF];
-
-			if ((d & 0x80000000) == 0x80000000) {
-				// Error decoding Hamming 24/18
-				qDebug("X/%d/%d triplet %d decoding error", readPacketNumber, readDesignationCode, i);
-				if (readPacketNumber == 26) {
-					// Enhancements packet, set to "dummy" Address 41, Mode 0x1e, Data 0
-					inLine[b]   = 41;
-					inLine[b+1] = 0x1e;
-					inLine[b+2] = 0;
-				} else {
-					// Zero out whole decoded triplet, bound to make things go wrong...
-					inLine[b]   = 0x00;
-					inLine[b+1] = 0x00;
-					inLine[b+2] = 0x00;
-				}
-			} else {
-				inLine[b]   = d & 0x0003f;
-				inLine[b+1] = (d & 0x00fc0) >> 6;
-				inLine[b+2] = d >> 12;
-			}
-		}
-		document->subPage(0)->setPacket(readPacketNumber, readDesignationCode, QByteArray((const char *)&inLine[2], 40));
-	}
-
-	if (!firstPacket0Found)
-		qDebug("No X/0 found");
-	else if (!pageBodyPacketsFound)
-		qDebug("X/0 found, but no page body packets were found");
-}
-
-// Used by saveTTI and HashString
-int controlBitsToPS(PageBase *subPage)
-{
-	// C4 Erase page is stored in bit 14
-	int pageStatus = 0x8000 | (subPage->controlBit(PageBase::C4ErasePage) << 14); 
-	// C5 to C11 stored in order from bits 1 to 6
-	for (int i=PageBase::C5Newsflash; i<=PageBase::C11SerialMagazine; i++)
-		pageStatus |= subPage->controlBit(i) << (i-1);
-	// Apparently the TTI format stores the NOS bits backwards
-	pageStatus |= subPage->controlBit(PageBase::C12NOS) << 9;
-	pageStatus |= subPage->controlBit(PageBase::C13NOS) << 8;
-	pageStatus |= subPage->controlBit(PageBase::C14NOS) << 7;
-	return pageStatus;
-}
-
-void saveTTI(QSaveFile &file, const TeletextDocument &document)
-{
-	int p;
-	QTextStream outStream(&file);
-
-	auto write7bitPacket=[&](int packetNumber)
-	{
-		if (document.subPage(p)->packetExists(packetNumber)) {
-			QByteArray outLine = document.subPage(p)->packet(packetNumber);
-
-			outStream << QString("OL,%1,").arg(packetNumber);
-			for (int c=0; c<outLine.size(); c++)
-				if (outLine.at(c) < 0x20) {
-					// TTI files are plain text, so put in escape followed by control code with bit 6 set
-					outLine[c] = outLine.at(c) | 0x40;
-					outLine.insert(c, 0x1b);
-					c++;
-				}
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-			outStream << outLine << Qt::endl;
-#else
-			outStream << outLine << endl;
-#endif
-		}
-	};
-
-	auto writeHammingPacket=[&](int packetNumber, int designationCode=0)
-	{
-		if (document.subPage(p)->packetExists(packetNumber, designationCode)) {
-			QByteArray outLine = document.subPage(p)->packet(packetNumber, designationCode);
-
-			outStream << QString("OL,%1,").arg(packetNumber);
-			// TTI stores raw values with bit 6 set, doesn't do Hamming encoding
-			outLine[0] = designationCode | 0x40;
-			for (int c=1; c<outLine.size(); c++)
-				outLine[c] = outLine.at(c) | 0x40;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-			outStream << outLine << Qt::endl;
-#else
-			outStream << outLine << endl;
-#endif
-		}
-	};
-
-#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-	outStream.setCodec("ISO-8859-1");
-#else
-	outStream.setEncoding(QStringConverter::Latin1);
-#endif
-
-	if (!document.description().isEmpty())
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-		outStream << "DE," << document.description() << Qt::endl;
-#else
-		outStream << "DE," << document.description() << endl;
-#endif
-
-	// TODO DS and SP commands
-
-	// If there's just one subpage then we save it with a subcode of 0000
-	// otherwise start with a subcode of 0001
-	int subPageNumber = document.numberOfSubPages() > 1;
-
-	for (p=0; p<document.numberOfSubPages(); p++) {
-
-		// Page number
-		outStream << QString("PN,%1%2").arg(document.pageNumber(), 3, 16, QChar('0')).arg(subPageNumber & 0xff, 2, 10, QChar('0'));
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-			outStream << Qt::endl;
-#else
-			outStream << endl;
-#endif
-
-		// Subpage
-		// Magazine Organisation Table and Magazine Inventory Page don't have subpages
-		if (document.pageFunction() != TeletextDocument::PFMOT && document.pageFunction() != TeletextDocument::PFMIP) {
-			outStream << QString("SC,%1").arg(subPageNumber, 4, 10, QChar('0'));
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-			outStream << Qt::endl;
-#else
-			outStream << endl;
-#endif
-		}
-
-		// Status bits
-		outStream << QString("PS,%1").arg(0x8000 | controlBitsToPS(document.subPage(p)), 4, 16, QChar('0'));
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-		outStream << Qt::endl;
-#else
-		outStream << endl;
-#endif
-
-		// Cycle time
-		if (document.pageFunction() == TeletextDocument::PFLevelOnePage)
-			// Assume that only Level One Pages have configurable cycle times
-			outStream << QString("CT,%1,%2").arg(document.subPage(p)->cycleValue()).arg(document.subPage(p)->cycleType()==LevelOnePage::CTcycles ? 'C' : 'T');
-		else
-			// X/28/0 specifies page function and coding but the PF command
-			// should make it obvious to a human that this isn't a Level One Page
-			outStream << QString("PF,%1,%2").arg(document.pageFunction()).arg(document.packetCoding());
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-		outStream << Qt::endl;
-#else
-		outStream << endl;
-#endif
-
-		// FastText links
-		bool writeFLCommand = false;
-		if (document.pageFunction() == TeletextDocument::PFLevelOnePage && document.subPage(p)->packetExists(27,0)) {
-			// Subpage has FastText links - if any link to a specific subpage, we need to write X/27/0 as raw
-			// otherwise we write the links as a human-readable FL command later on
-			writeFLCommand = true;
-			// TODO uncomment this when we can edit FastText subpage links
-			/*for (int i=0; i<6; i++)
-				if (document.subPage(p)->fastTextLinkSubPageNumber(i) != 0x3f7f) {
-					writeFLCommand = false;
-					break;
-				}*/
-		}
-
-		// X/27 then X/28 always come first
-		for (int i=(writeFLCommand ? 1 : 0); i<16; i++)
-			writeHammingPacket(27, i);
-		for (int i=0; i<16; i++)
-			writeHammingPacket(28, i);
-
-		if (document.packetCoding() == TeletextDocument::Coding7bit) {
-			// For 7 bit coding i.e. Level One Pages, X/26 are written before X/1 to X/25
-			for (int i=0; i<16; i++)
-				writeHammingPacket(26, i);
-			for (int i=1; i<=24; i++)
-				write7bitPacket(i);
-		} else {
-			// For others (especially (G)POP pages) X/1 to X/25 are written before X/26
-			for (int i=1; i<=25; i++)
-				writeHammingPacket(i);
-			for (int i=0; i<16; i++)
-				writeHammingPacket(26, i);
-		}
-
-		if (writeFLCommand) {
-			outStream << "FL,";
-			for (int i=0; i<6; i++) {
-				// Stored as page link with relative magazine number, convert to absolute page number for display
-				int absoluteLinkPageNumber = document.subPage(p)->fastTextLinkPageNumber(i) ^ (document.pageNumber() & 0x700);
-				// Fix magazine 0 to 8
-				if ((absoluteLinkPageNumber & 0x700) == 0x000)
-					absoluteLinkPageNumber |= 0x800;
-
-				outStream << QString("%1").arg(absoluteLinkPageNumber, 3, 16, QChar('0'));
-				if (i<5)
-					outStream << ',';
-			}
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-			outStream << Qt::endl;
-#else
-			outStream << endl;
-#endif
-		}
-
-		subPageNumber++;
-	}
-}
-
-void exportM29File(QSaveFile &file, const TeletextDocument &document)
-{
-	const PageBase &subPage = *document.currentSubPage();
-	QTextStream outStream(&file);
-
-	auto writeM29Packet=[&](int designationCode)
-	{
-		if (subPage.packetExists(28, designationCode)) {
-			QByteArray outLine = subPage.packet(28, designationCode);
-
-			outStream << QString("OL,29,");
-			// TTI stores raw values with bit 6 set, doesn't do Hamming encoding
-			outLine[0] = designationCode | 0x40;
-			for (int c=1; c<outLine.size(); c++)
-				outLine[c] = outLine.at(c) | 0x40;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-			outStream << outLine << Qt::endl;
-#else
-			outStream << outLine << endl;
-#endif
-		}
-	};
-
-#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
-	outStream.setCodec("ISO-8859-1");
-#else
-	outStream.setEncoding(QStringConverter::Latin1);
-#endif
-
-	if (!document.description().isEmpty())
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-	outStream << "DE," << document.description() << Qt::endl;
-#else
-	outStream << "DE," << document.description() << endl;
-#endif
-
-	// Force page number to xFF
-	outStream << QString("PN,%1ff00").arg(document.pageNumber() >> 8, 1, 16);
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-	outStream << Qt::endl;
-#else
-	outStream << endl;
-#endif
-
-	outStream << "PS,8000";
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-	outStream << Qt::endl;
-#else
-	outStream << endl;
-#endif
-
-	writeM29Packet(0);
-	writeM29Packet(1);
-	writeM29Packet(4);
-}
-
-void exportT42File(QSaveFile &file, const TeletextDocument &document)
-{
-	const PageBase &subPage = *document.currentSubPage();
-
-	QDataStream outStream(&file);
-	// Displayable row header we export as spaces, hence the (odd parity valid) 0x20 init value
-	QByteArray outLine(42, 0x20);
-	int magazineNumber = (document.pageNumber() & 0xf00) >> 8;
-
-	auto write7bitPacket=[&](int packetNumber)
-	{
-		if (subPage.packetExists(packetNumber)) {
-			outLine[0] = hamming_8_4_encode[magazineNumber | ((packetNumber & 0x01) << 3)];
-			outLine[1] = hamming_8_4_encode[packetNumber >> 1];
-			outLine.replace(2, 40, subPage.packet(packetNumber));
-
-			// Odd parity encoding
-			for (int c=0; c<outLine.size(); c++) {
-				char p = outLine.at(c);
-
-				// Recursively divide integer into two equal halves and take their XOR until only 1 bit is left
-				p ^= p >> 4;
-				p ^= p >> 2;
-				p ^= p >> 1;
-				// If last bit left is 0 then it started with an even number of bits, so do the odd parity
-				if (!(p & 1))
-					outLine[c] = outLine.at(c) | 0x80;
-			}
-			outStream.writeRawData(outLine.constData(), 42);
-		}
-	};
-
-	auto writeHamming8_4Packet=[&](int packetNumber, int designationCode=0)
-	{
-		if (subPage.packetExists(packetNumber, designationCode)) {
-			outLine[0] = hamming_8_4_encode[magazineNumber | ((packetNumber & 0x01) << 3)];
-			outLine[1] = hamming_8_4_encode[packetNumber >> 1];
-			outLine.replace(2, 40, subPage.packet(packetNumber, designationCode));
-			outLine[2] = hamming_8_4_encode[designationCode];
-
-			for (int c=3; c<outLine.size(); c++)
-				outLine[c] = hamming_8_4_encode[(int)outLine.at(c)];
-
-			outStream.writeRawData(outLine.constData(), 42);
-		}
-	};
-
-	auto writeHamming24_18Packet=[&](int packetNumber, int designationCode=0)
-	{
-		if (subPage.packetExists(packetNumber, designationCode)) {
-			outLine[0] = hamming_8_4_encode[magazineNumber | ((packetNumber & 0x01) << 3)];
-			outLine[1] = hamming_8_4_encode[packetNumber >> 1];
-			outLine.replace(2, 40, subPage.packet(packetNumber, designationCode));
-			outLine[2] = hamming_8_4_encode[designationCode];
-
-			for (int c=3; c<outLine.size(); c+=3) {
-				unsigned int D5_D11;
-				unsigned int D12_D18;
-				unsigned int P5, P6;
-				unsigned int Byte_0;
-
-				const unsigned int toEncode = outLine[c] | (outLine[c+1] << 6) | (outLine[c+2] << 12);
-
-				Byte_0 = (hamming_24_18_forward[0][(toEncode >> 0) & 0xff] ^ hamming_24_18_forward[1][(toEncode >> 8) & 0xff] ^ hamming_24_18_forward_2[(toEncode >> 16) & 0x03]);
-				outLine[c] = Byte_0;
-
-				D5_D11 = (toEncode >> 4) & 0x7f;
-				D12_D18 = (toEncode >> 11) & 0x7f;
-
-				P5 = 0x80 & ~(hamming_24_18_parities[0][D12_D18] << 2);
-				outLine[c+1] = D5_D11 | P5;
-
-				P6 = 0x80 & ((hamming_24_18_parities[0][Byte_0] ^ hamming_24_18_parities[0][D5_D11]) << 2);
-				outLine[c+2] = D12_D18 | P6;
-			}
-
-			outStream.writeRawData(outLine.constData(), 42);
-		}
-	};
-
-
-	if (magazineNumber == 8)
-		magazineNumber = 0;
-
-	// Write X/0 separately as it features both Hamming 8/4 and 7-bit odd parity within
-	outLine[0] = magazineNumber & 0x07;
-	outLine[1] = 0; // Packet number 0
-	outLine[2] = document.pageNumber() & 0x00f;
-	outLine[3] = (document.pageNumber() & 0x0f0) >> 4;
-	outLine[4] = 0; // Subcode S1 - always export as 0
-	outLine[5] = subPage.controlBit(PageBase::C4ErasePage) << 3;
-	outLine[6] = 0; // Subcode S3 - always export as 0
-	outLine[7] = (subPage.controlBit(PageBase::C5Newsflash) << 2) | (subPage.controlBit(PageBase::C6Subtitle) << 3);
-	outLine[8] = subPage.controlBit(PageBase::C7SuppressHeader) | (subPage.controlBit(PageBase::C8Update) << 1) | (subPage.controlBit(PageBase::C9InterruptedSequence) << 2) | (subPage.controlBit(PageBase::C10InhibitDisplay) << 3);
-	outLine[9] = subPage.controlBit(PageBase::C11SerialMagazine) | (subPage.controlBit(PageBase::C14NOS) << 1) | (subPage.controlBit(PageBase::C13NOS) << 2) | (subPage.controlBit(PageBase::C12NOS) << 3);
-
-	for (int i=0; i<10; i++)
-		outLine[i] = hamming_8_4_encode[(int)outLine.at(i)];
-
-	// If we allow text in the row header, we'd odd-parity encode it here
-
-	outStream.writeRawData(outLine.constData(), 42);
-
-	// After X/0, X/27 then X/28 always come next
-	for (int i=0; i<4; i++)
-		writeHamming8_4Packet(27, i);
-	for (int i=4; i<16; i++)
-		writeHamming24_18Packet(27, i);
-	for (int i=0; i<16; i++)
-		writeHamming24_18Packet(28, i);
-
-	if (document.packetCoding() == TeletextDocument::Coding7bit) {
-		// For 7 bit coding i.e. Level One Pages, X/26 are written before X/1 to X/25
-		for (int i=0; i<16; i++)
-			writeHamming24_18Packet(26, i);
-		for (int i=1; i<=24; i++)
-			write7bitPacket(i);
-	} else {
-		// For others (especially (G)POP pages) X/1 to X/25 are written before X/26
-		if (document.packetCoding() == TeletextDocument::Coding18bit)
-			for (int i=1; i<=25; i++)
-				writeHamming24_18Packet(i);
-		else if (document.packetCoding() == TeletextDocument::Coding4bit)
-			for (int i=1; i<=25; i++)
-				writeHamming8_4Packet(i);
-		else
-			qDebug("Exported broken file as page coding is not supported");
-		for (int i=0; i<16; i++)
-			writeHamming24_18Packet(26, i);
-	}
-}
-
-QByteArray rowPacketAlways(PageBase *subPage, int packetNumber)
-{
-	if (subPage->packetExists(packetNumber))
-		return subPage->packet(packetNumber);
-	else
-		return QByteArray(40, ' ');
-}
-
-QString exportHashStringPage(LevelOnePage *subPage)
-{
-	int hashDigits[1167]={0};
-	int totalBits, charBit;
-	const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
-	QString hashString;
-
-	// TODO int editTFCharacterSet = 5;
-	bool blackForeground = false;
-
-	for (int r=0; r<25; r++) {
-		QByteArray rowPacket = rowPacketAlways(subPage, r);
-		for (int c=0; c<40; c++) {
-			if (rowPacket.at(c) == 0x00 || rowPacket.at(c) == 0x10)
-				blackForeground = true;
-			for (int b=0; b<7; b++) {
-				totalBits = (r * 40 + c) * 7 + b;
-				charBit = ((rowPacket.at(c)) >> (6 - b)) & 0x01;
-				hashDigits[totalBits / 6] |= charBit << (5 - (totalBits % 6));
-			}
-		}
-	}
-
-	hashString.append(QString("#%1:").arg(blackForeground ? 8 : 0, 1, 16));
-
-	for (int i=0; i<1167; i++)
-		hashString.append(base64[hashDigits[i]]);
-
-	return hashString;
-}
-
-QString exportHashStringPackets(LevelOnePage *subPage)
-{
-	auto colourToHexString=[&](int whichCLUT)
-	{
-		QString resultHexString;
-
-		for (int i=whichCLUT*8; i<whichCLUT*8+8; i++)
-			resultHexString.append(QString("%1").arg(subPage->CLUT(i), 3, 16, QChar('0')));
-		return resultHexString;
-	};
-
-	const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
-	QString result;
-
-	if (subPage->packetExists(28,0) || subPage->packetExists(28,4)) {
-		// X/28/0 and X/28/4 are duplicates apart from the CLUT definitions
-		// Assemble the duplicate beginning and ending of both packets
-		QString x28StringBegin, x28StringEnd;
-
-		x28StringBegin.append(QString("00%1").arg((subPage->defaultCharSet() << 3) | subPage->defaultNOS(), 2, 16, QChar('0')).toUpper());
-		x28StringBegin.append(QString("%1").arg((subPage->secondCharSet() << 3) | subPage->secondNOS(), 2, 16, QChar('0')).toUpper());
-		x28StringBegin.append(QString("%1%2%3%4").arg(subPage->leftSidePanelDisplayed(), 1, 10).arg(subPage->rightSidePanelDisplayed(), 1, 10).arg(subPage->sidePanelStatusL25(), 1, 10).arg(subPage->sidePanelColumns(), 1, 16));
-
-		x28StringEnd = QString("%1%2%3%4").arg(subPage->defaultScreenColour(), 2, 16, QChar('0')).arg(subPage->defaultRowColour(), 2, 16, QChar('0')).arg(subPage->blackBackgroundSubst(), 1, 10).arg(subPage->colourTableRemap(), 1, 10);
-
-		if (subPage->packetExists(28,0))
-			result.append(":X280=" + x28StringBegin + colourToHexString(2) + colourToHexString(3) + x28StringEnd);
-		if (subPage->packetExists(28,4))
-			result.append(":X284=" + x28StringBegin + colourToHexString(0) + colourToHexString(1) + x28StringEnd);
-	}
-
-	if (!subPage->enhancements()->isEmpty()) {
-		result.append(":X26=");
-		for (int i=0; i<subPage->enhancements()->size(); i++) {
-			result.append(base64[subPage->enhancements()->at(i).data() >> 1]);
-			result.append(base64[subPage->enhancements()->at(i).mode() | ((subPage->enhancements()->at(i).data() & 1) << 5)]);
-			result.append(base64[subPage->enhancements()->at(i).address()]);
-		}
-	}
-
-	result.append(QString(":PS=%1").arg(0x8000 | controlBitsToPS(subPage), 0, 16, QChar('0')));
-	return result;
-}

src/qteletextmaker/main.cpp

@@ -30,7 +30,7 @@ int main(int argc, char *argv[])
 	QApplication::setApplicationDisplayName(QApplication::applicationName());
 	QApplication::setOrganizationName("gkmac.co.uk");
 	QApplication::setOrganizationDomain("gkmac.co.uk");
-	QApplication::setApplicationVersion("0.7.1-beta");
+	QApplication::setApplicationVersion("0.7.2-beta");
 	QCommandLineParser parser;
 	parser.setApplicationDescription(QApplication::applicationName());
 	parser.addHelpOption();

src/qteletextmaker/mainwidget.cpp

@@ -543,8 +543,10 @@ QPair<int, int> TeletextWidget::mouseToRowAndColumn(const QPoint &mousePosition)
 {
 	int row = mousePosition.y() / 10;
 	int column = mousePosition.x() / 12 - m_pageDecode.leftSidePanelColumns();
-	if (row < 1)
-		row = 1;
+	const int topRow = (int)!m_teletextDocument->rowZeroAllowed();
+
+	if (row < topRow)
+		row = topRow;
 	if (row > 24)
 		row = 24;
 	if (column < 0)
@@ -647,6 +649,9 @@ LevelOneScene::LevelOneScene(QWidget *levelOneWidget, QObject *parent) : QGraphi
 	m_mainGridItemGroup = new QGraphicsItemGroup;
 	m_mainGridItemGroup->setVisible(false);
 	addItem(m_mainGridItemGroup);
+	m_rowZeroGridItemGroup = new QGraphicsItemGroup;
+	m_rowZeroGridItemGroup->setVisible(false);
+	addItem(m_rowZeroGridItemGroup);
 	// Additional vertical pieces of grid for side panels
 	for (int i=0; i<32; i++) {
 		m_sidePanelGridNeeded[i] = false;
@@ -654,14 +659,17 @@ LevelOneScene::LevelOneScene(QWidget *levelOneWidget, QObject *parent) : QGraphi
 		m_sidePanelGridItemGroup[i]->setVisible(false);
 		addItem(m_sidePanelGridItemGroup[i]);
 	}
-	for (int r=1; r<25; r++) {
+	for (int r=0; r<25; r++) {
 		for (int c=0; c<40; c++) {
 			QGraphicsRectItem *gridPiece = new QGraphicsRectItem(c*12, r*10, 12, 10);
-			gridPiece->setPen(QPen(QBrush(QColor(128, 128, 128, r<24 ? 192 : 128)), 0));
+			gridPiece->setPen(QPen(QBrush(QColor(128, 128, 128, (r != 0 && r != 24) ? 192 : 128)), 0));
+			if (r == 0)
+				m_rowZeroGridItemGroup->addToGroup(gridPiece);
+			else
 				m_mainGridItemGroup->addToGroup(gridPiece);
 		}
 
-		if (r < 24)
+		if (r != 0 && r != 24)
 			for (int c=0; c<32; c++) {
 				QGraphicsRectItem *gridPiece = new QGraphicsRectItem(0, r*10, 12, 10);
 				gridPiece->setPen(QPen(QBrush(QColor(128, 128, 128, 64)), 0));
@@ -686,6 +694,7 @@ void LevelOneScene::setBorderDimensions(int sceneWidth, int sceneHeight, int wid
 
 	// Position grid to cover central 40 columns
 	m_mainGridItemGroup->setPos(leftRightBorders + leftSidePanelColumns*12, topBottomBorders);
+	m_rowZeroGridItemGroup->setPos(leftRightBorders + leftSidePanelColumns*12, topBottomBorders);
 
 	updateCursor();
 	updateSelection();
@@ -772,12 +781,23 @@ void LevelOneScene::setRenderMode(TeletextPageRender::RenderMode renderMode)
 void LevelOneScene::toggleGrid(bool gridOn)
 {
 	m_grid = gridOn;
+
 	m_mainGridItemGroup->setVisible(gridOn);
+	if (static_cast<TeletextWidget *>(m_levelOneProxyWidget->widget())->document()->rowZeroAllowed())
+		m_rowZeroGridItemGroup->setVisible(gridOn);
 	for (int i=0; i<32; i++)
 		if (m_sidePanelGridNeeded[i])
 			m_sidePanelGridItemGroup[i]->setVisible(gridOn);
 }
 
+void LevelOneScene::toggleRowZeroAllowed(bool allowed)
+{
+	static_cast<TeletextWidget *>(m_levelOneProxyWidget->widget())->document()->setRowZeroAllowed(allowed);
+
+	if (m_grid)
+		m_rowZeroGridItemGroup->setVisible(allowed);
+}
+
 void LevelOneScene::hideGUIElements(bool hidden)
 {
 	if (hidden) {

src/qteletextmaker/mainwidget.h

@@ -125,6 +125,7 @@ public slots:
 	void updateSelection();
 	void setRenderMode(TeletextPageRender::RenderMode renderMode);
 	void toggleGrid(bool gridOn);
+	void toggleRowZeroAllowed(bool allowed);
 	void hideGUIElements(bool hidden);
 	void setFullScreenColour(const QColor &newColor);
 	void setFullRowColour(int row, const QColor &newColor);
@@ -143,7 +144,7 @@ private:
 	QGraphicsRectItem *m_fullRowLeftRectItem[25], *m_fullRowRightRectItem[25];
 	QGraphicsProxyWidget *m_levelOneProxyWidget;
 	QGraphicsRectItem *m_cursorRectItem, *m_selectionRectItem;
-	QGraphicsItemGroup *m_mainGridItemGroup, *m_sidePanelGridItemGroup[32];
+	QGraphicsItemGroup *m_mainGridItemGroup, *m_rowZeroGridItemGroup, *m_sidePanelGridItemGroup[32];
 	bool m_grid, m_sidePanelGridNeeded[32];
 };
 

src/qteletextmaker/mainwindow.cpp

@@ -41,13 +41,15 @@
 
 #include "mainwindow.h"
 
+#include "hashformats.h"
 #include "levelonecommands.h"
-#include "loadsave.h"
+#include "loadformats.h"
 #include "mainwidget.h"
 #include "pagecomposelinksdockwidget.h"
 #include "pageenhancementsdockwidget.h"
 #include "pageoptionsdockwidget.h"
 #include "palettedockwidget.h"
+#include "saveformats.h"
 #include "x26dockwidget.h"
 
 #include "gifimage/qgifimage.h"
@@ -84,7 +86,7 @@ void MainWindow::newFile()
 
 void MainWindow::open()
 {
-	const QString fileName = QFileDialog::getOpenFileName(this);
+	const QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), QString(), m_loadFormats.filters());
 	if (!fileName.isEmpty())
 		openFile(fileName);
 }
@@ -114,39 +116,37 @@ void MainWindow::openFile(const QString &fileName)
 	other->show();
 }
 
-static inline bool hasTTISuffix(const QString &filename)
-{
-	return filename.endsWith(".tti", Qt::CaseInsensitive) || filename.endsWith(".ttix", Qt::CaseInsensitive);
-}
-
-static inline void changeSuffixFromTTI(QString &filename, const QString &newSuffix)
-{
-	if (filename.endsWith(".tti", Qt::CaseInsensitive)) {
-		filename.chop(4);
-		filename.append("." + newSuffix);
-	} else if (filename.endsWith(".ttix", Qt::CaseInsensitive)) {
-		filename.chop(5);
-		filename.append("." + newSuffix);
-	}
-}
-
 bool MainWindow::save()
 {
-	// If imported from non-.tti, force "Save As" so we don't clobber the original imported file
-	return m_isUntitled || !hasTTISuffix(m_curFile) ? saveAs() : saveFile(m_curFile);
+	// If imported from a format we only export, force "Save As" so we don't clobber the original imported file
+	if (m_isUntitled || m_saveFormats.isExportOnly(QFileInfo(m_curFile).suffix()))
+		return saveAs();
+	else
+		return saveFile(m_curFile);
 }
 
 bool MainWindow::saveAs()
 {
 	QString suggestedName = m_curFile;
 
-	// If imported from non-.tti, change extension so we don't clobber the original imported file
-	if (suggestedName.endsWith(".t42", Qt::CaseInsensitive)) {
-		suggestedName.chop(4);
+	// If imported from a format we only export, change suffix so we don't clobber the original imported file
+	if (m_saveFormats.isExportOnly(QFileInfo(suggestedName).suffix())) {
+		const int pos = suggestedName.lastIndexOf(QChar('.'));
+		if (pos != -1)
+			suggestedName.truncate(pos);
+
 		suggestedName.append(".tti");
 	}
 
-	QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"), suggestedName, "TTI teletext page (*.tti *.ttix)");
+	// Set the filter in the file dialog to the same as the current filename extension
+	QString dialogFilter;
+
+	SaveFormat *savingFormat = m_saveFormats.findExportFormat(QFileInfo(suggestedName).suffix());
+
+	if (savingFormat != nullptr)
+		dialogFilter = savingFormat->fileDialogFilter();
+
+	QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"), suggestedName, m_saveFormats.filters(), &dialogFilter);
 	if (fileName.isEmpty())
 		return false;
 
@@ -332,6 +332,7 @@ void MainWindow::init()
 	setAttribute(Qt::WA_DeleteOnClose);
 
 	m_isUntitled = true;
+	m_reExportWarning = false;
 
 	m_textWidget = new TeletextWidget;
 
@@ -461,9 +462,9 @@ void MainWindow::createActions()
 	connect(fileMenu, &QMenu::aboutToShow, this, &MainWindow::updateExportAutoAction);
 	connect(m_exportAutoAct, &QAction::triggered, this, &MainWindow::exportAuto);
 
-	QAction *exportT42Act = fileMenu->addAction(tr("Export subpage as t42..."));
-	exportT42Act->setStatusTip("Export this subpage as a t42 file");
-	connect(exportT42Act, &QAction::triggered, this, [=]() { exportT42(false); });
+	QAction *exportFileAct = fileMenu->addAction(tr("Export subpage as..."));
+	exportFileAct->setStatusTip("Export this subpage to various formats");
+	connect(exportFileAct, &QAction::triggered, this, [=]() { exportFile(false); });
 
 	QMenu *exportHashStringSubMenu = fileMenu->addMenu(tr("Export subpage to online editor"));
 
@@ -575,6 +576,13 @@ void MainWindow::createActions()
 	m_deleteSubPageAction->setStatusTip(tr("Delete this subpage"));
 	connect(m_deleteSubPageAction, &QAction::triggered, this, &MainWindow::deleteSubPage);
 
+	editMenu->addSeparator();
+
+	m_rowZeroAct = editMenu->addAction(tr("Edit header row"));
+	m_rowZeroAct->setCheckable(true);
+	m_rowZeroAct->setStatusTip(tr("Allow editing of header row"));
+	connect(m_rowZeroAct, &QAction::toggled, m_textScene, &LevelOneScene::toggleRowZeroAllowed);
+
 	QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
 
 	QAction *revealAct = viewMenu->addAction(tr("&Reveal"));
@@ -589,7 +597,7 @@ void MainWindow::createActions()
 	gridAct->setStatusTip(tr("Toggle the text grid"));
 	connect(gridAct, &QAction::toggled, m_textScene, &LevelOneScene::toggleGrid);
 
-	QAction *showControlCodesAct = viewMenu->addAction(tr("Show control codes"));
+	QAction *showControlCodesAct = viewMenu->addAction(tr("Control codes"));
 	showControlCodesAct->setCheckable(true);
 	showControlCodesAct->setShortcut(QKeySequence(Qt::CTRL | Qt::Key_T));
 	showControlCodesAct->setStatusTip(tr("Toggle showing of control codes"));
@@ -1042,28 +1050,35 @@ void MainWindow::loadFile(const QString &fileName)
 	int levelSeen;
 
 	QFile file(fileName);
-	const QFileInfo fileInfo(file);
-	QIODevice::OpenMode fileOpenMode;
 
-	if (fileInfo.suffix() == "t42")
-		fileOpenMode = QFile::ReadOnly;
-	else
-		fileOpenMode = QFile::ReadOnly | QFile::Text;
+	LoadFormat *loadingFormat = m_loadFormats.findFormat(QFileInfo(fileName).suffix());
+	if (loadingFormat == nullptr) {
+		QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("Cannot load file %1:\nUnknown file format or extension").arg(QDir::toNativeSeparators(fileName)));
+		setCurrentFile(QString());
 
-	if (!file.open(fileOpenMode)) {
+		return;
+	}
+
+	if (!file.open(QFile::ReadOnly)) {
 		QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("Cannot read file %1:\n%2.").arg(QDir::toNativeSeparators(fileName), file.errorString()));
 		setCurrentFile(QString());
+
 		return;
 	}
 
 	QApplication::setOverrideCursor(Qt::WaitCursor);
 
-	if (fileInfo.suffix() == "t42") {
-		importT42(&file, m_textWidget->document());
+	if (loadingFormat->load(&file, m_textWidget->document())) {
+		if (m_saveFormats.isExportOnly(QFileInfo(file).suffix()))
 			m_exportAutoFileName = fileName;
-	} else {
-		loadTTI(&file, m_textWidget->document());
+		else
 			m_exportAutoFileName.clear();
+	} else {
+		QApplication::restoreOverrideCursor();
+		QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("Cannot load file %1\n%2").arg(QDir::toNativeSeparators(fileName), loadingFormat->errorString()));
+		setCurrentFile(QString());
+
+		return;
 	}
 
 	levelSeen = m_textWidget->document()->levelRequired();
@@ -1075,6 +1090,17 @@ void MainWindow::loadFile(const QString &fileName)
 
 	QApplication::restoreOverrideCursor();
 
+	if (!loadingFormat->warningStrings().isEmpty())
+		QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("The following issues were encountered when loading<br>%1:<ul><li>%2</li></ul>").arg(QDir::toNativeSeparators(fileName), loadingFormat->warningStrings().join("</li><li>")));
+
+	m_reExportWarning = loadingFormat->reExportWarning();
+
+	for (int i=0; i<m_textWidget->document()->numberOfSubPages(); i++)
+		if (m_textWidget->document()->subPage(i)->packetExists(0)) {
+			m_rowZeroAct->setChecked(true);
+			break;
+		}
+
 	setCurrentFile(fileName);
 	statusBar()->showMessage(tr("File loaded"), 2000);
 }
@@ -1172,14 +1198,23 @@ bool MainWindow::saveFile(const QString &fileName)
 {
 	QString errorMessage;
 
+	SaveFormat *savingFormat = m_saveFormats.findFormat(QFileInfo(fileName).suffix());
+	if (savingFormat == nullptr) {
+		QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("Cannot save file %1:\nUnknown file format or extension").arg(QDir::toNativeSeparators(fileName)));
+		return false;
+	}
+
 	QApplication::setOverrideCursor(Qt::WaitCursor);
+
 	QSaveFile file(fileName);
-	if (file.open(QFile::WriteOnly | QFile::Text)) {
-		saveTTI(file, *m_textWidget->document());
+	if (file.open(QFile::WriteOnly)) {
+		savingFormat->saveAllPages(file, *m_textWidget->document());
+
 		if (!file.commit())
 			errorMessage = tr("Cannot write file %1:\n%2.").arg(QDir::toNativeSeparators(fileName), file.errorString());
 	} else
 		errorMessage = tr("Cannot open file %1 for writing:\n%2.").arg(QDir::toNativeSeparators(fileName), file.errorString());
+
 	QApplication::restoreOverrideCursor();
 
 	if (!errorMessage.isEmpty()) {
@@ -1198,33 +1233,66 @@ void MainWindow::exportAuto()
 	if (m_exportAutoFileName.isEmpty())
 		return;
 
-	exportT42(true);
+	exportFile(true);
 }
 
-void MainWindow::exportT42(bool fromAuto)
+void MainWindow::exportFile(bool fromAuto)
 {
 	QString errorMessage;
 	QString exportFileName;
+	SaveFormat *exportFormat = nullptr;
 
-	if (fromAuto)
+	if (fromAuto) {
+		if (m_reExportWarning) {
+			QMessageBox::StandardButton ret = QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("Will not overwrite imported file %1:\nAll other subpages in that file would be erased.\nPlease save or export to a different file.").arg(strippedName(m_exportAutoFileName)));
+
+			return;
+		}
 		exportFileName = m_exportAutoFileName;
-	else {
+	} else {
+		if (m_exportAutoFileName.isEmpty())
 			exportFileName = m_curFile;
-		changeSuffixFromTTI(exportFileName, "t42");
+		else
+			exportFileName = m_exportAutoFileName;
 
-		exportFileName = QFileDialog::getSaveFileName(this, tr("Export t42"), exportFileName, "t42 stream (*.t42)");
+		// Set the filter in the file dialog to the same as the current filename extension
+		QString dialogFilter;
+
+		exportFormat = m_saveFormats.findExportFormat(QFileInfo(exportFileName).suffix());
+
+		if (exportFormat != nullptr)
+			dialogFilter = exportFormat->fileDialogFilter();
+
+		exportFileName = QFileDialog::getSaveFileName(this, tr("Export subpage"), exportFileName, m_saveFormats.exportFilters(), &dialogFilter);
 		if (exportFileName.isEmpty())
 			return;
 	}
 
+	exportFormat = m_saveFormats.findExportFormat(QFileInfo(exportFileName).suffix());
+	if (exportFormat == nullptr) {
+		QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("Cannot export file %1:\nUnknown file format or extension").arg(QDir::toNativeSeparators(exportFileName)));
+		return;
+	}
+
+	if (!fromAuto && exportFormat->getWarnings(*m_textWidget->document()->currentSubPage())) {
+		const QMessageBox::StandardButton ret = QMessageBox::warning(this, QApplication::applicationDisplayName(), tr("The following issues will be encountered when exporting<br>%1:<ul><li>%2</li></ul>Do you want to export?").arg(strippedName(exportFileName)).arg(exportFormat->warningStrings().join("</li><li>")), QMessageBox::Yes | QMessageBox::No);
+
+		if (ret != QMessageBox::Yes)
+			return;
+	}
+
 	QApplication::setOverrideCursor(Qt::WaitCursor);
+
 	QSaveFile file(exportFileName);
+
 	if (file.open(QFile::WriteOnly)) {
-		exportT42File(file, *m_textWidget->document());
+		exportFormat->saveCurrentSubPage(file, *m_textWidget->document());
+
 		if (!file.commit())
 			errorMessage = tr("Cannot write file %1:\n%2.").arg(QDir::toNativeSeparators(exportFileName), file.errorString());
 	} else
 			errorMessage = tr("Cannot open file %1 for writing:\n%2.").arg(QDir::toNativeSeparators(exportFileName), file.errorString());
+
 	QApplication::restoreOverrideCursor();
 
 	if (!errorMessage.isEmpty()) {
@@ -1235,6 +1303,7 @@ void MainWindow::exportT42(bool fromAuto)
 	MainWindow::prependToRecentFiles(exportFileName);
 
 	m_exportAutoFileName = exportFileName;
+	m_reExportWarning = false;
 	statusBar()->showMessage(tr("File exported"), 2000);
 }
 
@@ -1271,18 +1340,23 @@ void MainWindow::exportM29()
 		exportFileName = QDir(QFileInfo(m_curFile).absoluteDir()).filePath(exportFileName);
 	}
 
-	exportFileName = QFileDialog::getSaveFileName(this, tr("Export M/29 tti"), exportFileName, "TTI teletext page (*.tti *.ttix)");
+	exportFileName = QFileDialog::getSaveFileName(this, tr("Export M/29 tti"), exportFileName, "MRG Systems TTI (*.tti *.ttix)");
 	if (exportFileName.isEmpty())
 		return;
 
 	QApplication::setOverrideCursor(Qt::WaitCursor);
+
 	QSaveFile file(exportFileName);
-	if (file.open(QFile::WriteOnly | QFile::Text)) {
-		exportM29File(file, *m_textWidget->document());
+	if (file.open(QFile::WriteOnly)) {
+		SaveM29Format saveM29Format;
+
+		saveM29Format.saveCurrentSubPage(file, *m_textWidget->document());
+
 		if (!file.commit())
 			errorMessage = tr("Cannot write file %1:\n%2.").arg(QDir::toNativeSeparators(exportFileName), file.errorString());
 	} else
 		errorMessage = tr("Cannot open file %1 for writing:\n%2.").arg(QDir::toNativeSeparators(exportFileName), file.errorString());
+
 	QApplication::restoreOverrideCursor();
 
 	if (!errorMessage.isEmpty())

src/qteletextmaker/mainwindow.h

@@ -30,11 +30,13 @@
 #include <QSlider>
 #include <QToolButton>
 
+#include "loadformats.h"
 #include "mainwidget.h"
 #include "pagecomposelinksdockwidget.h"
 #include "pageenhancementsdockwidget.h"
 #include "pageoptionsdockwidget.h"
 #include "palettedockwidget.h"
+#include "saveformats.h"
 #include "x26dockwidget.h"
 
 class QAction;
@@ -61,7 +63,7 @@ private slots:
 	bool saveAs();
 	void reload();
 	void exportAuto();
-	void exportT42(bool fromAuto);
+	void exportFile(bool fromAuto);
 	void exportZXNet();
 	void exportEditTF();
 	void exportImage();
@@ -129,6 +131,7 @@ private:
 	QAction *m_borderActs[3];
 	QAction *m_aspectRatioActs[4];
 	QAction *m_smoothTransformAction;
+	QAction *m_rowZeroAct;
 
 	QLabel *m_subPageLabel, *m_cursorPositionLabel;
 	QToolButton *m_previousSubPageButton, *m_nextSubPageButton;
@@ -137,7 +140,10 @@ private:
 	QRadioButton *m_levelRadioButton[4];
 
 	QString m_curFile, m_exportAutoFileName, m_exportImageFileName;
-	bool m_isUntitled;
+	bool m_isUntitled, m_reExportWarning;
+
+	LoadFormats m_loadFormats;
+	SaveFormats m_saveFormats;
 };
 
 #endif

src/qteletextmaker/saveformats.cpp

@@ -0,0 +1,588 @@
+/*
+ * Copyright (C) 2020-2025 Gavin MacGregor
+ *
+ * This file is part of QTeletextMaker.
+ *
+ * QTeletextMaker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QTeletextMaker is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "saveformats.h"
+
+#include <QByteArray>
+#include <QDataStream>
+#include <QSaveFile>
+#include <QString>
+
+#include "document.h"
+#include "hamming.h"
+#include "levelonepage.h"
+#include "pagebase.h"
+
+void SaveFormat::saveAllPages(QSaveFile &outFile, const TeletextDocument &document)
+{
+	m_document = &document;
+	m_outFile = &outFile;
+	m_outStream.setDevice(m_outFile);
+	m_warnings.clear();
+	m_error.clear();
+
+	writeDocumentStart();
+	writeAllPages();
+	writeDocumentEnd();
+}
+
+void SaveFormat::saveCurrentSubPage(QSaveFile &outFile, const TeletextDocument &document)
+{
+	m_document = &document;
+	m_outFile = &outFile;
+	m_outStream.setDevice(m_outFile);
+	m_warnings.clear();
+	m_error.clear();
+
+	writeDocumentStart();
+	writeSubPage(*m_document->currentSubPage());
+	writeDocumentEnd();
+}
+
+void SaveFormat::writeAllPages()
+{
+	for (int p=0; p<m_document->numberOfSubPages(); p++)
+		writeSubPage(*m_document->subPage(p), (m_document->numberOfSubPages() == 1) ? 0 : p+1);
+}
+
+void SaveFormat::writeSubPage(const PageBase &subPage, int subPageNumber)
+{
+	writeSubPageStart(subPage, subPageNumber);
+	writeSubPageBody(subPage);
+	writeSubPageEnd(subPage);
+}
+
+void SaveFormat::writeSubPageBody(const PageBase &subPage)
+{
+	writeX27Packets(subPage);
+	writeX28Packets(subPage);
+	if (m_document->pageFunction() == TeletextDocument::PFLevelOnePage) {
+		writeX26Packets(subPage);
+		writeX1to25Packets(subPage);
+	} else {
+		qDebug("Not LevelOnePage, assuming 7-bit packets!");
+		writeX1to25Packets(subPage);
+		writeX26Packets(subPage);
+	}
+}
+
+void SaveFormat::writeX27Packets(const PageBase &subPage)
+{
+	for (int i=0; i<4; i++)
+		if (subPage.packetExists(27, i))
+			writePacket(format4BitPacket(subPage.packet(27, i)), 27, i);
+	for (int i=4; i<16; i++)
+		if (subPage.packetExists(27, i))
+			writePacket(format18BitPacket(subPage.packet(27, i)), 27, i);
+}
+
+void SaveFormat::writeX28Packets(const PageBase &subPage)
+{
+	for (int i=0; i<16; i++)
+		if (subPage.packetExists(28, i))
+			writePacket(format18BitPacket(subPage.packet(28, i)), 28, i);
+}
+
+void SaveFormat::writeX26Packets(const PageBase &subPage)
+{
+	for (int i=0; i<16; i++)
+		if (subPage.packetExists(26, i))
+			writePacket(format18BitPacket(subPage.packet(26, i)), 26, i);
+}
+
+void SaveFormat::writeX1to25Packets(const PageBase &subPage)
+{
+	for (int i=1; i<26; i++)
+		if (subPage.packetExists(i))
+			// BUG must check m_document->packetCoding() !!
+			writePacket(format7BitPacket(subPage.packet(i)), i);
+}
+
+int SaveFormat::writePacket(QByteArray packet, int packetNumber, int designationCode)
+{
+	return writeRawData(packet, packet.size());
+}
+
+int SaveFormat::writeRawData(const char *s, int len)
+{
+	return m_outStream.writeRawData(s, len);
+}
+
+
+inline void SaveTTIFormat::writeString(const QString &command)
+{
+	QByteArray result = command.toUtf8() + "\r\n";
+
+	writeRawData(result, result.size());
+}
+
+void SaveTTIFormat::writeDocumentStart()
+{
+	if (!m_document->description().isEmpty())
+		writeString(QString("DE,%1").arg(m_document->description()));
+
+	// TODO DS and SP commands
+}
+
+QByteArray SaveTTIFormat::format7BitPacket(QByteArray packet)
+{
+	for (int i=0; i<packet.size(); i++)
+		if (packet.at(i) < 0x20) {
+			// TTI files are plain text, so put in escape followed by control code with bit 6 set
+			packet[i] = packet.at(i) | 0x40;
+			packet.insert(i, 0x1b);
+			i++;
+		}
+
+	return packet;
+}
+
+// format4BitPacket in this class calls this method as the encoding is the same
+// i.e. the bytes as-is with bit 6 set to make them ASCII friendly
+QByteArray SaveTTIFormat::format18BitPacket(QByteArray packet)
+{
+	// TTI stores the triplets 6 bits at a time like we do, without Hamming encoding
+	// We don't touch the first byte; the caller replaces it with the designation code
+	// unless it's X/1-X/25 used in (G)POP pages
+	for (int i=1; i<packet.size(); i++)
+		packet[i] = packet.at(i) | 0x40;
+
+	return packet;
+}
+
+void SaveTTIFormat::writeSubPageStart(const PageBase &subPage, int subPageNumber)
+{
+	// Page number
+	writeString(QString("PN,%1%2").arg(m_document->pageNumber(), 3, 16, QChar('0')).arg(subPageNumber & 0xff, 2, 10, QChar('0')));
+
+	// Subpage
+	// Magazine Organisation Table and Magazine Inventory Page don't have subpages
+	if (m_document->pageFunction() != TeletextDocument::PFMOT && m_document->pageFunction() != TeletextDocument::PFMIP)
+		writeString(QString("SC,%1").arg(subPageNumber, 4, 10, QChar('0')));
+
+	// Status bits
+	// We assume that bit 15 "transmit page" is always wanted
+	// C4 stored in bit 14
+	int statusBits = 0x8000 | (subPage.controlBit(PageBase::C4ErasePage) << 14);
+	// C5 to C11 stored in order from bits 1 to 6
+	for (int i=PageBase::C5Newsflash; i<=PageBase::C11SerialMagazine; i++)
+		statusBits |= subPage.controlBit(i) << (i-1);
+	// NOS in bits 7 to 9
+	statusBits |= subPage.controlBit(PageBase::C12NOS) << 9;
+	statusBits |= subPage.controlBit(PageBase::C13NOS) << 8;
+	statusBits |= subPage.controlBit(PageBase::C14NOS) << 7;
+
+	writeString(QString("PS,%1").arg(0x8000 | statusBits, 4, 16, QChar('0')));
+
+	if (m_document->pageFunction() == TeletextDocument::PFLevelOnePage) {
+		// Level One Page: page region and cycle
+		writeString(QString("RE,%1").arg(static_cast<const LevelOnePage *>(&subPage)->defaultCharSet()));
+		writeString(QString("CT,%1,%2").arg(static_cast<const LevelOnePage *>(&subPage)->cycleValue()).arg(static_cast<const LevelOnePage *>(&subPage)->cycleType()==LevelOnePage::CTcycles ? 'C' : 'T'));
+	} else
+		// Not a Level One Page: X/28/0 specifies page function and coding but the PF command
+		// should make it obvious to a human that this is not a Level One Page
+		writeString(QString("PF,%1,%2").arg(m_document->pageFunction()).arg(m_document->packetCoding()));
+}
+
+void SaveTTIFormat::writeSubPageBody(const PageBase &subPage)
+{
+	// Header row
+	if (subPage.packetExists(0))
+		writePacket(format7BitPacket(subPage.packet(0)), 0);
+
+	// FLOF links
+	bool writeFLCommand = false;
+	if (m_document->pageFunction() == TeletextDocument::PFLevelOnePage && subPage.packetExists(27,0)) {
+		// Subpage has FLOF links - if any link to a specific subpage we need to write X/27/0
+		// as raw, otherwise we write the links as a human-readable FL command later on
+		writeFLCommand = true;
+		// TODO uncomment this when we can edit FLOF subpage links
+		/*for (int i=0; i<6; i++)
+			if (document.subPage(p)->fastTextLinkSubPageNumber(i) != 0x3f7f) {
+				writeFLCommand = false;
+				break;
+			}*/
+	}
+
+	// Don't write X/27/0 if FL command will be written
+	// but write the rest of the X/27 packets
+	for (int i=(writeFLCommand ? 1 : 0); i<4; i++)
+		if (subPage.packetExists(27, i))
+			writePacket(format4BitPacket(subPage.packet(27, i)), 27, i);
+	for (int i=4; i<16; i++)
+		if (subPage.packetExists(27, i))
+			writePacket(format18BitPacket(subPage.packet(27, i)), 27, i);
+
+	// Now write the other packets like the rest of writeSubPageBody does
+	writeX28Packets(subPage);
+	if (m_document->pageFunction() == TeletextDocument::PFLevelOnePage) {
+		writeX26Packets(subPage);
+		writeX1to25Packets(subPage);
+	} else {
+		qDebug("Not LevelOnePage, assuming 7-bit packets!");
+		writeX1to25Packets(subPage);
+		writeX26Packets(subPage);
+	}
+
+	if (writeFLCommand) {
+		QString flofLine;
+		flofLine.reserve(26);
+		flofLine="FL,";
+
+		for (int i=0; i<6; i++) {
+			// Stored as page link with relative magazine number, convert to absolute page number for display
+			int absoluteLinkPageNumber = static_cast<const LevelOnePage *>(&subPage)->fastTextLinkPageNumber(i) ^ (m_document->pageNumber() & 0x700);
+			// Fix magazine 0 to 8
+			if ((absoluteLinkPageNumber & 0x700) == 0x000)
+				absoluteLinkPageNumber |= 0x800;
+
+			flofLine.append(QString("%1").arg(absoluteLinkPageNumber, 3, 16, QChar('0')));
+			if (i < 5)
+				flofLine.append(',');
+		}
+
+		writeString(flofLine);
+	}
+}
+
+int SaveTTIFormat::writePacket(QByteArray packet, int packetNumber, int designationCode)
+{
+	if (designationCode != -1)
+		packet[0] = designationCode | 0x40;
+
+	packet.prepend("OL," + QByteArray::number(packetNumber) + ",");
+	packet.append("\r\n");
+
+	return(writeRawData(packet, packet.size()));
+}
+
+
+void SaveM29Format::writeSubPageStart(const PageBase &subPage, int subPageNumber)
+{
+	Q_UNUSED(subPageNumber);
+
+	// Force page number to 0xFF and subpage to 0
+	writeString(QString("PN,%1ff00").arg(m_document->pageNumber() >> 8, 1, 16));
+	// Not sure if this PS forcing is necessary
+	writeString("PS,8000");
+}
+
+void SaveM29Format::writeSubPageBody(const PageBase &subPage)
+{
+	if (subPage.packetExists(28, 0))
+		writePacket(format18BitPacket(subPage.packet(28, 0)), 29, 0);
+	if (subPage.packetExists(28, 1))
+		writePacket(format18BitPacket(subPage.packet(28, 1)), 29, 1);
+	if (subPage.packetExists(28, 4))
+		writePacket(format18BitPacket(subPage.packet(28, 4)), 29, 4);
+}
+
+
+QByteArray SaveT42Format::format7BitPacket(QByteArray packet)
+{
+	// Odd parity encoding
+	for (int c=0; c<packet.size(); c++) {
+		char p = packet.at(c);
+
+		// Recursively divide integer into two equal halves and take their XOR until only 1 bit is left
+		p ^= p >> 4;
+		p ^= p >> 2;
+		p ^= p >> 1;
+		// If last bit left is 0 then it started with an even number of bits, so do the odd parity
+		if (!(p & 1))
+			packet[c] = packet.at(c) | 0x80;
+	}
+
+	return packet;
+}
+
+QByteArray SaveT42Format::format4BitPacket(QByteArray packet)
+{
+	for (int c=0; c<packet.size(); c++)
+		packet[c] = hamming_8_4_encode[(int)packet.at(c)];
+
+	return packet;
+}
+
+QByteArray SaveT42Format::format18BitPacket(QByteArray packet)
+{
+	for (int c=1; c<packet.size(); c+=3) {
+		unsigned int D5_D11;
+		unsigned int D12_D18;
+		unsigned int P5, P6;
+		unsigned int Byte_0;
+
+		const unsigned int toEncode = packet[c] | (packet[c+1] << 6) | (packet[c+2] << 12);
+
+		Byte_0 = (hamming_24_18_forward[0][(toEncode >> 0) & 0xff] ^ hamming_24_18_forward[1][(toEncode >> 8) & 0xff] ^ hamming_24_18_forward_2[(toEncode >> 16) & 0x03]);
+		packet[c] = Byte_0;
+
+		D5_D11 = (toEncode >> 4) & 0x7f;
+		D12_D18 = (toEncode >> 11) & 0x7f;
+
+		P5 = 0x80 & ~(hamming_24_18_parities[0][D12_D18] << 2);
+		packet[c+1] = D5_D11 | P5;
+
+		P6 = 0x80 & ((hamming_24_18_parities[0][Byte_0] ^ hamming_24_18_parities[0][D5_D11]) << 2);
+		packet[c+2] = D12_D18 | P6;
+	}
+
+	return packet;
+}
+
+int SaveT42Format::writePacket(QByteArray packet, int packetNumber, int designationCode)
+{
+	// Byte 2 - designation code
+	if (designationCode != - 1)
+		packet[0] = hamming_8_4_encode[designationCode];
+
+	// Byte 1 of MRAG
+	packet.prepend(hamming_8_4_encode[packetNumber >> 1]);
+	// Byte 0 of MRAG
+	packet.prepend(hamming_8_4_encode[m_magazineNumber | ((packetNumber & 0x01) << 3)]);
+
+	return(writeRawData(packet, packet.size()));
+}
+
+void SaveT42Format::writeSubPageStart(const PageBase &subPage, int subPageNumber)
+{
+	QByteArray packet;
+
+	// Convert integer to Binary Coded Decimal
+	subPageNumber = QString::number(subPageNumber).toInt(nullptr, 16);
+
+	m_magazineNumber = (m_document->pageNumber() & 0xf00) >> 8;
+	if (m_magazineNumber == 8)
+		m_magazineNumber = 0;
+
+	// Retrieve and apply odd parity to header row if there's text there,
+	// otherwise create an initial packet of (odd parity valid) spaces
+	if (subPage.packetExists(0))
+		packet = format7BitPacket(subPage.packet(0));
+	else
+		packet.fill(0x20, 40);
+
+	// Byte 1 of MRAG - packet number 0
+	packet.prepend((char)0);
+	// Byte 0 of MRAG - magazine number, and packet number 0
+	packet.prepend(m_magazineNumber & 0x07);
+
+	packet[2] = m_document->pageNumber() & 0x00f;
+	packet[3] = (m_document->pageNumber() & 0x0f0) >> 4;
+	packet[4] = subPageNumber & 0xf;
+	packet[5] = ((subPageNumber >> 4) & 0x7) | (subPage.controlBit(PageBase::C4ErasePage) << 3);
+	packet[6] = ((subPageNumber >> 8) & 0xf);
+	packet[7] = ((subPageNumber >> 12) & 0x3) | (subPage.controlBit(PageBase::C5Newsflash) << 2) | (subPage.controlBit(PageBase::C6Subtitle) << 3);
+	packet[8] = subPage.controlBit(PageBase::C7SuppressHeader) | (subPage.controlBit(PageBase::C8Update) << 1) | (subPage.controlBit(PageBase::C9InterruptedSequence) << 2) | (subPage.controlBit(PageBase::C10InhibitDisplay) << 3);
+	packet[9] = subPage.controlBit(PageBase::C11SerialMagazine) | (subPage.controlBit(PageBase::C14NOS) << 1) | (subPage.controlBit(PageBase::C13NOS) << 2) | (subPage.controlBit(PageBase::C12NOS) << 3);
+
+	for (int i=0; i<10; i++)
+		packet[i] = hamming_8_4_encode[(int)packet.at(i)];
+
+	writeRawData(packet.constData(), 42);
+}
+
+
+int SaveHTTFormat::writeRawData(const char *s, int len)
+{
+	char httLine[45];
+
+	httLine[0] = 0xaa;
+	httLine[1] = 0xaa;
+	httLine[2] = 0xe4;
+
+	for (int i=0; i<42; i++) {
+		unsigned char b = s[i];
+		b = (b & 0xf0) >> 4 | (b & 0x0f) << 4;
+		b = (b & 0xcc) >> 2 | (b & 0x33) << 2;
+		b = (b & 0xaa) >> 1 | (b & 0x55) << 1;
+		httLine[i+3] = b;
+	}
+
+	return m_outStream.writeRawData(httLine, len+3);
+}
+
+
+bool SaveEP1Format::getWarnings(const PageBase &subPage)
+{
+	m_warnings.clear();
+
+	if (!m_languageCode.contains((static_cast<const LevelOnePage *>(&subPage)->defaultCharSet() << 3) | static_cast<const LevelOnePage *>(&subPage)->defaultNOS()))
+		m_warnings.append("Page language not supported, will be exported as English.");
+
+	if (subPage.packetExists(24) || subPage.packetExists(27, 0))
+		m_warnings.append("FLOF display row and page links will not be exported.");
+
+	if (subPage.packetExists(27, 4) || subPage.packetExists(27, 5))
+		m_warnings.append("X/27/4-5 compositional links will not be exported.");
+
+	if (subPage.packetExists(28, 0) || subPage.packetExists(28, 4))
+		m_warnings.append("X/28 page enhancements will not be exported.");
+
+	return (!m_warnings.isEmpty());
+}
+
+QByteArray SaveEP1Format::format18BitPacket(QByteArray packet)
+{
+	for (int c=1; c<packet.size(); c+=3) {
+		// Shuffle triplet bits to 6 bit address, 5 bit mode, 7 bit data
+		packet[c+2] = ((packet.at(c+2) & 0x3f) << 1) | ((packet.at(c+1) & 0x20) >> 5);
+		packet[c+1] = packet.at(c+1) & 0x1f;
+		// Address of termination marker is 7f instead of 3f
+		if (packet.at(c+1) == 0x1f && packet.at(c) == 0x3f)
+			packet[c] = 0x7f;
+	}
+
+	return packet;
+}
+
+void SaveEP1Format::writeSubPageStart(const PageBase &subPage, int subPageNumber)
+{
+	Q_UNUSED(subPageNumber);
+
+	QByteArray pageStart(3, 0x00);
+
+	// First two bytes always 0xfe, 0x01
+	pageStart[0] = 0xfe;
+	pageStart[1] = 0x01;
+	// Next byte is language code unique to EP1
+	// Unknown values are mapped to English, after warning the user
+	pageStart[2] = m_languageCode.value((static_cast<const LevelOnePage *>(&subPage)->defaultCharSet() << 3) | static_cast<const LevelOnePage *>(&subPage)->defaultNOS(), 0x09);
+
+	writeRawData(pageStart.constData(), 3);
+}
+
+void SaveEP1Format::writeSubPageBody(const PageBase &subPage)
+{
+	// Following the first three bytes already written by writeSubPageStart,
+	// the next three bytes for pages with X/26 packets are 0xca
+	// then little-endian offset to start of Level 1 page data.
+	// For pages with no X/26 packets, just three zeroes.
+	QByteArray offsetData(4, 0x00);
+
+	int numOfX26Packets = 0;
+
+	if (subPage.packetExists(26, 0)) {
+		offsetData[0] = 0xca;
+
+		while (subPage.packetExists(26, numOfX26Packets))
+			numOfX26Packets++;
+
+		const int level1Offset = numOfX26Packets * 40 + 4;
+		offsetData[1] = level1Offset & 0xff;
+		offsetData[2] = level1Offset >> 8;
+	}
+
+	writeRawData(offsetData.constData(), 3);
+
+	// We should really re-implement writeX26Packets but I can't be bothered
+	// to count the number of X/26 packets twice...
+	if (numOfX26Packets > 0) {
+		// Reuse offsetData for this 4-byte header of the enhancement data
+		// Bytes are 0xc2, 0x00, then little-endian length of enhancement data
+		offsetData[0] = 0xc2;
+		offsetData[1] = 0x00;
+		offsetData[2] = (numOfX26Packets * 40) & 0xff;
+		offsetData[3] = (numOfX26Packets * 40) >> 8;
+		writeRawData(offsetData.constData(), 4);
+
+		for (int i=0; i<numOfX26Packets; i++) {
+			QByteArray packet = format18BitPacket(subPage.packet(26, i));
+			packet[0] = i;
+			writeRawData(packet.constData(), 40);
+		}
+	}
+
+	writeX1to25Packets(subPage);
+}
+
+void SaveEP1Format::writeSubPageEnd(const PageBase &subPage)
+{
+	// 40 byte buffer for undo purposes or something? Just write a blank row of spaces
+	writeRawData(QByteArray(40, 0x20).constData(), 40);
+
+	// Last two bytes always 0x00, 0x00
+	writeRawData(QByteArray(2, 0x00).constData(), 2);
+}
+
+void SaveEP1Format::writeX1to25Packets(const PageBase &subPage)
+{
+	for (int i=0; i<24; i++)
+		if (subPage.packetExists(i))
+			writePacket(format7BitPacket(subPage.packet(i)), i, 0);
+		else
+			writeRawData(QByteArray(40, 0x20).constData(), 40);
+}
+
+
+int SaveFormats::s_instances = 0;
+
+SaveFormats::SaveFormats()
+{
+	if (s_instances == 0) {
+		s_fileFormat[0] = new SaveTTIFormat;
+		s_fileFormat[1] = new SaveT42Format;
+		s_fileFormat[2] = new SaveEP1Format;
+		s_fileFormat[3] = new SaveHTTFormat;
+
+		for (int i=0; i<s_size; i++) {
+			if (i != 0)
+				s_exportFilters.append(";;");
+			s_exportFilters.append(s_fileFormat[i]->fileDialogFilter());
+			if (i < s_nativeSize) {
+				if (i != 0)
+					s_filters.append(";;");
+				s_filters.append(s_fileFormat[i]->fileDialogFilter());
+			}
+		}
+	}
+
+	s_instances++;
+}
+
+SaveFormats::~SaveFormats()
+{
+	s_instances--;
+
+	if (s_instances == 0)
+		for (int i=s_size-1; i>=0; i--)
+			delete s_fileFormat[i];
+}
+
+SaveFormat *SaveFormats::findFormat(const QString &suffix) const
+{
+	// TTI is the only official save format at the moment...
+//	for (int i=0; i<s_nativeSize; i++)
+//		if (s_fileFormat[i]->extensions().contains(suffix, Qt::CaseInsensitive))
+//			return s_fileFormat[i];
+
+	if (s_fileFormat[0]->extensions().contains(suffix, Qt::CaseInsensitive))
+		return s_fileFormat[0];
+
+	return nullptr;
+}
+
+SaveFormat *SaveFormats::findExportFormat(const QString &suffix) const
+{
+	for (int i=0; i<s_size; i++)
+		if (s_fileFormat[i]->extensions().contains(suffix, Qt::CaseInsensitive))
+			return s_fileFormat[i];
+
+	return nullptr;
+}

src/qteletextmaker/saveformats.h

@@ -0,0 +1,178 @@
+/*
+ * Copyright (C) 2020-2025 Gavin MacGregor
+ *
+ * This file is part of QTeletextMaker.
+ *
+ * QTeletextMaker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * QTeletextMaker is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef SAVEFORMATS_H
+#define SAVEFORMATS_H
+
+#include <QByteArray>
+#include <QDataStream>
+#include <QSaveFile>
+#include <QString>
+
+#include "document.h"
+#include "levelonepage.h"
+#include "pagebase.h"
+
+class SaveFormat
+{
+public:
+	virtual ~SaveFormat() { };
+
+	virtual void saveAllPages(QSaveFile &outFile, const TeletextDocument &document);
+	virtual void saveCurrentSubPage(QSaveFile &outFile, const TeletextDocument &document);
+
+	virtual QString description() const =0;
+	virtual QStringList extensions() const =0;
+	QString fileDialogFilter() const { return QString(description() + " (*." + extensions().join(" *.") + ')'); };
+	virtual bool getWarnings(const PageBase &subPage) { return false; };
+	QStringList warningStrings() const { return m_warnings; };
+	QString errorString() const { return m_error; };
+
+protected:
+	virtual void writeDocumentStart() { };
+	virtual void writeAllPages();
+	virtual void writeSubPage(const PageBase &subPage, int subPageNumber=0);
+	virtual void writeSubPageStart(const PageBase &subPage, int subPageNumber=0) { };
+	virtual void writeSubPageBody(const PageBase &subPage);
+	virtual void writeSubPageEnd(const PageBase &subPage) { };
+	virtual void writeDocumentEnd() { };
+
+	virtual void writeX27Packets(const PageBase &subPage);
+	virtual void writeX28Packets(const PageBase &subPage);
+	virtual void writeX26Packets(const PageBase &subPage);
+	virtual void writeX1to25Packets(const PageBase &subPage);
+
+	virtual QByteArray format7BitPacket(QByteArray packet) { return packet; };
+	virtual QByteArray format4BitPacket(QByteArray packet) { return packet; };
+	virtual QByteArray format18BitPacket(QByteArray packet) { return packet; };
+
+	virtual int writePacket(QByteArray packet, int packetNumber, int designationCode = -1);
+	virtual int writeRawData(const char *s, int len);
+
+	TeletextDocument const *m_document;
+	QSaveFile *m_outFile;
+	QDataStream m_outStream;
+	QStringList m_warnings;
+	QString m_error;
+};
+
+class SaveTTIFormat : public SaveFormat
+{
+public:
+	QString description() const override { return QString("MRG Systems TTI"); };
+	QStringList extensions() const override { return QStringList { "tti", "ttix" }; };
+
+protected:
+	virtual void writeDocumentStart();
+	virtual void writeSubPageStart(const PageBase &subPage, int subPageNumber=0);
+	virtual void writeSubPageBody(const PageBase &subPage);
+
+	virtual int writePacket(QByteArray packet, int packetNumber, int designationCode = -1);
+	void writeString(const QString &command);
+
+	QByteArray format7BitPacket(QByteArray packet);
+	QByteArray format4BitPacket(QByteArray packet) { return format18BitPacket(packet); };
+	QByteArray format18BitPacket(QByteArray packet);
+};
+
+class SaveM29Format : public SaveTTIFormat
+{
+protected:
+	void writeSubPageStart(const PageBase &subPage, int subPageNumber=0);
+	void writeSubPageBody(const PageBase &subPage);
+};
+
+class SaveT42Format : public SaveFormat
+{
+public:
+	QString description() const override { return QString("t42 packet stream"); };
+	QStringList extensions() const override { return QStringList { "t42" }; };
+
+protected:
+	void writeSubPageStart(const PageBase &subPage, int subPageNumber=0);
+	virtual int writePacket(QByteArray packet, int packetNumber, int designationCode = -1);
+
+	virtual QByteArray format7BitPacket(QByteArray packet);
+	virtual QByteArray format4BitPacket(QByteArray packet);
+	virtual QByteArray format18BitPacket(QByteArray packet);
+
+	int m_magazineNumber;
+};
+
+class SaveHTTFormat : public SaveT42Format
+{
+public:
+	QString description() const override { return QString("HMS SD-Teletext HTT"); };
+	QStringList extensions() const override { return QStringList { "htt" }; };
+
+protected:
+	int writeRawData(const char *s, int len) override;
+};
+
+class SaveEP1Format : public SaveFormat
+{
+public:
+	QString description() const override { return QString("Softel EP1"); };
+	QStringList extensions() const override { return QStringList { "ep1" }; };
+	virtual bool getWarnings(const PageBase &subPage);
+
+protected:
+	void writeSubPageStart(const PageBase &subPage, int subPageNumber=0);
+	void writeSubPageBody(const PageBase &subPage);
+	void writeSubPageEnd(const PageBase &subPage);
+
+	virtual void writeX1to25Packets(const PageBase &subPage);
+
+	virtual QByteArray format18BitPacket(QByteArray packet);
+
+	// Language codes unique to EP1
+	// FIXME duplicated in loadformats.h
+	const QMap<int, int> m_languageCode {
+		{ 0x00, 0x09 }, { 0x01, 0x0d }, { 0x02, 0x18 }, { 0x03, 0x11 }, { 0x04, 0x0b }, { 0x05, 0x17 }, { 0x06, 0x07 },
+		{ 0x08, 0x14 }, { 0x09, 0x0d }, { 0x0a, 0x18 }, { 0x0b, 0x11 }, { 0x0c, 0x0b }, { 0x0e, 0x07 },
+		{ 0x10, 0x09 }, { 0x11, 0x0d }, { 0x12, 0x18 }, { 0x13, 0x11 }, { 0x14, 0x0b }, { 0x15, 0x17 }, { 0x16, 0x1c },
+		{ 0x1d, 0x1e }, { 0x1f, 0x16 },
+		{ 0x21, 0x0d }, { 0x22, 0xff }, { 0x23, 0xff }, { 0x26, 0x07 },
+		{ 0x36, 0x1c }, { 0x37, 0x0e },
+		{ 0x40, 0x09 }, { 0x44, 0x0b }
+	};
+};
+
+
+class SaveFormats
+{
+public:
+	SaveFormats();
+	~SaveFormats();
+
+	SaveFormat *findFormat(const QString &suffix) const;
+	SaveFormat *findExportFormat(const QString &suffix) const;
+	QString filters() const { return s_filters; };
+	QString exportFilters() const { return s_exportFilters; };
+	bool isExportOnly(const QString &suffix) const { return findFormat(suffix) == nullptr; };
+
+private:
+	static const inline int s_size = 4;
+	static const inline int s_nativeSize = 1;
+	static int s_instances;
+	inline static SaveFormat *s_fileFormat[s_size];
+	inline static QString s_filters, s_exportFilters;
+};
+
+#endif

src/qteletextmaker/x26dockwidget.cpp

@@ -74,7 +74,7 @@ void CharacterListModel::setCharacterSet(int characterSet)
 	if (characterSet != m_characterSet || m_mosaic) {
 		m_characterSet = characterSet;
 		m_mosaic = false;
-		emit dataChanged(createIndex(0, 0), createIndex(95, 0), QVector<int>(Qt::DecorationRole));
+		emit dataChanged(createIndex(0, 0), createIndex(95, 0), QList<int>(Qt::DecorationRole));
 	}
 }
 
@@ -83,7 +83,7 @@ void CharacterListModel::setG1AndBlastCharacterSet(int characterSet)
 	if (characterSet != m_characterSet || !m_mosaic) {
 		m_characterSet = characterSet;
 		m_mosaic = true;
-		emit dataChanged(createIndex(0, 0), createIndex(95, 0), QVector<int>(Qt::DecorationRole));
+		emit dataChanged(createIndex(0, 0), createIndex(95, 0), QList<int>(Qt::DecorationRole));
 	}
 }