Port to CMake from qmake, and split decoder into subdirectory

Qt 5 has had to be dropped as CMakeLists.txt uses qt_* specific commands
which are implemented in Qt 6 onwards.

cmake --install is only working on Linux at the moment; it installs the
executable and the bundled example tti files into /usr/local/share/doc

The teletext decoder with its document storage has been moved to a
subdirectory with the intention of making it possible to use in other
projects, but some further separation of editing stuff will be needed.

src/qteletextmaker/x28commands.h

@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2020-2024 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 X28COMMANDS_H
+#define X28COMMANDS_H
+
+#include <QUndoCommand>
+
+#include "document.h"
+
+class X28Command : public QUndoCommand
+{
+public:
+	X28Command(TeletextDocument *teletextDocument, QUndoCommand *parent = 0);
+
+protected:
+	TeletextDocument *m_teletextDocument;
+	int m_subPageIndex;
+};
+
+class SetFullScreenColourCommand : public X28Command
+{
+public:
+	enum { Id = 301 };
+
+	SetFullScreenColourCommand(TeletextDocument *teletextDocument, int newColour, QUndoCommand *parent = 0);
+
+	void redo() override;
+	void undo() override;
+	bool mergeWith(const QUndoCommand *command) override;
+	int id() const override { return Id; }
+
+private:
+	int m_oldColour, m_newColour;
+};
+
+class SetFullRowColourCommand : public X28Command
+{
+public:
+	enum { Id = 302 };
+
+	SetFullRowColourCommand(TeletextDocument *teletextDocument, int newColour, QUndoCommand *parent = 0);
+
+	void redo() override;
+	void undo() override;
+	bool mergeWith(const QUndoCommand *command) override;
+	int id() const override { return Id; }
+
+private:
+	int m_oldColour, m_newColour;
+};
+
+class SetCLUTRemapCommand : public X28Command
+{
+public:
+	enum { Id = 303 };
+
+	SetCLUTRemapCommand(TeletextDocument *teletextDocument, int newMap, QUndoCommand *parent = 0);
+
+	void redo() override;
+	void undo() override;
+	bool mergeWith(const QUndoCommand *command) override;
+	int id() const override { return Id; }
+
+private:
+	int m_oldMap, m_newMap;
+};
+
+class SetBlackBackgroundSubstCommand : public X28Command
+{
+public:
+	enum { Id = 304 };
+
+	SetBlackBackgroundSubstCommand(TeletextDocument *teletextDocument, bool newSub, QUndoCommand *parent = 0);
+
+	void redo() override;
+	void undo() override;
+	bool mergeWith(const QUndoCommand *command) override;
+	int id() const override { return Id; }
+
+private:
+	int m_oldSub, m_newSub;
+};
+
+class SetColourCommand : public X28Command
+{
+public:
+	SetColourCommand(TeletextDocument *teletextDocument, int colourIndex, int newColour, QUndoCommand *parent = 0);
+
+	void redo() override;
+	void undo() override;
+
+private:
+	int m_colourIndex, m_oldColour, m_newColour;
+};
+
+class ResetCLUTCommand : public X28Command
+{
+public:
+	ResetCLUTCommand(TeletextDocument *teletextDocument, int colourTable, QUndoCommand *parent = 0);
+
+	void redo() override;
+	void undo() override;
+
+private:
+	int m_colourTable;
+	int m_oldColourEntry[8];
+};
+
+#endif