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/qteletextdecoder/render.h

@@ -0,0 +1,90 @@
+/*
+ * 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 RENDER_H
+#define RENDER_H
+
+#include <QBitmap>
+#include <QColor>
+#include <QIcon>
+#include <QImage>
+#include <QPixmap>
+
+#include "decode.h"
+
+class TeletextFontBitmap
+{
+public:
+	TeletextFontBitmap();
+	~TeletextFontBitmap();
+
+	QImage *image() const { return s_fontImage; }
+	QPixmap charBitmap(int c, int s) const { return s_fontBitmap->copy((c-32)*12, s*10, 12, 10); }
+	QIcon charIcon(int c, int s) const { return QIcon(charBitmap(c, s)); }
+
+private:
+	static int s_instances;
+	static QBitmap* s_fontBitmap;
+	static QImage* s_fontImage;
+};
+
+class TeletextPageRender : public QObject
+{
+	Q_OBJECT
+
+public:
+	TeletextPageRender();
+	~TeletextPageRender();
+
+	QImage* image(int i) const { return m_pageImage[i]; };
+	bool mix() const { return m_mix; };
+	void setDecoder(TeletextPageDecode *decoder);
+	void renderPage(bool force=false);
+	bool showControlCodes() const { return m_showControlCodes; };
+
+public slots:
+	void colourChanged(int index);
+	void setReveal(bool reveal);
+	void setMix(bool mix);
+	void setShowControlCodes(bool showControlCodes);
+
+signals:
+	void flashChanged(int newFlashHz);
+
+protected:
+	TeletextFontBitmap m_fontBitmap;
+	QImage* m_pageImage[6];
+	unsigned char m_controlCodeCache[25][40];
+	bool m_reveal, m_mix, m_showControlCodes;
+	int m_flashBuffersHz;
+	int m_flashingRow[25];
+
+private:
+	inline void drawFromBitmap(QPainter &, int, int, const QImage, TeletextPageDecode::CharacterFragment);
+	inline void drawFromFontBitmap(QPainter &painter, int r, int c, unsigned char characterCode, int characterSet, TeletextPageDecode::CharacterFragment characterFragment);
+	inline void drawCharacter(QPainter &painter, int r, int c, unsigned char characterCode, int characterSet, int characterDiacritical, TeletextPageDecode::CharacterFragment characterFragment);
+	inline void drawBoldOrItalicCharacter(QPainter &painter, int r, int c, unsigned char characterCode, int characterSet, TeletextPageDecode::CharacterFragment characterFragment);
+	void renderRow(int r, int ph, bool force=false);
+	void setRowFlashStatus(int r, int rowFlashHz);
+
+	QColor m_foregroundQColor, m_backgroundQColor;
+	TeletextPageDecode *m_decoder;
+};
+
+#endif