Bodgy code to write PNG files the size of the LCD screen.

firmware/common/png_writer.hpp

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+/*
+ * Copyright (C) 2016 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program 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 2, or (at your option)
+ * any later version.
+ *
+ * This program 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 this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __PNG_WRITER_H__
+#define __PNG_WRITER_H__
+
+#include <cstdint>
+#include <cstddef>
+#include <string>
+#include <array>
+
+#include "ui.hpp"
+#include "file.hpp"
+#include "crc.hpp"
+
+class PNGWriter {
+public:
+	explicit PNGWriter(const std::string& filename);
+	~PNGWriter();
+
+	void write_scanline(const std::array<ui::ColorRGB888, 240>& scanline);
+
+private:
+	// TODO: These constants are baked in a few places, do not change blithely.
+	static constexpr int width { 240 };
+	static constexpr int height { 320 };
+
+	File file;
+	int scanline_count { 0 };
+	CRC<32, true, true> crc { 0x04c11db7, 0xffffffff, 0xffffffff };
+	Adler32 adler_32;
+
+	void write_chunk_header(const size_t length, const std::array<uint8_t, 4>& type);
+	void write_chunk_content(const void* const p, const size_t count);
+
+	template<size_t N>
+	void write_chunk_content(const std::array<uint8_t, N>& data) {
+		write_chunk_content(data.data(), sizeof(data));
+	}
+
+	void write_chunk_crc();
+	void write_uint32_be(const uint32_t v);
+};
+
+#endif/*__PNG_WRITER_H__*/