portapack-mayhem/firmware/common/png_writer.cpp
Jared Boone 38ba02a68f Change File::open to File::open_for_writing.
Not thrilled about the File API right now...
2016-04-10 15:55:01 -07:00

128 lines
3.9 KiB
C++

/*
* 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.
*/
#include "png_writer.hpp"
static constexpr std::array<uint8_t, 8> png_file_header { {
0x89, 0x50, 0x4e, 0x47,
0x0d, 0x0a, 0x1a, 0x0a,
} };
static constexpr std::array<uint8_t, 25> png_ihdr_screen_capture { {
0x00, 0x00, 0x00, 0x0d, // IHDR length
0x49, 0x48, 0x44, 0x52, // IHDR type
0x00, 0x00, 0x00, 0xf0, // width = 240
0x00, 0x00, 0x01, 0x40, // height = 320
0x08, // bit_depth = 8
0x02, // color_type = 2
0x00, // compression_method = 0
0x00, // filter_method = 0
0x00, // interlace_method = 0
0x0d, 0x8a, 0x66, 0x04, // CRC
} };
static constexpr std::array<uint8_t, 4> png_idat_chunk_type { {
0x49, 0x44, 0x41, 0x54, // IDAT type
} };
static constexpr std::array<uint8_t, 12> png_iend { {
0x00, 0x00, 0x00, 0x00, // IEND length
0x49, 0x45, 0x4e, 0x44, // IEND type
0xae, 0x42, 0x60, 0x82, // CRC
} };
PNGWriter::PNGWriter(
const std::string& filename
)
{
file.open_for_writing(filename);
file.write(png_file_header);
file.write(png_ihdr_screen_capture);
write_chunk_header(
2 + height * (5 + 1 + width * 3) + 4,
png_idat_chunk_type
);
constexpr std::array<uint8_t, 2> zlib_header { 0x78, 0x01 }; // Zlib CM, CINFO, FLG.
write_chunk_content(zlib_header);
}
PNGWriter::~PNGWriter() {
write_chunk_content(adler_32.bytes());
write_chunk_crc();
file.write(png_iend);
}
void PNGWriter::write_scanline(const std::array<ui::ColorRGB888, 240>& scanline) {
constexpr uint8_t scanline_filter_type = 0;
constexpr uint32_t deflate_block_length = 1 + sizeof(scanline);
const std::array<uint8_t, 6> deflate_and_scanline_header {
static_cast<uint8_t>((scanline_count == (height - 1)) ? 0x01 : 0x00), // DEFLATE header bits, bfinal=0, btype=00
static_cast<uint8_t>((deflate_block_length >> 0) & 0xff), // Length LSB
static_cast<uint8_t>((deflate_block_length >> 8) & 0xff), // Length MSB
static_cast<uint8_t>((deflate_block_length >> 0) & 0xff) ^ 0xff, // ~Length LSB
static_cast<uint8_t>((deflate_block_length >> 8) & 0xff) ^ 0xff, // ~Length MSB
scanline_filter_type,
};
write_chunk_content(deflate_and_scanline_header);
adler_32.feed(scanline_filter_type);
adler_32.feed(scanline);
// Small writes to avoid some sort of large-transfer plus block
// boundary FatFs or SDC driver bug?
write_chunk_content(&scanline[ 0], 80 * sizeof(ui::ColorRGB888));
write_chunk_content(&scanline[ 80], 80 * sizeof(ui::ColorRGB888));
write_chunk_content(&scanline[160], 80 * sizeof(ui::ColorRGB888));
scanline_count++;
}
void PNGWriter::write_chunk_header(
const size_t length,
const std::array<uint8_t, 4>& type
) {
write_uint32_be(length);
crc.reset();
write_chunk_content(type);
}
void PNGWriter::write_chunk_content(const void* const p, const size_t count) {
file.write(p, count);
crc.process_bytes(p, count);
}
void PNGWriter::write_chunk_crc() {
write_uint32_be(crc.checksum());
}
void PNGWriter::write_uint32_be(const uint32_t v) {
file.write(std::array<uint8_t, 4> { {
static_cast<uint8_t>((v >> 24) & 0xff),
static_cast<uint8_t>((v >> 16) & 0xff),
static_cast<uint8_t>((v >> 8) & 0xff),
static_cast<uint8_t>((v >> 0) & 0xff),
} });
}