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This commit is contained in:
Ian Gulliver
214
piphoto.cc
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214
piphoto.cc
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#include <arpa/inet.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <png.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <array>
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#include <experimental/string_view>
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#include <iostream>
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#include <string>
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namespace std {
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using string_view = experimental::string_view;
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}
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std::string ReadFile(const std::string& filename);
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void WriteFile(const std::string& filename, const std::string& contents);
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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class PiRaw {
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public:
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struct Pixel {
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// 32-bit for compiler convenience, but values are 16-bit
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uint32_t r;
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uint32_t g;
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uint32_t b;
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};
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typedef std::array<std::array<Pixel, X>, Y> Image;
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PiRaw(std::unique_ptr<Image>);
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static PiRaw FromJpeg(const std::string_view& jpeg);
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static PiRaw FromRaw(const std::string_view& raw);
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std::string ToPng();
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private:
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static constexpr uint32_t kJpegHeaderBytes = 32768;
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static constexpr const char* kJpegHeaderMagic = "BRCM";
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static constexpr uint32_t kPixelsPerChunk = 4;
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static constexpr uint32_t kBitsPerByte = 8;
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static constexpr uint32_t GetRawBytes();
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static constexpr uint32_t GetRowBytes();
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static constexpr uint32_t GetNumRows();
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static constexpr uint32_t GetChunkBytes();
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static constexpr uint32_t Align(uint32_t val);
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typedef std::array<uint32_t, kPixelsPerChunk> Chunk;
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static Chunk GetChunk(const std::string_view& raw, const uint32_t x_chunk, const uint32_t y);
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static Pixel CombineRaw(uint32_t y0x0, uint32_t y0x1, uint32_t y1x0, uint32_t y1x1);
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std::unique_ptr<Image> image_;
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};
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typedef PiRaw<3280,2464,10,16,2> PiRaw2;
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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PiRaw<X,Y,D,A,P>::PiRaw(std::unique_ptr<Image> image)
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: image_(std::move(image)) {}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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PiRaw<X,Y,D,A,P> PiRaw<X,Y,D,A,P>::FromJpeg(const std::string_view& jpeg) {
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auto container_len = GetRawBytes() + kJpegHeaderBytes;
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assert(jpeg.substr(jpeg.size() - container_len, 4) == kJpegHeaderMagic);
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return FromRaw(jpeg.substr(jpeg.size() - GetRawBytes(), GetRawBytes()));
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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PiRaw<X,Y,D,A,P> PiRaw<X,Y,D,A,P>::FromRaw(const std::string_view& raw) {
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static_assert(X % 2 == 0);
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static_assert(Y % 2 == 0);
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static_assert(kPixelsPerChunk == 4);
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assert(raw.size() == GetRawBytes());
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auto image = std::make_unique<Image>();
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for (uint32_t y = 0, out_y = 0; y < Y; y += 2, ++out_y) {
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for (uint32_t x_chunk = 0, out_x = 0; x_chunk < X / kPixelsPerChunk; ++x_chunk, out_x += kPixelsPerChunk / 2) {
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auto chunk1 = GetChunk(raw, x_chunk, y + 0);
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auto chunk2 = GetChunk(raw, x_chunk, y + 1);
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image->at(out_y).at(out_x + 0) = CombineRaw(chunk1.at(0), chunk1.at(1), chunk2.at(0), chunk2.at(1));
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image->at(out_y).at(out_x + 1) = CombineRaw(chunk1.at(2), chunk1.at(3), chunk2.at(2), chunk2.at(3));
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}
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}
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return PiRaw<X,Y,D,A,P>(std::move(image));
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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constexpr uint32_t PiRaw<X,Y,D,A,P>::GetRawBytes() {
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return GetRowBytes() * GetNumRows();
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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constexpr uint32_t PiRaw<X,Y,D,A,P>::GetRowBytes() {
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return Align(Align(X + P) * D / kBitsPerByte);
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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constexpr uint32_t PiRaw<X,Y,D,A,P>::GetNumRows() {
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return Align(Y + P);
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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constexpr uint32_t PiRaw<X,Y,D,A,P>::GetChunkBytes() {
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return D * kPixelsPerChunk / kBitsPerByte;
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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constexpr uint32_t PiRaw<X,Y,D,A,P>::Align(uint32_t val) {
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return (~(A - 1)) & ((val) + (A - 1));
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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typename PiRaw<X,Y,D,A,P>::Chunk PiRaw<X,Y,D,A,P>::GetChunk(const std::string_view& raw, const uint32_t x_chunk, const uint32_t y) {
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// Function is bit depth & layout specific
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static_assert(D == 10);
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auto start = y * GetRowBytes() + x_chunk * GetChunkBytes();
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auto high0 = static_cast<uint32_t>(raw.at(start + 0));
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auto high1 = static_cast<uint32_t>(raw.at(start + 1));
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auto high2 = static_cast<uint32_t>(raw.at(start + 2));
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auto high3 = static_cast<uint32_t>(raw.at(start + 3));
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auto packed_low = static_cast<uint32_t>(raw.at(start + 4));
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Chunk ret;
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ret.at(0) = ((high0 << 2) | ((packed_low >> 6) & 0b11)) << 6;
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ret.at(1) = ((high1 << 2) | ((packed_low >> 4) & 0b11)) << 6;
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ret.at(2) = ((high2 << 2) | ((packed_low >> 2) & 0b11)) << 6;
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ret.at(3) = ((high3 << 2) | ((packed_low >> 0) & 0b11)) << 6;
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return ret;
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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typename PiRaw<X,Y,D,A,P>::Pixel PiRaw<X,Y,D,A,P>::CombineRaw(uint32_t y0x0, uint32_t y0x1, uint32_t y1x0, uint32_t y1x1) {
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// Function is bit layout specific
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Pixel ret;
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ret.r = y1x1;
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ret.g = (y0x1 + y1x0) / 2;
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ret.b = y0x0;
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return ret;
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}
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static void WriteCallback(png_structp png_ptr, png_bytep data, png_size_t length) {
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auto dest = static_cast<std::string*>(png_get_io_ptr(png_ptr));
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dest->append(reinterpret_cast<char*>(data), length);
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}
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template <uint32_t X, uint32_t Y, uint32_t D, uint32_t A, uint32_t P>
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std::string PiRaw<X,Y,D,A,P>::ToPng() {
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std::string ret;
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auto png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
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assert(png_ptr);
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auto info_ptr = png_create_info_struct(png_ptr);
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assert(info_ptr);
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png_set_write_fn(png_ptr, &ret, &WriteCallback, nullptr);
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png_set_IHDR(png_ptr, info_ptr, X / 2, Y / 2,
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16, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
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PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
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png_write_info(png_ptr, info_ptr);
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for (auto& row : *image_) {
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std::array<uint16_t, X * 3> out_row;
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for (uint32_t x = 0; x < X; ++x) {
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out_row[x * 3 + 0] = htons(static_cast<uint16_t>(row[x].r));
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out_row[x * 3 + 1] = htons(static_cast<uint16_t>(row[x].g));
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out_row[x * 3 + 2] = htons(static_cast<uint16_t>(row[x].b));
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}
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png_write_row(png_ptr, reinterpret_cast<unsigned char*>(out_row.data()));
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}
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png_write_end(png_ptr, nullptr);
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png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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return ret;
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}
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std::string ReadFile(const std::string& filename) {
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int fh = open(filename.c_str(), O_RDONLY);
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assert(fh != -1);
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struct stat st;
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assert(fstat(fh, &st) == 0);
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std::string contents;
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contents.resize(static_cast<size_t>(st.st_size));
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assert(read(fh, &contents[0], static_cast<size_t>(st.st_size)) == st.st_size);
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assert(close(fh) == 0);
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return contents;
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}
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void WriteFile(const std::string& filename, const std::string& contents) {
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int fh = open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0644);
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assert(fh != -1);
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assert(write(fh, &contents[0], contents.size()) == static_cast<ssize_t>(contents.size()));
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assert(close(fh) == 0);
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}
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int main() {
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auto raw = PiRaw2::FromJpeg(ReadFile("test.jpg"));
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WriteFile("test.png", raw.ToPng());
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}
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