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LibImage: Add support for PNG images 

I have not tested images with less than 8 bits per color or images with
indexed color as gimp could not export those. There is currently no
support for interlaced images.
This commit is contained in:
Bananymous 2024-06-18 02:37:46 +03:00
parent f233715b70
commit 1b5a01a6c9
1 changed files with 247 additions and 55 deletions
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302
LibImage/PNG.cpp
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@ -5,6 +5,12 @@
#include <ctype.h>
#define DEBUG_PNG 0
// PNG https://www.w3.org/TR/png-3/
// ZLIB https://www.rfc-editor.org/rfc/rfc1950
// DEFLATE https://www.rfc-editor.org/rfc/rfc1951
namespace LibImage
{
@ -34,6 +40,15 @@ namespace LibImage
Adaptive = 0,
};
enum class FilterType : uint8_t
{
None = 0,
Sub = 1,
Up = 2,
Average = 3,
Paeth = 4,
};
enum class InterlaceMethod : uint8_t
{
NoInterlace = 0,
@ -51,13 +66,6 @@ namespace LibImage
InterlaceMethod interlace_method;
} __attribute__((packed));
struct PaletteEntry
{
uint8_t red;
uint8_t green;
uint8_t blue;
};
struct ZLibStream
{
uint8_t cm : 4;
@ -73,10 +81,10 @@ namespace LibImage
BAN::ConstByteSpan data;
};
class BinaryBuffer
class BitBuffer
{
public:
BinaryBuffer(BAN::Vector<BAN::ConstByteSpan> data)
BitBuffer(BAN::Vector<BAN::ConstByteSpan> data)
: m_data(data)
{}
@ -134,7 +142,6 @@ namespace LibImage
return reverse;
}
// https://www.rfc-editor.org/rfc/rfc1951
class HuffmanTree
{
public:
@ -237,17 +244,44 @@ namespace LibImage
{
public:
DeflateDecoder(BAN::Vector<BAN::ConstByteSpan> data)
: m_buffer(BinaryBuffer(BAN::move(data)))
: m_buffer(BitBuffer(BAN::move(data)))
{}
BAN::ErrorOr<BAN::ConstByteSpan> decode_stream()
BAN::ErrorOr<BAN::ByteSpan> decode_stream()
{
while (!TRY(decode_block()))
continue;
return BAN::ConstByteSpan(m_decoded.span());
m_buffer.skip_to_byte_boundary();
uint32_t checksum = 0;
for (int i = 0; i < 4; i++)
checksum = (checksum << 8) | TRY(m_buffer.get_bits(8));
if (decoded_adler32() != checksum)
{
dwarnln_if(DEBUG_PNG, "decode checksum does not match");
return BAN::Error::from_errno(EINVAL);
}
return BAN::ByteSpan(m_decoded.span());
}
private:
uint32_t decoded_adler32() const
{
uint32_t a = 1;
uint32_t b = 0;
for (uint8_t byte : m_decoded)
{
a = (a + byte) % 65521;
b = (b + a) % 65521;
}
return (b << 16) | a;
}
BAN::ErrorOr<bool> decode_block()
{
bool bfinal = TRY(m_buffer.get_bits(1));
@ -259,7 +293,7 @@ namespace LibImage
case 1: TRY(decode_type1()); break;
case 2: TRY(decode_type2()); break;
default:
dwarnln("Deflate block has invalid method {}", btype);
dwarnln_if(DEBUG_PNG, "Deflate block has invalid method {}", btype);
return BAN::Error::from_errno(EINVAL);
}
@ -274,7 +308,7 @@ namespace LibImage
uint16_t nlen = TRY(m_buffer.get_bits(16));
if (len != 0xFFFF - nlen)
{
dwarnln("Deflate block uncompressed data length is invalid");
dwarnln_if(DEBUG_PNG, "Deflate block uncompressed data length is invalid");
return BAN::Error::from_errno(EINVAL);
}
@ -423,14 +457,14 @@ namespace LibImage
private:
BAN::Vector<uint8_t> m_decoded;
BinaryBuffer m_buffer;
BitBuffer m_buffer;
};
BAN::ErrorOr<PNGChunk> read_and_take_chunk(BAN::ConstByteSpan& image_data)
{
if (image_data.size() < 12)
{
dwarnln("PNG stream does not contain any more chunks");
dwarnln_if(DEBUG_PNG, "PNG stream does not contain any more chunks");
return BAN::Error::from_errno(EINVAL);
}
@ -439,7 +473,7 @@ namespace LibImage
if (image_data.size() < length + 8)
{
dwarnln("PNG stream does not contain any more chunks");
dwarnln_if(DEBUG_PNG, "PNG stream does not contain any more chunks");
return BAN::Error::from_errno(EINVAL);
}
@ -448,7 +482,6 @@ namespace LibImage
result.name = BAN::StringView(image_data.as_span<const char>().data(), 4);
image_data = image_data.slice(4);
// skip chunk data
result.data = image_data.slice(0, length);
image_data = image_data.slice(length);
@ -501,7 +534,7 @@ namespace LibImage
{
if (!probe_png(image_data))
{
dwarnln("Invalid PNG data");
dwarnln_if(DEBUG_PNG, "Invalid PNG data");
return BAN::Error::from_errno(EINVAL);
}
image_data = image_data.slice(8);
@ -509,50 +542,59 @@ namespace LibImage
auto ihdr_chunk = TRY(read_and_take_chunk(image_data));
if (ihdr_chunk.name != "IHDR")
{
dwarnln("PNG stream does not start with IHDR chunk");
dwarnln_if(DEBUG_PNG, "PNG stream does not start with IHDR chunk");
return BAN::Error::from_errno(EINVAL);
}
if (ihdr_chunk.data.size() != sizeof(IHDR))
{
dwarnln("PNG stream has invalid IHDR chunk size: {}, expected {}", ihdr_chunk.data.size(), sizeof(IHDR));
dwarnln_if(DEBUG_PNG, "PNG stream has invalid IHDR chunk size: {}, expected {}", ihdr_chunk.data.size(), sizeof(IHDR));
return BAN::Error::from_errno(EINVAL);
}
const auto& ihdr = ihdr_chunk.data.as<const IHDR>();
if (ihdr.width == 0 || ihdr.height == 0 || ihdr.width > 0x7FFFFFFF || ihdr.height > 0x7FFFFFFF)
{
dwarnln("PNG IHDR has invalid size {}x{}", (uint32_t)ihdr.width, (uint32_t)ihdr.height);
dwarnln_if(DEBUG_PNG, "PNG IHDR has invalid size {}x{}", (uint32_t)ihdr.width, (uint32_t)ihdr.height);
return BAN::Error::from_errno(EINVAL);
}
if (!validate_ihdr_colour_type_and_bit_depth(ihdr))
{
dwarnln("PNG IHDR has invalid bit depth {} for colour type {}", ihdr.bit_depth, static_cast<uint8_t>(ihdr.colour_type));
dwarnln_if(DEBUG_PNG, "PNG IHDR has invalid bit depth {} for colour type {}", ihdr.bit_depth, static_cast<uint8_t>(ihdr.colour_type));
return BAN::Error::from_errno(EINVAL);
}
if (ihdr.compression_method != CompressionMethod::Deflate)
{
dwarnln("PNG IHDR has invalid compression method {}", static_cast<uint8_t>(ihdr.compression_method));
dwarnln_if(DEBUG_PNG, "PNG IHDR has invalid compression method {}", static_cast<uint8_t>(ihdr.compression_method));
return BAN::Error::from_errno(EINVAL);
}
if (ihdr.filter_method != FilterMethod::Adaptive)
{
dwarnln("PNG IHDR has invalid filter method {}", static_cast<uint8_t>(ihdr.filter_method));
dwarnln_if(DEBUG_PNG, "PNG IHDR has invalid filter method {}", static_cast<uint8_t>(ihdr.filter_method));
return BAN::Error::from_errno(EINVAL);
}
if (ihdr.interlace_method != InterlaceMethod::NoInterlace && ihdr.interlace_method != InterlaceMethod::Adam7)
{
dwarnln("PNG IHDR has invalid interlace method {}", static_cast<uint8_t>(ihdr.interlace_method));
dwarnln_if(DEBUG_PNG, "PNG IHDR has invalid interlace method {}", static_cast<uint8_t>(ihdr.interlace_method));
return BAN::Error::from_errno(EINVAL);
}
dprintln("Decoding {}x{} PNG image", (uint32_t)ihdr.width, (uint32_t)ihdr.height);
dprintln(" bit depth: {}", ihdr.bit_depth);
dprintln(" colour type: {}", static_cast<uint8_t>(ihdr.colour_type));
dprintln(" compression method: {}", static_cast<uint8_t>(ihdr.compression_method));
dprintln(" filter method: {}", static_cast<uint8_t>(ihdr.filter_method));
dprintln(" interlace method: {}", static_cast<uint8_t>(ihdr.interlace_method));
if (ihdr.interlace_method == InterlaceMethod::Adam7)
{
dwarnln_if(DEBUG_PNG, "PNG with interlacing is not supported");
return BAN::Error::from_errno(ENOTSUP);
}
BAN::Vector<PaletteEntry> palette;
const uint64_t image_width = ihdr.width;
const uint64_t image_height = ihdr.height;
dprintln_if(DEBUG_PNG, "Decoding {}x{} PNG image", image_width, image_height);
dprintln_if(DEBUG_PNG, " bit depth: {}", ihdr.bit_depth);
dprintln_if(DEBUG_PNG, " colour type: {}", static_cast<uint8_t>(ihdr.colour_type));
dprintln_if(DEBUG_PNG, " compression method: {}", static_cast<uint8_t>(ihdr.compression_method));
dprintln_if(DEBUG_PNG, " filter method: {}", static_cast<uint8_t>(ihdr.filter_method));
dprintln_if(DEBUG_PNG, " interlace method: {}", static_cast<uint8_t>(ihdr.interlace_method));
BAN::Vector<Image::Color> palette;
BAN::Vector<BAN::ConstByteSpan> zlib_stream;
while (true)
@ -562,35 +604,40 @@ namespace LibImage
chunk = ret.release_value();
else
{
dwarnln("PNG stream does not end with IEND chunk");
dwarnln_if(DEBUG_PNG, "PNG stream does not end with IEND chunk");
return BAN::Error::from_errno(EINVAL);
}
if (chunk.name == "IHDR"sv)
{
dwarnln("PNG stream has IDHR chunk defined multiple times");
dwarnln_if(DEBUG_PNG, "PNG stream has IDHR chunk defined multiple times");
return BAN::Error::from_errno(EINVAL);
}
else if (chunk.name == "PLTE"sv)
{
if (chunk.data.size() == 0 || chunk.data.size() % 3)
{
dwarnln("PNG PLTE has invalid data size {}", chunk.data.size());
dwarnln_if(DEBUG_PNG, "PNG PLTE has invalid data size {}", chunk.data.size());
return BAN::Error::from_errno(EINVAL);
}
if (!palette.empty())
{
dwarnln("PNG PLTE defined multiple times");
dwarnln_if(DEBUG_PNG, "PNG PLTE defined multiple times");
return BAN::Error::from_errno(EINVAL);
}
if (ihdr.colour_type != ColourType::IndexedColour && ihdr.colour_type != ColourType::Truecolour && ihdr.colour_type != ColourType::TruecolourAlpha)
{
dwarnln("PNG PLTE defined for colour type {} which does not use palette", static_cast<uint8_t>(ihdr.colour_type));
dwarnln_if(DEBUG_PNG, "PNG PLTE defined for colour type {} which does not use palette", static_cast<uint8_t>(ihdr.colour_type));
return BAN::Error::from_errno(EINVAL);
}
TRY(palette.resize(chunk.data.size() / 3));
for (size_t i = 0; i < palette.size(); i++)
palette[i] = chunk.data.as_span<const PaletteEntry>()[i];
for (size_t i = 0; i < palette.size(); i += 3)
{
palette[i].r = chunk.data[i + 0];
palette[i].g = chunk.data[i + 1];
palette[i].b = chunk.data[i + 2];
palette[i].a = 0xFF;
}
}
else if (chunk.name == "IDAT"sv)
{
@ -604,12 +651,12 @@ namespace LibImage
{
auto data_sv = BAN::StringView(chunk.data.as_span<const char>().data(), chunk.data.size());
if (auto idx = data_sv.find('\0'); !idx.has_value())
dwarnln("PNG tEXt chunk does not contain null-byte");
dwarnln_if(DEBUG_PNG, "PNG tEXt chunk does not contain null-byte");
else
{
auto keyword = data_sv.substring(0, idx.value());
auto text = data_sv.substring(idx.value() + 1);
dprintln("'{}': '{}'", keyword, text);
dprintln_if(DEBUG_PNG, "'{}': '{}'", keyword, text);
}
}
else
@ -617,35 +664,34 @@ namespace LibImage
bool ancillary = islower(chunk.name[0]);
if (!ancillary)
{
dwarnln("Unsupported critical chunk '{}'", chunk.name);
dwarnln_if(DEBUG_PNG, "Unsupported critical chunk '{}'", chunk.name);
return BAN::Error::from_errno(ENOTSUP);
}
dwarnln("Skipping unsupported ancillary chunk '{}'", chunk.name);
dwarnln_if(DEBUG_PNG, "Skipping unsupported ancillary chunk '{}'", chunk.name);
}
}
{
if (zlib_stream.empty() || zlib_stream.front().size() < 2)
{
dwarnln("PNG does not have zlib stream");
dwarnln_if(DEBUG_PNG, "PNG does not have zlib stream");
return BAN::Error::from_errno(EINVAL);
}
if (zlib_stream[0].as<const BAN::BigEndian<uint16_t>>() % 31)
{
dwarnln("PNG zlib stream checksum failed");
dwarnln_if(DEBUG_PNG, "PNG zlib stream checksum failed");
return BAN::Error::from_errno(EINVAL);
}
auto zlib_header = zlib_stream[0].as<const ZLibStream>();
if (zlib_header.fdict)
{
dwarnln("PNG IDAT zlib stream has fdict set");
dwarnln_if(DEBUG_PNG, "PNG IDAT zlib stream has fdict set");
return BAN::Error::from_errno(EINVAL);
}
if (zlib_header.cm != 8)
{
dwarnln("PNG IDAT has invalid zlib compression method {}", (uint8_t)zlib_header.cm);
dwarnln_if(DEBUG_PNG, "PNG IDAT has invalid zlib compression method {}", (uint8_t)zlib_header.cm);
return BAN::Error::from_errno(EINVAL);
}
zlib_stream[0] = zlib_stream[0].slice(2);
@ -654,15 +700,161 @@ namespace LibImage
uint64_t total_size = 0;
for (auto stream : zlib_stream)
total_size += stream.size();
dprintln("PNG has {} byte zlib stream", total_size);
dprintln_if(DEBUG_PNG, "PNG has {} byte zlib stream", total_size);
DeflateDecoder decoder(BAN::move(zlib_stream));
auto decoded = TRY(decoder.decode_stream());
auto inflated_data = TRY(decoder.decode_stream());
dprintln(" uncompressed size {}", decoded.size());
dprintln(" compression ratio {}", (double)decoded.size() / total_size);
dprintln_if(DEBUG_PNG, " uncompressed size {}", inflated_data.size());
dprintln_if(DEBUG_PNG, " compression ratio {}", (double)inflated_data.size() / total_size);
return BAN::Error::from_errno(ENOTSUP);
uint8_t bits_per_channel = ihdr.bit_depth;
uint8_t channels = 0;
switch (ihdr.colour_type)
{
case ColourType::Greyscale: channels = 1; break;
case ColourType::Truecolour: channels = 3; break;
case ColourType::IndexedColour: channels = 1; break;
case ColourType::GreyscaleAlpha: channels = 2; break;
case ColourType::TruecolourAlpha: channels = 4; break;
default:
ASSERT_NOT_REACHED();
}
const auto extract_channel =
[&](auto& bit_buffer) -> uint8_t
{
uint16_t tmp = MUST(bit_buffer.get_bits(bits_per_channel));
switch (bits_per_channel)
{
case 1: return tmp * 0xFF;
case 2: return tmp * 0xFF / 3;
case 4: return tmp * 0xFF / 15;
case 8: return tmp;
case 16: return tmp & 0xFF; // NOTE: stored in big endian
}
ASSERT_NOT_REACHED();
};
const auto extract_color =
[&](auto& bit_buffer) -> Image::Color
{
uint8_t tmp;
switch (ihdr.colour_type)
{
case ColourType::Greyscale:
tmp = extract_channel(bit_buffer);
return Image::Color {
.r = tmp,
.g = tmp,
.b = tmp,
.a = 0xFF
};
case ColourType::Truecolour:
return Image::Color {
.r = extract_channel(bit_buffer),
.g = extract_channel(bit_buffer),
.b = extract_channel(bit_buffer),
.a = 0xFF
};
case ColourType::IndexedColour:
return palette[MUST(bit_buffer.get_bits(bits_per_channel))];
case ColourType::GreyscaleAlpha:
tmp = extract_channel(bit_buffer);
return Image::Color {
.r = tmp,
.g = tmp,
.b = tmp,
.a = extract_channel(bit_buffer)
};
case ColourType::TruecolourAlpha:
return Image::Color {
.r = extract_channel(bit_buffer),
.g = extract_channel(bit_buffer),
.b = extract_channel(bit_buffer),
.a = extract_channel(bit_buffer)
};
}
ASSERT_NOT_REACHED();
};
constexpr auto paeth_predictor =
[](int16_t a, int16_t b, int16_t c) -> uint8_t
{
int16_t p = a + b - c;
int16_t pa = BAN::Math::abs(p - a);
int16_t pb = BAN::Math::abs(p - b);
int16_t pc = BAN::Math::abs(p - c);
if (pa <= pb && pa <= pc)
return a;
if (pb <= pc)
return b;
return c;
};
const uint64_t bytes_per_scanline = BAN::Math::div_round_up<uint64_t>(image_width * channels * bits_per_channel, 8);
const uint64_t pitch = bytes_per_scanline + 1;
if (inflated_data.size() < pitch * image_height)
{
dwarnln_if(DEBUG_PNG, "PNG does not contain enough image data");
return BAN::Error::from_errno(ENODATA);
}
BAN::Vector<uint8_t> zero_scanline;
TRY(zero_scanline.resize(bytes_per_scanline, 0));
BAN::Vector<Image::Color> color_bitmap;
TRY(color_bitmap.resize(image_width * image_height));
BAN::Vector<BAN::ConstByteSpan> inflated_data_wrapper;
TRY(inflated_data_wrapper.push_back({}));
const uint8_t filter_offset = (bits_per_channel < 8) ? 1 : channels * (bits_per_channel / 8);
for (uint64_t y = 0; y < image_height; y++)
{
auto scanline = inflated_data.slice((y - 0) * pitch + 1, bytes_per_scanline);
auto scanline_above = (y > 0) ? inflated_data.slice((y - 1) * pitch + 1, bytes_per_scanline) : BAN::ConstByteSpan(zero_scanline.span());
auto filter_type = static_cast<FilterType>(inflated_data[y * pitch]);
switch (filter_type)
{
case FilterType::None:
break;
case FilterType::Sub:
for (uint64_t x = filter_offset; x < bytes_per_scanline; x++)
scanline[x] += scanline[x - filter_offset];
break;
case FilterType::Up:
for (uint64_t x = 0; x < bytes_per_scanline; x++)
scanline[x] += scanline_above[x];
break;
case FilterType::Average:
for (uint8_t i = 0; i < filter_offset; i++)
scanline[i] += scanline_above[i] / 2;
for (uint64_t x = filter_offset; x < bytes_per_scanline; x++)
scanline[x] += ((uint16_t)scanline[x - filter_offset] + (uint16_t)scanline_above[x]) / 2;
break;
case FilterType::Paeth:
for (uint8_t i = 0; i < filter_offset; i++)
scanline[i] += paeth_predictor(0, scanline_above[i], 0);
for (uint64_t x = filter_offset; x < bytes_per_scanline; x++)
scanline[x] += paeth_predictor(scanline[x - filter_offset], scanline_above[x], scanline_above[x - filter_offset]);
break;
default:
dwarnln_if(DEBUG_PNG, "invalid filter type {}", static_cast<uint8_t>(filter_type));
return BAN::Error::from_errno(EINVAL);
}
inflated_data_wrapper[0] = scanline;
BitBuffer bit_buffer(inflated_data_wrapper);
for (uint64_t x = 0; x < image_width; x++)
color_bitmap[y * image_width + x] = extract_color(bit_buffer);
}
return TRY(BAN::UniqPtr<Image>::create(image_width, image_height, BAN::move(color_bitmap)));
}
}