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LibGfx: Move implementation code for Tables.h into Tables.cpp

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Sam Atkins 2023-10-21 16:12:23 +01:00 committed by Andreas Kling
parent 61ac554a34
commit dfa79ba6d8
4 changed files with 691 additions and 664 deletions
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1
Userland/Libraries/LibGfx/CMakeLists.txt
View file

@ -21,6 +21,7 @@ set(SOURCES
Font/OpenType/Font.cpp
Font/OpenType/Glyf.cpp
Font/OpenType/Hinting/Opcodes.cpp
Font/OpenType/Tables.cpp
Font/ScaledFont.cpp
Font/Typeface.cpp
Font/WOFF/Font.cpp

664
Userland/Libraries/LibGfx/Font/OpenType/Font.cpp
View file

@ -7,9 +7,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/BinarySearch.h>
#include <AK/Checked.h>
#include <AK/Debug.h>
#include <AK/MemoryStream.h>
#include <AK/Try.h>
#include <LibCore/MappedFile.h>
@ -20,7 +18,6 @@
#include <LibGfx/Font/OpenType/Glyf.h>
#include <LibGfx/Font/OpenType/Tables.h>
#include <LibGfx/ImageFormats/PNGLoader.h>
#include <LibTextCodec/Decoder.h>
#include <math.h>
#include <sys/mman.h>
@ -57,301 +54,6 @@ u32 tag_from_str(char const* str)
return be_u32((u8 const*)str);
}
Optional<Head> Head::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(FontHeaderTable)) {
return {};
}
return Head(slice);
}
u16 Head::units_per_em() const
{
return header().units_per_em;
}
i16 Head::xmin() const
{
return header().x_min;
}
i16 Head::ymin() const
{
return header().y_min;
}
i16 Head::xmax() const
{
return header().x_max;
}
i16 Head::ymax() const
{
return header().y_max;
}
u16 Head::style() const
{
return header().mac_style;
}
u16 Head::lowest_recommended_ppem() const
{
return header().lowest_rec_ppem;
}
IndexToLocFormat Head::index_to_loc_format() const
{
switch (header().index_to_loc_format) {
case 0:
return IndexToLocFormat::Offset16;
case 1:
return IndexToLocFormat::Offset32;
default:
VERIFY_NOT_REACHED();
}
}
Optional<Hhea> Hhea::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(HorizontalHeaderTable)) {
return {};
}
return Hhea(slice);
}
i16 Hhea::ascender() const
{
return header().ascender;
}
i16 Hhea::descender() const
{
return header().descender;
}
i16 Hhea::line_gap() const
{
return header().line_gap;
}
u16 Hhea::advance_width_max() const
{
return header().advance_width_max;
}
u16 Hhea::number_of_h_metrics() const
{
return header().number_of_h_metrics;
}
Optional<Maxp> Maxp::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(MaximumProfileVersion0_5)) {
return {};
}
return Maxp(slice);
}
u16 Maxp::num_glyphs() const
{
return header().num_glyphs;
}
Optional<Hmtx> Hmtx::from_slice(ReadonlyBytes slice, u32 num_glyphs, u32 number_of_h_metrics)
{
if (slice.size() < number_of_h_metrics * sizeof(LongHorMetric) + (num_glyphs - number_of_h_metrics) * sizeof(u16)) {
return {};
}
return Hmtx(slice, num_glyphs, number_of_h_metrics);
}
Optional<Name> Name::from_slice(ReadonlyBytes slice)
{
return Name(slice);
}
ErrorOr<Kern> Kern::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(Header))
return Error::from_string_literal("Invalid kern table header");
// We only support the old (2x u16) version of the header
auto const& header = *bit_cast<Header const*>(slice.data());
auto version = header.version;
auto number_of_subtables = header.n_tables;
if (version != 0)
return Error::from_string_literal("Unsupported kern table version");
if (number_of_subtables == 0)
return Error::from_string_literal("Kern table does not contain any subtables");
// Read all subtable offsets
auto subtable_offsets = TRY(FixedArray<size_t>::create(number_of_subtables));
size_t offset = sizeof(Header);
for (size_t i = 0; i < number_of_subtables; ++i) {
if (slice.size() < offset + sizeof(SubtableHeader))
return Error::from_string_literal("Invalid kern subtable header");
auto const& subtable_header = *bit_cast<SubtableHeader const*>(slice.offset_pointer(offset));
subtable_offsets[i] = offset;
offset += subtable_header.length;
}
return Kern(slice, move(subtable_offsets));
}
i16 Kern::get_glyph_kerning(u16 left_glyph_id, u16 right_glyph_id) const
{
VERIFY(left_glyph_id > 0 && right_glyph_id > 0);
i16 glyph_kerning = 0;
for (auto subtable_offset : m_subtable_offsets) {
auto subtable_slice = m_slice.slice(subtable_offset);
auto const& subtable_header = *bit_cast<SubtableHeader const*>(subtable_slice.data());
auto version = subtable_header.version;
auto length = subtable_header.length;
auto coverage = subtable_header.coverage;
if (version != 0) {
dbgln("OpenType::Kern: unsupported subtable version {}", version);
continue;
}
if (subtable_slice.size() < length) {
dbgln("OpenType::Kern: subtable has an invalid size {}", length);
continue;
}
auto is_horizontal = (coverage & (1 << 0)) > 0;
auto is_minimum = (coverage & (1 << 1)) > 0;
auto is_cross_stream = (coverage & (1 << 2)) > 0;
auto is_override = (coverage & (1 << 3)) > 0;
auto reserved_bits = (coverage & 0xF0);
auto format = (coverage & 0xFF00) >> 8;
// FIXME: implement support for these features
if (!is_horizontal || is_minimum || is_cross_stream || (reserved_bits > 0)) {
dbgln("OpenType::Kern: FIXME: implement missing feature support for subtable");
continue;
}
// FIXME: implement support for subtable formats other than 0
Optional<i16> subtable_kerning;
switch (format) {
case 0:
subtable_kerning = read_glyph_kerning_format0(subtable_slice.slice(sizeof(SubtableHeader)), left_glyph_id, right_glyph_id);
break;
default:
dbgln("OpenType::Kern: FIXME: subtable format {} is unsupported", format);
continue;
}
if (!subtable_kerning.has_value())
continue;
auto kerning_value = subtable_kerning.release_value();
if (is_override)
glyph_kerning = kerning_value;
else
glyph_kerning += kerning_value;
}
return glyph_kerning;
}
Optional<i16> Kern::read_glyph_kerning_format0(ReadonlyBytes slice, u16 left_glyph_id, u16 right_glyph_id)
{
if (slice.size() < sizeof(Format0))
return {};
auto const& format0 = *bit_cast<Format0 const*>(slice.data());
u16 number_of_pairs = format0.n_pairs;
u16 search_range = format0.search_range;
u16 entry_selector = format0.entry_selector;
u16 range_shift = format0.range_shift;
// Sanity checks for this table format
auto pairs_in_search_range = search_range / sizeof(Format0Pair);
if (number_of_pairs == 0)
return {};
if (pairs_in_search_range > number_of_pairs)
return {};
if ((1 << entry_selector) * sizeof(Format0Pair) != search_range)
return {};
if ((number_of_pairs - pairs_in_search_range) * sizeof(Format0Pair) != range_shift)
return {};
// FIXME: implement a possibly slightly more efficient binary search using the parameters above
ReadonlySpan<Format0Pair> pairs { bit_cast<Format0Pair const*>(slice.slice(sizeof(Format0)).data()), number_of_pairs };
// The left and right halves of the kerning pair make an unsigned 32-bit number, which is then used to order the kerning pairs numerically.
auto needle = (static_cast<u32>(left_glyph_id) << 16u) | static_cast<u32>(right_glyph_id);
auto* pair = binary_search(pairs, nullptr, nullptr, [&](void*, Format0Pair const& pair) {
auto as_u32 = (static_cast<u32>(pair.left) << 16u) | static_cast<u32>(pair.right);
return needle - as_u32;
});
if (!pair)
return 0;
return pair->value;
}
String Name::string_for_id(NameId id) const
{
auto const count = header().count;
auto const storage_offset = header().storage_offset;
Vector<int> valid_ids;
for (size_t i = 0; i < count; ++i) {
auto this_id = header().name_record[i].name_id;
if (this_id == to_underlying(id))
valid_ids.append(i);
}
if (valid_ids.is_empty())
return String {};
auto it = valid_ids.find_if([this](auto const& i) {
// check if font has naming table for en-US language id
auto const& name_record = header().name_record[i];
auto const platform_id = name_record.platform_id;
auto const language_id = name_record.language_id;
return (platform_id == to_underlying(Platform::Macintosh) && language_id == to_underlying(MacintoshLanguage::English))
|| (platform_id == to_underlying(Platform::Windows) && language_id == to_underlying(WindowsLanguage::EnglishUnitedStates));
});
auto i = it != valid_ids.end() ? *it : valid_ids.first();
auto const& name_record = header().name_record[i];
auto const platform_id = name_record.platform_id;
auto const length = name_record.length;
auto const offset = name_record.string_offset;
if (platform_id == to_underlying(Platform::Windows)) {
static auto& decoder = *TextCodec::decoder_for("utf-16be"sv);
return decoder.to_utf8(StringView { (char const*)m_slice.offset(storage_offset + offset), length }).release_value_but_fixme_should_propagate_errors();
}
return String::from_utf8(m_slice.slice(storage_offset + offset, length)).release_value_but_fixme_should_propagate_errors();
}
GlyphHorizontalMetrics Hmtx::get_glyph_horizontal_metrics(u32 glyph_id) const
{
VERIFY(glyph_id < m_num_glyphs);
auto const* long_hor_metrics = bit_cast<LongHorMetric const*>(m_slice.data());
if (glyph_id < m_number_of_h_metrics) {
return GlyphHorizontalMetrics {
.advance_width = static_cast<u16>(long_hor_metrics[glyph_id].advance_width),
.left_side_bearing = static_cast<i16>(long_hor_metrics[glyph_id].lsb),
};
}
auto const* left_side_bearings = bit_cast<BigEndian<u16> const*>(m_slice.offset(m_number_of_h_metrics * sizeof(LongHorMetric)));
return GlyphHorizontalMetrics {
.advance_width = static_cast<u16>(long_hor_metrics[m_number_of_h_metrics - 1].advance_width),
.left_side_bearing = static_cast<i16>(left_side_bearings[glyph_id - m_number_of_h_metrics]),
};
}
ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_resource(Core::Resource const& resource, unsigned index)
{
auto font = TRY(try_load_from_externally_owned_memory(resource.data(), index));
@ -856,48 +558,6 @@ bool Font::is_fixed_width() const
return glyph_metrics(glyph_id_for_code_point('.'), 1, 1, 1, 1).advance_width == glyph_metrics(glyph_id_for_code_point('X'), 1, 1, 1, 1).advance_width;
}
u16 OS2::weight_class() const
{
return header().us_weight_class;
}
u16 OS2::width_class() const
{
return header().us_width_class;
}
u16 OS2::selection() const
{
return header().fs_selection;
}
i16 OS2::typographic_ascender() const
{
return header().s_typo_ascender;
}
i16 OS2::typographic_descender() const
{
return header().s_typo_descender;
}
i16 OS2::typographic_line_gap() const
{
return header().s_typo_line_gap;
}
bool OS2::use_typographic_metrics() const
{
return header().fs_selection & 0x80;
}
Optional<i16> OS2::x_height() const
{
if (header().version < 2)
return {};
return header_v2().sx_height;
}
Optional<ReadonlyBytes> Font::font_program() const
{
if (m_fpgm.has_value())
@ -958,88 +618,11 @@ void Font::populate_glyph_page(GlyphPage& glyph_page, size_t page_index) const
glyph_page.glyph_ids[i] = m_cmap.glyph_id_for_code_point(code_point);
}
}
ErrorOr<CBLC> CBLC::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(CblcHeader))
return Error::from_string_literal("CBLC table too small");
auto const& header = *bit_cast<CblcHeader const*>(slice.data());
size_t num_sizes = header.num_sizes;
Checked<size_t> size_used_by_bitmap_sizes = num_sizes;
size_used_by_bitmap_sizes *= sizeof(BitmapSize);
if (size_used_by_bitmap_sizes.has_overflow())
return Error::from_string_literal("Integer overflow in CBLC table");
Checked<size_t> total_size = sizeof(CblcHeader);
total_size += size_used_by_bitmap_sizes;
if (total_size.has_overflow())
return Error::from_string_literal("Integer overflow in CBLC table");
if (slice.size() < total_size)
return Error::from_string_literal("CBLC table too small");
return CBLC { slice };
}
Optional<CBLC::BitmapSize const&> CBLC::bitmap_size_for_glyph_id(u32 glyph_id) const
{
for (auto const& bitmap_size : this->bitmap_sizes()) {
if (glyph_id >= bitmap_size.start_glyph_index && glyph_id <= bitmap_size.end_glyph_index) {
return bitmap_size;
}
}
return {};
}
ErrorOr<CBDT> CBDT::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(CbdtHeader))
return Error::from_string_literal("CBDT table too small");
return CBDT { slice };
}
bool Font::has_color_bitmaps() const
{
return m_cblc.has_value() && m_cbdt.has_value();
}
Optional<EBLC::IndexSubHeader const&> CBLC::index_subtable_for_glyph_id(u32 glyph_id, u16& first_glyph_index, u16& last_glyph_index) const
{
auto maybe_bitmap_size = bitmap_size_for_glyph_id(glyph_id);
if (!maybe_bitmap_size.has_value()) {
return {};
}
auto const& bitmap_size = maybe_bitmap_size.value();
Checked<size_t> required_size = static_cast<u32>(bitmap_size.index_subtable_array_offset);
required_size += bitmap_size.index_tables_size;
if (m_slice.size() < required_size) {
dbgln("CBLC index subtable array goes out of bounds");
return {};
}
auto index_subtables_slice = m_slice.slice(bitmap_size.index_subtable_array_offset, bitmap_size.index_tables_size);
ReadonlySpan<EBLC::IndexSubTableArray> index_subtable_arrays {
bit_cast<EBLC::IndexSubTableArray const*>(index_subtables_slice.data()), bitmap_size.number_of_index_subtables
};
EBLC::IndexSubTableArray const* index_subtable_array = nullptr;
for (auto const& array : index_subtable_arrays) {
if (glyph_id >= array.first_glyph_index && glyph_id <= array.last_glyph_index)
index_subtable_array = &array;
}
if (!index_subtable_array) {
return {};
}
auto index_subtable_slice = m_slice.slice(bitmap_size.index_subtable_array_offset + index_subtable_array->additional_offset_to_index_subtable);
first_glyph_index = index_subtable_array->first_glyph_index;
last_glyph_index = index_subtable_array->last_glyph_index;
return *bit_cast<EBLC::IndexSubHeader const*>(index_subtable_slice.data());
}
RefPtr<Gfx::Bitmap> Font::color_bitmap(u32 glyph_id) const
{
return embedded_bitmap_data_for_glyph(glyph_id).visit(
@ -1059,251 +642,4 @@ RefPtr<Gfx::Bitmap> Font::color_bitmap(u32 glyph_id) const
});
}
Optional<i16> GPOS::glyph_kerning(u16 left_glyph_id, u16 right_glyph_id) const
{
auto read_value_record = [&](u16 value_format, FixedMemoryStream& stream) -> ValueRecord {
ValueRecord value_record;
if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT))
value_record.x_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT))
value_record.y_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE))
value_record.x_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE))
value_record.y_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT_DEVICE))
value_record.x_placement_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT_DEVICE))
value_record.y_placement_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE_DEVICE))
value_record.x_advance_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE_DEVICE))
value_record.y_advance_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
return value_record;
};
auto const& header = this->header();
dbgln_if(OPENTYPE_GPOS_DEBUG, "GPOS header:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " Version: {}.{}", header.major_version, header.minor_version);
dbgln_if(OPENTYPE_GPOS_DEBUG, " Feature list offset: {}", header.feature_list_offset);
// FIXME: Make sure everything is bounds-checked appropriately.
auto feature_list_slice = m_slice.slice(header.feature_list_offset);
if (feature_list_slice.size() < sizeof(FeatureList)) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "GPOS table feature list slice is too small");
return {};
}
auto const& feature_list = *bit_cast<FeatureList const*>(feature_list_slice.data());
auto lookup_list_slice = m_slice.slice(header.lookup_list_offset);
if (lookup_list_slice.size() < sizeof(LookupList)) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "GPOS table lookup list slice is too small");
return {};
}
auto const& lookup_list = *bit_cast<LookupList const*>(lookup_list_slice.data());
Optional<Offset16> kern_feature_offset;
for (size_t i = 0; i < feature_list.feature_count; ++i) {
auto const& feature_record = feature_list.feature_records[i];
if (feature_record.feature_tag == tag_from_str("kern")) {
kern_feature_offset = feature_record.feature_offset;
break;
}
}
if (!kern_feature_offset.has_value()) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "No 'kern' feature found in GPOS table");
return {};
}
auto feature_slice = feature_list_slice.slice(kern_feature_offset.value());
auto const& feature = *bit_cast<Feature const*>(feature_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "Feature:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " featureParamsOffset: {}", feature.feature_params_offset);
dbgln_if(OPENTYPE_GPOS_DEBUG, " lookupIndexCount: {}", feature.lookup_index_count);
for (size_t i = 0; i < feature.lookup_index_count; ++i) {
auto lookup_index = feature.lookup_list_indices[i];
dbgln_if(OPENTYPE_GPOS_DEBUG, "Lookup index: {}", lookup_index);
auto lookup_slice = lookup_list_slice.slice(lookup_list.lookup_offsets[lookup_index]);
auto const& lookup = *bit_cast<Lookup const*>(lookup_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "Lookup:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " lookupType: {}", lookup.lookup_type);
dbgln_if(OPENTYPE_GPOS_DEBUG, " lookupFlag: {}", lookup.lookup_flag);
dbgln_if(OPENTYPE_GPOS_DEBUG, " subtableCount: {}", lookup.subtable_count);
// NOTE: We only support lookup type 2 (Pair adjustment) at the moment.
if (lookup.lookup_type != 2) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement GPOS lookup type {}", lookup.lookup_type);
continue;
}
for (size_t j = 0; j < lookup.subtable_count; ++j) {
auto pair_pos_format_offset = lookup.subtable_offsets[j];
auto pair_pos_format_slice = lookup_slice.slice(pair_pos_format_offset);
auto const& pair_pos_format = *bit_cast<BigEndian<u16> const*>(pair_pos_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "PairPosFormat{}", pair_pos_format);
if (pair_pos_format == 1) {
auto const& pair_pos_format1 = *bit_cast<GPOS::PairPosFormat1 const*>(pair_pos_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format1.pos_format);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format1.value_format1);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format1.value_format2);
dbgln_if(OPENTYPE_GPOS_DEBUG, " pairSetCount: {}", pair_pos_format1.pair_set_count);
auto get_coverage_index = [&](u16 glyph_id, Offset16 coverage_format_offset) -> Optional<u16> {
auto coverage_format_slice = pair_pos_format_slice.slice(coverage_format_offset);
auto const& coverage_format = *bit_cast<BigEndian<u16> const*>(coverage_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "Coverage table format: {}", coverage_format);
if (coverage_format == 1) {
auto const& coverage_format1 = *bit_cast<CoverageFormat1 const*>(coverage_format_slice.data());
for (size_t k = 0; k < coverage_format1.glyph_count; ++k)
if (coverage_format1.glyph_array[k] == glyph_id)
return k;
dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID {} not covered", glyph_id);
return {};
}
else if (coverage_format == 2) {
auto const& coverage_format2 = *bit_cast<CoverageFormat2 const*>(coverage_format_slice.data());
for (size_t k = 0; k < coverage_format2.range_count; ++k) {
auto range_record = coverage_format2.range_records[k];
if ((range_record.start_glyph_id <= glyph_id) && (glyph_id <= range_record.end_glyph_id))
return range_record.start_coverage_index + glyph_id - range_record.start_glyph_id;
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID {} not covered", glyph_id);
return {};
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "No valid coverage table for format {}", coverage_format);
return {};
};
auto coverage_index = get_coverage_index(left_glyph_id, pair_pos_format1.coverage_offset);
if (!coverage_index.has_value()) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID not covered by table");
continue;
}
size_t value1_size = popcount(static_cast<u32>(pair_pos_format1.value_format1 & 0xff)) * sizeof(u16);
size_t value2_size = popcount(static_cast<u32>(pair_pos_format1.value_format2 & 0xff)) * sizeof(u16);
dbgln_if(OPENTYPE_GPOS_DEBUG, "ValueSizes: {}, {}", value1_size, value2_size);
// Manually iterate over the PairSet table, as the size of each PairValueRecord is not known at compile time.
auto pair_set_offset = pair_pos_format1.pair_set_offsets[coverage_index.value()];
auto pair_set_slice = pair_pos_format_slice.slice(pair_set_offset);
FixedMemoryStream stream(pair_set_slice);
auto pair_value_count = stream.read_value<BigEndian<u16>>().release_value_but_fixme_should_propagate_errors();
bool found_matching_glyph = false;
for (size_t k = 0; k < pair_value_count; ++k) {
auto second_glyph = stream.read_value<BigEndian<u16>>().release_value_but_fixme_should_propagate_errors();
if (right_glyph_id == second_glyph) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Found matching second glyph {}", second_glyph);
found_matching_glyph = true;
break;
}
(void)stream.discard(value1_size + value2_size).release_value_but_fixme_should_propagate_errors();
}
if (!found_matching_glyph) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Did not find second glyph matching {}", right_glyph_id);
continue;
}
[[maybe_unused]] auto value_record1 = read_value_record(pair_pos_format1.value_format1, stream);
[[maybe_unused]] auto value_record2 = read_value_record(pair_pos_format1.value_format2, stream);
dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", value_record1.x_advance);
return value_record1.x_advance;
}
else if (pair_pos_format == 2) {
auto const& pair_pos_format2 = *bit_cast<GPOS::PairPosFormat2 const*>(pair_pos_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format2.pos_format);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format2.value_format1);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format2.value_format2);
dbgln_if(OPENTYPE_GPOS_DEBUG, " class1Count: {}", pair_pos_format2.class1_count);
dbgln_if(OPENTYPE_GPOS_DEBUG, " class2Count: {}", pair_pos_format2.class2_count);
auto get_class = [&](u16 glyph_id, Offset16 glyph_def_offset) -> Optional<u16> {
auto class_def_format_slice = pair_pos_format_slice.slice(glyph_def_offset);
auto const& class_def_format = *bit_cast<BigEndian<u16> const*>(class_def_format_slice.data());
if (class_def_format == 1) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement ClassDefFormat1");
return {};
}
auto const& class_def_format2 = *bit_cast<ClassDefFormat2 const*>(class_def_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "ClassDefFormat2:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " classFormat: {}", class_def_format2.class_format);
dbgln_if(OPENTYPE_GPOS_DEBUG, " classRangeCount: {}", class_def_format2.class_range_count);
for (size_t i = 0; i < class_def_format2.class_range_count; ++i) {
auto const& range = class_def_format2.class_range_records[i];
if (glyph_id >= range.start_glyph_id && glyph_id <= range.end_glyph_id) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Found class {} for glyph ID {}", range.class_, glyph_id);
return range.class_;
}
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "No class found for glyph {}", glyph_id);
return {};
};
auto left_class = get_class(left_glyph_id, pair_pos_format2.class_def1_offset);
auto right_class = get_class(right_glyph_id, pair_pos_format2.class_def2_offset);
if (!left_class.has_value() || !right_class.has_value()) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Need glyph class for both sides");
continue;
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "Classes: {}, {}", left_class.value(), right_class.value());
size_t value1_size = popcount(static_cast<u32>(pair_pos_format2.value_format1 & 0xff)) * sizeof(u16);
size_t value2_size = popcount(static_cast<u32>(pair_pos_format2.value_format2 & 0xff)) * sizeof(u16);
dbgln_if(OPENTYPE_GPOS_DEBUG, "ValueSizes: {}, {}", value1_size, value2_size);
size_t class2_record_size = value1_size + value2_size;
dbgln_if(OPENTYPE_GPOS_DEBUG, "Class2RecordSize: {}", class2_record_size);
size_t class1_record_size = pair_pos_format2.class2_count * class2_record_size;
dbgln_if(OPENTYPE_GPOS_DEBUG, "Class1RecordSize: {}", class1_record_size);
size_t item_offset = (left_class.value() * class1_record_size) + (right_class.value() * class2_record_size);
dbgln_if(OPENTYPE_GPOS_DEBUG, "Item offset: {}", item_offset);
auto item_slice = pair_pos_format_slice.slice(sizeof(PairPosFormat2) + item_offset);
FixedMemoryStream stream(item_slice);
[[maybe_unused]] auto value_record1 = read_value_record(pair_pos_format2.value_format1, stream);
[[maybe_unused]] auto value_record2 = read_value_record(pair_pos_format2.value_format2, stream);
dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", value_record1.x_advance);
return value_record1.x_advance;
}
}
}
(void)left_glyph_id;
(void)right_glyph_id;
return {};
}
}

689
Userland/Libraries/LibGfx/Font/OpenType/Tables.cpp Normal file
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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
* Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
* Copyright (c) 2023, Lukas Affolter <git@lukasach.dev>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/BinarySearch.h>
#include <AK/BuiltinWrappers.h>
#include <AK/Debug.h>
#include <AK/MemoryStream.h>
#include <LibGfx/Font/OpenType/Tables.h>
#include <LibTextCodec/Decoder.h>
namespace OpenType {
static u32 be_u32(u8 const* ptr)
{
return (((u32)ptr[0]) << 24) | (((u32)ptr[1]) << 16) | (((u32)ptr[2]) << 8) | ((u32)ptr[3]);
}
static u32 tag_from_str(char const* str)
{
return be_u32((u8 const*)str);
}
Optional<Head> Head::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(FontHeaderTable)) {
return {};
}
return Head(slice);
}
u16 Head::units_per_em() const
{
return header().units_per_em;
}
i16 Head::xmin() const
{
return header().x_min;
}
i16 Head::ymin() const
{
return header().y_min;
}
i16 Head::xmax() const
{
return header().x_max;
}
i16 Head::ymax() const
{
return header().y_max;
}
u16 Head::style() const
{
return header().mac_style;
}
u16 Head::lowest_recommended_ppem() const
{
return header().lowest_rec_ppem;
}
IndexToLocFormat Head::index_to_loc_format() const
{
switch (header().index_to_loc_format) {
case 0:
return IndexToLocFormat::Offset16;
case 1:
return IndexToLocFormat::Offset32;
default:
VERIFY_NOT_REACHED();
}
}
Optional<Hhea> Hhea::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(HorizontalHeaderTable)) {
return {};
}
return Hhea(slice);
}
i16 Hhea::ascender() const
{
return header().ascender;
}
i16 Hhea::descender() const
{
return header().descender;
}
i16 Hhea::line_gap() const
{
return header().line_gap;
}
u16 Hhea::advance_width_max() const
{
return header().advance_width_max;
}
u16 Hhea::number_of_h_metrics() const
{
return header().number_of_h_metrics;
}
Optional<Maxp> Maxp::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(MaximumProfileVersion0_5)) {
return {};
}
return Maxp(slice);
}
u16 Maxp::num_glyphs() const
{
return header().num_glyphs;
}
Optional<Hmtx> Hmtx::from_slice(ReadonlyBytes slice, u32 num_glyphs, u32 number_of_h_metrics)
{
if (slice.size() < number_of_h_metrics * sizeof(LongHorMetric) + (num_glyphs - number_of_h_metrics) * sizeof(u16)) {
return {};
}
return Hmtx(slice, num_glyphs, number_of_h_metrics);
}
GlyphHorizontalMetrics Hmtx::get_glyph_horizontal_metrics(u32 glyph_id) const
{
VERIFY(glyph_id < m_num_glyphs);
auto const* long_hor_metrics = bit_cast<LongHorMetric const*>(m_slice.data());
if (glyph_id < m_number_of_h_metrics) {
return GlyphHorizontalMetrics {
.advance_width = static_cast<u16>(long_hor_metrics[glyph_id].advance_width),
.left_side_bearing = static_cast<i16>(long_hor_metrics[glyph_id].lsb),
};
}
auto const* left_side_bearings = bit_cast<BigEndian<u16> const*>(m_slice.offset(m_number_of_h_metrics * sizeof(LongHorMetric)));
return GlyphHorizontalMetrics {
.advance_width = static_cast<u16>(long_hor_metrics[m_number_of_h_metrics - 1].advance_width),
.left_side_bearing = static_cast<i16>(left_side_bearings[glyph_id - m_number_of_h_metrics]),
};
}
Optional<Name> Name::from_slice(ReadonlyBytes slice)
{
return Name(slice);
}
String Name::string_for_id(NameId id) const
{
auto const count = header().count;
auto const storage_offset = header().storage_offset;
Vector<int> valid_ids;
for (size_t i = 0; i < count; ++i) {
auto this_id = header().name_record[i].name_id;
if (this_id == to_underlying(id))
valid_ids.append(i);
}
if (valid_ids.is_empty())
return String {};
auto it = valid_ids.find_if([this](auto const& i) {
// check if font has naming table for en-US language id
auto const& name_record = header().name_record[i];
auto const platform_id = name_record.platform_id;
auto const language_id = name_record.language_id;
return (platform_id == to_underlying(Platform::Macintosh) && language_id == to_underlying(MacintoshLanguage::English))
|| (platform_id == to_underlying(Platform::Windows) && language_id == to_underlying(WindowsLanguage::EnglishUnitedStates));
});
auto i = it != valid_ids.end() ? *it : valid_ids.first();
auto const& name_record = header().name_record[i];
auto const platform_id = name_record.platform_id;
auto const length = name_record.length;
auto const offset = name_record.string_offset;
if (platform_id == to_underlying(Platform::Windows)) {
static auto& decoder = *TextCodec::decoder_for("utf-16be"sv);
return decoder.to_utf8(StringView { (char const*)m_slice.offset(storage_offset + offset), length }).release_value_but_fixme_should_propagate_errors();
}
return String::from_utf8(m_slice.slice(storage_offset + offset, length)).release_value_but_fixme_should_propagate_errors();
}
ErrorOr<Kern> Kern::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(Header))
return Error::from_string_literal("Invalid kern table header");
// We only support the old (2x u16) version of the header
auto const& header = *bit_cast<Header const*>(slice.data());
auto version = header.version;
auto number_of_subtables = header.n_tables;
if (version != 0)
return Error::from_string_literal("Unsupported kern table version");
if (number_of_subtables == 0)
return Error::from_string_literal("Kern table does not contain any subtables");
// Read all subtable offsets
auto subtable_offsets = TRY(FixedArray<size_t>::create(number_of_subtables));
size_t offset = sizeof(Header);
for (size_t i = 0; i < number_of_subtables; ++i) {
if (slice.size() < offset + sizeof(SubtableHeader))
return Error::from_string_literal("Invalid kern subtable header");
auto const& subtable_header = *bit_cast<SubtableHeader const*>(slice.offset_pointer(offset));
subtable_offsets[i] = offset;
offset += subtable_header.length;
}
return Kern(slice, move(subtable_offsets));
}
i16 Kern::get_glyph_kerning(u16 left_glyph_id, u16 right_glyph_id) const
{
VERIFY(left_glyph_id > 0 && right_glyph_id > 0);
i16 glyph_kerning = 0;
for (auto subtable_offset : m_subtable_offsets) {
auto subtable_slice = m_slice.slice(subtable_offset);
auto const& subtable_header = *bit_cast<SubtableHeader const*>(subtable_slice.data());
auto version = subtable_header.version;
auto length = subtable_header.length;
auto coverage = subtable_header.coverage;
if (version != 0) {
dbgln("OpenType::Kern: unsupported subtable version {}", version);
continue;
}
if (subtable_slice.size() < length) {
dbgln("OpenType::Kern: subtable has an invalid size {}", length);
continue;
}
auto is_horizontal = (coverage & (1 << 0)) > 0;
auto is_minimum = (coverage & (1 << 1)) > 0;
auto is_cross_stream = (coverage & (1 << 2)) > 0;
auto is_override = (coverage & (1 << 3)) > 0;
auto reserved_bits = (coverage & 0xF0);
auto format = (coverage & 0xFF00) >> 8;
// FIXME: implement support for these features
if (!is_horizontal || is_minimum || is_cross_stream || (reserved_bits > 0)) {
dbgln("OpenType::Kern: FIXME: implement missing feature support for subtable");
continue;
}
// FIXME: implement support for subtable formats other than 0
Optional<i16> subtable_kerning;
switch (format) {
case 0:
subtable_kerning = read_glyph_kerning_format0(subtable_slice.slice(sizeof(SubtableHeader)), left_glyph_id, right_glyph_id);
break;
default:
dbgln("OpenType::Kern: FIXME: subtable format {} is unsupported", format);
continue;
}
if (!subtable_kerning.has_value())
continue;
auto kerning_value = subtable_kerning.release_value();
if (is_override)
glyph_kerning = kerning_value;
else
glyph_kerning += kerning_value;
}
return glyph_kerning;
}
Optional<i16> Kern::read_glyph_kerning_format0(ReadonlyBytes slice, u16 left_glyph_id, u16 right_glyph_id)
{
if (slice.size() < sizeof(Format0))
return {};
auto const& format0 = *bit_cast<Format0 const*>(slice.data());
u16 number_of_pairs = format0.n_pairs;
u16 search_range = format0.search_range;
u16 entry_selector = format0.entry_selector;
u16 range_shift = format0.range_shift;
// Sanity checks for this table format
auto pairs_in_search_range = search_range / sizeof(Format0Pair);
if (number_of_pairs == 0)
return {};
if (pairs_in_search_range > number_of_pairs)
return {};
if ((1 << entry_selector) * sizeof(Format0Pair) != search_range)
return {};
if ((number_of_pairs - pairs_in_search_range) * sizeof(Format0Pair) != range_shift)
return {};
// FIXME: implement a possibly slightly more efficient binary search using the parameters above
ReadonlySpan<Format0Pair> pairs { bit_cast<Format0Pair const*>(slice.slice(sizeof(Format0)).data()), number_of_pairs };
// The left and right halves of the kerning pair make an unsigned 32-bit number, which is then used to order the kerning pairs numerically.
auto needle = (static_cast<u32>(left_glyph_id) << 16u) | static_cast<u32>(right_glyph_id);
auto* pair = binary_search(pairs, nullptr, nullptr, [&](void*, Format0Pair const& pair) {
auto as_u32 = (static_cast<u32>(pair.left) << 16u) | static_cast<u32>(pair.right);
return needle - as_u32;
});
if (!pair)
return 0;
return pair->value;
}
u16 OS2::weight_class() const
{
return header().us_weight_class;
}
u16 OS2::width_class() const
{
return header().us_width_class;
}
u16 OS2::selection() const
{
return header().fs_selection;
}
i16 OS2::typographic_ascender() const
{
return header().s_typo_ascender;
}
i16 OS2::typographic_descender() const
{
return header().s_typo_descender;
}
i16 OS2::typographic_line_gap() const
{
return header().s_typo_line_gap;
}
bool OS2::use_typographic_metrics() const
{
return header().fs_selection & 0x80;
}
Optional<i16> OS2::x_height() const
{
if (header().version < 2)
return {};
return header_v2().sx_height;
}
ErrorOr<CBLC> CBLC::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(CblcHeader))
return Error::from_string_literal("CBLC table too small");
auto const& header = *bit_cast<CblcHeader const*>(slice.data());
size_t num_sizes = header.num_sizes;
Checked<size_t> size_used_by_bitmap_sizes = num_sizes;
size_used_by_bitmap_sizes *= sizeof(BitmapSize);
if (size_used_by_bitmap_sizes.has_overflow())
return Error::from_string_literal("Integer overflow in CBLC table");
Checked<size_t> total_size = sizeof(CblcHeader);
total_size += size_used_by_bitmap_sizes;
if (total_size.has_overflow())
return Error::from_string_literal("Integer overflow in CBLC table");
if (slice.size() < total_size)
return Error::from_string_literal("CBLC table too small");
return CBLC { slice };
}
Optional<CBLC::BitmapSize const&> CBLC::bitmap_size_for_glyph_id(u32 glyph_id) const
{
for (auto const& bitmap_size : this->bitmap_sizes()) {
if (glyph_id >= bitmap_size.start_glyph_index && glyph_id <= bitmap_size.end_glyph_index) {
return bitmap_size;
}
}
return {};
}
Optional<EBLC::IndexSubHeader const&> CBLC::index_subtable_for_glyph_id(u32 glyph_id, u16& first_glyph_index, u16& last_glyph_index) const
{
auto maybe_bitmap_size = bitmap_size_for_glyph_id(glyph_id);
if (!maybe_bitmap_size.has_value()) {
return {};
}
auto const& bitmap_size = maybe_bitmap_size.value();
Checked<size_t> required_size = static_cast<u32>(bitmap_size.index_subtable_array_offset);
required_size += bitmap_size.index_tables_size;
if (m_slice.size() < required_size) {
dbgln("CBLC index subtable array goes out of bounds");
return {};
}
auto index_subtables_slice = m_slice.slice(bitmap_size.index_subtable_array_offset, bitmap_size.index_tables_size);
ReadonlySpan<EBLC::IndexSubTableArray> index_subtable_arrays {
bit_cast<EBLC::IndexSubTableArray const*>(index_subtables_slice.data()), bitmap_size.number_of_index_subtables
};
EBLC::IndexSubTableArray const* index_subtable_array = nullptr;
for (auto const& array : index_subtable_arrays) {
if (glyph_id >= array.first_glyph_index && glyph_id <= array.last_glyph_index)
index_subtable_array = &array;
}
if (!index_subtable_array) {
return {};
}
auto index_subtable_slice = m_slice.slice(bitmap_size.index_subtable_array_offset + index_subtable_array->additional_offset_to_index_subtable);
first_glyph_index = index_subtable_array->first_glyph_index;
last_glyph_index = index_subtable_array->last_glyph_index;
return *bit_cast<EBLC::IndexSubHeader const*>(index_subtable_slice.data());
}
ErrorOr<CBDT> CBDT::from_slice(ReadonlyBytes slice)
{
if (slice.size() < sizeof(CbdtHeader))
return Error::from_string_literal("CBDT table too small");
return CBDT { slice };
}
Optional<i16> GPOS::glyph_kerning(u16 left_glyph_id, u16 right_glyph_id) const
{
auto read_value_record = [&](u16 value_format, FixedMemoryStream& stream) -> ValueRecord {
ValueRecord value_record;
if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT))
value_record.x_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT))
value_record.y_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE))
value_record.x_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE))
value_record.y_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT_DEVICE))
value_record.x_placement_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT_DEVICE))
value_record.y_placement_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE_DEVICE))
value_record.x_advance_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE_DEVICE))
value_record.y_advance_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
return value_record;
};
auto const& header = this->header();
dbgln_if(OPENTYPE_GPOS_DEBUG, "GPOS header:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " Version: {}.{}", header.major_version, header.minor_version);
dbgln_if(OPENTYPE_GPOS_DEBUG, " Feature list offset: {}", header.feature_list_offset);
// FIXME: Make sure everything is bounds-checked appropriately.
auto feature_list_slice = m_slice.slice(header.feature_list_offset);
if (feature_list_slice.size() < sizeof(FeatureList)) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "GPOS table feature list slice is too small");
return {};
}
auto const& feature_list = *bit_cast<FeatureList const*>(feature_list_slice.data());
auto lookup_list_slice = m_slice.slice(header.lookup_list_offset);
if (lookup_list_slice.size() < sizeof(LookupList)) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "GPOS table lookup list slice is too small");
return {};
}
auto const& lookup_list = *bit_cast<LookupList const*>(lookup_list_slice.data());
Optional<Offset16> kern_feature_offset;
for (size_t i = 0; i < feature_list.feature_count; ++i) {
auto const& feature_record = feature_list.feature_records[i];
if (feature_record.feature_tag == tag_from_str("kern")) {
kern_feature_offset = feature_record.feature_offset;
break;
}
}
if (!kern_feature_offset.has_value()) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "No 'kern' feature found in GPOS table");
return {};
}
auto feature_slice = feature_list_slice.slice(kern_feature_offset.value());
auto const& feature = *bit_cast<Feature const*>(feature_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "Feature:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " featureParamsOffset: {}", feature.feature_params_offset);
dbgln_if(OPENTYPE_GPOS_DEBUG, " lookupIndexCount: {}", feature.lookup_index_count);
for (size_t i = 0; i < feature.lookup_index_count; ++i) {
auto lookup_index = feature.lookup_list_indices[i];
dbgln_if(OPENTYPE_GPOS_DEBUG, "Lookup index: {}", lookup_index);
auto lookup_slice = lookup_list_slice.slice(lookup_list.lookup_offsets[lookup_index]);
auto const& lookup = *bit_cast<Lookup const*>(lookup_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "Lookup:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " lookupType: {}", lookup.lookup_type);
dbgln_if(OPENTYPE_GPOS_DEBUG, " lookupFlag: {}", lookup.lookup_flag);
dbgln_if(OPENTYPE_GPOS_DEBUG, " subtableCount: {}", lookup.subtable_count);
// NOTE: We only support lookup type 2 (Pair adjustment) at the moment.
if (lookup.lookup_type != 2) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement GPOS lookup type {}", lookup.lookup_type);
continue;
}
for (size_t j = 0; j < lookup.subtable_count; ++j) {
auto pair_pos_format_offset = lookup.subtable_offsets[j];
auto pair_pos_format_slice = lookup_slice.slice(pair_pos_format_offset);
auto const& pair_pos_format = *bit_cast<BigEndian<u16> const*>(pair_pos_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "PairPosFormat{}", pair_pos_format);
if (pair_pos_format == 1) {
auto const& pair_pos_format1 = *bit_cast<GPOS::PairPosFormat1 const*>(pair_pos_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format1.pos_format);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format1.value_format1);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format1.value_format2);
dbgln_if(OPENTYPE_GPOS_DEBUG, " pairSetCount: {}", pair_pos_format1.pair_set_count);
auto get_coverage_index = [&](u16 glyph_id, Offset16 coverage_format_offset) -> Optional<u16> {
auto coverage_format_slice = pair_pos_format_slice.slice(coverage_format_offset);
auto const& coverage_format = *bit_cast<BigEndian<u16> const*>(coverage_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "Coverage table format: {}", coverage_format);
if (coverage_format == 1) {
auto const& coverage_format1 = *bit_cast<CoverageFormat1 const*>(coverage_format_slice.data());
for (size_t k = 0; k < coverage_format1.glyph_count; ++k)
if (coverage_format1.glyph_array[k] == glyph_id)
return k;
dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID {} not covered", glyph_id);
return {};
}
else if (coverage_format == 2) {
auto const& coverage_format2 = *bit_cast<CoverageFormat2 const*>(coverage_format_slice.data());
for (size_t k = 0; k < coverage_format2.range_count; ++k) {
auto range_record = coverage_format2.range_records[k];
if ((range_record.start_glyph_id <= glyph_id) && (glyph_id <= range_record.end_glyph_id))
return range_record.start_coverage_index + glyph_id - range_record.start_glyph_id;
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID {} not covered", glyph_id);
return {};
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "No valid coverage table for format {}", coverage_format);
return {};
};
auto coverage_index = get_coverage_index(left_glyph_id, pair_pos_format1.coverage_offset);
if (!coverage_index.has_value()) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID not covered by table");
continue;
}
size_t value1_size = popcount(static_cast<u32>(pair_pos_format1.value_format1 & 0xff)) * sizeof(u16);
size_t value2_size = popcount(static_cast<u32>(pair_pos_format1.value_format2 & 0xff)) * sizeof(u16);
dbgln_if(OPENTYPE_GPOS_DEBUG, "ValueSizes: {}, {}", value1_size, value2_size);
// Manually iterate over the PairSet table, as the size of each PairValueRecord is not known at compile time.
auto pair_set_offset = pair_pos_format1.pair_set_offsets[coverage_index.value()];
auto pair_set_slice = pair_pos_format_slice.slice(pair_set_offset);
FixedMemoryStream stream(pair_set_slice);
auto pair_value_count = stream.read_value<BigEndian<u16>>().release_value_but_fixme_should_propagate_errors();
bool found_matching_glyph = false;
for (size_t k = 0; k < pair_value_count; ++k) {
auto second_glyph = stream.read_value<BigEndian<u16>>().release_value_but_fixme_should_propagate_errors();
if (right_glyph_id == second_glyph) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Found matching second glyph {}", second_glyph);
found_matching_glyph = true;
break;
}
(void)stream.discard(value1_size + value2_size).release_value_but_fixme_should_propagate_errors();
}
if (!found_matching_glyph) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Did not find second glyph matching {}", right_glyph_id);
continue;
}
[[maybe_unused]] auto value_record1 = read_value_record(pair_pos_format1.value_format1, stream);
[[maybe_unused]] auto value_record2 = read_value_record(pair_pos_format1.value_format2, stream);
dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", value_record1.x_advance);
return value_record1.x_advance;
}
else if (pair_pos_format == 2) {
auto const& pair_pos_format2 = *bit_cast<GPOS::PairPosFormat2 const*>(pair_pos_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format2.pos_format);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format2.value_format1);
dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format2.value_format2);
dbgln_if(OPENTYPE_GPOS_DEBUG, " class1Count: {}", pair_pos_format2.class1_count);
dbgln_if(OPENTYPE_GPOS_DEBUG, " class2Count: {}", pair_pos_format2.class2_count);
auto get_class = [&](u16 glyph_id, Offset16 glyph_def_offset) -> Optional<u16> {
auto class_def_format_slice = pair_pos_format_slice.slice(glyph_def_offset);
auto const& class_def_format = *bit_cast<BigEndian<u16> const*>(class_def_format_slice.data());
if (class_def_format == 1) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement ClassDefFormat1");
return {};
}
auto const& class_def_format2 = *bit_cast<ClassDefFormat2 const*>(class_def_format_slice.data());
dbgln_if(OPENTYPE_GPOS_DEBUG, "ClassDefFormat2:");
dbgln_if(OPENTYPE_GPOS_DEBUG, " classFormat: {}", class_def_format2.class_format);
dbgln_if(OPENTYPE_GPOS_DEBUG, " classRangeCount: {}", class_def_format2.class_range_count);
for (size_t i = 0; i < class_def_format2.class_range_count; ++i) {
auto const& range = class_def_format2.class_range_records[i];
if (glyph_id >= range.start_glyph_id && glyph_id <= range.end_glyph_id) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Found class {} for glyph ID {}", range.class_, glyph_id);
return range.class_;
}
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "No class found for glyph {}", glyph_id);
return {};
};
auto left_class = get_class(left_glyph_id, pair_pos_format2.class_def1_offset);
auto right_class = get_class(right_glyph_id, pair_pos_format2.class_def2_offset);
if (!left_class.has_value() || !right_class.has_value()) {
dbgln_if(OPENTYPE_GPOS_DEBUG, "Need glyph class for both sides");
continue;
}
dbgln_if(OPENTYPE_GPOS_DEBUG, "Classes: {}, {}", left_class.value(), right_class.value());
size_t value1_size = popcount(static_cast<u32>(pair_pos_format2.value_format1 & 0xff)) * sizeof(u16);
size_t value2_size = popcount(static_cast<u32>(pair_pos_format2.value_format2 & 0xff)) * sizeof(u16);
dbgln_if(OPENTYPE_GPOS_DEBUG, "ValueSizes: {}, {}", value1_size, value2_size);
size_t class2_record_size = value1_size + value2_size;
dbgln_if(OPENTYPE_GPOS_DEBUG, "Class2RecordSize: {}", class2_record_size);
size_t class1_record_size = pair_pos_format2.class2_count * class2_record_size;
dbgln_if(OPENTYPE_GPOS_DEBUG, "Class1RecordSize: {}", class1_record_size);
size_t item_offset = (left_class.value() * class1_record_size) + (right_class.value() * class2_record_size);
dbgln_if(OPENTYPE_GPOS_DEBUG, "Item offset: {}", item_offset);
auto item_slice = pair_pos_format_slice.slice(sizeof(PairPosFormat2) + item_offset);
FixedMemoryStream stream(item_slice);
[[maybe_unused]] auto value_record1 = read_value_record(pair_pos_format2.value_format1, stream);
[[maybe_unused]] auto value_record2 = read_value_record(pair_pos_format2.value_format2, stream);
dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", value_record1.x_advance);
return value_record1.x_advance;
}
}
}
(void)left_glyph_id;
(void)right_glyph_id;
return {};
}
}

1
Userland/Libraries/LibGfx/Font/OpenType/Tables.h
View file

@ -15,6 +15,7 @@
#include <AK/FixedArray.h>
#include <AK/Forward.h>
#include <AK/Span.h>
#include <AK/String.h>
namespace OpenType {