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LibGfx/OpenType: Extend support for GPOS glyph positioning
This patch extends the kerning support using the GPOS table to fonts which use PairPosFormat1. Previously, only PairPosFormat2 was supported.
This commit is contained in:
LukasACH
Andreas Kling
parent
f0ceaca2f4
commit
83eca15e51
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@ -1042,111 +1042,163 @@ Optional<i16> GPOS::glyph_kerning(u16 left_glyph_id, u16 right_glyph_id) const
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dbgln_if(OPENTYPE_GPOS_DEBUG, " subtableCount: {}", lookup.subtable_count);
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for (size_t j = 0; j < lookup.subtable_count; ++j) {
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auto subtable_offset = lookup.subtable_offsets[j];
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auto subtable_slice = lookup_slice.slice(subtable_offset);
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auto pair_pos_format_offset = lookup.subtable_offsets[j];
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auto pair_pos_format_slice = lookup_slice.slice(pair_pos_format_offset);
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auto const& pair_pos_format = *bit_cast<BigEndian<u16> const*>(subtable_slice.data());
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auto const& pair_pos_format = *bit_cast<BigEndian<u16> const*>(pair_pos_format_slice.data());
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dbgln_if(OPENTYPE_GPOS_DEBUG, "PairPosFormat{}", pair_pos_format);
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if (pair_pos_format == 1) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement PairPosFormat1");
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continue;
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}
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auto const& pair_pos_format2 = *bit_cast<GPOS::PairPosFormat2 const*>(subtable_slice.data());
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auto const& pair_pos_format1 = *bit_cast<GPOS::PairPosFormat1 const*>(pair_pos_format_slice.data());
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dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format2.pos_format);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format2.value_format1);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format2.value_format2);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " class1Count: {}", pair_pos_format2.class1_count);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " class2Count: {}", pair_pos_format2.class2_count);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format1.pos_format);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format1.value_format1);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format1.value_format2);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " pairSetCount: {}", pair_pos_format1.pair_set_count);
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auto get_class = [&](u16 glyph_id, Offset16 glyph_def_offset) -> Optional<u16> {
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auto class_def_format_slice = subtable_slice.slice(glyph_def_offset);
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if (pair_pos_format1.value_format1 == 0)
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continue;
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auto const& class_def_format = *bit_cast<BigEndian<u16> const*>(class_def_format_slice.data());
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if (class_def_format == 1) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement ClassDefFormat1");
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auto get_coverage_index = [&](u16 glyph_id, Offset16 coverage_format_offset) -> Optional<u16> {
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auto coverage_format_slice = pair_pos_format_slice.slice(coverage_format_offset);
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auto const& coverage_format = *bit_cast<BigEndian<u16> const*>(coverage_format_slice.data());
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Coverage table format: {}", coverage_format);
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if (coverage_format == 1) {
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auto const& coverage_format1 = *bit_cast<CoverageFormat1 const*>(coverage_format_slice.data());
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for (size_t k = 0; k < coverage_format1.glyph_count; ++k)
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if (coverage_format1.glyph_array[k] == glyph_id)
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return k;
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID {} not covered", glyph_id);
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return {};
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}
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else if (coverage_format == 2) {
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auto const& coverage_format2 = *bit_cast<CoverageFormat2 const*>(coverage_format_slice.data());
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for (size_t k = 0; k < coverage_format2.range_count; ++k) {
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auto range_record = coverage_format2.range_records[k];
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if ((range_record.start_glyph_id <= glyph_id) && (glyph_id <= range_record.end_glyph_id))
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return range_record.start_coverage_index + glyph_id - range_record.start_glyph_id;
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}
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID {} not covered", glyph_id);
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return {};
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}
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dbgln_if(OPENTYPE_GPOS_DEBUG, "No valid coverage table for format {}", coverage_format);
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return {};
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};
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auto coverage_index = get_coverage_index(left_glyph_id, pair_pos_format1.coverage_offset);
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if (!coverage_index.has_value()) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Glyph ID not covered by table");
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return {};
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}
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auto const& class_def_format2 = *bit_cast<ClassDefFormat2 const*>(class_def_format_slice.data());
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dbgln_if(OPENTYPE_GPOS_DEBUG, "ClassDefFormat2:");
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dbgln_if(OPENTYPE_GPOS_DEBUG, " classFormat: {}", class_def_format2.class_format);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " classRangeCount: {}", class_def_format2.class_range_count);
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auto pair_set_offset = pair_pos_format1.pair_set_offsets[coverage_index.value()];
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auto pair_set_slice = pair_pos_format_slice.slice(pair_set_offset);
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for (size_t i = 0; i < class_def_format2.class_range_count; ++i) {
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auto const& range = class_def_format2.class_range_records[i];
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if (glyph_id >= range.start_glyph_id && glyph_id <= range.end_glyph_id) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Found class {} for glyph ID {}", range.class_, glyph_id);
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return range.class_;
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auto const& pair_set = *bit_cast<GPOS::PairSet const*>(pair_set_slice.data());
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for (size_t k = 0; k < pair_set.pair_value_count; ++k) {
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auto pair_value_record = pair_set.pair_value_records[k];
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if (right_glyph_id == pair_value_record.second_glyph) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", pair_value_record.value_record1.x_advance);
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return pair_value_record.value_record1.x_advance;
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}
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}
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dbgln_if(OPENTYPE_GPOS_DEBUG, "No class found for glyph {}", glyph_id);
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return {};
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};
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auto left_class = get_class(left_glyph_id, pair_pos_format2.class_def1_offset);
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auto right_class = get_class(right_glyph_id, pair_pos_format2.class_def2_offset);
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if (!left_class.has_value() || !right_class.has_value()) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Need glyph class for both sides");
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return {};
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}
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Classes: {}, {}", left_class.value(), right_class.value());
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else if (pair_pos_format == 2) {
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auto const& pair_pos_format2 = *bit_cast<GPOS::PairPosFormat2 const*>(pair_pos_format_slice.data());
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size_t value1_size = popcount(static_cast<u32>(pair_pos_format2.value_format1 & 0xff)) * sizeof(u16);
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size_t value2_size = popcount(static_cast<u32>(pair_pos_format2.value_format2 & 0xff)) * sizeof(u16);
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dbgln_if(OPENTYPE_GPOS_DEBUG, "ValueSizes: {}, {}", value1_size, value2_size);
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size_t class2_record_size = value1_size + value2_size;
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Class2RecordSize: {}", class2_record_size);
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size_t class1_record_size = pair_pos_format2.class2_count * class2_record_size;
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Class1RecordSize: {}", class1_record_size);
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size_t item_offset = (left_class.value() * class1_record_size) + (right_class.value() * class2_record_size);
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Item offset: {}", item_offset);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " posFormat: {}", pair_pos_format2.pos_format);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat1: {}", pair_pos_format2.value_format1);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " valueFormat2: {}", pair_pos_format2.value_format2);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " class1Count: {}", pair_pos_format2.class1_count);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " class2Count: {}", pair_pos_format2.class2_count);
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auto item_slice = subtable_slice.slice(sizeof(PairPosFormat2) + item_offset);
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FixedMemoryStream stream(item_slice);
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auto get_class = [&](u16 glyph_id, Offset16 glyph_def_offset) -> Optional<u16> {
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auto class_def_format_slice = pair_pos_format_slice.slice(glyph_def_offset);
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struct ValueRecord {
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i16 x_placement = 0;
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i16 y_placement = 0;
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i16 x_advance = 0;
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i16 y_advance = 0;
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i16 x_placement_device = 0;
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i16 y_placement_device = 0;
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i16 x_advance_device = 0;
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i16 y_advance_device = 0;
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};
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auto const& class_def_format = *bit_cast<BigEndian<u16> const*>(class_def_format_slice.data());
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if (class_def_format == 1) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "FIXME: Implement ClassDefFormat1");
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return {};
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}
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auto read_value_record = [&](u16 value_format) -> ValueRecord {
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ValueRecord value_record;
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if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT))
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value_record.x_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT))
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value_record.y_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE))
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value_record.x_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE))
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value_record.y_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT_DEVICE))
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value_record.x_placement_device = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT_DEVICE))
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value_record.y_placement_device = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE_DEVICE))
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value_record.x_advance_device = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE_DEVICE))
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value_record.y_advance_device = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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return value_record;
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};
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auto const& class_def_format2 = *bit_cast<ClassDefFormat2 const*>(class_def_format_slice.data());
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dbgln_if(OPENTYPE_GPOS_DEBUG, "ClassDefFormat2:");
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dbgln_if(OPENTYPE_GPOS_DEBUG, " classFormat: {}", class_def_format2.class_format);
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dbgln_if(OPENTYPE_GPOS_DEBUG, " classRangeCount: {}", class_def_format2.class_range_count);
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[[maybe_unused]] auto value_record1 = read_value_record(pair_pos_format2.value_format1);
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[[maybe_unused]] auto value_record2 = read_value_record(pair_pos_format2.value_format2);
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for (size_t i = 0; i < class_def_format2.class_range_count; ++i) {
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auto const& range = class_def_format2.class_range_records[i];
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if (glyph_id >= range.start_glyph_id && glyph_id <= range.end_glyph_id) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Found class {} for glyph ID {}", range.class_, glyph_id);
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return range.class_;
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}
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}
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", value_record1.x_advance);
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return value_record1.x_advance;
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dbgln_if(OPENTYPE_GPOS_DEBUG, "No class found for glyph {}", glyph_id);
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return {};
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};
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auto left_class = get_class(left_glyph_id, pair_pos_format2.class_def1_offset);
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auto right_class = get_class(right_glyph_id, pair_pos_format2.class_def2_offset);
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if (!left_class.has_value() || !right_class.has_value()) {
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Need glyph class for both sides");
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return {};
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}
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Classes: {}, {}", left_class.value(), right_class.value());
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size_t value1_size = popcount(static_cast<u32>(pair_pos_format2.value_format1 & 0xff)) * sizeof(u16);
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size_t value2_size = popcount(static_cast<u32>(pair_pos_format2.value_format2 & 0xff)) * sizeof(u16);
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dbgln_if(OPENTYPE_GPOS_DEBUG, "ValueSizes: {}, {}", value1_size, value2_size);
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size_t class2_record_size = value1_size + value2_size;
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Class2RecordSize: {}", class2_record_size);
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size_t class1_record_size = pair_pos_format2.class2_count * class2_record_size;
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Class1RecordSize: {}", class1_record_size);
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size_t item_offset = (left_class.value() * class1_record_size) + (right_class.value() * class2_record_size);
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Item offset: {}", item_offset);
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auto item_slice = pair_pos_format_slice.slice(sizeof(PairPosFormat2) + item_offset);
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FixedMemoryStream stream(item_slice);
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auto read_value_record = [&](u16 value_format) -> ValueRecord {
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ValueRecord value_record;
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if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT))
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value_record.x_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT))
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value_record.y_placement = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE))
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value_record.x_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE))
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value_record.y_advance = stream.read_value<BigEndian<i16>>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::X_PLACEMENT_DEVICE))
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value_record.x_placement_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_PLACEMENT_DEVICE))
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value_record.y_placement_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::X_ADVANCE_DEVICE))
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value_record.x_advance_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
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if (value_format & static_cast<i16>(ValueFormat::Y_ADVANCE_DEVICE))
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value_record.y_advance_device_offset = stream.read_value<Offset16>().release_value_but_fixme_should_propagate_errors();
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return value_record;
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};
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[[maybe_unused]] auto value_record1 = read_value_record(pair_pos_format2.value_format1);
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[[maybe_unused]] auto value_record2 = read_value_record(pair_pos_format2.value_format2);
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dbgln_if(OPENTYPE_GPOS_DEBUG, "Returning x advance {}", value_record1.x_advance);
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return value_record1.x_advance;
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}
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}
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}
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@ -568,6 +568,27 @@ struct LookupList {
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Offset16 lookup_offsets[];
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/chapter2#coverage-format-1
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struct CoverageFormat1 {
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BigEndian<u16> coverage_format;
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BigEndian<u16> glyph_count;
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BigEndian<u16> glyph_array[];
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/chapter2#coverage-format-2
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struct RangeRecord {
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BigEndian<u16> start_glyph_id;
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BigEndian<u16> end_glyph_id;
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BigEndian<u16> start_coverage_index;
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/chapter2#coverage-format-2
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struct CoverageFormat2 {
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BigEndian<u16> coverage_format;
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BigEndian<u16> range_count;
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RangeRecord range_records[];
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/chapter2#class-definition-table-format-2
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struct ClassRangeRecord {
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BigEndian<u16> start_glyph_id;
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@ -594,6 +615,41 @@ public:
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Offset16 lookup_list_offset;
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/gpos#pair-adjustment-positioning-format-1-adjustments-for-glyph-pairs
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struct PairPosFormat1 {
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BigEndian<u16> pos_format;
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Offset16 coverage_offset;
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BigEndian<u16> value_format1;
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BigEndian<u16> value_format2;
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BigEndian<u16> pair_set_count;
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Offset16 pair_set_offsets[];
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/gpos#value-record
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struct ValueRecord {
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BigEndian<i16> x_placement;
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BigEndian<i16> y_placement;
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BigEndian<i16> x_advance;
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BigEndian<i16> y_advance;
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Offset16 x_placement_device_offset;
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Offset16 y_placement_device_offset;
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Offset16 x_advance_device_offset;
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Offset16 y_advance_device_offset;
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/gpos#pair-adjustment-positioning-format-1-adjustments-for-glyph-pairs
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struct PairValueRecord {
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BigEndian<u16> second_glyph;
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ValueRecord value_record1;
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ValueRecord value_record2;
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};
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// https://learn.microsoft.com/en-us/typography/opentype/spec/gpos#pair-adjustment-positioning-format-1-adjustments-for-glyph-pairs
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struct PairSet {
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BigEndian<u16> pair_value_count;
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PairValueRecord pair_value_records[];
|
||||
};
|
||||
|
||||
// https://learn.microsoft.com/en-us/typography/opentype/spec/gpos#pair-adjustment-positioning-format-2-class-pair-adjustment
|
||||
struct PairPosFormat2 {
|
||||
BigEndian<u16> pos_format;
|
||||
|
|
|
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Reference in a new issue