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LibGfx: Move TTF files from TrueTypeFont/ to Font/TrueType/

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This commit is contained in:
Simon Wanner 2022-04-09 08:52:59 +02:00 • committed by Andreas Kling
parent e84bbfed44
commit 6f8fd91f22
15 changed files with 36 additions and 36 deletions
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158
Userland/Libraries/LibGfx/Font/TrueType/Cmap.cpp Normal file
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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Optional.h>
#include <LibGfx/Font/TrueType/Cmap.h>
namespace TTF {
extern u16 be_u16(u8 const*);
extern u32 be_u32(u8 const*);
extern i16 be_i16(u8 const*);
Optional<Cmap::Subtable::Platform> Cmap::Subtable::platform_id() const
{
switch (m_raw_platform_id) {
case 0:
return Platform::Unicode;
case 1:
return Platform::Macintosh;
case 3:
return Platform::Windows;
case 4:
return Platform::Custom;
default:
return {};
}
}
Cmap::Subtable::Format Cmap::Subtable::format() const
{
switch (be_u16(m_slice.offset_pointer(0))) {
case 0:
return Format::ByteEncoding;
case 2:
return Format::HighByte;
case 4:
return Format::SegmentToDelta;
case 6:
return Format::TrimmedTable;
case 8:
return Format::Mixed16And32;
case 10:
return Format::TrimmedArray;
case 12:
return Format::SegmentedCoverage;
case 13:
return Format::ManyToOneRange;
case 14:
return Format::UnicodeVariationSequences;
default:
VERIFY_NOT_REACHED();
}
}
u32 Cmap::num_subtables() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::NumTables));
}
Optional<Cmap::Subtable> Cmap::subtable(u32 index) const
{
if (index >= num_subtables()) {
return {};
}
u32 record_offset = (u32)Sizes::TableHeader + index * (u32)Sizes::EncodingRecord;
u16 platform_id = be_u16(m_slice.offset_pointer(record_offset));
u16 encoding_id = be_u16(m_slice.offset_pointer(record_offset + (u32)Offsets::EncodingRecord_EncodingID));
u32 subtable_offset = be_u32(m_slice.offset_pointer(record_offset + (u32)Offsets::EncodingRecord_Offset));
if (subtable_offset >= m_slice.size())
return {};
auto subtable_slice = ReadonlyBytes(m_slice.offset_pointer(subtable_offset), m_slice.size() - subtable_offset);
return Subtable(subtable_slice, platform_id, encoding_id);
}
// FIXME: This only handles formats 4 (SegmentToDelta) and 12 (SegmentedCoverage) for now.
u32 Cmap::Subtable::glyph_id_for_code_point(u32 code_point) const
{
switch (format()) {
case Format::SegmentToDelta:
return glyph_id_for_code_point_table_4(code_point);
case Format::SegmentedCoverage:
return glyph_id_for_code_point_table_12(code_point);
default:
return 0;
}
}
u32 Cmap::Subtable::glyph_id_for_code_point_table_4(u32 code_point) const
{
u32 segcount_x2 = be_u16(m_slice.offset_pointer((u32)Table4Offsets::SegCountX2));
if (m_slice.size() < segcount_x2 * (u32)Table4Sizes::NonConstMultiplier + (u32)Table4Sizes::Constant)
return 0;
u32 segcount = segcount_x2 / 2;
u32 l = 0, r = segcount - 1;
while (l < r) {
u32 mid = l + (r - l) / 2;
u32 end_code_point_at_mid = be_u16(m_slice.offset_pointer((u32)Table4Offsets::EndConstBase + (mid * 2)));
if (code_point <= end_code_point_at_mid)
r = mid;
else
l = mid + 1;
}
u32 offset = l * 2;
u32 start_code_point = be_u16(m_slice.offset_pointer((u32)Table4Offsets::StartConstBase + segcount_x2 + offset));
if (start_code_point > code_point)
return 0;
u32 delta = be_u16(m_slice.offset_pointer((u32)Table4Offsets::DeltaConstBase + segcount_x2 * 2 + offset));
u32 range = be_u16(m_slice.offset_pointer((u32)Table4Offsets::RangeConstBase + segcount_x2 * 3 + offset));
if (range == 0)
return (code_point + delta) & 0xffff;
u32 glyph_offset = (u32)Table4Offsets::GlyphOffsetConstBase + segcount_x2 * 3 + offset + range + (code_point - start_code_point) * 2;
VERIFY(glyph_offset + 2 <= m_slice.size());
return (be_u16(m_slice.offset_pointer(glyph_offset)) + delta) & 0xffff;
}
u32 Cmap::Subtable::glyph_id_for_code_point_table_12(u32 code_point) const
{
u32 num_groups = be_u32(m_slice.offset_pointer((u32)Table12Offsets::NumGroups));
VERIFY(m_slice.size() >= (u32)Table12Sizes::Header + (u32)Table12Sizes::Record * num_groups);
for (u32 offset = 0; offset < num_groups * (u32)Table12Sizes::Record; offset += (u32)Table12Sizes::Record) {
u32 start_code_point = be_u32(m_slice.offset_pointer((u32)Table12Offsets::Record_StartCode + offset));
if (code_point < start_code_point)
break;
u32 end_code_point = be_u32(m_slice.offset_pointer((u32)Table12Offsets::Record_EndCode + offset));
if (code_point > end_code_point)
continue;
u32 glyph_offset = be_u32(m_slice.offset_pointer((u32)Table12Offsets::Record_StartGlyph + offset));
return code_point - start_code_point + glyph_offset;
}
return 0;
}
u32 Cmap::glyph_id_for_code_point(u32 code_point) const
{
auto opt_subtable = subtable(m_active_index);
if (!opt_subtable.has_value())
return 0;
auto subtable = opt_subtable.value();
return subtable.glyph_id_for_code_point(code_point);
}
Optional<Cmap> Cmap::from_slice(ReadonlyBytes slice)
{
if (slice.size() < (size_t)Sizes::TableHeader)
return {};
return Cmap(slice);
}
}

111
Userland/Libraries/LibGfx/Font/TrueType/Cmap.h Normal file
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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Span.h>
#include <stdint.h>
namespace TTF {
class Cmap {
public:
class Subtable {
public:
enum class Platform {
Unicode = 0,
Macintosh = 1,
Windows = 3,
Custom = 4,
};
enum class Format {
ByteEncoding = 0,
HighByte = 2,
SegmentToDelta = 4,
TrimmedTable = 6,
Mixed16And32 = 8,
TrimmedArray = 10,
SegmentedCoverage = 12,
ManyToOneRange = 13,
UnicodeVariationSequences = 14,
};
enum class WindowsEncoding {
UnicodeBMP = 1,
UnicodeFullRepertoire = 10,
};
Subtable(ReadonlyBytes slice, u16 platform_id, u16 encoding_id)
: m_slice(slice)
, m_raw_platform_id(platform_id)
, m_encoding_id(encoding_id)
{
}
// Returns 0 if glyph not found. This corresponds to the "missing glyph"
u32 glyph_id_for_code_point(u32 code_point) const;
Optional<Platform> platform_id() const;
u16 encoding_id() const { return m_encoding_id; }
Format format() const;
private:
enum class Table4Offsets {
SegCountX2 = 6,
EndConstBase = 14,
StartConstBase = 16,
DeltaConstBase = 16,
RangeConstBase = 16,
GlyphOffsetConstBase = 16,
};
enum class Table4Sizes {
Constant = 16,
NonConstMultiplier = 4,
};
enum class Table12Offsets {
NumGroups = 12,
Record_StartCode = 16,
Record_EndCode = 20,
Record_StartGlyph = 24,
};
enum class Table12Sizes {
Header = 16,
Record = 12,
};
u32 glyph_id_for_code_point_table_4(u32 code_point) const;
u32 glyph_id_for_code_point_table_12(u32 code_point) const;
ReadonlyBytes m_slice;
u16 m_raw_platform_id { 0 };
u16 m_encoding_id { 0 };
};
static Optional<Cmap> from_slice(ReadonlyBytes);
u32 num_subtables() const;
Optional<Subtable> subtable(u32 index) const;
void set_active_index(u32 index) { m_active_index = index; }
// Returns 0 if glyph not found. This corresponds to the "missing glyph"
u32 glyph_id_for_code_point(u32 code_point) const;
private:
enum class Offsets {
NumTables = 2,
EncodingRecord_EncodingID = 2,
EncodingRecord_Offset = 4,
};
enum class Sizes {
TableHeader = 4,
EncodingRecord = 8,
};
Cmap(ReadonlyBytes slice)
: m_slice(slice)
{
}
ReadonlyBytes m_slice;
u32 m_active_index { UINT32_MAX };
};
}

766
Userland/Libraries/LibGfx/Font/TrueType/Font.cpp Normal file
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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Checked.h>
#include <AK/Try.h>
#include <AK/Utf32View.h>
#include <AK/Utf8View.h>
#include <LibCore/MappedFile.h>
#include <LibGfx/Font/TrueType/Cmap.h>
#include <LibGfx/Font/TrueType/Font.h>
#include <LibGfx/Font/TrueType/Glyf.h>
#include <LibGfx/Font/TrueType/Tables.h>
#include <LibTextCodec/Decoder.h>
#include <math.h>
#include <sys/mman.h>
namespace TTF {
u16 be_u16(u8 const*);
u32 be_u32(u8 const*);
i16 be_i16(u8 const*);
float be_fword(u8 const*);
u32 tag_from_str(char const*);
u16 be_u16(u8 const* ptr)
{
return (((u16)ptr[0]) << 8) | ((u16)ptr[1]);
}
u32 be_u32(u8 const* ptr)
{
return (((u32)ptr[0]) << 24) | (((u32)ptr[1]) << 16) | (((u32)ptr[2]) << 8) | ((u32)ptr[3]);
}
i16 be_i16(u8 const* ptr)
{
return (((i16)ptr[0]) << 8) | ((i16)ptr[1]);
}
float be_fword(u8 const* ptr)
{
return (float)be_i16(ptr) / (float)(1 << 14);
}
u32 tag_from_str(char const* str)
{
return be_u32((u8 const*)str);
}
Optional<Head> Head::from_slice(ReadonlyBytes slice)
{
if (slice.size() < (size_t)Sizes::Table) {
return {};
}
return Head(slice);
}
u16 Head::units_per_em() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::UnitsPerEM));
}
i16 Head::xmin() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::XMin));
}
i16 Head::ymin() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::YMin));
}
i16 Head::xmax() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::XMax));
}
i16 Head::ymax() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::YMax));
}
u16 Head::style() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::Style));
}
u16 Head::lowest_recommended_ppem() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::LowestRecPPEM));
}
IndexToLocFormat Head::index_to_loc_format() const
{
i16 raw = be_i16(m_slice.offset_pointer((u32)Offsets::IndexToLocFormat));
switch (raw) {
case 0:
return IndexToLocFormat::Offset16;
case 1:
return IndexToLocFormat::Offset32;
default:
VERIFY_NOT_REACHED();
}
}
Optional<Hhea> Hhea::from_slice(ReadonlyBytes slice)
{
if (slice.size() < (size_t)Sizes::Table) {
return {};
}
return Hhea(slice);
}
i16 Hhea::ascender() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::Ascender));
}
i16 Hhea::descender() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::Descender));
}
i16 Hhea::line_gap() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::LineGap));
}
u16 Hhea::advance_width_max() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::AdvanceWidthMax));
}
u16 Hhea::number_of_h_metrics() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::NumberOfHMetrics));
}
Optional<Maxp> Maxp::from_slice(ReadonlyBytes slice)
{
if (slice.size() < (size_t)Sizes::TableV0p5) {
return {};
}
return Maxp(slice);
}
u16 Maxp::num_glyphs() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::NumGlyphs));
}
Optional<Hmtx> Hmtx::from_slice(ReadonlyBytes slice, u32 num_glyphs, u32 number_of_h_metrics)
{
if (slice.size() < number_of_h_metrics * (u32)Sizes::LongHorMetric + (num_glyphs - number_of_h_metrics) * (u32)Sizes::LeftSideBearing) {
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(u32))
return Error::from_string_literal("Invalid kern table header"sv);
// We only support the old (2x u16) version of the header
auto version = be_u16(slice.data());
auto number_of_subtables = be_u16(slice.offset(sizeof(u16)));
if (version != 0)
return Error::from_string_literal("Unsupported kern table version"sv);
if (number_of_subtables == 0)
return Error::from_string_literal("Kern table does not contain any subtables"sv);
// Read all subtable offsets
auto subtable_offsets = TRY(FixedArray<size_t>::try_create(number_of_subtables));
size_t offset = 2 * sizeof(u16);
for (size_t i = 0; i < number_of_subtables; ++i) {
if (slice.size() < offset + Sizes::SubtableHeader)
return Error::from_string_literal("Invalid kern subtable header"sv);
subtable_offsets[i] = offset;
auto subtable_size = be_u16(slice.offset(offset + sizeof(u16)));
offset += subtable_size;
}
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 version = be_u16(subtable_slice.data());
auto length = be_u16(subtable_slice.offset(sizeof(u16)));
auto coverage = be_u16(subtable_slice.offset(2 * sizeof(u16)));
if (version != 0) {
dbgln("TTF::Kern: unsupported subtable version {}", version);
continue;
}
if (subtable_slice.size() < length) {
dbgln("TTF::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("TTF::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(Sizes::SubtableHeader), left_glyph_id, right_glyph_id);
break;
default:
dbgln("TTF::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() < 4 * sizeof(u16))
return {};
u16 number_of_pairs = be_u16(slice.data());
u16 search_range = be_u16(slice.offset_pointer(sizeof(u16)));
u16 entry_selector = be_u16(slice.offset_pointer(2 * sizeof(u16)));
u16 range_shift = be_u16(slice.offset_pointer(3 * sizeof(u16)));
// Sanity checks for this table format
auto pairs_in_search_range = search_range / Sizes::Format0Entry;
if (number_of_pairs == 0)
return {};
if (pairs_in_search_range > number_of_pairs)
return {};
if ((1 << entry_selector) * Sizes::Format0Entry != search_range)
return {};
if ((number_of_pairs - pairs_in_search_range) * Sizes::Format0Entry != range_shift)
return {};
// FIXME: implement a possibly slightly more efficient binary search using the parameters above
auto search_slice = slice.slice(4 * sizeof(u16));
size_t left_idx = 0;
size_t right_idx = number_of_pairs - 1;
for (auto i = 0; i < 16; ++i) {
size_t pivot_idx = (left_idx + right_idx) / 2;
u16 pivot_left_glyph_id = be_u16(search_slice.offset(pivot_idx * Sizes::Format0Entry + 0));
u16 pivot_right_glyph_id = be_u16(search_slice.offset(pivot_idx * Sizes::Format0Entry + 2));
// Match
if (pivot_left_glyph_id == left_glyph_id && pivot_right_glyph_id == right_glyph_id)
return be_i16(search_slice.offset(pivot_idx * Sizes::Format0Entry + 4));
// Narrow search area
if (pivot_left_glyph_id < left_glyph_id || (pivot_left_glyph_id == left_glyph_id && pivot_right_glyph_id < right_glyph_id))
left_idx = pivot_idx + 1;
else if (pivot_idx == left_idx)
break;
else
right_idx = pivot_idx - 1;
}
return 0;
}
String Name::string_for_id(NameId id) const
{
auto num_entries = be_u16(m_slice.offset_pointer(2));
auto string_offset = be_u16(m_slice.offset_pointer(4));
Vector<int> valid_ids;
for (int i = 0; i < num_entries; ++i) {
auto this_id = be_u16(m_slice.offset_pointer(6 + i * 12 + 6));
if (this_id == (u16)id)
valid_ids.append(i);
}
if (valid_ids.is_empty())
return String::empty();
auto it = valid_ids.find_if([this](auto const& i) {
// check if font has naming table for en-US language id
auto platform = be_u16(m_slice.offset_pointer(6 + i * 12 + 0));
auto language_id = be_u16(m_slice.offset_pointer(6 + i * 12 + 4));
return (platform == (u16)Platform::Macintosh && language_id == (u16)MacintoshLanguage::English)
|| (platform == (u16)Platform::Windows && language_id == (u16)WindowsLanguage::EnglishUnitedStates);
});
auto i = it != valid_ids.end() ? *it : valid_ids.first();
auto platform = be_u16(m_slice.offset_pointer(6 + i * 12 + 0));
auto length = be_u16(m_slice.offset_pointer(6 + i * 12 + 8));
auto offset = be_u16(m_slice.offset_pointer(6 + i * 12 + 10));
if (platform == (u16)Platform::Windows) {
static auto& decoder = *TextCodec::decoder_for("utf-16be");
return decoder.to_utf8(StringView { (char const*)m_slice.offset_pointer(string_offset + offset), length });
}
return String((char const*)m_slice.offset_pointer(string_offset + offset), length);
}
GlyphHorizontalMetrics Hmtx::get_glyph_horizontal_metrics(u32 glyph_id) const
{
VERIFY(glyph_id < m_num_glyphs);
if (glyph_id < m_number_of_h_metrics) {
auto offset = glyph_id * (u32)Sizes::LongHorMetric;
u16 advance_width = be_u16(m_slice.offset_pointer(offset));
i16 left_side_bearing = be_i16(m_slice.offset_pointer(offset + 2));
return GlyphHorizontalMetrics {
.advance_width = advance_width,
.left_side_bearing = left_side_bearing,
};
}
auto offset = m_number_of_h_metrics * (u32)Sizes::LongHorMetric + (glyph_id - m_number_of_h_metrics) * (u32)Sizes::LeftSideBearing;
u16 advance_width = be_u16(m_slice.offset_pointer((m_number_of_h_metrics - 1) * (u32)Sizes::LongHorMetric));
i16 left_side_bearing = be_i16(m_slice.offset_pointer(offset));
return GlyphHorizontalMetrics {
.advance_width = advance_width,
.left_side_bearing = left_side_bearing,
};
}
ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_file(String path, unsigned index)
{
auto file = TRY(Core::MappedFile::map(path));
auto font = TRY(try_load_from_externally_owned_memory(file->bytes(), index));
font->m_mapped_file = move(file);
return font;
}
ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_externally_owned_memory(ReadonlyBytes buffer, unsigned index)
{
if (buffer.size() < 4)
return Error::from_string_literal("Font file too small"sv);
u32 tag = be_u32(buffer.data());
if (tag == tag_from_str("ttcf")) {
// It's a font collection
if (buffer.size() < (u32)Sizes::TTCHeaderV1 + sizeof(u32) * (index + 1))
return Error::from_string_literal("Font file too small"sv);
u32 offset = be_u32(buffer.offset_pointer((u32)Sizes::TTCHeaderV1 + sizeof(u32) * index));
return try_load_from_offset(buffer, offset);
}
if (tag == tag_from_str("OTTO"))
return Error::from_string_literal("CFF fonts not supported yet"sv);
if (tag != 0x00010000)
return Error::from_string_literal("Not a valid font"sv);
return try_load_from_offset(buffer, 0);
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_offset(ReadonlyBytes buffer, u32 offset)
{
if (Checked<u32>::addition_would_overflow(offset, (u32)Sizes::OffsetTable))
return Error::from_string_literal("Invalid offset in font header"sv);
if (buffer.size() < offset + (u32)Sizes::OffsetTable)
return Error::from_string_literal("Font file too small"sv);
Optional<ReadonlyBytes> opt_head_slice = {};
Optional<ReadonlyBytes> opt_name_slice = {};
Optional<ReadonlyBytes> opt_hhea_slice = {};
Optional<ReadonlyBytes> opt_maxp_slice = {};
Optional<ReadonlyBytes> opt_hmtx_slice = {};
Optional<ReadonlyBytes> opt_cmap_slice = {};
Optional<ReadonlyBytes> opt_loca_slice = {};
Optional<ReadonlyBytes> opt_glyf_slice = {};
Optional<ReadonlyBytes> opt_os2_slice = {};
Optional<ReadonlyBytes> opt_kern_slice = {};
Optional<Head> opt_head = {};
Optional<Name> opt_name = {};
Optional<Hhea> opt_hhea = {};
Optional<Maxp> opt_maxp = {};
Optional<Hmtx> opt_hmtx = {};
Optional<Cmap> opt_cmap = {};
Optional<Loca> opt_loca = {};
Optional<OS2> opt_os2 = {};
Optional<Kern> opt_kern = {};
auto num_tables = be_u16(buffer.offset_pointer(offset + (u32)Offsets::NumTables));
if (buffer.size() < offset + (u32)Sizes::OffsetTable + num_tables * (u32)Sizes::TableRecord)
return Error::from_string_literal("Font file too small"sv);
for (auto i = 0; i < num_tables; i++) {
u32 record_offset = offset + (u32)Sizes::OffsetTable + i * (u32)Sizes::TableRecord;
u32 tag = be_u32(buffer.offset_pointer(record_offset));
u32 table_offset = be_u32(buffer.offset_pointer(record_offset + (u32)Offsets::TableRecord_Offset));
u32 table_length = be_u32(buffer.offset_pointer(record_offset + (u32)Offsets::TableRecord_Length));
if (Checked<u32>::addition_would_overflow(table_offset, table_length))
return Error::from_string_literal("Invalid table offset or length in font"sv);
if (buffer.size() < table_offset + table_length)
return Error::from_string_literal("Font file too small"sv);
auto buffer_here = ReadonlyBytes(buffer.offset_pointer(table_offset), table_length);
// Get the table offsets we need.
if (tag == tag_from_str("head")) {
opt_head_slice = buffer_here;
} else if (tag == tag_from_str("name")) {
opt_name_slice = buffer_here;
} else if (tag == tag_from_str("hhea")) {
opt_hhea_slice = buffer_here;
} else if (tag == tag_from_str("maxp")) {
opt_maxp_slice = buffer_here;
} else if (tag == tag_from_str("hmtx")) {
opt_hmtx_slice = buffer_here;
} else if (tag == tag_from_str("cmap")) {
opt_cmap_slice = buffer_here;
} else if (tag == tag_from_str("loca")) {
opt_loca_slice = buffer_here;
} else if (tag == tag_from_str("glyf")) {
opt_glyf_slice = buffer_here;
} else if (tag == tag_from_str("OS/2")) {
opt_os2_slice = buffer_here;
} else if (tag == tag_from_str("kern")) {
opt_kern_slice = buffer_here;
}
}
if (!opt_head_slice.has_value() || !(opt_head = Head::from_slice(opt_head_slice.value())).has_value())
return Error::from_string_literal("Could not load Head"sv);
auto head = opt_head.value();
if (!opt_name_slice.has_value() || !(opt_name = Name::from_slice(opt_name_slice.value())).has_value())
return Error::from_string_literal("Could not load Name"sv);
auto name = opt_name.value();
if (!opt_hhea_slice.has_value() || !(opt_hhea = Hhea::from_slice(opt_hhea_slice.value())).has_value())
return Error::from_string_literal("Could not load Hhea"sv);
auto hhea = opt_hhea.value();
if (!opt_maxp_slice.has_value() || !(opt_maxp = Maxp::from_slice(opt_maxp_slice.value())).has_value())
return Error::from_string_literal("Could not load Maxp"sv);
auto maxp = opt_maxp.value();
if (!opt_hmtx_slice.has_value() || !(opt_hmtx = Hmtx::from_slice(opt_hmtx_slice.value(), maxp.num_glyphs(), hhea.number_of_h_metrics())).has_value())
return Error::from_string_literal("Could not load Hmtx"sv);
auto hmtx = opt_hmtx.value();
if (!opt_cmap_slice.has_value() || !(opt_cmap = Cmap::from_slice(opt_cmap_slice.value())).has_value())
return Error::from_string_literal("Could not load Cmap"sv);
auto cmap = opt_cmap.value();
if (!opt_loca_slice.has_value() || !(opt_loca = Loca::from_slice(opt_loca_slice.value(), maxp.num_glyphs(), head.index_to_loc_format())).has_value())
return Error::from_string_literal("Could not load Loca"sv);
auto loca = opt_loca.value();
if (!opt_glyf_slice.has_value())
return Error::from_string_literal("Could not load Glyf"sv);
auto glyf = Glyf(opt_glyf_slice.value());
if (!opt_os2_slice.has_value())
return Error::from_string_literal("Could not load OS/2"sv);
auto os2 = OS2(opt_os2_slice.value());
Optional<Kern> kern {};
if (opt_kern_slice.has_value())
kern = TRY(Kern::from_slice(opt_kern_slice.value()));
// Select cmap table. FIXME: Do this better. Right now, just looks for platform "Windows"
// and corresponding encoding "Unicode full repertoire", or failing that, "Unicode BMP"
for (u32 i = 0; i < cmap.num_subtables(); i++) {
auto opt_subtable = cmap.subtable(i);
if (!opt_subtable.has_value()) {
continue;
}
auto subtable = opt_subtable.value();
auto platform = subtable.platform_id();
if (!platform.has_value())
return Error::from_string_literal("Invalid Platform ID"sv);
if (platform.value() == Cmap::Subtable::Platform::Windows) {
if (subtable.encoding_id() == (u16)Cmap::Subtable::WindowsEncoding::UnicodeFullRepertoire) {
cmap.set_active_index(i);
break;
}
if (subtable.encoding_id() == (u16)Cmap::Subtable::WindowsEncoding::UnicodeBMP) {
cmap.set_active_index(i);
break;
}
}
}
return adopt_ref(*new Font(move(buffer), move(head), move(name), move(hhea), move(maxp), move(hmtx), move(cmap), move(loca), move(glyf), move(os2), move(kern)));
}
ScaledFontMetrics Font::metrics([[maybe_unused]] float x_scale, float y_scale) const
{
auto ascender = m_hhea.ascender() * y_scale;
auto descender = m_hhea.descender() * y_scale;
auto line_gap = m_hhea.line_gap() * y_scale;
return ScaledFontMetrics {
.ascender = ascender,
.descender = descender,
.line_gap = line_gap,
};
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
ScaledGlyphMetrics Font::glyph_metrics(u32 glyph_id, float x_scale, float y_scale) const
{
if (glyph_id >= glyph_count()) {
glyph_id = 0;
}
auto horizontal_metrics = m_hmtx.get_glyph_horizontal_metrics(glyph_id);
auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
auto glyph = m_glyf.glyph(glyph_offset);
int ascender = glyph.ascender();
int descender = glyph.descender();
return ScaledGlyphMetrics {
.ascender = (int)roundf(ascender * y_scale),
.descender = (int)roundf(descender * y_scale),
.advance_width = (int)roundf(horizontal_metrics.advance_width * x_scale),
.left_side_bearing = (int)roundf(horizontal_metrics.left_side_bearing * x_scale),
};
}
float Font::glyphs_horizontal_kerning(u32 left_glyph_id, u32 right_glyph_id, float x_scale) const
{
if (!m_kern.has_value())
return 0.f;
return m_kern->get_glyph_kerning(left_glyph_id, right_glyph_id) * x_scale;
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
RefPtr<Gfx::Bitmap> Font::rasterize_glyph(u32 glyph_id, float x_scale, float y_scale) const
{
if (glyph_id >= glyph_count()) {
glyph_id = 0;
}
auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
auto glyph = m_glyf.glyph(glyph_offset);
return glyph.rasterize(m_hhea.ascender(), m_hhea.descender(), x_scale, y_scale, [&](u16 glyph_id) {
if (glyph_id >= glyph_count()) {
glyph_id = 0;
}
auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
return m_glyf.glyph(glyph_offset);
});
}
u32 Font::glyph_count() const
{
return m_maxp.num_glyphs();
}
u16 Font::units_per_em() const
{
return m_head.units_per_em();
}
String Font::family() const
{
auto string = m_name.typographic_family_name();
if (!string.is_empty())
return string;
return m_name.family_name();
}
String Font::variant() const
{
auto string = m_name.typographic_subfamily_name();
if (!string.is_empty())
return string;
return m_name.subfamily_name();
}
u16 Font::weight() const
{
constexpr u16 bold_bit { 1 };
if (m_os2.weight_class())
return m_os2.weight_class();
if (m_head.style() & bold_bit)
return 700;
return 400;
}
u8 Font::slope() const
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/os2
constexpr u16 italic_selection_bit { 1 };
constexpr u16 oblique_selection_bit { 512 };
// https://docs.microsoft.com/en-us/typography/opentype/spec/head
constexpr u16 italic_style_bit { 2 };
if (m_os2.selection() & oblique_selection_bit)
return 2;
if (m_os2.selection() & italic_selection_bit)
return 1;
if (m_head.style() & italic_style_bit)
return 1;
return 0;
}
bool Font::is_fixed_width() const
{
// FIXME: Read this information from the font file itself.
// FIXME: Although, it appears some application do similar hacks
return glyph_metrics(glyph_id_for_code_point('.'), 1, 1).advance_width == glyph_metrics(glyph_id_for_code_point('X'), 1, 1).advance_width;
}
int ScaledFont::width(StringView view) const { return unicode_view_width(Utf8View(view)); }
int ScaledFont::width(Utf8View const& view) const { return unicode_view_width(view); }
int ScaledFont::width(Utf32View const& view) const { return unicode_view_width(view); }
template<typename T>
ALWAYS_INLINE int ScaledFont::unicode_view_width(T const& view) const
{
if (view.is_empty())
return 0;
int width = 0;
int longest_width = 0;
u32 last_code_point = 0;
for (auto code_point : view) {
if (code_point == '\n' || code_point == '\r') {
longest_width = max(width, longest_width);
width = 0;
last_code_point = code_point;
continue;
}
u32 glyph_id = glyph_id_for_code_point(code_point);
auto kerning = glyphs_horizontal_kerning(last_code_point, code_point);
width += kerning + glyph_metrics(glyph_id).advance_width;
last_code_point = code_point;
}
longest_width = max(width, longest_width);
return longest_width;
}
RefPtr<Gfx::Bitmap> ScaledFont::rasterize_glyph(u32 glyph_id) const
{
auto glyph_iterator = m_cached_glyph_bitmaps.find(glyph_id);
if (glyph_iterator != m_cached_glyph_bitmaps.end())
return glyph_iterator->value;
auto glyph_bitmap = m_font->rasterize_glyph(glyph_id, m_x_scale, m_y_scale);
m_cached_glyph_bitmaps.set(glyph_id, glyph_bitmap);
return glyph_bitmap;
}
Gfx::Glyph ScaledFont::glyph(u32 code_point) const
{
auto id = glyph_id_for_code_point(code_point);
auto bitmap = rasterize_glyph(id);
auto metrics = glyph_metrics(id);
return Gfx::Glyph(bitmap, metrics.left_side_bearing, metrics.advance_width, metrics.ascender);
}
u8 ScaledFont::glyph_width(u32 code_point) const
{
auto id = glyph_id_for_code_point(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
int ScaledFont::glyph_or_emoji_width(u32 code_point) const
{
auto id = glyph_id_for_code_point(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
float ScaledFont::glyphs_horizontal_kerning(u32 left_code_point, u32 right_code_point) const
{
if (left_code_point == 0 || right_code_point == 0)
return 0.f;
auto left_glyph_id = glyph_id_for_code_point(left_code_point);
auto right_glyph_id = glyph_id_for_code_point(right_code_point);
if (left_glyph_id == 0 || right_glyph_id == 0)
return 0.f;
return m_font->glyphs_horizontal_kerning(left_glyph_id, right_glyph_id, m_x_scale);
}
u8 ScaledFont::glyph_fixed_width() const
{
return glyph_metrics(glyph_id_for_code_point(' ')).advance_width;
}
Gfx::FontPixelMetrics ScaledFont::pixel_metrics() const
{
auto metrics = m_font->metrics(m_x_scale, m_y_scale);
return Gfx::FontPixelMetrics {
.size = (float)pixel_size(),
.x_height = (float)x_height(),
.advance_of_ascii_zero = (float)glyph_width('0'),
.glyph_spacing = (float)glyph_spacing(),
.ascent = metrics.ascender,
.descent = -metrics.descender,
.line_gap = metrics.line_gap,
};
}
u16 OS2::weight_class() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::WeightClass));
}
u16 OS2::selection() const
{
return be_u16(m_slice.offset_pointer((u32)Offsets::Selection));
}
i16 OS2::typographic_ascender() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::TypographicAscender));
}
i16 OS2::typographic_descender() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::TypographicDescender));
}
i16 OS2::typographic_line_gap() const
{
return be_i16(m_slice.offset_pointer((u32)Offsets::TypographicLineGap));
}
}

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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <AK/Noncopyable.h>
#include <AK/RefCounted.h>
#include <AK/StringView.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/Font.h>
#include <LibGfx/Size.h>
#include <LibGfx/Font/TrueType/Cmap.h>
#include <LibGfx/Font/TrueType/Glyf.h>
#include <LibGfx/Font/TrueType/Tables.h>
#define POINTS_PER_INCH 72.0f
#define DEFAULT_DPI 96
namespace TTF {
struct ScaledFontMetrics {
float ascender { 0 };
float descender { 0 };
float line_gap { 0 };
int height() const
{
return ascender - descender;
}
};
struct ScaledGlyphMetrics {
int ascender;
int descender;
int advance_width;
int left_side_bearing;
};
class Font : public RefCounted<Font> {
AK_MAKE_NONCOPYABLE(Font);
public:
static ErrorOr<NonnullRefPtr<Font>> try_load_from_file(String path, unsigned index = 0);
static ErrorOr<NonnullRefPtr<Font>> try_load_from_externally_owned_memory(ReadonlyBytes bytes, unsigned index = 0);
ScaledFontMetrics metrics(float x_scale, float y_scale) const;
ScaledGlyphMetrics glyph_metrics(u32 glyph_id, float x_scale, float y_scale) const;
float glyphs_horizontal_kerning(u32 left_glyph_id, u32 right_glyph_id, float x_scale) const;
RefPtr<Gfx::Bitmap> rasterize_glyph(u32 glyph_id, float x_scale, float y_scale) const;
u32 glyph_count() const;
u16 units_per_em() const;
u32 glyph_id_for_code_point(u32 code_point) const { return m_cmap.glyph_id_for_code_point(code_point); }
String family() const;
String variant() const;
u16 weight() const;
u8 slope() const;
bool is_fixed_width() const;
private:
enum class Offsets {
NumTables = 4,
TableRecord_Offset = 8,
TableRecord_Length = 12,
};
enum class Sizes {
TTCHeaderV1 = 12,
OffsetTable = 12,
TableRecord = 16,
};
static ErrorOr<NonnullRefPtr<Font>> try_load_from_offset(ReadonlyBytes, unsigned index = 0);
Font(ReadonlyBytes bytes, Head&& head, Name&& name, Hhea&& hhea, Maxp&& maxp, Hmtx&& hmtx, Cmap&& cmap, Loca&& loca, Glyf&& glyf, OS2&& os2, Optional<Kern>&& kern)
: m_buffer(move(bytes))
, m_head(move(head))
, m_name(move(name))
, m_hhea(move(hhea))
, m_maxp(move(maxp))
, m_hmtx(move(hmtx))
, m_loca(move(loca))
, m_glyf(move(glyf))
, m_cmap(move(cmap))
, m_os2(move(os2))
, m_kern(move(kern))
{
}
RefPtr<Core::MappedFile> m_mapped_file;
ReadonlyBytes m_buffer;
// These are stateful wrappers around non-owning slices
Head m_head;
Name m_name;
Hhea m_hhea;
Maxp m_maxp;
Hmtx m_hmtx;
Loca m_loca;
Glyf m_glyf;
Cmap m_cmap;
OS2 m_os2;
Optional<Kern> m_kern;
};
class ScaledFont : public Gfx::Font {
public:
ScaledFont(NonnullRefPtr<TTF::Font> font, float point_width, float point_height, unsigned dpi_x = DEFAULT_DPI, unsigned dpi_y = DEFAULT_DPI)
: m_font(move(font))
, m_point_width(point_width)
, m_point_height(point_height)
{
float units_per_em = m_font->units_per_em();
m_x_scale = (point_width * dpi_x) / (POINTS_PER_INCH * units_per_em);
m_y_scale = (point_height * dpi_y) / (POINTS_PER_INCH * units_per_em);
}
u32 glyph_id_for_code_point(u32 code_point) const { return m_font->glyph_id_for_code_point(code_point); }
ScaledFontMetrics metrics() const { return m_font->metrics(m_x_scale, m_y_scale); }
ScaledGlyphMetrics glyph_metrics(u32 glyph_id) const { return m_font->glyph_metrics(glyph_id, m_x_scale, m_y_scale); }
RefPtr<Gfx::Bitmap> rasterize_glyph(u32 glyph_id) const;
// ^Gfx::Font
virtual NonnullRefPtr<Font> clone() const override { return *this; } // FIXME: clone() should not need to be implemented
virtual u8 presentation_size() const override { return m_point_height; }
virtual int pixel_size() const override { return m_point_height * 1.33333333f; }
virtual float point_size() const override { return m_point_height; }
virtual Gfx::FontPixelMetrics pixel_metrics() const override;
virtual u8 slope() const override { return m_font->slope(); }
virtual u16 weight() const override { return m_font->weight(); }
virtual Gfx::Glyph glyph(u32 code_point) const override;
virtual bool contains_glyph(u32 code_point) const override { return m_font->glyph_id_for_code_point(code_point) > 0; }
virtual u8 glyph_width(u32 code_point) const override;
virtual int glyph_or_emoji_width(u32 code_point) const override;
virtual float glyphs_horizontal_kerning(u32 left_code_point, u32 right_code_point) const override;
virtual int preferred_line_height() const override { return metrics().height() + metrics().line_gap; }
virtual u8 glyph_height() const override { return m_point_height; }
virtual int x_height() const override { return m_point_height; } // FIXME: Read from font
virtual u8 min_glyph_width() const override { return 1; } // FIXME: Read from font
virtual u8 max_glyph_width() const override { return m_point_width; } // FIXME: Read from font
virtual u8 glyph_fixed_width() const override;
virtual u8 baseline() const override { return m_point_height; } // FIXME: Read from font
virtual u8 mean_line() const override { return m_point_height; } // FIXME: Read from font
virtual int width(StringView) const override;
virtual int width(Utf8View const&) const override;
virtual int width(Utf32View const&) const override;
virtual String name() const override { return String::formatted("{} {}", family(), variant()); }
virtual bool is_fixed_width() const override { return m_font->is_fixed_width(); }
virtual u8 glyph_spacing() const override { return 0; }
virtual size_t glyph_count() const override { return m_font->glyph_count(); }
virtual String family() const override { return m_font->family(); }
virtual String variant() const override { return m_font->variant(); }
virtual String qualified_name() const override { return String::formatted("{} {} {} {}", family(), presentation_size(), weight(), slope()); }
virtual String human_readable_name() const override { return String::formatted("{} {} {}", family(), variant(), presentation_size()); }
private:
NonnullRefPtr<TTF::Font> m_font;
float m_x_scale { 0.0f };
float m_y_scale { 0.0f };
float m_point_width { 0.0f };
float m_point_height { 0.0f };
mutable HashMap<u32, RefPtr<Gfx::Bitmap>> m_cached_glyph_bitmaps;
template<typename T>
int unicode_view_width(T const& view) const;
};
}

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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/Font/TrueType/Glyf.h>
#include <LibGfx/Path.h>
#include <LibGfx/Point.h>
namespace TTF {
extern u16 be_u16(u8 const* ptr);
extern u32 be_u32(u8 const* ptr);
extern i16 be_i16(u8 const* ptr);
extern float be_fword(u8 const* ptr);
enum class SimpleGlyfFlags {
// From spec.
OnCurve = 0x01,
XShortVector = 0x02,
YShortVector = 0x04,
RepeatFlag = 0x08,
XIsSameOrPositiveXShortVector = 0x10,
YIsSameOrPositiveYShortVector = 0x20,
// Combinations
XMask = 0x12,
YMask = 0x24,
XLongVector = 0x00,
YLongVector = 0x00,
XNegativeShortVector = 0x02,
YNegativeShortVector = 0x04,
XPositiveShortVector = 0x12,
YPositiveShortVector = 0x24,
};
enum class CompositeGlyfFlags {
Arg1AndArg2AreWords = 0x0001,
ArgsAreXYValues = 0x0002,
RoundXYToGrid = 0x0004,
WeHaveAScale = 0x0008,
MoreComponents = 0x0020,
WeHaveAnXAndYScale = 0x0040,
WeHaveATwoByTwo = 0x0080,
WeHaveInstructions = 0x0100,
UseMyMetrics = 0x0200,
OverlapCompound = 0x0400, // Not relevant - can overlap without this set
ScaledComponentOffset = 0x0800,
UnscaledComponentOffset = 0x1000,
};
class PointIterator {
public:
struct Item {
bool on_curve;
Gfx::FloatPoint point;
};
PointIterator(ReadonlyBytes slice, u16 num_points, u32 flags_offset, u32 x_offset, u32 y_offset, Gfx::AffineTransform affine)
: m_slice(slice)
, m_points_remaining(num_points)
, m_flags_offset(flags_offset)
, m_x_offset(x_offset)
, m_y_offset(y_offset)
, m_affine(affine)
{
}
Optional<Item> next()
{
if (m_points_remaining == 0) {
return {};
}
if (m_flags_remaining > 0) {
m_flags_remaining--;
} else {
m_flag = m_slice[m_flags_offset++];
if (m_flag & (u8)SimpleGlyfFlags::RepeatFlag) {
m_flags_remaining = m_slice[m_flags_offset++];
}
}
switch (m_flag & (u8)SimpleGlyfFlags::XMask) {
case (u8)SimpleGlyfFlags::XLongVector:
m_last_point.set_x(m_last_point.x() + be_i16(m_slice.offset_pointer(m_x_offset)));
m_x_offset += 2;
break;
case (u8)SimpleGlyfFlags::XNegativeShortVector:
m_last_point.set_x(m_last_point.x() - m_slice[m_x_offset++]);
break;
case (u8)SimpleGlyfFlags::XPositiveShortVector:
m_last_point.set_x(m_last_point.x() + m_slice[m_x_offset++]);
break;
default:
break;
}
switch (m_flag & (u8)SimpleGlyfFlags::YMask) {
case (u8)SimpleGlyfFlags::YLongVector:
m_last_point.set_y(m_last_point.y() + be_i16(m_slice.offset_pointer(m_y_offset)));
m_y_offset += 2;
break;
case (u8)SimpleGlyfFlags::YNegativeShortVector:
m_last_point.set_y(m_last_point.y() - m_slice[m_y_offset++]);
break;
case (u8)SimpleGlyfFlags::YPositiveShortVector:
m_last_point.set_y(m_last_point.y() + m_slice[m_y_offset++]);
break;
default:
break;
}
m_points_remaining--;
Item ret = {
.on_curve = (m_flag & (u8)SimpleGlyfFlags::OnCurve) != 0,
.point = m_affine.map(m_last_point),
};
return ret;
}
private:
ReadonlyBytes m_slice;
u16 m_points_remaining;
u8 m_flag { 0 };
Gfx::FloatPoint m_last_point = { 0.0f, 0.0f };
u32 m_flags_remaining = { 0 };
u32 m_flags_offset;
u32 m_x_offset;
u32 m_y_offset;
Gfx::AffineTransform m_affine;
};
Optional<Glyf::Glyph::ComponentIterator::Item> Glyf::Glyph::ComponentIterator::next()
{
if (!m_has_more) {
return {};
}
u16 flags = be_u16(m_slice.offset_pointer(m_offset));
m_offset += 2;
u16 glyph_id = be_u16(m_slice.offset_pointer(m_offset));
m_offset += 2;
i16 arg1 = 0, arg2 = 0;
if (flags & (u16)CompositeGlyfFlags::Arg1AndArg2AreWords) {
arg1 = be_i16(m_slice.offset_pointer(m_offset));
m_offset += 2;
arg2 = be_i16(m_slice.offset_pointer(m_offset));
m_offset += 2;
} else {
arg1 = (i8)m_slice[m_offset++];
arg2 = (i8)m_slice[m_offset++];
}
float a = 1.0, b = 0.0, c = 0.0, d = 1.0, e = 0.0, f = 0.0;
if (flags & (u16)CompositeGlyfFlags::WeHaveATwoByTwo) {
a = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
b = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
c = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
d = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
} else if (flags & (u16)CompositeGlyfFlags::WeHaveAnXAndYScale) {
a = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
d = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
} else if (flags & (u16)CompositeGlyfFlags::WeHaveAScale) {
a = be_fword(m_slice.offset_pointer(m_offset));
m_offset += 2;
d = a;
}
// FIXME: Handle UseMyMetrics, ScaledComponentOffset, UnscaledComponentOffset, non-ArgsAreXYValues
if (flags & (u16)CompositeGlyfFlags::ArgsAreXYValues) {
e = arg1;
f = arg2;
} else {
// FIXME: Implement this. There's no TODO() here since many fonts work just fine without this.
}
if (flags & (u16)CompositeGlyfFlags::UseMyMetrics) {
// FIXME: Implement this. There's no TODO() here since many fonts work just fine without this.
}
if (flags & (u16)CompositeGlyfFlags::ScaledComponentOffset) {
// FIXME: Implement this. There's no TODO() here since many fonts work just fine without this.
}
if (flags & (u16)CompositeGlyfFlags::UnscaledComponentOffset) {
// FIXME: Implement this. There's no TODO() here since many fonts work just fine without this.
}
m_has_more = (flags & (u16)CompositeGlyfFlags::MoreComponents);
return Item {
.glyph_id = glyph_id,
.affine = Gfx::AffineTransform(a, b, c, d, e, f),
};
}
Rasterizer::Rasterizer(Gfx::IntSize size)
: m_size(size)
{
m_data.resize(m_size.width() * m_size.height());
for (int i = 0; i < m_size.width() * m_size.height(); i++) {
m_data[i] = 0.0f;
}
}
void Rasterizer::draw_path(Gfx::Path& path)
{
for (auto& line : path.split_lines()) {
draw_line(line.from, line.to);
}
}
RefPtr<Gfx::Bitmap> Rasterizer::accumulate()
{
auto bitmap_or_error = Gfx::Bitmap::try_create(Gfx::BitmapFormat::BGRA8888, m_size);
if (bitmap_or_error.is_error())
return {};
auto bitmap = bitmap_or_error.release_value_but_fixme_should_propagate_errors();
Color base_color = Color::from_rgb(0xffffff);
for (int y = 0; y < m_size.height(); y++) {
float accumulator = 0.0;
for (int x = 0; x < m_size.width(); x++) {
accumulator += m_data[y * m_size.width() + x];
float value = accumulator;
if (value < 0.0f) {
value = -value;
}
if (value > 1.0f) {
value = 1.0;
}
u8 alpha = value * 255.0f;
bitmap->set_pixel(x, y, base_color.with_alpha(alpha));
}
}
return bitmap;
}
void Rasterizer::draw_line(Gfx::FloatPoint p0, Gfx::FloatPoint p1)
{
// FIXME: Shift x and y according to dy/dx
if (p0.x() < 0.0f) {
p0.set_x(roundf(p0.x()));
}
if (p0.y() < 0.0f) {
p0.set_y(roundf(p0.y()));
}
if (p1.x() < 0.0f) {
p1.set_x(roundf(p1.x()));
}
if (p1.y() < 0.0f) {
p1.set_y(roundf(p1.y()));
}
if (!(p0.x() >= 0.0f && p0.y() >= 0.0f && p0.x() <= m_size.width() && p0.y() <= m_size.height())) {
dbgln("!P0({},{})", p0.x(), p0.y());
return;
}
if (!(p1.x() >= 0.0f && p1.y() >= 0.0f && p1.x() <= m_size.width() && p1.y() <= m_size.height())) {
dbgln("!P1({},{})", p1.x(), p1.y());
return;
}
VERIFY(p0.x() >= 0.0f && p0.y() >= 0.0f && p0.x() <= m_size.width() && p0.y() <= m_size.height());
VERIFY(p1.x() >= 0.0f && p1.y() >= 0.0f && p1.x() <= m_size.width() && p1.y() <= m_size.height());
// If we're on the same Y, there's no need to draw
if (p0.y() == p1.y()) {
return;
}
float direction = -1.0;
if (p1.y() < p0.y()) {
direction = 1.0;
auto tmp = p0;
p0 = p1;
p1 = tmp;
}
float dxdy = (p1.x() - p0.x()) / (p1.y() - p0.y());
u32 y0 = floorf(p0.y());
u32 y1 = ceilf(p1.y());
float x_cur = p0.x();
for (u32 y = y0; y < y1; y++) {
u32 line_offset = m_size.width() * y;
float dy = min(y + 1.0f, p1.y()) - max((float)y, p0.y());
float directed_dy = dy * direction;
float x_next = x_cur + dy * dxdy;
if (x_next < 0.0f) {
x_next = 0.0f;
}
float x0 = x_cur;
float x1 = x_next;
if (x1 < x0) {
x1 = x_cur;
x0 = x_next;
}
float x0_floor = floorf(x0);
float x1_ceil = ceilf(x1);
u32 x0i = x0_floor;
if (x1_ceil <= x0_floor + 1.0f) {
// If x0 and x1 are within the same pixel, then area to the right is (1 - (mid(x0, x1) - x0_floor)) * dy
float area = ((x0 + x1) * 0.5f) - x0_floor;
m_data[line_offset + x0i] += directed_dy * (1.0f - area);
m_data[line_offset + x0i + 1] += directed_dy * area;
} else {
float dydx = 1.0f / dxdy;
if (dydx < 0)
dydx = -dydx;
float x0_right = 1.0f - (x0 - x0_floor);
u32 x1_floor_i = floorf(x1);
float area_upto_here = 0.5f * x0_right * x0_right * dydx;
m_data[line_offset + x0i] += direction * area_upto_here;
for (u32 x = x0i + 1; x < x1_floor_i; x++) {
m_data[line_offset + x] += direction * dydx;
area_upto_here += dydx;
}
float remaining_area = (dy - area_upto_here);
m_data[line_offset + x1_floor_i] += direction * remaining_area;
}
x_cur = x_next;
}
}
Optional<Loca> Loca::from_slice(ReadonlyBytes slice, u32 num_glyphs, IndexToLocFormat index_to_loc_format)
{
switch (index_to_loc_format) {
case IndexToLocFormat::Offset16:
if (slice.size() < num_glyphs * 2) {
return {};
}
break;
case IndexToLocFormat::Offset32:
if (slice.size() < num_glyphs * 4) {
return {};
}
break;
}
return Loca(slice, num_glyphs, index_to_loc_format);
}
u32 Loca::get_glyph_offset(u32 glyph_id) const
{
VERIFY(glyph_id < m_num_glyphs);
switch (m_index_to_loc_format) {
case IndexToLocFormat::Offset16:
return ((u32)be_u16(m_slice.offset_pointer(glyph_id * 2))) * 2;
case IndexToLocFormat::Offset32:
return be_u32(m_slice.offset_pointer(glyph_id * 4));
default:
VERIFY_NOT_REACHED();
}
}
static void get_ttglyph_offsets(ReadonlyBytes slice, u32 num_points, u32 flags_offset, u32* x_offset, u32* y_offset)
{
u32 flags_size = 0;
u32 x_size = 0;
u32 repeat_count;
while (num_points > 0) {
u8 flag = slice[flags_offset + flags_size];
if (flag & (u8)SimpleGlyfFlags::RepeatFlag) {
flags_size++;
repeat_count = slice[flags_offset + flags_size] + 1;
} else {
repeat_count = 1;
}
flags_size++;
switch (flag & (u8)SimpleGlyfFlags::XMask) {
case (u8)SimpleGlyfFlags::XLongVector:
x_size += repeat_count * 2;
break;
case (u8)SimpleGlyfFlags::XNegativeShortVector:
case (u8)SimpleGlyfFlags::XPositiveShortVector:
x_size += repeat_count;
break;
default:
break;
}
num_points -= repeat_count;
}
*x_offset = flags_offset + flags_size;
*y_offset = *x_offset + x_size;
}
void Glyf::Glyph::rasterize_impl(Rasterizer& rasterizer, Gfx::AffineTransform const& transform) const
{
// Get offset for flags, x, and y.
u16 num_points = be_u16(m_slice.offset_pointer((m_num_contours - 1) * 2)) + 1;
u16 num_instructions = be_u16(m_slice.offset_pointer(m_num_contours * 2));
u32 flags_offset = m_num_contours * 2 + 2 + num_instructions;
u32 x_offset = 0;
u32 y_offset = 0;
get_ttglyph_offsets(m_slice, num_points, flags_offset, &x_offset, &y_offset);
// Prepare to render glyph.
Gfx::Path path;
PointIterator point_iterator(m_slice, num_points, flags_offset, x_offset, y_offset, transform);
int last_contour_end = -1;
i32 contour_index = 0;
u32 contour_size = 0;
Optional<Gfx::FloatPoint> contour_start = {};
Optional<Gfx::FloatPoint> last_offcurve_point = {};
// Render glyph
while (true) {
if (!contour_start.has_value()) {
if (contour_index >= m_num_contours) {
break;
}
int current_contour_end = be_u16(m_slice.offset_pointer(contour_index++ * 2));
contour_size = current_contour_end - last_contour_end;
last_contour_end = current_contour_end;
auto opt_item = point_iterator.next();
VERIFY(opt_item.has_value());
contour_start = opt_item.value().point;
path.move_to(contour_start.value());
contour_size--;
} else if (!last_offcurve_point.has_value()) {
if (contour_size > 0) {
auto opt_item = point_iterator.next();
// FIXME: Should we draw a line to the first point here?
if (!opt_item.has_value()) {
break;
}
auto item = opt_item.value();
contour_size--;
if (item.on_curve) {
path.line_to(item.point);
} else if (contour_size > 0) {
auto opt_next_item = point_iterator.next();
// FIXME: Should we draw a quadratic bezier to the first point here?
if (!opt_next_item.has_value()) {
break;
}
auto next_item = opt_next_item.value();
contour_size--;
if (next_item.on_curve) {
path.quadratic_bezier_curve_to(item.point, next_item.point);
} else {
auto mid_point = (item.point + next_item.point) * 0.5f;
path.quadratic_bezier_curve_to(item.point, mid_point);
last_offcurve_point = next_item.point;
}
} else {
path.quadratic_bezier_curve_to(item.point, contour_start.value());
contour_start = {};
}
} else {
path.line_to(contour_start.value());
contour_start = {};
}
} else {
auto point0 = last_offcurve_point.value();
last_offcurve_point = {};
if (contour_size > 0) {
auto opt_item = point_iterator.next();
// FIXME: Should we draw a quadratic bezier to the first point here?
if (!opt_item.has_value()) {
break;
}
auto item = opt_item.value();
contour_size--;
if (item.on_curve) {
path.quadratic_bezier_curve_to(point0, item.point);
} else {
auto mid_point = (point0 + item.point) * 0.5f;
path.quadratic_bezier_curve_to(point0, mid_point);
last_offcurve_point = item.point;
}
} else {
path.quadratic_bezier_curve_to(point0, contour_start.value());
contour_start = {};
}
}
}
rasterizer.draw_path(path);
}
RefPtr<Gfx::Bitmap> Glyf::Glyph::rasterize_simple(i16 font_ascender, i16 font_descender, float x_scale, float y_scale) const
{
u32 width = (u32)(ceilf((m_xmax - m_xmin) * x_scale)) + 2;
u32 height = (u32)(ceilf((font_ascender - font_descender) * y_scale)) + 2;
Rasterizer rasterizer(Gfx::IntSize(width, height));
auto affine = Gfx::AffineTransform().scale(x_scale, -y_scale).translate(-m_xmin, -font_ascender);
rasterize_impl(rasterizer, affine);
return rasterizer.accumulate();
}
Glyf::Glyph Glyf::glyph(u32 offset) const
{
VERIFY(m_slice.size() >= offset + (u32)Sizes::GlyphHeader);
i16 num_contours = be_i16(m_slice.offset_pointer(offset));
i16 xmin = be_i16(m_slice.offset_pointer(offset + (u32)Offsets::XMin));
i16 ymin = be_i16(m_slice.offset_pointer(offset + (u32)Offsets::YMin));
i16 xmax = be_i16(m_slice.offset_pointer(offset + (u32)Offsets::XMax));
i16 ymax = be_i16(m_slice.offset_pointer(offset + (u32)Offsets::YMax));
auto slice = ReadonlyBytes(m_slice.offset_pointer(offset + (u32)Sizes::GlyphHeader), m_slice.size() - offset - (u32)Sizes::GlyphHeader);
return Glyph(slice, xmin, ymin, xmax, ymax, num_contours);
}
}

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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Span.h>
#include <AK/Vector.h>
#include <LibGfx/AffineTransform.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/Font/TrueType/Tables.h>
#include <math.h>
namespace TTF {
class Rasterizer {
public:
Rasterizer(Gfx::IntSize);
void draw_path(Gfx::Path&);
RefPtr<Gfx::Bitmap> accumulate();
private:
void draw_line(Gfx::FloatPoint, Gfx::FloatPoint);
Gfx::IntSize m_size;
Vector<float> m_data;
};
class Loca {
public:
static Optional<Loca> from_slice(ReadonlyBytes, u32 num_glyphs, IndexToLocFormat);
u32 get_glyph_offset(u32 glyph_id) const;
private:
Loca(ReadonlyBytes slice, u32 num_glyphs, IndexToLocFormat index_to_loc_format)
: m_slice(slice)
, m_num_glyphs(num_glyphs)
, m_index_to_loc_format(index_to_loc_format)
{
}
ReadonlyBytes m_slice;
u32 m_num_glyphs { 0 };
IndexToLocFormat m_index_to_loc_format;
};
class Glyf {
public:
class Glyph {
public:
Glyph(ReadonlyBytes slice, i16 xmin, i16 ymin, i16 xmax, i16 ymax, i16 num_contours = -1)
: m_xmin(xmin)
, m_ymin(ymin)
, m_xmax(xmax)
, m_ymax(ymax)
, m_num_contours(num_contours)
, m_slice(slice)
{
if (m_num_contours >= 0) {
m_type = Type::Simple;
}
}
template<typename GlyphCb>
RefPtr<Gfx::Bitmap> rasterize(i16 font_ascender, i16 font_descender, float x_scale, float y_scale, GlyphCb glyph_callback) const
{
switch (m_type) {
case Type::Simple:
return rasterize_simple(font_ascender, font_descender, x_scale, y_scale);
case Type::Composite:
return rasterize_composite(font_ascender, font_descender, x_scale, y_scale, glyph_callback);
}
VERIFY_NOT_REACHED();
}
int ascender() const { return m_ymax; }
int descender() const { return m_ymin; }
private:
enum class Type {
Simple,
Composite,
};
class ComponentIterator {
public:
struct Item {
u16 glyph_id;
Gfx::AffineTransform affine;
};
ComponentIterator(ReadonlyBytes slice)
: m_slice(slice)
{
}
Optional<Item> next();
private:
ReadonlyBytes m_slice;
bool m_has_more { true };
u32 m_offset { 0 };
};
void rasterize_impl(Rasterizer&, Gfx::AffineTransform const&) const;
RefPtr<Gfx::Bitmap> rasterize_simple(i16 ascender, i16 descender, float x_scale, float y_scale) const;
template<typename GlyphCb>
RefPtr<Gfx::Bitmap> rasterize_composite(i16 font_ascender, i16 font_descender, float x_scale, float y_scale, GlyphCb glyph_callback) const
{
u32 width = (u32)(ceilf((m_xmax - m_xmin) * x_scale)) + 1;
u32 height = (u32)(ceilf((font_ascender - font_descender) * y_scale)) + 1;
Rasterizer rasterizer(Gfx::IntSize(width, height));
auto affine = Gfx::AffineTransform().scale(x_scale, -y_scale).translate(-m_xmin, -font_ascender);
ComponentIterator component_iterator(m_slice);
while (true) {
auto opt_item = component_iterator.next();
if (!opt_item.has_value()) {
break;
}
auto item = opt_item.value();
auto affine_here = affine.multiply(item.affine);
auto glyph = glyph_callback(item.glyph_id);
glyph.rasterize_impl(rasterizer, affine_here);
}
return rasterizer.accumulate();
}
Type m_type { Type::Composite };
i16 m_xmin { 0 };
i16 m_ymin { 0 };
i16 m_xmax { 0 };
i16 m_ymax { 0 };
i16 m_num_contours { -1 };
ReadonlyBytes m_slice;
};
Glyf(ReadonlyBytes slice)
: m_slice(slice)
{
}
Glyph glyph(u32 offset) const;
private:
enum class Offsets {
XMin = 2,
YMin = 4,
XMax = 6,
YMax = 8,
};
enum class Sizes {
GlyphHeader = 10,
};
ReadonlyBytes m_slice;
};
}

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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
* Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Error.h>
#include <AK/FixedArray.h>
#include <AK/Span.h>
#include <AK/String.h>
namespace TTF {
enum class IndexToLocFormat {
Offset16,
Offset32,
};
class Head {
public:
static Optional<Head> from_slice(ReadonlyBytes);
u16 units_per_em() const;
i16 xmin() const;
i16 ymin() const;
i16 xmax() const;
i16 ymax() const;
u16 style() const;
u16 lowest_recommended_ppem() const;
IndexToLocFormat index_to_loc_format() const;
private:
enum class Offsets {
UnitsPerEM = 18,
XMin = 36,
YMin = 38,
XMax = 40,
YMax = 42,
Style = 44,
LowestRecPPEM = 46,
IndexToLocFormat = 50,
};
enum class Sizes {
Table = 54,
};
Head(ReadonlyBytes slice)
: m_slice(slice)
{
}
ReadonlyBytes m_slice;
};
class Hhea {
public:
static Optional<Hhea> from_slice(ReadonlyBytes);
i16 ascender() const;
i16 descender() const;
i16 line_gap() const;
u16 advance_width_max() const;
u16 number_of_h_metrics() const;
private:
enum class Offsets {
Ascender = 4,
Descender = 6,
LineGap = 8,
AdvanceWidthMax = 10,
NumberOfHMetrics = 34,
};
enum class Sizes {
Table = 36,
};
Hhea(ReadonlyBytes slice)
: m_slice(slice)
{
}
ReadonlyBytes m_slice;
};
class Maxp {
public:
static Optional<Maxp> from_slice(ReadonlyBytes);
u16 num_glyphs() const;
private:
enum class Offsets {
NumGlyphs = 4
};
enum class Sizes {
TableV0p5 = 6,
};
Maxp(ReadonlyBytes slice)
: m_slice(slice)
{
}
ReadonlyBytes m_slice;
};
struct GlyphHorizontalMetrics {
u16 advance_width;
i16 left_side_bearing;
};
class Hmtx {
public:
static Optional<Hmtx> from_slice(ReadonlyBytes, u32 num_glyphs, u32 number_of_h_metrics);
GlyphHorizontalMetrics get_glyph_horizontal_metrics(u32 glyph_id) const;
private:
enum class Sizes {
LongHorMetric = 4,
LeftSideBearing = 2
};
Hmtx(ReadonlyBytes slice, u32 num_glyphs, u32 number_of_h_metrics)
: m_slice(slice)
, m_num_glyphs(num_glyphs)
, m_number_of_h_metrics(number_of_h_metrics)
{
}
ReadonlyBytes m_slice;
u32 m_num_glyphs { 0 };
u32 m_number_of_h_metrics { 0 };
};
class OS2 {
public:
enum class Offsets {
WeightClass = 4,
Selection = 62,
TypographicAscender = 68,
TypographicDescender = 70,
TypographicLineGap = 72,
};
u16 weight_class() const;
u16 selection() const;
i16 typographic_ascender() const;
i16 typographic_descender() const;
i16 typographic_line_gap() const;
explicit OS2(ReadonlyBytes slice)
: m_slice(slice)
{
}
private:
ReadonlyBytes m_slice;
};
class Name {
public:
enum class Platform {
Unicode = 0,
Macintosh = 1,
Windows = 3,
};
enum class MacintoshLanguage {
English = 0,
};
enum class WindowsLanguage {
EnglishUnitedStates = 0x0409,
};
static Optional<Name> from_slice(ReadonlyBytes);
String family_name() const { return string_for_id(NameId::FamilyName); }
String subfamily_name() const { return string_for_id(NameId::SubfamilyName); }
String typographic_family_name() const { return string_for_id(NameId::TypographicFamilyName); }
String typographic_subfamily_name() const { return string_for_id(NameId::TypographicSubfamilyName); }
private:
enum class NameId {
Copyright = 0,
FamilyName = 1,
SubfamilyName = 2,
UniqueIdentifier = 3,
FullName = 4,
VersionString = 5,
PostscriptName = 6,
Trademark = 7,
Manufacturer = 8,
Designer = 9,
Description = 10,
TypographicFamilyName = 16,
TypographicSubfamilyName = 17,
};
Name(ReadonlyBytes slice)
: m_slice(slice)
{
}
String string_for_id(NameId id) const;
ReadonlyBytes m_slice;
};
class Kern {
public:
static ErrorOr<Kern> from_slice(ReadonlyBytes);
i16 get_glyph_kerning(u16 left_glyph_id, u16 right_glyph_id) const;
private:
enum Sizes : size_t {
SubtableHeader = 6,
Format0Entry = 6,
};
Kern(ReadonlyBytes slice, FixedArray<size_t> subtable_offsets)
: m_slice(slice)
, m_subtable_offsets(move(subtable_offsets))
{
}
static Optional<i16> read_glyph_kerning_format0(ReadonlyBytes slice, u16 left_glyph_id, u16 right_glyph_id);
ReadonlyBytes m_slice;
FixedArray<size_t> m_subtable_offsets;
};
}