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/*
* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "AK/ByteBuffer.h"
#include <AK/Checked.h>
#include <AK/Utf32View.h>
#include <AK/Utf8View.h>
#include <LibCore/File.h>
#include <LibTTF/Cmap.h>
#include <LibTTF/Font.h>
#include <LibTTF/Glyf.h>
#include <LibTTF/Tables.h>
#include <LibTextCodec/Decoder.h>
#include <math.h>
namespace TTF {
u16 be_u16(const u8* ptr);
u32 be_u32(const u8* ptr);
i16 be_i16(const u8* ptr);
float be_fword(const u8* ptr);
u32 tag_from_str(const char* str);
u16 be_u16(const u8* ptr)
{
return (((u16)ptr[0]) << 8) | ((u16)ptr[1]);
}
u32 be_u32(const u8* ptr)
{
return (((u32)ptr[0]) << 24) | (((u32)ptr[1]) << 16) | (((u32)ptr[2]) << 8) | ((u32)ptr[3]);
}
i16 be_i16(const u8* ptr)
{
return (((i16)ptr[0]) << 8) | ((i16)ptr[1]);
}
float be_fword(const u8* ptr)
{
return (float)be_i16(ptr) / (float)(1 << 14);
}
u32 tag_from_str(const char* str)
{
return be_u32((const u8*)str);
}
Optional<Head> Head::from_slice(const 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::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(const 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(const 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(const 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(const ReadonlyBytes& slice)
{
return Name(slice);
}
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));
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)
continue;
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 { (const char*)m_slice.offset_pointer(string_offset + offset), length });
}
return String((const char*)m_slice.offset_pointer(string_offset + offset), length);
}
return String::empty();
}
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,
};
}
RefPtr<Font> Font::load_from_file(String path, unsigned index)
{
auto file_or_error = Core::File::open(move(path), Core::IODevice::ReadOnly);
if (file_or_error.is_error()) {
dbgln("Could not open file: {}", file_or_error.error());
return nullptr;
}
auto file = file_or_error.value();
if (!file->open(Core::IODevice::ReadOnly)) {
dbgln("Could not open file");
return nullptr;
}
auto buffer = file->read_all();
return load_from_memory(buffer, index);
}
RefPtr<Font> Font::load_from_memory(ByteBuffer& buffer, unsigned index)
{
if (buffer.size() < 4) {
dbgln("Font file too small");
return nullptr;
}
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)) {
dbgln("Font file too small");
return nullptr;
}
u32 offset = be_u32(buffer.offset_pointer((u32)Sizes::TTCHeaderV1 + sizeof(u32) * index));
return load_from_offset(move(buffer), offset);
}
if (tag == tag_from_str("OTTO")) {
dbgln("CFF fonts not supported yet");
return nullptr;
}
if (tag != 0x00010000) {
dbgln("Not a valid font");
return nullptr;
}
return load_from_offset(move(buffer), 0);
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
RefPtr<Font> Font::load_from_offset(ByteBuffer&& buffer, u32 offset)
{
if (Checked<u32>::addition_would_overflow(offset, (u32)Sizes::OffsetTable)) {
dbgln("Invalid offset in font header");
return nullptr;
}
if (buffer.size() < offset + (u32)Sizes::OffsetTable) {
dbgln("Font file too small");
return nullptr;
}
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<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 = {};
auto num_tables = be_u16(buffer.offset_pointer(offset + (u32)Offsets::NumTables));
if (buffer.size() < offset + (u32)Sizes::OffsetTable + num_tables * (u32)Sizes::TableRecord) {
dbgln("Font file too small");
return nullptr;
}
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)) {
dbgln("Invalid table offset/length in font.");
return nullptr;
}
if (buffer.size() < table_offset + table_length) {
dbgln("Font file too small");
return nullptr;
}
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;
}
}
if (!opt_head_slice.has_value() || !(opt_head = Head::from_slice(opt_head_slice.value())).has_value()) {
dbgln("Could not load Head");
return nullptr;
}
auto head = opt_head.value();
if (!opt_name_slice.has_value() || !(opt_name = Name::from_slice(opt_name_slice.value())).has_value()) {
dbgln("Could not load Name");
return nullptr;
}
auto name = opt_name.value();
if (!opt_hhea_slice.has_value() || !(opt_hhea = Hhea::from_slice(opt_hhea_slice.value())).has_value()) {
dbgln("Could not load Hhea");
return nullptr;
}
auto hhea = opt_hhea.value();
if (!opt_maxp_slice.has_value() || !(opt_maxp = Maxp::from_slice(opt_maxp_slice.value())).has_value()) {
dbgln("Could not load Maxp");
return nullptr;
}
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()) {
dbgln("Could not load Hmtx");
return nullptr;
}
auto hmtx = opt_hmtx.value();
if (!opt_cmap_slice.has_value() || !(opt_cmap = Cmap::from_slice(opt_cmap_slice.value())).has_value()) {
dbgln("Could not load Cmap");
return nullptr;
}
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()) {
dbgln("Could not load Loca");
return nullptr;
}
auto loca = opt_loca.value();
if (!opt_glyf_slice.has_value()) {
dbgln("Could not load Glyf");
return nullptr;
}
auto glyf = Glyf(opt_glyf_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();
if (subtable.platform_id() == 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(*new Font(move(buffer), move(head), move(name), move(hhea), move(maxp), move(hmtx), move(cmap), move(loca), move(glyf)));
}
ScaledFontMetrics Font::metrics(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;
auto advance_width_max = m_hhea.advance_width_max() * x_scale;
return ScaledFontMetrics {
.ascender = (int)roundf(ascender),
.descender = (int)roundf(descender),
.line_gap = (int)roundf(line_gap),
.advance_width_max = (int)roundf(advance_width_max),
};
}
// 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),
};
}
// FIXME: "loca" and "glyf" are not available for CFF fonts.
RefPtr<Gfx::Bitmap> Font::raster_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.raster(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
{
// FIXME: This is pretty naive, read weight from the actual font table(s)
auto variant_name = variant();
if (variant_name == "Thin")
return 100;
if (variant_name == "Extra Light")
return 200;
if (variant_name == "Light")
return 300;
if (variant_name == "Regular")
return 400;
if (variant_name == "Medium")
return 500;
if (variant_name == "Semi Bold")
return 600;
if (variant_name == "Bold")
return 700;
if (variant_name == "Extra Bold")
return 800;
if (variant_name == "Black")
return 900;
if (variant_name == "Extra Black")
return 950;
return 400;
}
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_codepoint('.'), 1, 1).advance_width == glyph_metrics(glyph_id_for_codepoint('X'), 1, 1).advance_width;
}
int ScaledFont::width(const StringView& string) const
{
Utf8View utf8 { string };
return width(utf8);
}
int ScaledFont::width(const Utf8View& utf8) const
{
int width = 0;
for (u32 codepoint : utf8) {
u32 glyph_id = glyph_id_for_codepoint(codepoint);
auto metrics = glyph_metrics(glyph_id);
width += metrics.advance_width;
}
return width;
}
int ScaledFont::width(const Utf32View& utf32) const
{
int width = 0;
for (size_t i = 0; i < utf32.length(); i++) {
u32 glyph_id = glyph_id_for_codepoint(utf32.code_points()[i]);
auto metrics = glyph_metrics(glyph_id);
width += metrics.advance_width;
}
return width;
}
RefPtr<Gfx::Bitmap> ScaledFont::raster_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->raster_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_codepoint(code_point);
auto bitmap = raster_glyph(id);
auto metrics = glyph_metrics(id);
return Gfx::Glyph(bitmap, metrics.left_side_bearing, metrics.advance_width, metrics.ascender);
}
u8 ScaledFont::glyph_width(size_t code_point) const
{
auto id = glyph_id_for_codepoint(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_codepoint(code_point);
auto metrics = glyph_metrics(id);
return metrics.advance_width;
}
u8 ScaledFont::glyph_fixed_width() const
{
return glyph_metrics(glyph_id_for_codepoint(' ')).advance_width;
}
}
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