mirror of
https://github.com/RGBCube/serenity
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458 lines
15 KiB
C++
458 lines
15 KiB
C++
/*
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* Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "AK/ByteBuffer.h"
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#include <AK/LogStream.h>
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#include <AK/Utf32View.h>
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#include <AK/Utf8View.h>
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#include <LibCore/File.h>
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#include <LibTTF/Cmap.h>
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#include <LibTTF/Font.h>
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#include <LibTTF/Glyf.h>
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#include <LibTTF/Tables.h>
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#include <bits/stdint.h>
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#include <math.h>
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namespace TTF {
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u16 be_u16(const u8* ptr);
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u32 be_u32(const u8* ptr);
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i16 be_i16(const u8* ptr);
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float be_fword(const u8* ptr);
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u32 tag_from_str(const char* str);
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u16 be_u16(const u8* ptr)
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{
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return (((u16)ptr[0]) << 8) | ((u16)ptr[1]);
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}
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u32 be_u32(const u8* ptr)
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{
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return (((u32)ptr[0]) << 24) | (((u32)ptr[1]) << 16) | (((u32)ptr[2]) << 8) | ((u32)ptr[3]);
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}
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i16 be_i16(const u8* ptr)
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{
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return (((i16)ptr[0]) << 8) | ((i16)ptr[1]);
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}
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float be_fword(const u8* ptr)
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{
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return (float)be_i16(ptr) / (float)(1 << 14);
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}
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u32 tag_from_str(const char* str)
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{
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return be_u32((const u8*)str);
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}
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Optional<Head> Head::from_slice(const ReadonlyBytes& slice)
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{
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if (slice.size() < (size_t)Sizes::Table) {
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return {};
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}
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return Head(slice);
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}
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u16 Head::units_per_em() const
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{
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return be_u16(m_slice.offset_pointer((u32)Offsets::UnitsPerEM));
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}
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i16 Head::xmin() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::XMin));
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}
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i16 Head::ymin() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::YMin));
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}
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i16 Head::xmax() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::XMax));
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}
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i16 Head::ymax() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::YMax));
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}
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u16 Head::lowest_recommended_ppem() const
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{
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return be_u16(m_slice.offset_pointer((u32)Offsets::LowestRecPPEM));
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}
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IndexToLocFormat Head::index_to_loc_format() const
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{
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i16 raw = be_i16(m_slice.offset_pointer((u32)Offsets::IndexToLocFormat));
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switch (raw) {
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case 0:
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return IndexToLocFormat::Offset16;
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case 1:
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return IndexToLocFormat::Offset32;
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default:
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ASSERT_NOT_REACHED();
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}
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}
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Optional<Hhea> Hhea::from_slice(const ReadonlyBytes& slice)
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{
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if (slice.size() < (size_t)Sizes::Table) {
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return {};
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}
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return Hhea(slice);
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}
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i16 Hhea::ascender() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::Ascender));
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}
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i16 Hhea::descender() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::Descender));
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}
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i16 Hhea::line_gap() const
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{
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return be_i16(m_slice.offset_pointer((u32)Offsets::LineGap));
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}
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u16 Hhea::advance_width_max() const
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{
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return be_u16(m_slice.offset_pointer((u32)Offsets::AdvanceWidthMax));
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}
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u16 Hhea::number_of_h_metrics() const
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{
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return be_u16(m_slice.offset_pointer((u32)Offsets::NumberOfHMetrics));
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}
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Optional<Maxp> Maxp::from_slice(const ReadonlyBytes& slice)
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{
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if (slice.size() < (size_t)Sizes::TableV0p5) {
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return {};
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}
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return Maxp(slice);
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}
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u16 Maxp::num_glyphs() const
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{
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return be_u16(m_slice.offset_pointer((u32)Offsets::NumGlyphs));
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}
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Optional<Hmtx> Hmtx::from_slice(const ReadonlyBytes& slice, u32 num_glyphs, u32 number_of_h_metrics)
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{
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if (slice.size() < number_of_h_metrics * (u32)Sizes::LongHorMetric + (num_glyphs - number_of_h_metrics) * (u32)Sizes::LeftSideBearing) {
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return {};
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}
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return Hmtx(slice, num_glyphs, number_of_h_metrics);
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}
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GlyphHorizontalMetrics Hmtx::get_glyph_horizontal_metrics(u32 glyph_id) const
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{
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ASSERT(glyph_id < m_num_glyphs);
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if (glyph_id < m_number_of_h_metrics) {
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auto offset = glyph_id * (u32)Sizes::LongHorMetric;
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u16 advance_width = be_u16(m_slice.offset_pointer(offset));
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i16 left_side_bearing = be_i16(m_slice.offset_pointer(offset + 2));
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return GlyphHorizontalMetrics {
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.advance_width = advance_width,
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.left_side_bearing = left_side_bearing,
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};
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}
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auto offset = m_number_of_h_metrics * (u32)Sizes::LongHorMetric + (glyph_id - m_number_of_h_metrics) * (u32)Sizes::LeftSideBearing;
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u16 advance_width = be_u16(m_slice.offset_pointer((m_number_of_h_metrics - 1) * (u32)Sizes::LongHorMetric));
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i16 left_side_bearing = be_i16(m_slice.offset_pointer(offset));
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return GlyphHorizontalMetrics {
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.advance_width = advance_width,
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.left_side_bearing = left_side_bearing,
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};
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}
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RefPtr<Font> Font::load_from_file(const StringView& path, unsigned index)
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{
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auto file_or_error = Core::File::open(String(path), Core::IODevice::ReadOnly);
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if (file_or_error.is_error()) {
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dbg() << "Could not open file: " << file_or_error.error();
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return nullptr;
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}
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auto file = file_or_error.value();
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if (!file->open(Core::IODevice::ReadOnly)) {
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dbg() << "Could not open file";
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return nullptr;
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}
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auto buffer = file->read_all();
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if (buffer.size() < 4) {
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dbg() << "Font file too small";
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return nullptr;
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}
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u32 tag = be_u32(buffer.data());
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if (tag == tag_from_str("ttcf")) {
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// It's a font collection
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if (buffer.size() < (u32)Sizes::TTCHeaderV1 + sizeof(u32) * (index + 1)) {
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dbg() << "Font file too small";
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return nullptr;
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}
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u32 offset = be_u32(buffer.offset_pointer((u32)Sizes::TTCHeaderV1 + sizeof(u32) * index));
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return load_from_offset(move(buffer), offset);
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}
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if (tag == tag_from_str("OTTO")) {
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dbg() << "CFF fonts not supported yet";
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return nullptr;
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}
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if (tag != 0x00010000) {
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dbg() << "Not a valid font";
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return nullptr;
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}
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return load_from_offset(move(buffer), 0);
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}
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// FIXME: "loca" and "glyf" are not available for CFF fonts.
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RefPtr<Font> Font::load_from_offset(ByteBuffer&& buffer, u32 offset)
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{
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if (buffer.size() < offset + (u32)Sizes::OffsetTable) {
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dbg() << "Font file too small";
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return nullptr;
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}
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Optional<ReadonlyBytes> opt_head_slice = {};
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Optional<ReadonlyBytes> opt_hhea_slice = {};
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Optional<ReadonlyBytes> opt_maxp_slice = {};
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Optional<ReadonlyBytes> opt_hmtx_slice = {};
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Optional<ReadonlyBytes> opt_cmap_slice = {};
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Optional<ReadonlyBytes> opt_loca_slice = {};
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Optional<ReadonlyBytes> opt_glyf_slice = {};
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Optional<Head> opt_head = {};
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Optional<Hhea> opt_hhea = {};
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Optional<Maxp> opt_maxp = {};
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Optional<Hmtx> opt_hmtx = {};
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Optional<Cmap> opt_cmap = {};
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Optional<Loca> opt_loca = {};
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auto num_tables = be_u16(buffer.offset_pointer(offset + (u32)Offsets::NumTables));
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if (buffer.size() < offset + (u32)Sizes::OffsetTable + num_tables * (u32)Sizes::TableRecord) {
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dbg() << "Font file too small";
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return nullptr;
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}
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for (auto i = 0; i < num_tables; i++) {
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u32 record_offset = offset + (u32)Sizes::OffsetTable + i * (u32)Sizes::TableRecord;
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u32 tag = be_u32(buffer.offset_pointer(record_offset));
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u32 table_offset = be_u32(buffer.offset_pointer(record_offset + (u32)Offsets::TableRecord_Offset));
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u32 table_length = be_u32(buffer.offset_pointer(record_offset + (u32)Offsets::TableRecord_Length));
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if (buffer.size() < table_offset + table_length) {
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dbg() << "Font file too small";
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return nullptr;
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}
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auto buffer_here = ReadonlyBytes(buffer.offset_pointer(table_offset), table_length);
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// Get the table offsets we need.
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if (tag == tag_from_str("head")) {
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opt_head_slice = buffer_here;
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} else if (tag == tag_from_str("hhea")) {
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opt_hhea_slice = buffer_here;
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} else if (tag == tag_from_str("maxp")) {
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opt_maxp_slice = buffer_here;
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} else if (tag == tag_from_str("hmtx")) {
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opt_hmtx_slice = buffer_here;
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} else if (tag == tag_from_str("cmap")) {
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opt_cmap_slice = buffer_here;
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} else if (tag == tag_from_str("loca")) {
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opt_loca_slice = buffer_here;
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} else if (tag == tag_from_str("glyf")) {
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opt_glyf_slice = buffer_here;
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}
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}
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if (!opt_head_slice.has_value() || !(opt_head = Head::from_slice(opt_head_slice.value())).has_value()) {
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dbg() << "Could not load Head";
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return nullptr;
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}
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auto head = opt_head.value();
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if (!opt_hhea_slice.has_value() || !(opt_hhea = Hhea::from_slice(opt_hhea_slice.value())).has_value()) {
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dbg() << "Could not load Hhea";
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return nullptr;
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}
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auto hhea = opt_hhea.value();
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if (!opt_maxp_slice.has_value() || !(opt_maxp = Maxp::from_slice(opt_maxp_slice.value())).has_value()) {
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dbg() << "Could not load Maxp";
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return nullptr;
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}
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auto maxp = opt_maxp.value();
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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()) {
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dbg() << "Could not load Hmtx";
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return nullptr;
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}
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auto hmtx = opt_hmtx.value();
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if (!opt_cmap_slice.has_value() || !(opt_cmap = Cmap::from_slice(opt_cmap_slice.value())).has_value()) {
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dbg() << "Could not load Cmap";
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return nullptr;
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}
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auto cmap = opt_cmap.value();
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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()) {
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dbg() << "Could not load Loca";
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return nullptr;
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}
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auto loca = opt_loca.value();
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if (!opt_glyf_slice.has_value()) {
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dbg() << "Could not load Glyf";
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return nullptr;
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}
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auto glyf = Glyf(opt_glyf_slice.value());
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// Select cmap table. FIXME: Do this better. Right now, just looks for platform "Windows"
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// and corresponding encoding "Unicode full repertoire", or failing that, "Unicode BMP"
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for (u32 i = 0; i < cmap.num_subtables(); i++) {
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auto opt_subtable = cmap.subtable(i);
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if (!opt_subtable.has_value()) {
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continue;
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}
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auto subtable = opt_subtable.value();
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if (subtable.platform_id() == Cmap::Subtable::Platform::Windows) {
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if (subtable.encoding_id() == (u16)Cmap::Subtable::WindowsEncoding::UnicodeFullRepertoire) {
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cmap.set_active_index(i);
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break;
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}
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if (subtable.encoding_id() == (u16)Cmap::Subtable::WindowsEncoding::UnicodeBMP) {
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cmap.set_active_index(i);
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break;
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}
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}
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}
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return adopt(*new Font(move(buffer), move(head), move(hhea), move(maxp), move(hmtx), move(cmap), move(loca), move(glyf)));
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}
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ScaledFontMetrics Font::metrics(float x_scale, float y_scale) const
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{
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auto ascender = m_hhea.ascender() * y_scale;
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auto descender = m_hhea.descender() * y_scale;
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auto line_gap = m_hhea.line_gap() * y_scale;
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auto advance_width_max = m_hhea.advance_width_max() * x_scale;
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return ScaledFontMetrics {
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.ascender = (int)roundf(ascender),
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.descender = (int)roundf(descender),
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.line_gap = (int)roundf(line_gap),
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.advance_width_max = (int)roundf(advance_width_max),
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};
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}
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// FIXME: "loca" and "glyf" are not available for CFF fonts.
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ScaledGlyphMetrics Font::glyph_metrics(u32 glyph_id, float x_scale, float y_scale) const
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{
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if (glyph_id >= glyph_count()) {
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glyph_id = 0;
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}
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auto horizontal_metrics = m_hmtx.get_glyph_horizontal_metrics(glyph_id);
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auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
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auto glyph = m_glyf.glyph(glyph_offset);
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int ascender = glyph.ascender();
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int descender = glyph.descender();
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return ScaledGlyphMetrics {
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.ascender = (int)roundf(ascender * y_scale),
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.descender = (int)roundf(descender * y_scale),
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.advance_width = (int)roundf(horizontal_metrics.advance_width * x_scale),
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.left_side_bearing = (int)roundf(horizontal_metrics.left_side_bearing * x_scale),
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};
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}
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// FIXME: "loca" and "glyf" are not available for CFF fonts.
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RefPtr<Gfx::Bitmap> Font::raster_glyph(u32 glyph_id, float x_scale, float y_scale) const
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{
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if (glyph_id >= glyph_count()) {
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glyph_id = 0;
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}
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auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
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auto glyph = m_glyf.glyph(glyph_offset);
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return glyph.raster(x_scale, y_scale, [&](u16 glyph_id) {
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if (glyph_id >= glyph_count()) {
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glyph_id = 0;
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}
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auto glyph_offset = m_loca.get_glyph_offset(glyph_id);
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return m_glyf.glyph(glyph_offset);
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});
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}
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u32 Font::glyph_count() const
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{
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return m_maxp.num_glyphs();
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}
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u16 Font::units_per_em() const
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{
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return m_head.units_per_em();
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}
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int ScaledFont::width(const StringView& string) const
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{
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Utf8View utf8 { string };
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return width(utf8);
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}
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int ScaledFont::width(const Utf8View& utf8) const
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{
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int width = 0;
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for (u32 codepoint : utf8) {
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u32 glyph_id = glyph_id_for_codepoint(codepoint);
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auto metrics = glyph_metrics(glyph_id);
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width += metrics.advance_width;
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}
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return width;
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}
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int ScaledFont::width(const Utf32View& utf32) const
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{
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int width = 0;
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for (size_t i = 0; i < utf32.length(); i++) {
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u32 glyph_id = glyph_id_for_codepoint(utf32.code_points()[i]);
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auto metrics = glyph_metrics(glyph_id);
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width += metrics.advance_width;
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}
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return width;
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}
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RefPtr<Gfx::Bitmap> ScaledFont::raster_glyph(u32 glyph_id) const
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{
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auto glyph_iterator = m_cached_glyph_bitmaps.find(glyph_id);
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if (glyph_iterator != m_cached_glyph_bitmaps.end())
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return glyph_iterator->value;
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auto glyph_bitmap = m_font->raster_glyph(glyph_id, m_x_scale, m_y_scale);
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m_cached_glyph_bitmaps.set(glyph_id, glyph_bitmap);
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return glyph_bitmap;
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}
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}
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