LibPDF: Add very basic support for Adobe Type 1 font rendering

Previously we would draw all text, no matter what font type, as
Liberation Serif, which results in things like ugly character spacing.

We now have partial support for drawing Type 1 glyphs, which are part of
a PostScript font program. We completely ignore hinting for now, which
results in ugly looking characters at low resolutions, but gain support
for a large number of typefaces, including most of the default fonts
used in TeX.
This commit is contained in:
Julian Offenhäuser 2022-08-25 11:06:21 +02:00 committed by Andreas Kling
commit b14f0950a5
Notes: sideshowbarker 2024-07-17 05:40:58 +09:00
9 changed files with 752 additions and 16 deletions

View file

@ -643,25 +643,37 @@ void Renderer::show_text(String const& string)
{
auto& text_rendering_matrix = calculate_text_rendering_matrix();
auto font_type = text_state().font->type();
auto font_size = text_rendering_matrix.x_scale() * text_state().font_size;
auto font_size_int = static_cast<int>(text_rendering_matrix.x_scale() * text_state().font_size);
auto font = Gfx::FontDatabase::the().get(text_state().font_family, text_state().font_variant, font_size_int);
VERIFY(font);
auto glyph_position = text_rendering_matrix.map(Gfx::FloatPoint { 0.0f, 0.0f });
// Account for the reversed font baseline
glyph_position.set_y(glyph_position.y() - static_cast<float>(font->baseline()));
RefPtr<Gfx::Font> font;
// For types other than Type 1 and the standard 14 fonts, use Liberation Serif for now
if (font_type != PDFFont::Type::Type1 || text_state().font->is_standard_font()) {
font = Gfx::FontDatabase::the().get(text_state().font_family, text_state().font_variant, font_size);
VERIFY(font);
// Account for the reversed font baseline
glyph_position.set_y(glyph_position.y() - static_cast<float>(font->baseline()));
}
auto original_position = glyph_position;
for (auto char_code : string.bytes()) {
auto code_point = text_state().font->char_code_to_code_point(char_code);
auto char_width = text_state().font->get_char_width(char_code, font_size);
if (code_point != 0x20)
m_painter.draw_glyph(glyph_position.to_type<int>(), code_point, *font, state().paint_color);
auto glyph_width = char_width * font_size;
if (code_point != 0x20) {
if (font.is_null()) {
text_state().font->draw_glyph(m_painter, glyph_position.to_type<int>(), glyph_width, code_point, state().paint_color);
} else {
m_painter.draw_glyph(glyph_position.to_type<int>(), code_point, *font, state().paint_color);
}
}
auto tx = glyph_width;
tx += text_state().character_spacing;