RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-27 02:07:36 +00:00
Code Issues Activity Actions

LibGfx: Cache family, width, weight, and slope for OpenType fonts

Browse source 
These properties could be cached in the font object once they are
decoded from the table for the first time to make subsequent access
faster.

This change makes `Node::scaled_font()` in LibWeb go down from 6% to
1.5% in my profiles because building a font cache key is now a lot
cheaper.
This commit is contained in:
Aliaksandr Kalenik 2023-12-09 09:03:36 +01:00 • committed by Andreas Kling
parent af13bd8af0
commit 7ae229ead7
2 changed files with 49 additions and 28 deletions
Download patch file Download diff file Expand all files Collapse all files

72
Userland/Libraries/LibGfx/Font/OpenType/Font.cpp
View file

@ -495,10 +495,15 @@ u16 Font::units_per_em() const
String Font::family() const
{
auto string = m_name.typographic_family_name();
if (!string.is_empty())
return string;
return m_name.family_name();
if (!m_family.has_value()) {
m_family = [&] {
auto string = m_name.typographic_family_name();
if (!string.is_empty())
return string;
return m_name.family_name();
}();
}
return *m_family;
}
String Font::variant() const
@ -511,40 +516,51 @@ String Font::variant() const
u16 Font::weight() const
{
constexpr u16 bold_bit { 1 };
if (m_os2.has_value() && m_os2->weight_class())
return m_os2->weight_class();
if (m_head.style() & bold_bit)
return 700;
return 400;
if (!m_weight.has_value()) {
m_weight = [&]() -> u16 {
constexpr u16 bold_bit { 1 };
if (m_os2.has_value() && m_os2->weight_class())
return m_os2->weight_class();
if (m_head.style() & bold_bit)
return 700;
return 400;
}();
}
return *m_weight;
}
u16 Font::width() const
{
if (m_os2.has_value()) {
return m_os2->width_class();
if (!m_width.has_value()) {
m_width = [&]() -> u16 {
if (m_os2.has_value())
return m_os2->width_class();
return Gfx::FontWidth::Normal;
}();
}
return Gfx::FontWidth::Normal;
return *m_width;
}
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_slope.has_value()) {
m_slope = [&]() -> u8 {
// 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.has_value() && m_os2->selection() & oblique_selection_bit)
return 2;
if (m_os2.has_value() && m_os2->selection() & italic_selection_bit)
return 1;
if (m_head.style() & italic_style_bit)
return 1;
return 0;
if (m_os2.has_value() && m_os2->selection() & oblique_selection_bit)
return 2;
if (m_os2.has_value() && m_os2->selection() & italic_selection_bit)
return 1;
if (m_head.style() & italic_style_bit)
return 1;
return 0;
}();
}
return *m_slope;
}
bool Font::is_fixed_width() const

5
Userland/Libraries/LibGfx/Font/OpenType/Font.h
View file

@ -138,6 +138,11 @@ private:
mutable HashMap<u32, i16> m_kerning_cache;
Optional<String> mutable m_family;
Optional<u16> mutable m_width;
Optional<u16> mutable m_weight;
Optional<u8> mutable m_slope;
GlyphPage const& glyph_page(size_t page_index) const;
void populate_glyph_page(GlyphPage&, size_t page_index) const;
};