LibGfx: Use LibUnicode to filter code points that cannot start an emoji

This commit is contained in:
Timothy Flynn 2023-02-23 08:53:35 -05:00 committed by Linus Groh
parent 392c8c99aa
commit 8be43cd3bf
2 changed files with 7 additions and 37 deletions

View file

@ -51,35 +51,10 @@ Bitmap const* Emoji::emoji_for_code_points(ReadonlySpan<u32> const& code_points)
return bitmap.ptr();
}
template<typename CodePointIterator>
static bool could_be_emoji(CodePointIterator const& it)
{
if (it.done())
return false;
static constexpr u32 supplementary_private_use_area_b_first_code_point = 0x100000;
if (*it >= supplementary_private_use_area_b_first_code_point) {
// We use Supplementary Private Use Area-B for custom Serenity emoji.
return true;
}
static auto const emoji_property = Unicode::property_from_string("Emoji"sv);
if (!emoji_property.has_value()) {
// This means Unicode data generation is disabled. Always check the disk in that case.
return true;
}
return Unicode::code_point_has_property(*it, *emoji_property);
}
template<typename CodePointIterator>
static Bitmap const* emoji_for_code_point_iterator_impl(CodePointIterator& it)
{
// NOTE: I'm sure this could be more efficient, e.g. by checking if each code point falls
// into a certain range in the loop below (emojis, modifiers, variation selectors, ZWJ),
// and bailing out early if not. Current worst case is 10 file lookups for any sequence of
// code points (if the first glyph isn't part of the font in regular text rendering).
if (!could_be_emoji(it))
if (!Unicode::could_be_start_of_emoji_sequence(it))
return nullptr;
constexpr size_t max_emoji_code_point_sequence_length = 10;

View file

@ -34,6 +34,7 @@
#include <LibGfx/TextDirection.h>
#include <LibGfx/TextLayout.h>
#include <LibUnicode/CharacterTypes.h>
#include <LibUnicode/Emoji.h>
#include <stdio.h>
#if defined(AK_COMPILER_GCC)
@ -1396,13 +1397,14 @@ void Painter::draw_glyph_or_emoji(FloatPoint point, u32 code_point, Font const&
void Painter::draw_glyph_or_emoji(FloatPoint point, Utf8CodePointIterator& it, Font const& font, Color color)
{
static auto const emoji_component_property = Unicode::property_from_string("Emoji_Component"sv);
static auto const variation_selector = Unicode::property_from_string("Variation_Selector"sv);
u32 code_point = *it;
auto next_code_point = it.peek(1);
ScopeGuard consume_variation_selector = [&, initial_it = it] {
static auto const variation_selector = Unicode::property_from_string("Variation_Selector"sv);
if (!variation_selector.has_value())
return;
// If we advanced the iterator to consume an emoji sequence, don't look for another variation selector.
if (initial_it != it)
return;
@ -1413,14 +1415,7 @@ void Painter::draw_glyph_or_emoji(FloatPoint point, Utf8CodePointIterator& it, F
};
auto font_contains_glyph = font.contains_glyph(code_point);
auto check_for_emoji = false;
if (emoji_component_property.has_value()) {
auto code_point_is_emoji_component = Unicode::code_point_has_property(code_point, *emoji_component_property);
auto next_code_point_is_emoji_component = next_code_point.has_value() && Unicode::code_point_has_property(*next_code_point, *emoji_component_property);
check_for_emoji = code_point_is_emoji_component || next_code_point_is_emoji_component;
}
auto check_for_emoji = Unicode::could_be_start_of_emoji_sequence(it);
// If the font contains the glyph, and we know it's not the start of an emoji, draw a text glyph.
if (font_contains_glyph && !check_for_emoji) {