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/*
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Utf32View.h>
#include <AK/Vector.h>
namespace Gfx {
enum class BidirectionalClass {
STRONG_LTR,
STRONG_RTL,
WEAK_NUMBERS,
WEAK_SEPARATORS,
NEUTRAL,
};
extern const Array<BidirectionalClass, 0x1F000> char_bidi_class_lookup_table;
constexpr BidirectionalClass get_char_bidi_class(u32 ch)
{
if (ch >= char_bidi_class_lookup_table.size())
return BidirectionalClass::STRONG_LTR;
return char_bidi_class_lookup_table[ch];
}
// FIXME: These should be parsed from the official BidiMirroring.txt that specifies the mirroring character for each character (this function doesn't take into account a large amount of characters)
constexpr u32 get_mirror_char(u32 ch)
{
if (ch == 0x28)
return 0x29;
if (ch == 0x29)
return 0x28;
if (ch == 0x3C)
return 0x3E;
if (ch == 0x3E)
return 0x3C;
if (ch == 0x5B)
return 0x5D;
if (ch == 0x7B)
return 0x7D;
if (ch == 0x7D)
return 0x7B;
if (ch == 0xAB)
return 0xBB;
if (ch == 0xBB)
return 0xAB;
if (ch == 0x2039)
return 0x203A;
if (ch == 0x203A)
return 0x2039;
return ch;
}
enum class TextDirection {
LTR,
RTL,
};
constexpr TextDirection bidi_class_to_direction(BidirectionalClass class_)
{
VERIFY(class_ != BidirectionalClass::NEUTRAL);
if (class_ == BidirectionalClass::STRONG_LTR || class_ == BidirectionalClass::WEAK_NUMBERS || class_ == BidirectionalClass::WEAK_SEPARATORS)
return TextDirection::LTR;
return TextDirection::RTL;
}
// Assumes the text has a homogeneous direction
template<typename TextType>
constexpr TextDirection get_text_direction(TextType text)
{
for (u32 code_point : text) {
auto char_direction = get_char_bidi_class(code_point);
if (char_direction != BidirectionalClass::NEUTRAL)
return bidi_class_to_direction(char_direction);
}
return TextDirection::LTR;
}
class DirectionalRun {
public:
DirectionalRun(Vector<u32> code_points, u8 embedding_level)
: m_code_points(move(code_points))
, m_embedding_level(embedding_level)
{
}
[[nodiscard]] Utf32View text() const { return { m_code_points.data(), m_code_points.size() }; }
[[nodiscard]] u8 embedding_level() const { return m_embedding_level; }
[[nodiscard]] TextDirection direction() const { return (m_embedding_level % 2) == 0 ? TextDirection::LTR : TextDirection::RTL; }
Vector<u32>& code_points() { return m_code_points; }
private:
Vector<u32> m_code_points;
u8 m_embedding_level;
};
}
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