text_shaper.hpp

// Copyright Take Vos 2021-2022.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "text_shaper_char.hpp"
#include "text_shaper_line.hpp"
#include "text_cursor.hpp"
#include "text_style.hpp"
#include "../layout/box_constraints.hpp"
#include "../font/module.hpp"
#include "../geometry/module.hpp"
#include "../unicode/unicode_description.hpp"
#include "../unicode/unicode_break_opportunity.hpp"
#include "../unicode/unicode_bidi.hpp"
#include "../unicode/grapheme.hpp"
#include "../unicode/gstring.hpp"
#include <vector>
#include <tuple>
 
namespace hi::inline v1 {
class font_book;
 
class text_shaper {
public:
    using char_vector = std::vector<text_shaper_char>;
    using char_iterator = char_vector::iterator;
    using char_const_iterator = char_vector::const_iterator;
    using char_reference = char_vector::reference;
    using char_const_reference = char_vector::const_reference;
    using line_vector = std::vector<text_shaper_line>;
    using line_iterator = line_vector::iterator;
    using line_const_iterator = line_vector::const_iterator;
 
    constexpr text_shaper() noexcept = default;
    constexpr text_shaper(text_shaper const&) noexcept = default;
    constexpr text_shaper(text_shaper&&) noexcept = default;
    constexpr text_shaper& operator=(text_shaper const&) noexcept = default;
    constexpr text_shaper& operator=(text_shaper&&) noexcept = default;
 
    [[nodiscard]] text_shaper(
        hi::font_book& font_book,
        gstring const& text,
        text_style const& style,
        float dpi_scale,
        hi::alignment alignment,
        unicode_bidi_class text_direction,
        unicode_script script = unicode_script::Common) noexcept;
 
    [[nodiscard]] text_shaper(
        hi::font_book& font_book,
        std::string_view text,
        text_style const& style,
        float dpi_scale,
        hi::alignment alignment,
        unicode_bidi_class text_direction,
        unicode_script script = unicode_script::Common) noexcept;
 
    [[nodiscard]] bool empty() const noexcept
    {
        return _text.empty();
    }
 
    [[nodiscard]] size_t size() const noexcept
    {
        return _text.size();
    }
 
    [[nodiscard]] char_iterator begin() noexcept
    {
        return _text.begin();
    }
 
    [[nodiscard]] char_const_iterator begin() const noexcept
    {
        return _text.begin();
    }
 
    [[nodiscard]] char_const_iterator cbegin() const noexcept
    {
        return _text.cbegin();
    }
 
    [[nodiscard]] char_iterator end() noexcept
    {
        return _text.end();
    }
 
    [[nodiscard]] char_const_iterator end() const noexcept
    {
        return _text.end();
    }
 
    [[nodiscard]] char_const_iterator cend() const noexcept
    {
        return _text.cend();
    }
 
    auto const& lines() const noexcept
    {
        return _lines;
    }
 
    [[nodiscard]] aarectangle
    bounding_rectangle(float maximum_line_width, float line_spacing = 1.0f, float paragraph_spacing = 1.5f) noexcept;
 
    [[nodiscard]] void layout(
        aarectangle rectangle,
        float baseline,
        extent2 sub_pixel_size,
        float line_spacing = 1.0f,
        float paragraph_spacing = 1.5f) noexcept;
 
    [[nodiscard]] aarectangle rectangle() const noexcept
    {
        return _rectangle;
    }
 
    [[nodiscard]] unicode_bidi_class text_direction() const noexcept
    {
        return _text_direction;
    }
 
    [[nodiscard]] alignment resolved_alignment() const noexcept
    {
        return resolve(_alignment, _text_direction == unicode_bidi_class::L);
    }
 
    [[nodiscard]] char_const_iterator get_it(size_t index) const noexcept;
 
    [[nodiscard]] char_const_iterator get_it(text_cursor cursor) const noexcept
    {
        return get_it(cursor.index());
    }
 
    [[nodiscard]] char_const_iterator get_it(size_t column, size_t row) const noexcept;
 
    [[nodiscard]] char_const_iterator get_it(std::pair<size_t, size_t> column_row) const noexcept
    {
        return get_it(column_row.first, column_row.second);
    }
 
    [[nodiscard]] std::pair<size_t, size_t> get_column_line(text_shaper::char_const_iterator it) const noexcept;
 
    [[nodiscard]] std::pair<size_t, size_t> get_column_line(size_t index) const noexcept
    {
        return get_column_line(get_it(index));
    }
 
    [[nodiscard]] std::pair<size_t, size_t> get_column_line(text_cursor cursor) const noexcept
    {
        return get_column_line(cursor.index());
    }
 
    [[nodiscard]] size_t get_index(text_shaper::char_const_iterator it) const noexcept;
 
    [[nodiscard]] text_cursor get_begin_cursor() const noexcept;
 
    [[nodiscard]] text_cursor get_end_cursor() const noexcept;
 
    [[nodiscard]] text_cursor get_before_cursor(size_t index) const noexcept;
 
    [[nodiscard]] text_cursor get_after_cursor(size_t index) const noexcept;
 
    [[nodiscard]] text_cursor get_before_cursor(text_shaper::char_const_iterator it) const noexcept
    {
        return get_before_cursor(get_index(it));
    }
 
    [[nodiscard]] text_cursor get_after_cursor(text_shaper::char_const_iterator it) const noexcept
    {
        return get_after_cursor(get_index(it));
    }
 
    [[nodiscard]] text_cursor get_left_cursor(text_shaper::char_const_iterator it) const noexcept;
 
    [[nodiscard]] text_cursor get_right_cursor(text_shaper::char_const_iterator it) const noexcept;
 
    [[nodiscard]] bool is_on_left(text_cursor cursor) const noexcept;
 
    [[nodiscard]] bool is_on_right(text_cursor cursor) const noexcept;
 
    [[nodiscard]] text_cursor get_nearest_cursor(point2 point) const noexcept;
 
    [[nodiscard]] std::pair<text_cursor, text_cursor> select_char(text_cursor cursor) const noexcept;
 
    [[nodiscard]] std::pair<text_cursor, text_cursor> select_word(text_cursor cursor) const noexcept;
 
    [[nodiscard]] std::pair<text_cursor, text_cursor> select_sentence(text_cursor cursor) const noexcept;
 
    [[nodiscard]] std::pair<text_cursor, text_cursor> select_paragraph(text_cursor cursor) const noexcept;
 
    [[nodiscard]] std::pair<text_cursor, text_cursor> select_document(text_cursor cursor) const noexcept;
 
    [[nodiscard]] char_const_iterator move_left_char(char_const_iterator it) const noexcept;
 
    [[nodiscard]] char_const_iterator move_right_char(char_const_iterator it) const noexcept;
 
    [[nodiscard]] text_cursor move_left_char(text_cursor cursor, bool overwrite_mode) const noexcept;
    [[nodiscard]] text_cursor move_right_char(text_cursor cursor, bool overwrite_mode) const noexcept;
    [[nodiscard]] text_cursor move_down_char(text_cursor cursor, float& x) const noexcept;
    [[nodiscard]] text_cursor move_up_char(text_cursor cursor, float& x) const noexcept;
    [[nodiscard]] text_cursor move_left_word(text_cursor cursor, bool overwrite_mode) const noexcept;
    [[nodiscard]] text_cursor move_right_word(text_cursor cursor, bool overwrite_mode) const noexcept;
    [[nodiscard]] text_cursor move_begin_line(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_end_line(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_begin_sentence(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_end_sentence(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_begin_paragraph(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_end_paragraph(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_begin_document(text_cursor cursor) const noexcept;
    [[nodiscard]] text_cursor move_end_document(text_cursor cursor) const noexcept;
 
private:
    font_book *_font_book = nullptr;
 
    float _dpi_scale;
 
    char_vector _text;
 
    hi::alignment _alignment;
 
    unicode_break_vector _line_break_opportunities;
 
    std::vector<float> _line_break_widths;
 
    unicode_break_vector _word_break_opportunities;
 
    unicode_break_vector _sentence_break_opportunities;
 
    unicode_bidi_context _bidi_context;
 
    unicode_bidi_class _text_direction;
 
    unicode_script _script;
 
    line_vector _lines;
 
    font_metrics _initial_line_metrics;
 
    aarectangle _rectangle;
 
    [[nodiscard]] line_vector make_lines(
        aarectangle rectangle,
        float baseline,
        extent2 sub_pixel_size,
        float line_spacing,
        float paragraph_spacing) noexcept;
 
    void position_glyphs(aarectangle rectangle, extent2 sub_pixel_size) noexcept;
 
    void resolve_script() noexcept;
 
    [[nodiscard]] std::pair<text_cursor, text_cursor>
    get_selection_from_break(text_cursor cursor, unicode_break_vector const& break_opportunities) const noexcept;
 
    [[nodiscard]] std::pair<font_metrics, unicode_general_category>
    get_line_metrics(text_shaper::char_const_iterator first, text_shaper::char_const_iterator last) const noexcept;
 
    [[nodiscard]] float get_text_height(std::vector<size_t> const& lines) const noexcept;
};
 
} // namespace hi::inline v1