src/common/Font.hpp


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#pragma once

#include <common/defs.hpp>
#include <stb_truetype.h>

#include <memory>


struct AlphaBitmap {
    int32_t w;
    int32_t h;
    std::unique_ptr<uint8_t> pixels;
};


struct Glyph {
    int32_t xoff;
    int32_t yoff;
    int32_t xadvance;
    AlphaBitmap bitmap;
};


class Font {
public:
    ~Font();

    bool Init(const char* path, int font_size);
    AlphaBitmap& GetAlphaBitmap(char32_t c);
    Glyph& GetGlyph(char32_t c);


private:
    bool ReadFile(const char* path);
    void LoadGlyph(Glyph& glyph, char32_t c);


private:
    static constexpr char first_ascii_ch = ' ';
    static constexpr char last_ascii_ch = '~';
    static constexpr char ascii_glyph_count = last_ascii_ch - first_ascii_ch + 1;


    const char* m_file_content = nullptr;

    float m_font_scale;
    int m_font_baseline;
    int m_font_yadvance;

    stbtt_fontinfo m_font_info;
    Glyph m_glyphs[ascii_glyph_count];
    Glyph m_fail_glyph;
};