Font.h

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/* Copyright (C) 2022 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_FONT
#define INCLUDED_FONT

#include "graphics/Texture.h"

/**
 * Storage for a bitmap font. Loaded by CFontManager.
 */
class CFont
{
public:
    struct GlyphData
    {
        float u0, v0, u1, v1;
        i16 x0, y0, x1, y1;
        i16 xadvance;
        u8 defined;
    };

    /**
     * Relatively efficient lookup of GlyphData from 16-bit Unicode codepoint.
     * This is stored as a sparse 2D array, exploiting the knowledge that a font
     * typically only supports a small number of 256-codepoint blocks, so most
     * elements of m_Data will be NULL.
     */
    class GlyphMap
    {
        NONCOPYABLE(GlyphMap);
    public:
        GlyphMap();
        ~GlyphMap();
        void set(u16 i, const GlyphData& val);

        const GlyphData* get(u16 i) const
        {
            if (!m_Data[i >> 8])
                return NULL;
            if (!m_Data[i >> 8][i & 0xff].defined)
                return NULL;
            return &m_Data[i >> 8][i & 0xff];
        }

    private:
        GlyphData* m_Data[256];
    };

    bool HasRGB() const { return m_HasRGB; }
    int GetLineSpacing() const { return m_LineSpacing; }
    int GetHeight() const { return m_Height; }
    int GetCharacterWidth(wchar_t c) const;
    void CalculateStringSize(const wchar_t* string, int& w, int& h) const;
    void GetGlyphBounds(float& x0, float& y0, float& x1, float& y1) const
    {
        x0 = m_BoundsX0;
        y0 = m_BoundsY0;
        x1 = m_BoundsX1;
        y1 = m_BoundsY1;
    }
    const GlyphMap& GetGlyphs() const { return m_Glyphs; }
    CTexturePtr GetTexture() const { return m_Texture; }

private:
    friend class CFontManager;

    CFont() = default;

    CTexturePtr m_Texture;

    bool m_HasRGB; // true if RGBA, false if ALPHA

    GlyphMap m_Glyphs;

    int m_LineSpacing;
    int m_Height; // height of a capital letter, roughly

    // Bounding box of all glyphs
    float m_BoundsX0;
    float m_BoundsY0;
    float m_BoundsX1;
    float m_BoundsY1;
};

#endif // INCLUDED_FONT