source: git/src/glbitmapfont.h

//
//  glbitmapfont.h
//
//  Draw text using glBitmap.
//
//  Copyright (C) 2011-2022 Olly Betts
//
//  This program 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.
//
//  This program 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 this program; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//

#ifndef GLBITMAPFONT_H_INCLUDED
#define GLBITMAPFONT_H_INCLUDED

#include "wx.h"

#ifdef HAVE_GL_GL_H
# include <GL/gl.h>
#elif defined HAVE_OPENGL_GL_H
# include <OpenGL/gl.h>
#endif

class BitmapFont {
    enum {
        // The highest character point to generate an OpenGL list for.
        //
        // We can't generate a GL list for every Unicode character, so we
        // generate them for the first BITMAPFONT_MAX_CHAR characters and then
        // use glBitmap directly to draw other characters if they are needed.
        //
        // FIXME: We could perhaps even store strings consisting of only the
        // first 256 points as ISO8859-1.
        BITMAPFONT_MAX_CHAR = 256
    };

    int gllist_base;

    mutable const unsigned char * extra_data;

    mutable int * extra_chars;

    unsigned char char_width[BITMAPFONT_MAX_CHAR];

    void init_extra_chars() const;

    int glyph_width(wxChar ch) const;

    void write_glyph(wxChar ch) const;

    wxString font_file;

    int font_size;

  public:

    BitmapFont() : gllist_base(0), extra_data(0), extra_chars(0) { }

    ~BitmapFont();

    bool load(const wxString & font_file, bool double_size);

    int get_font_size() const { return font_size; }

    void get_text_extent(const wxChar *s, size_t len, int *width, int *height) const {
        if (width) {
            int total_width = 0;
            while (len--) {
                int ch = *s++;
                if (ch < BITMAPFONT_MAX_CHAR)
                    total_width += char_width[ch];
                else
                    total_width += glyph_width(ch);
            }
            *width = total_width;
        }
        if (height) {
            *height = get_font_size() + 1;
        }
    }

    void write_string(const wxChar *s, size_t len) const;
};

#endif