stb_easy_font.h

// stb_easy_font.h - v1.0 - bitmap font for 3D rendering - public domain
// Sean Barrett, Feb 2015
//
//    Easy-to-deploy,
//    reasonably compact,
//    extremely inefficient performance-wise,
//    crappy-looking,
//    ASCII-only,
//    bitmap font for use in 3D APIs.
//
// Intended for when you just want to get some text displaying
// in a 3D app as quickly as possible.
//
// Doesn't use any textures, instead builds characters out of quads.
//
// DOCUMENTATION:
//
//   int stb_easy_font_width(char *text)
//   int stb_easy_font_height(char *text)
//
//      Takes a string and returns the horizontal size and the
//      vertical size (which can vary if 'text' has newlines).
//
//   int stb_easy_font_print(float x, float y,
//                           char *text, unsigned char color[4],
//                           void *vertex_buffer, int vbuf_size)
//
//      Takes a string (which can contain '\n') and fills out a
//      vertex buffer with renderable data to draw the string.
//      Output data assumes increasing x is rightwards, increasing y
//      is downwards.
//
//      The vertex data is divided into quads, i.e. there are four
//      vertices in the vertex buffer for each quad.
//
//      The vertices are stored in an interleaved format:
//
//         x:float
//         y:float
//         z:float
//         color:uint8[4]
//
//      You can ignore z and color if you get them from elsewhere
//      This format was chosen in the hopes it would make it
//      easier for you to reuse existing vertex-buffer-drawing code.
//
//      If you pass in NULL for color, it becomes 255,255,255,255.
//
//      Returns the number of quads.
//
//      If the buffer isn't large enough, it will truncate.
//      Expect it to use an average of ~270 bytes per character.
//
//      If your API doesn't draw quads, build a reusable index
//      list that allows you to render quads as indexed triangles.
//
//   void stb_easy_font_spacing(float spacing)
//
//      Use positive values to expand the space between characters,
//      and small negative values (no smaller than -1.5) to contract
//      the space between characters. 
//
//      E.g. spacing = 1 adds one "pixel" of spacing between the
//      characters. spacing = -1 is reasonable but feels a bit too
//      compact to me; -0.5 is a reasonable compromise as long as
//      you're scaling the font up.
//
// LICENSE
//
//   See end of file for license information.
//
// VERSION HISTORY
//
//   (2017-01-15)  1.0   space character takes same space as numbers; fix bad spacing of 'f'
//   (2016-01-22)  0.7   width() supports multiline text; add height()
//   (2015-09-13)  0.6   #include <math.h>; updated license
//   (2015-02-01)  0.5   First release
//
// CONTRIBUTORS
//
//   github:vassvik  --  bug report

#if 0
// SAMPLE CODE:
//
//    Here's sample code for old OpenGL; it's a lot more complicated
//    to make work on modern APIs, and that's your problem.
//
void print_string(float x, float y, char *text, float r, float g, float b)
{
  static char buffer[99999]; // ~500 chars
  int num_quads;

  num_quads = stb_easy_font_print(x, y, text, NULL, buffer, sizeof(buffer));

  glColor3f(r,g,b);
  glEnableClientState(GL_VERTEX_ARRAY);
  glVertexPointer(2, GL_FLOAT, 16, buffer);
  glDrawArrays(GL_QUADS, 0, num_quads*4);
  glDisableClientState(GL_VERTEX_ARRAY);
}
#endif

#ifndef INCLUDE_STB_EASY_FONT_H
#define INCLUDE_STB_EASY_FONT_H

#include <stdlib.h>
#include <math.h>

struct stb_easy_font_info_struct {
    unsigned char advance;
    unsigned char h_seg;
    unsigned char v_seg;
} stb_easy_font_charinfo[96] = {
    {  6,  0,  0 },  {  3,  0,  0 },  {  5,  1,  1 },  {  7,  1,  4 },
    {  7,  3,  7 },  {  7,  6, 12 },  {  7,  8, 19 },  {  4, 16, 21 },
    {  4, 17, 22 },  {  4, 19, 23 },  { 23, 21, 24 },  { 23, 22, 31 },
    { 20, 23, 34 },  { 22, 23, 36 },  { 19, 24, 36 },  { 21, 25, 36 },
    {  6, 25, 39 },  {  6, 27, 43 },  {  6, 28, 45 },  {  6, 30, 49 },
    {  6, 33, 53 },  {  6, 34, 57 },  {  6, 40, 58 },  {  6, 46, 59 },
    {  6, 47, 62 },  {  6, 55, 64 },  { 19, 57, 68 },  { 20, 59, 68 },
    { 21, 61, 69 },  { 22, 66, 69 },  { 21, 68, 69 },  {  7, 73, 69 },
    {  9, 75, 74 },  {  6, 78, 81 },  {  6, 80, 85 },  {  6, 83, 90 },
    {  6, 85, 91 },  {  6, 87, 95 },  {  6, 90, 96 },  {  7, 92, 97 },
    {  6, 96,102 },  {  5, 97,106 },  {  6, 99,107 },  {  6,100,110 },
    {  6,100,115 },  {  7,101,116 },  {  6,101,121 },  {  6,101,125 },
    {  6,102,129 },  {  7,103,133 },  {  6,104,140 },  {  6,105,145 },
    {  7,107,149 },  {  6,108,151 },  {  7,109,155 },  {  7,109,160 },
    {  7,109,165 },  {  7,118,167 },  {  6,118,172 },  {  4,120,176 },
    {  6,122,177 },  {  4,122,181 },  { 23,124,182 },  { 22,129,182 },
    {  4,130,182 },  { 22,131,183 },  {  6,133,187 },  { 22,135,191 },
    {  6,137,192 },  { 22,139,196 },  {  6,144,197 },  { 22,147,198 },
    {  6,150,202 },  { 19,151,206 },  { 21,152,207 },  {  6,155,209 },
    {  3,160,210 },  { 23,160,211 },  { 22,164,216 },  { 22,165,220 },
    { 22,167,224 },  { 22,169,228 },  { 21,171,232 },  { 21,173,233 },
    {  5,178,233 },  { 22,179,234 },  { 23,180,238 },  { 23,180,243 },
    { 23,180,248 },  { 22,189,248 },  { 22,191,252 },  {  5,196,252 },
    {  3,203,252 },  {  5,203,253 },  { 22,210,253 },  {  0,214,253 },
};

unsigned char stb_easy_font_hseg[214] = {
   97,37,69,84,28,51,2,18,10,49,98,41,65,25,81,105,33,9,97,1,97,37,37,36,
    81,10,98,107,3,100,3,99,58,51,4,99,58,8,73,81,10,50,98,8,73,81,4,10,50,
    98,8,25,33,65,81,10,50,17,65,97,25,33,25,49,9,65,20,68,1,65,25,49,41,
    11,105,13,101,76,10,50,10,50,98,11,99,10,98,11,50,99,11,50,11,99,8,57,
    58,3,99,99,107,10,10,11,10,99,11,5,100,41,65,57,41,65,9,17,81,97,3,107,
    9,97,1,97,33,25,9,25,41,100,41,26,82,42,98,27,83,42,98,26,51,82,8,41,
    35,8,10,26,82,114,42,1,114,8,9,73,57,81,41,97,18,8,8,25,26,26,82,26,82,
    26,82,41,25,33,82,26,49,73,35,90,17,81,41,65,57,41,65,25,81,90,114,20,
    84,73,57,41,49,25,33,65,81,9,97,1,97,25,33,65,81,57,33,25,41,25,
};

unsigned char stb_easy_font_vseg[253] = {
   4,2,8,10,15,8,15,33,8,15,8,73,82,73,57,41,82,10,82,18,66,10,21,29,1,65,
    27,8,27,9,65,8,10,50,97,74,66,42,10,21,57,41,29,25,14,81,73,57,26,8,8,
    26,66,3,8,8,15,19,21,90,58,26,18,66,18,105,89,28,74,17,8,73,57,26,21,
    8,42,41,42,8,28,22,8,8,30,7,8,8,26,66,21,7,8,8,29,7,7,21,8,8,8,59,7,8,
    8,15,29,8,8,14,7,57,43,10,82,7,7,25,42,25,15,7,25,41,15,21,105,105,29,
    7,57,57,26,21,105,73,97,89,28,97,7,57,58,26,82,18,57,57,74,8,30,6,8,8,
    14,3,58,90,58,11,7,74,43,74,15,2,82,2,42,75,42,10,67,57,41,10,7,2,42,
    74,106,15,2,35,8,8,29,7,8,8,59,35,51,8,8,15,35,30,35,8,8,30,7,8,8,60,
    36,8,45,7,7,36,8,43,8,44,21,8,8,44,35,8,8,43,23,8,8,43,35,8,8,31,21,15,
    20,8,8,28,18,58,89,58,26,21,89,73,89,29,20,8,8,30,7,
};

typedef struct
{
   unsigned char c[4];
} stb_easy_font_color;

static int stb_easy_font_draw_segs(float x, float y, unsigned char *segs, int num_segs, int vertical, stb_easy_font_color c, char *vbuf, int vbuf_size, int offset)
{
    int i,j;
    for (i=0; i < num_segs; ++i) {
        int len = segs[i] & 7;
        x += (float) ((segs[i] >> 3) & 1);
        if (len && offset+64 <= vbuf_size) {
            float y0 = y + (float) (segs[i]>>4);
            for (j=0; j < 4; ++j) {
                * (float *) (vbuf+offset+0) = x  + (j==1 || j==2 ? (vertical ? 1 : len) : 0);
                * (float *) (vbuf+offset+4) = y0 + (    j >= 2   ? (vertical ? len : 1) : 0);
                * (float *) (vbuf+offset+8) = 0.f;
                * (stb_easy_font_color *) (vbuf+offset+12) = c;
                offset += 16;
            }
        }
    }
    return offset;
}

float stb_easy_font_spacing_val = 0;
static void stb_easy_font_spacing(float spacing)
{
   stb_easy_font_spacing_val = spacing;
}

static int stb_easy_font_print(float x, float y, char *text, unsigned char color[4], void *vertex_buffer, int vbuf_size)
{
    char *vbuf = (char *) vertex_buffer;
    float start_x = x;
    int offset = 0;

    stb_easy_font_color c = { 255,255,255,255 }; // use structure copying to avoid needing depending on memcpy()
    if (color) { c.c[0] = color[0]; c.c[1] = color[1]; c.c[2] = color[2]; c.c[3] = color[3]; }

    while (*text && offset < vbuf_size) {
        if (*text == '\n') {
            y += 12;
            x = start_x;
        } else {
            unsigned char advance = stb_easy_font_charinfo[*text-32].advance;
            float y_ch = advance & 16 ? y+1 : y;
            int h_seg, v_seg, num_h, num_v;
            h_seg = stb_easy_font_charinfo[*text-32  ].h_seg;
            v_seg = stb_easy_font_charinfo[*text-32  ].v_seg;
            num_h = stb_easy_font_charinfo[*text-32+1].h_seg - h_seg;
            num_v = stb_easy_font_charinfo[*text-32+1].v_seg - v_seg;
            offset = stb_easy_font_draw_segs(x, y_ch, &stb_easy_font_hseg[h_seg], num_h, 0, c, vbuf, vbuf_size, offset);
            offset = stb_easy_font_draw_segs(x, y_ch, &stb_easy_font_vseg[v_seg], num_v, 1, c, vbuf, vbuf_size, offset);
            x += advance & 15;
            x += stb_easy_font_spacing_val;
        }
        ++text;
    }
    return (unsigned) offset/64;
}

static int stb_easy_font_width(char *text)
{
    float len = 0;
    float max_len = 0;
    while (*text) {
        if (*text == '\n') {
            if (len > max_len) max_len = len;
            len = 0;
        } else {
            len += stb_easy_font_charinfo[*text-32].advance & 15;
            len += stb_easy_font_spacing_val;
        }
        ++text;
    }
    if (len > max_len) max_len = len;
    return (int) ceil(max_len);
}

static int stb_easy_font_height(char *text)
{
    float y = 0;
    int nonempty_line=0;
    while (*text) {
        if (*text == '\n') {
            y += 12;
            nonempty_line = 0;
        } else {
            nonempty_line = 1;
        }
        ++text;
    }
    return (int) ceil(y + (nonempty_line ? 12 : 0));
}
#endif

/*
------------------------------------------------------------------------------
This software is available under 2 licenses -- choose whichever you prefer.
------------------------------------------------------------------------------
ALTERNATIVE A - MIT License
Copyright (c) 2017 Sean Barrett
Permission is hereby granted, free of charge, to any person obtaining a copy of 
this software and associated documentation files (the "Software"), to deal in 
the Software without restriction, including without limitation the rights to 
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
of the Software, and to permit persons to whom the Software is furnished to do 
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all 
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
SOFTWARE.
------------------------------------------------------------------------------
ALTERNATIVE B - Public Domain (www.unlicense.org)
This is free and unencumbered software released into the public domain.
Anyone is free to copy, modify, publish, use, compile, sell, or distribute this 
software, either in source code form or as a compiled binary, for any purpose, 
commercial or non-commercial, and by any means.
In jurisdictions that recognize copyright laws, the author or authors of this 
software dedicate any and all copyright interest in the software to the public 
domain. We make this dedication for the benefit of the public at large and to 
the detriment of our heirs and successors. We intend this dedication to be an 
overt act of relinquishment in perpetuity of all present and future rights to 
this software under copyright law.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
------------------------------------------------------------------------------
*/