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Simple truetype font library for SDL2
wboe


Joined: 09 Jan 2012
Posts: 41
Location: Amsterdam, Netherlands
Post Posted: Mon Oct 15, 2012 8:35 am
Hi,

SDL uses the SDL_ttf library for font rendering. The engine of this lib is the freetype lib, which is fine until you have to cross-compile for Android. This freetype lib consists of a huge number of C files, that must be compiled apart from the Android NDK environment because no Android.mk files are provided.

There is an alternative. A clever guy called Sean Barrett has written a parser and renderer for truetype fonts. It consists of one file (http://nothings.org/stb/stb_truetype.h), containing everything you need: a manual, examples, header file and C code.

From the examples I created a small demo program, listed hereunder.
If you call it test-stbtt.c it can be compiled as follows:
gcc test-stbtt.c -o test-stbtt $(sdl2-config --cflags) $(sdl2-config --libs) -lm

It can be run with 0, 1, 2 or 3 options, and will display a black text in a white window. Notice that there is a hard-coded path to a ttf spec file, modify this as needed.

I did'nt use all provided refinements in this demo program. Notice that the SDL.h file is included after the stb_truetype.h, that's because some big- and small endian magic occurs, which might get disturbed by #define statements in SDL.h. The characters that are displayed are not cached, so a big speed-up would still be possible.

wboe

Code:
#define STB_TRUETYPE_IMPLEMENTATION
#include "stb_truetype.h"

#include <SDL.h>

int main(int argc, char **argv) {
   if (SDL_Init(SDL_INIT_VIDEO) < 0) { printf("Init problem: %s\n",SDL_GetError()); exit(1); }
   SDL_Window *window = SDL_CreateWindow("test-stbtt", 100,100,200,100, SDL_WINDOW_SHOWN);
   if (!window) { printf("%s\n",SDL_GetError()); SDL_Quit(); }
   SDL_Renderer *renderer=SDL_CreateRenderer(window, -1,SDL_RENDERER_ACCELERATED);
   SDL_SetRenderDrawColor(renderer,0xff,0xff,0xff,0xff);
   SDL_RenderClear(renderer);
   SDL_RenderPresent(renderer);
   SDL_SetRenderDrawBlendMode(renderer,SDL_BLENDMODE_BLEND);

   stbtt_fontinfo font;
   unsigned char *bitmap=0;
   const char *text=(argc > 1 ? argv[1] : "Hallo!");
   int s = (argc > 2 ? atoi(argv[2]) : 20);

   FILE *ff=fopen(argc > 3 ? argv[3] : "/usr/share/fonts/google-droid/DroidSans.ttf","rb");
   if (!ff) { puts("font file not found"); exit(1); }
   fseek(ff,0,SEEK_END);
   int fsize=ftell(ff);
   rewind(ff);
   char ttf_buffer[fsize];
   fread(ttf_buffer, 1,fsize,ff);

   stbtt_InitFont(&font, ttf_buffer, stbtt_GetFontOffsetForIndex(ttf_buffer,0));
   float scale=stbtt_ScaleForPixelHeight(&font, s);
   int ascent,
       descent;
   stbtt_GetFontVMetrics(&font,&ascent,&descent,0);

   int ind,
       advance,
       x0,y0,
       h,w,
       xpos=10,
       ypos=10+scale*ascent;
   printf("ascent=%d descent=%d linedist=%d\n",(int)(scale*ascent),(int)(scale*descent),(int)(scale * (ascent-descent)));
   for (ind=0;text[ind];++ind) {
      bitmap = stbtt_GetCodepointBitmap(&font, 0,stbtt_ScaleForPixelHeight(&font, s), text[ind], &w, &h, 0,0);
      stbtt_GetCodepointHMetrics(&font, text[ind], &advance, 0);
      stbtt_GetCodepointBitmapBox(&font, text[ind], scale, scale, &x0, &y0, 0, 0);

      int i,j,
          x=xpos,
          y=ypos;
      for (j=0; j < h; ++j) {
         for (i=0; i < w; ++i) {
            if (bitmap[j*w+i]) {
              SDL_SetRenderDrawColor(renderer,0,0,0,bitmap[j*w+i]);
              SDL_RenderDrawPoint(renderer,x+x0,y+y0);
            }
            ++x;
         }
         x=xpos;
         ++y;
      }
      stbtt_FreeBitmap(bitmap,0);
      if (!text[ind+1]) break;
      xpos += scale*advance;
   }
   SDL_RenderPresent(renderer);
   SDL_Event event;
   while (1)
     while(SDL_PollEvent(&event))
       if (event.type==SDL_QUIT) { SDL_Quit(); exit(0); }
   return 0;
}
Simple truetype font library for SDL2
MrOzBarry


Joined: 26 Jun 2010
Posts: 620
Post Posted: Mon Oct 15, 2012 1:11 pm
Because of the open nature of the license, what I'd recommend (and this is something that I may do myself anyway) is to add some code to support SDL_RWops, and write an official SDL port of the library.  Once that's done, the community will have a chance to see it in action with SDL.  I don't think this needs to be a replacement for SDL_ttf, either - if it works, it's just another option.

The more I read through the code, the more I get this impression that I've looked at this before, and maybe it was on this mailing list a few years ago?  Anyway, good find, and nice example of it alongside SDL Smile

-Alex

On Mon, Oct 15, 2012 at 4:35 AM, wboe wrote:
Quote:
Hi,

SDL uses the SDL_ttf library for font rendering. The engine of this lib is the freetype lib, which is fine until you have to cross-compile for Android. This freetype lib consists of a huge number of C files, that must be compiled apart from the Android NDK environment because no Android.mk files are provided.

There is an alternative. A clever guy called Sean Barrett has written a parser and renderer for truetype fonts. It consists of one file (http://nothings.org/stb/stb_truetype.h), containing everything you need: a manual, examples, header file and C code.

From the examples I created a small demo program, listed hereunder.
If you call it test-stbtt.c it can be compiled as follows:
gcc test-stbtt.c -o test-stbtt $(sdl2-config --cflags) $(sdl2-config --libs) -lm

It can be run with 0, 1, 2 or 3 options, and will display a black text in a white window. Notice that there is a hard-coded path to a ttf spec file, modify this as needed.

I did'nt use all provided refinements in this demo program. Notice that the SDL.h file is included after the stb_truetype.h, that's because some big- and small endian magic occurs, which might get disturbed by #define statements in SDL.h. The characters that are displayed are not cached, so a big speed-up would still be possible.

wboe




Code:

#define STB_TRUETYPE_IMPLEMENTATION
#include "stb_truetype.h"

#include

int main(int argc, char **argv) {
   if (SDL_Init(SDL_INIT_VIDEO) < 0) { printf("Init problem: %s\n",SDL_GetError()); exit(1); }
   SDL_Window *window = SDL_CreateWindow("test-stbtt", 100,100,200,100, SDL_WINDOW_SHOWN);
   if (!window) { printf("%s\n",SDL_GetError()); SDL_Quit(); }
   SDL_Renderer *renderer=SDL_CreateRenderer(window, -1,SDL_RENDERER_ACCELERATED);
   SDL_SetRenderDrawColor(renderer,0xff,0xff,0xff,0xff);
   SDL_RenderClear(renderer);
   SDL_RenderPresent(renderer);
   SDL_SetRenderDrawBlendMode(renderer,SDL_BLENDMODE_BLEND);

   stbtt_fontinfo font;
   unsigned char *bitmap=0;
   const char *text=(argc > 1 ? argv[1] : "Hallo!");
   int s = (argc > 2 ? atoi(argv[2]) : 20);

   FILE *ff=fopen(argc > 3 ? argv[3] : "/usr/share/fonts/google-droid/DroidSans.ttf","rb");
   if (!ff) { puts("font file not found"); exit(1); }
   fseek(ff,0,SEEK_END);
   int fsize=ftell(ff);
   rewind(ff);
   char ttf_buffer[fsize];
   fread(ttf_buffer, 1,fsize,ff);

   stbtt_InitFont(&font, ttf_buffer, stbtt_GetFontOffsetForIndex(ttf_buffer,0));
   float scale=stbtt_ScaleForPixelHeight(&font, s);
   int ascent,
       descent;
   stbtt_GetFontVMetrics(&font,&ascent,&descent,0);

   int ind,
       advance,
       x0,y0,
       h,w,
       xpos=10,
       ypos=10+scale*ascent;
   printf("ascent=%d descent=%d linedist=%d\n",(int)(scale*ascent),(int)(scale*descent),(int)(scale * (ascent-descent)));
   for (ind=0;text[ind];++ind) {
      bitmap = stbtt_GetCodepointBitmap(&font, 0,stbtt_ScaleForPixelHeight(&font, s), text[ind], &w, &h, 0,0);
      stbtt_GetCodepointHMetrics(&font, text[ind], &advance, 0);
      stbtt_GetCodepointBitmapBoxSubpixel(&font, text[ind], scale,scale,0,0, &x0,&y0,0,0);

      int i,j,
          x=xpos,
          y=ypos;
      for (j=0; j < h; ++j) {
         for (i=0; i < w; ++i) {
            if (bitmap[j*w+i]) {
              SDL_SetRenderDrawColor(renderer,0,0,0,bitmap[j*w+i]);
              SDL_RenderDrawPoint(renderer,x+x0,y+y0);
            }
            ++x;
         }
         x=xpos;
         ++y;
      }
      stbtt_FreeBitmap(bitmap,0);
      if (!text[ind+1]) break;
      xpos += scale*advance;
   }
   SDL_RenderPresent(renderer);
   SDL_Event event;
   while (1)
     while(SDL_PollEvent(&event))
       if (event.type==SDL_QUIT) { SDL_Quit(); exit(0); }
   return 0;
}






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Simple truetype font library for SDL2
wahono


Joined: 18 Aug 2012
Posts: 37
Post Posted: Mon Oct 15, 2012 7:24 pm
SFML has internal font rendering, if this truetype rendering added in SDL, I think it would very usefull, we don't need freetype again, especially for iOS and Android.

regards
Simple truetype font library for SDL2
Vittorio Giovara
Guest
Post Posted: Tue Oct 16, 2012 1:03 am
Afaik there is no problem in compiling Freetype for Android.
You can find the Android.mk we use every day here: https://code.google.com/p/hedgewars/source/browse/#hg%2Fmisc%2Flibfreetype

Vittorio

On Mon, Oct 15, 2012 at 10:35 AM, wboe wrote:
Quote:
Hi,

SDL uses the SDL_ttf library for font rendering. The engine of this lib is the freetype lib, which is fine until you have to cross-compile for Android. This freetype lib consists of a huge number of C files, that must be compiled apart from the Android NDK environment because no Android.mk files are provided.

There is an alternative. A clever guy called Sean Barrett has written a parser and renderer for truetype fonts. It consists of one file (http://nothings.org/stb/stb_truetype.h), containing everything you need: a manual, examples, header file and C code.

From the examples I created a small demo program, listed hereunder.
If you call it test-stbtt.c it can be compiled as follows:
gcc test-stbtt.c -o test-stbtt $(sdl2-config --cflags) $(sdl2-config --libs) -lm

It can be run with 0, 1, 2 or 3 options, and will display a black text in a white window. Notice that there is a hard-coded path to a ttf spec file, modify this as needed.

I did'nt use all provided refinements in this demo program. Notice that the SDL.h file is included after the stb_truetype.h, that's because some big- and small endian magic occurs, which might get disturbed by #define statements in SDL.h. The characters that are displayed are not cached, so a big speed-up would still be possible.

wboe




Code:

#define STB_TRUETYPE_IMPLEMENTATION
#include "stb_truetype.h"

#include

int main(int argc, char **argv) {
   if (SDL_Init(SDL_INIT_VIDEO) < 0) { printf("Init problem: %s\n",SDL_GetError()); exit(1); }
   SDL_Window *window = SDL_CreateWindow("test-stbtt", 100,100,200,100, SDL_WINDOW_SHOWN);
   if (!window) { printf("%s\n",SDL_GetError()); SDL_Quit(); }
   SDL_Renderer *renderer=SDL_CreateRenderer(window, -1,SDL_RENDERER_ACCELERATED);
   SDL_SetRenderDrawColor(renderer,0xff,0xff,0xff,0xff);
   SDL_RenderClear(renderer);
   SDL_RenderPresent(renderer);
   SDL_SetRenderDrawBlendMode(renderer,SDL_BLENDMODE_BLEND);

   stbtt_fontinfo font;
   unsigned char *bitmap=0;
   const char *text=(argc > 1 ? argv[1] : "Hallo!");
   int s = (argc > 2 ? atoi(argv[2]) : 20);

   FILE *ff=fopen(argc > 3 ? argv[3] : "/usr/share/fonts/google-droid/DroidSans.ttf","rb");
   if (!ff) { puts("font file not found"); exit(1); }
   fseek(ff,0,SEEK_END);
   int fsize=ftell(ff);
   rewind(ff);
   char ttf_buffer[fsize];
   fread(ttf_buffer, 1,fsize,ff);

   stbtt_InitFont(&font, ttf_buffer, stbtt_GetFontOffsetForIndex(ttf_buffer,0));
   float scale=stbtt_ScaleForPixelHeight(&font, s);
   int ascent,
       descent;
   stbtt_GetFontVMetrics(&font,&ascent,&descent,0);

   int ind,
       advance,
       x0,y0,
       h,w,
       xpos=10,
       ypos=10+scale*ascent;
   printf("ascent=%d descent=%d linedist=%d\n",(int)(scale*ascent),(int)(scale*descent),(int)(scale * (ascent-descent)));
   for (ind=0;text[ind];++ind) {
      bitmap = stbtt_GetCodepointBitmap(&font, 0,stbtt_ScaleForPixelHeight(&font, s), text[ind], &w, &h, 0,0);
      stbtt_GetCodepointHMetrics(&font, text[ind], &advance, 0);
      stbtt_GetCodepointBitmapBoxSubpixel(&font, text[ind], scale,scale,0,0, &x0,&y0,0,0);

      int i,j,
          x=xpos,
          y=ypos;
      for (j=0; j < h; ++j) {
         for (i=0; i < w; ++i) {
            if (bitmap[j*w+i]) {
              SDL_SetRenderDrawColor(renderer,0,0,0,bitmap[j*w+i]);
              SDL_RenderDrawPoint(renderer,x+x0,y+y0);
            }
            ++x;
         }
         x=xpos;
         ++y;
      }
      stbtt_FreeBitmap(bitmap,0);
      if (!text[ind+1]) break;
      xpos += scale*advance;
   }
   SDL_RenderPresent(renderer);
   SDL_Event event;
   while (1)
     while(SDL_PollEvent(&event))
       if (event.type==SDL_QUIT) { SDL_Quit(); exit(0); }
   return 0;
}






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