ex.c

#include <stdio.h>
#include <SDL/SDL.h>
#include "psf.h"

struct psf_font font;

SDL_Surface *screen,*glyph[512];

/****************************************************************************************/
//This function creates a SDL_Surface in the same format as the screen
SDL_Surface *CreateSurface(Uint32 flags,int width,int height,const SDL_Surface* display)
{
  const SDL_PixelFormat fmt = *(display->format);
  return SDL_CreateRGBSurface(flags,width,height,fmt.BitsPerPixel,fmt.Rmask,fmt.Gmask,fmt.Bmask,fmt.Amask);
}

/****************************************************************************************/
//This function displays one character at a specific location
void DisplayChar(unsigned char c,int x,int y)
{
  SDL_Rect dest,src;
  src.x=0;
  src.y=0;
  src.w=screen->w;
  src.h=screen->h;

  dest.x=x;
  dest.y=y;
  dest.w=glyph[c]->w;
  dest.h=glyph[c]->h;

  //All we have to do is blit the glyph to the screen
  SDL_BlitSurface(glyph[c],&src,screen,&dest);
}

/****************************************************************************************/
//This function displays one entire string at a specific location
void DisplayStr(char *str,int x,int y)
{
  int i=0,cursorx=0,cursory=0;

  for (i=0;str[i]!='\0';i++)
  {
    if (str[i]==0x0D)
    {
      cursory++;
      cursorx=0;
    }
    else
      DisplayChar(str[i],x+(psf_get_glyph_width(&font)*cursorx++),y+(psf_get_glyph_height(&font)*cursory));
  }

  return;
}

/****************************************************************************************/
//Entry point
int main(int argc, char **argv)
{
  //First, we must choose a font and open it.
  if (argc==1)
    psf_open_font(&font,"font.psf"); //Use ./font.psf if no font is specified
  else
    psf_open_font(&font,argv[1]); //Allow the user to choose a font

  //Once the font is open, we have to first read the font's header
  //This will allow us to get information about the font
  //which is required for rendering (and reading)
  psf_read_header(&font);

  //Setup SDL and create a window where we can display the characters
  SDL_Init(SDL_INIT_EVERYTHING);
  screen=SDL_SetVideoMode(320,240,32,SDL_DOUBLEBUF);
  //Unicode allows us to display exactly which character the user types
  SDL_EnableUNICODE(1);

  //psf_get_glyph_total tells us how many glyphs are in the font
  int i;
  for (i=0;i<psf_get_glyph_total(&font);i++)
  {
    //Create a surface of exactly the right size for each glyph
    glyph[i]=CreateSurface(0,psf_get_glyph_width(&font),psf_get_glyph_height(&font),screen);

    //Read the glyph directly into the surface's memory
    psf_read_glyph(&font,glyph[i]->pixels,4,0x00000000,0xFFFFFFFF);
  }

  //After reading all the glyphs, close the font
  //We already have all the glyphs stored in memory
  psf_close_font(&font);

  //If the program should end
  int quit = 0;

  //Buffer for characters to be rendered
  char buf[512];

  //Where in the string to add new characters
  int pos=0;

  //Standard SDL event loop
  SDL_Event event;
  while (!quit)
  {
    while(SDL_PollEvent(&event))
    {
      if (event.type == SDL_QUIT)
      {
        quit = 1;
      }

      if (event.type == SDL_KEYDOWN)
      {
                            switch(event.key.keysym.sym) {
                            case SDLK_ESCAPE:
                                quit = 1;
                                break;
                            default:
                                if (event.key.keysym.unicode)                  
        {
          //Add the user's character to the string
          buf[pos++]=event.key.keysym.unicode;
          buf[pos]='\0';  //Make sure it's null terminated
        }
                            }
      }
    }

    //Clear the screen (the sloppy way)
    SDL_FillRect(screen,NULL,SDL_MapRGB(screen->format,0xFF,0xFF,0xFF));

    //Display the string
    DisplayStr(buf,50,50);

    SDL_Flip(screen); //Display everything
    usleep(100000); //Don't hog all the CPU
  }

  SDL_Quit();
}