sdl/font.cpp

   1 // DGen/SDL v1.14+
   2 // by Joe Groff
   3 // How's my programming? E-mail <joe@pknet.com>
   4
   5 /* DGen's font renderer.
   6  * I hope it's pretty well detached from the DGen core, so you can use it in
   7  * any other SDL app you like. */
   8
   9 /* Also note that these font renderers do no error detection, and absolutely
  10  * NO clipping whatsoever, so try to keep the glyphs on-screen. Thank you :-)
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <SDL.h>
  17
  18 #include "font.h"       /* The interface functions */
  19
  20 extern int *dgen_font[];
  21
  22 // Support function
  23 // Put a glyph at the specified coordinates
  24 // THIS IS REALLY A MACRO - SDL_LockSurface should have been called already if
  25 // necessary
  26 static inline void _putglyph(char *p, int Bpp, int pitch, char which)
  27 {
  28   int *glyph = dgen_font[which];
  29   int x = 0, i;
  30
  31   for(; *glyph != -1; ++glyph)
  32     {
  33       p += (((x += *glyph) >> 3) * pitch); x &= 7;
  34       for(i = 0; i < Bpp; ++i) p[(x * Bpp) + i] = 0xff;
  35     }
  36 }
  37
  38 // This writes a string of text at the given x and y coordinates
  39 void font_text(SDL_Surface *surf, int x, int y, const char *message)
  40 {
  41   int pitch = surf->pitch, Bpp = surf->format->BytesPerPixel;
  42   char *p = (char*)surf->pixels + (pitch * y) + (Bpp * x);
  43
  44   if(SDL_MUSTLOCK(surf))
  45     if(SDL_LockSurface(surf) < 0)
  46       {
  47         fprintf(stderr, "font: Couldn't lock screen: %s!", SDL_GetError());
  48         return;
  49       }
  50   for(; *message; p += (8 * Bpp), ++message)
  51     _putglyph(p, Bpp, pitch, *message);
  52   if(SDL_MUSTLOCK(surf)) SDL_UnlockSurface(surf);
  53 }
  54
  55 // This writes a string of text of fixed length n
  56 void font_text_n(SDL_Surface *surf, int x, int y, const char *message, int n)
  57 {
  58   int pitch = surf->pitch, Bpp = surf->format->BytesPerPixel;
  59   char *p = (char*)surf->pixels + (pitch * y) + (Bpp * x);
  60
  61   if(SDL_MUSTLOCK(surf))
  62     if(SDL_LockSurface(surf) < 0)
  63       {
  64         fprintf(stderr, "font: Couldn't lock screen: %s!", SDL_GetError());
  65         return;
  66       }
  67   for(; n > 0; p += (8 * Bpp), ++message, --n)
  68     _putglyph(p, Bpp, pitch, *message);
  69   if(SDL_MUSTLOCK(surf)) SDL_UnlockSurface(surf);
  70 }
  71