hrclock.cpp

   1 /* high resolution clock display
   2  * Copyright (C) 2010  Kirill Smelkov <kirr@navytux.spb.ru>
   3  *
   4  * This library is free software: you can Use, Study, Modify and Redistribute
   5  * it under the terms of the GNU Lesser General Public License version 2.1, or
   6  * any later version. This library is distributed WITHOUT ANY WARRANTY. See
   7  * COPYING.LIB file for full License terms.
   8  */
   9
  10 #include <SDL.h>
  11 #include <SDL_ttf.h>
  12
  13 #include <unistd.h>
  14
  15 // XXX error handling
  16
  17 SDL_Surface *display;
  18
  19 TTF_Font    *font;
  20 int          font_height;
  21 SDL_Surface *glyphs[128];   /* first 20 will be NULL */
  22
  23 SDL_Color   fg;
  24 SDL_Color   bg;
  25
  26
  27 /*
  28  * Utils
  29  */
  30 void die(const char *fmt, ...) __attribute__ ((noreturn));
  31 void die(const char *fmt, ...)
  32 {
  33     va_list ap;
  34     va_start(ap, fmt);
  35     vfprintf(stderr, fmt, ap);
  36     exit(1);
  37 }
  38
  39 double microtime()
  40 {
  41     return ((double)SDL_GetTicks()) / 1000;
  42 }
  43
  44 void display_text(const char *s)
  45 {
  46     SDL_Surface *g;
  47     SDL_Rect r;
  48
  49     r.x = 0;
  50     r.y = 0;
  51
  52     for (; *s!=0; ++s) {
  53         g = glyphs[(unsigned char)*s];
  54         r.w = g->w;
  55         r.h = g->h;
  56         r.y = font_height - g->h;
  57         SDL_BlitSurface(g, NULL/*whole glyph*/, display, &r);
  58
  59         r.x += g->w ? g->w : 32;
  60     }
  61
  62 }
  63
  64 int main(int argc, char *argv[])
  65 {
  66     int width = 300, height = 120;
  67     int ch;
  68     double now;
  69
  70     const char *fontname = argv[1] ?
  71         argv[1]
  72         : "/usr/share/fonts/truetype/ttf-bitstream-vera/VeraMono.ttf";
  73
  74     SDL_Init(SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE);
  75     TTF_Init();
  76
  77     font = TTF_OpenFont(fontname, 96);
  78     if (!font)
  79         die("TTF_OpenFont: %s\n", TTF_GetError());
  80
  81
  82     TTF_SetFontStyle(font, TTF_STYLE_NORMAL);
  83
  84     if (!TTF_FontFaceIsFixedWidth(font))
  85         fprintf(stderr, "W: non monospaced font...\n");
  86
  87     font_height = TTF_FontHeight(font);
  88
  89
  90     display = SDL_SetVideoMode(width, height, /*bpp=*/0, /*flags=*/0UL);
  91     if (!display)
  92         die("SDL_SetVideoMode: %s\n", SDL_GetError());
  93
  94     fg.r=0xff; fg.g=0xff; fg.b=0xff;
  95     bg.r=0x00; bg.g=0x00; bg.b=0x00;
  96
  97     /* render characters */
  98     for (ch=20; ch<128; ++ch) {
  99         glyphs[ch] = TTF_RenderGlyph_Solid(font, ch, fg);
 100         if (!glyphs[ch])
 101             die("TTF_RenderGlyph_Solid\n");
 102     }
 103
 104
 105
 106     while (1) {
 107         char tmp[80];
 108
 109         SDL_FillRect(display, NULL, SDL_MapRGB(display->format, bg.r, bg.g, bg.b));
 110
 111         now = microtime();
 112
 113         //sprintf(tmp, "%.3lf %.3lf %.3lf", now, now, now);
 114         sprintf(tmp, "%.3lf", now);
 115         display_text(tmp);
 116
 117         SDL_UpdateRect(display, 0,0,0,0);
 118
 119         usleep(1000/*=1ms*/);
 120     }
 121
 122
 123     TTF_CloseFont(font);
 124
 125     TTF_Quit();
 126     SDL_Quit();
 127
 128     return 0;
 129 }