sdl/font.cpp

   1 /**
   2  * DGen's font renderer.
   3  */
   4
   5 #include <stddef.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <assert.h>
   9 #include "font.h"       /* The interface functions */
  10
  11 #ifndef FONT_VISIBLE
  12 #define FONT_VISIBLE 24
  13 #endif
  14
  15 extern const short *dgen_font_8x13[0x80];
  16 extern const short *dgen_font_16x26[0x80];
  17 extern const short *dgen_font_7x5[0x80];
  18
  19 const struct dgen_font dgen_font[] = {
  20         { 16, 26, &dgen_font_16x26 },
  21         { 8, 13, &dgen_font_8x13 },
  22         { 7, 5, &dgen_font_7x5 },
  23         { 0, 0, NULL }
  24 };
  25
  26 const struct dgen_font *font_select(unsigned int max_width,
  27                                     unsigned int max_height,
  28                                     enum font_type type)
  29 {
  30         const struct dgen_font *font = dgen_font;
  31
  32         assert(type <= FONT_TYPE_AUTO);
  33         if (type != FONT_TYPE_AUTO) {
  34                 // Make sure we're able to display at least one character.
  35                 font = &font[type];
  36                 if ((max_width < font->w) || (max_height < font->h))
  37                         return NULL;
  38                 return font;
  39         }
  40         // Chose a font able to display at least FONT_VISIBLE characters.
  41         while ((font->data != NULL) &&
  42                ((font->h > max_height) ||
  43                 ((max_width / font->w) < FONT_VISIBLE))) {
  44                 ++font;
  45                 continue;
  46         }
  47         if (font->data == NULL)
  48                 return NULL;
  49         return font;
  50 }
  51
  52 static void font_mark(uint8_t *buf,
  53                       unsigned int max_width, unsigned int max_height,
  54                       unsigned int bytes_per_pixel, unsigned int pitch,
  55                       unsigned int mark_x,
  56                       unsigned int font_w, unsigned int font_h)
  57 {
  58         unsigned int y;
  59
  60         if (((mark_x + font_w) > max_width) || (max_height < font_h))
  61                 return;
  62         buf += (mark_x * bytes_per_pixel);
  63         for (y = 0; (y != font_h); ++y) {
  64                 unsigned int x;
  65                 unsigned int len = (bytes_per_pixel * font_w);
  66
  67                 for (x = 0; (x < len); ++x)
  68                         buf[x] ^= 0xff;
  69                 buf += pitch;
  70         }
  71 }
  72
  73 size_t font_text_width(const char *msg, size_t len,
  74                        unsigned int max_width, unsigned int max_height,
  75                        enum font_type type)
  76 {
  77         const struct dgen_font *font =
  78                 font_select(max_width, max_height, type);
  79         size_t width = 0;
  80
  81         if (font == NULL)
  82                 return 0;
  83         while ((*msg != '\0') && (len)) {
  84                 width += font->w;
  85                 ++msg;
  86                 --len;
  87         }
  88         return width;
  89 }
  90
  91 size_t font_text_max_len(unsigned int max_width, unsigned int max_height,
  92                          enum font_type type)
  93 {
  94         const struct dgen_font *font =
  95                 font_select(max_width, max_height, type);
  96
  97         if (font == NULL)
  98                 return ~(size_t)0;
  99         return (max_width / font->w);
 100 }
 101
 102 size_t font_text(uint8_t *buf,
 103                  unsigned int max_width, unsigned int max_height,
 104                  unsigned int bytes_per_pixel, unsigned int pitch,
 105                  const char *msg, size_t len, unsigned int mark,
 106                  enum font_type type)
 107 {
 108         const struct dgen_font *font;
 109         uint8_t *p_max;
 110         size_t r;
 111         unsigned int x;
 112
 113         if (len == 0)
 114                 return 0;
 115         if ((font = font_select(max_width, max_height, type)) == NULL) {
 116                 printf("info: %.*s\n", (unsigned int)len, msg);
 117                 if (mark <= len) {
 118                         printf("      ");
 119                         for (x = 0; (x != mark); ++x)
 120                                 putchar(' ');
 121                         puts("^");
 122                 }
 123                 return len;
 124         }
 125         p_max = (buf + (pitch * max_height));
 126         for (x = 0, r = 0;
 127              ((msg[r] != '\0') && (r != len) && ((x + font->w) <= max_width));
 128              ++r, x += font->w) {
 129                 const short *glyph = (*font->data)[(msg[r] & 0x7f)];
 130                 uint8_t *p = (buf + (x * bytes_per_pixel));
 131                 unsigned int n = 0;
 132                 short g;
 133
 134                 if (glyph == NULL)
 135                         continue;
 136                 while ((g = *glyph) != -1) {
 137                         unsigned int i;
 138
 139                         p += (((n += g) / font->w) * pitch);
 140                         n %= font->w;
 141                         for (i = 0; (i < bytes_per_pixel); ++i) {
 142                                 uint8_t *tmp = &p[((n * bytes_per_pixel) + i)];
 143
 144                                 if (tmp < p_max)
 145                                         *tmp = 0xff;
 146                         }
 147                         ++glyph;
 148                 }
 149                 if (r == mark)
 150                         font_mark(buf, max_width, max_height, bytes_per_pixel,
 151                                   pitch, x, font->w, font->h);
 152         }
 153         if (r == mark)
 154                 font_mark(buf, max_width, max_height, bytes_per_pixel, pitch,
 155                           x, font->w, font->h);
 156         return r;
 157 }