+void usage(void)
+{
+ printf("ttf2png 1.1 - True Type Font to PNG converter\n"
+ "Copyright (c) 2004-2018 Mikko Rasa, Mikkosoft Productions\n"
+ "Distributed under the GNU General Public License\n\n");
+
+ printf("Usage: ttf2png [options] <TTF file>\n\n");
+
+ printf("Accepted options (default values in [brackets])\n"
+ " -r Range of code points to convert [0,255]\n"
+ " -s Font size to use, in pixels [10]\n"
+ " -l Number of glyphs to put in one line [auto]\n"
+ " -c Glyph cell size, in pixels (grid mode only) [auto]\n"
+ " -o Output file name (or - for stdout) [font.png]\n");
+ printf(" -a Force autohinter\n"
+ " -t Render glyphs to alpha channel\n"
+ " -i Invert colors of the glyphs\n"
+ " -v Increase the level of verbosity\n"
+ " -e Use cells in sequence, without gaps (grid mode only)\n"
+ " -p Pack the glyphs tightly instead of in a grid\n"
+ " -m Margin around image edges (packed mode only) [0]\n"
+ " -n Padding between glyphs (packed mode only) [1]\n"
+ " -d File name for writing glyph definitions\n"
+ " -h Print this message\n");
+}
+
+int convert_numeric_option(char opt, int min_value)
+{
+ int value;
+ char *ptr;
+
+ value = strtol(optarg, &ptr, 0);
+ if(value<min_value || *ptr)
+ {
+ printf("Invalid option argument in -%c %s\n", opt, optarg);
+ exit(1);
+ }
+
+ return value;
+}
+
+void convert_code_point_range(char opt, unsigned *begin, unsigned *end)
+{
+ int value;
+ char *ptr;
+
+ if(!strcmp(optarg, "all"))
+ {
+ *begin = 0;
+ *end = 0x10FFFF;
+ return;
+ }
+
+ value = strtol(optarg, &ptr, 0);
+ if(value>0 && *ptr==',')
+ {
+ *begin = value;
+ value = strtol(ptr+1, &ptr, 0);
+ if(value>0 && !*ptr)
+ {
+ *end = value;
+ return;
+ }
+ }
+
+ printf("Invalid option argument in -%c %s\n", opt, optarg);
+ exit(1);
+}
+
+void convert_size(char opt, unsigned *width, unsigned *height)
+{
+ int value;
+ char *ptr;
+
+ if(!strcmp(optarg, "auto"))
+ {
+ *width = 0;
+ *height = 0;
+ return;
+ }
+ else if(!strcmp(optarg, "autorect"))
+ {
+ *width = 0;
+ *height = 1;
+ return;
+ }
+
+ value = strtol(optarg, &ptr, 0);
+ if(value>0)
+ {
+ *width = value;
+ if(*ptr=='x')
+ {
+ value = strtol(ptr+1, &ptr, 0);
+ if(value>0 && !*ptr)
+ {
+ *height = value;
+ return;
+ }
+ }
+ else if(!*ptr)
+ {
+ *height = *width;
+ return;
+ }
+ }
+
+ printf("Invalid option argument in -%c %s\n", opt, optarg);
+ exit(1);
+}
+