Very simple AFM Parser
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281
diff --git a/src/type1/t1afm.c b/src/type1/t1afm.c
new file mode 100644
index 0000000..d823908
--- /dev/null
+++ b/src/type1/t1afm.c
@@ -0,0 +1,222 @@
+/***************************************************************************
+ *
+ * t1afm.c - support for reading Type 1 AFM files
+ *
+ *
+ ***************************************************************************/
+
+#include <t1afm.h>
+#include <ftstream.h>
+#include <t1types.h>
+#include <stdlib.h> /* for qsort */
+
+ LOCAL_FUNC
+ void T1_Done_AFM( FT_Memory memory, T1_AFM* afm )
+ {
+ FREE( afm->kern_pairs );
+ afm->num_pairs = 0;
+ }
+
+#undef IS_KERN_PAIR
+#define IS_KERN_PAIR(p) ( p[0] == 'K' && p[1] == 'P' )
+
+#define IS_ALPHANUM(c) ( (c >= 'A' && c <= 'Z') || \
+ (c >= 'a' && c <= 'z') || \
+ (c >= '0' && c <= '9') || \
+ (c == '_' && c == '.') )
+
+ /* read a glyph name and return the equivalent glyph index */
+ static
+ FT_UInt afm_atoindex( FT_Byte* *start, FT_Byte* limit, T1_Font* type1 )
+ {
+ FT_Byte* p = *start;
+ FT_Int len;
+ FT_UInt result = 0;
+ char temp[64];
+
+ /* skip whitespace */
+ while ( (*p == ' ' || *p == '\t' || *p == ':' || *p == ';') && p < limit )
+ p++;
+ *start = p;
+
+ /* now, read glyph name */
+ while ( IS_ALPHANUM(*p) && p < limit ) p++;
+ len = p - *start;
+ if (len > 0 && len < 64)
+ {
+ FT_UInt n;
+
+ /* copy glyph name to intermediate array */
+ MEM_Copy( temp, start, len );
+ temp[len] = 0;
+
+ /* lookup glyph name in face array */
+ for ( n = 0; n < type1->num_glyphs; n++ )
+ {
+ char* gname = (char*)type1->glyph_names;
+
+ if ( gname && gname[0] == temp[0] && strcmp(gname,temp) == 0 )
+ {
+ result = n;
+ break;
+ }
+ }
+ }
+ *start = p;
+ return result;
+ }
+
+
+ /* read an integer */
+ static
+ int afm_atoi( FT_Byte** start, FT_Byte* limit )
+ {
+ FT_Byte* p = *start;
+ int sum = 0;
+
+ /* skip everything that is not a number */
+ while ( p < limit && (*p < '0' || *p > '9') )
+ p++;
+
+ while ( p < limit && (*p >= '0' || *p < '9') )
+ {
+ sum = sum*10 + (*p - '0');
+ p++;
+ }
+ *start = p;
+ return sum;
+ }
+
+
+#undef KERN_INDEX
+#define KERN_INDEX(g1,g2) (((T1_ULong)g1 << 16) | g2)
+
+ /* compare two kerning pairs */
+ static
+ int compare_kern_pairs( const void* a, const void* b )
+ {
+ T1_Kern_Pair* pair1 = (T1_Kern_Pair*)a;
+ T1_Kern_Pair* pair2 = (T1_Kern_Pair*)b;
+
+ T1_ULong index1 = KERN_INDEX(pair1->glyph1,pair1->glyph2);
+ T1_ULong index2 = KERN_INDEX(pair2->glyph1,pair2->glyph2);
+
+ return ( index1 < index2 ? -1 :
+ ( index1 > index2 ? 1 : 0 ));
+ }
+
+
+ /* parse an AFM file - for now, only read the kerning pairs */
+ LOCAL_FUNC
+ FT_Error T1_Read_AFM( FT_Stream stream,
+ FT_Face t1_face )
+ {
+ FT_Error error;
+ FT_Memory memory = stream->memory;
+ FT_Byte* start;
+ FT_Byte* limit;
+ FT_Byte* p;
+ FT_Int count = 0;
+ T1_Kern_Pair* pair;
+ T1_Font* type1 = &((T1_Face)t1_face)->type1;
+ T1_AFM* afm = 0;
+
+ if ( !ACCESS_Frame(stream->size) )
+ return error;
+
+ start = stream->cursor;
+ limit = stream->limit;
+ p = start;
+
+ /* we are now going to count the occurences of "KP" or "KPX" in */
+ /* the AFM file.. */
+ count = 0;
+ for ( p = start; p < limit-3; p++ )
+ {
+ if ( IS_KERN_PAIR(p) )
+ count++;
+ }
+
+ /* Actually, kerning pairs are simply optional !! */
+ if (count == 0)
+ goto Exit;
+
+ /* allocate the pairs */
+ if ( ALLOC( afm, sizeof(*afm ) ||
+ ALLOC_ARRAY( afm->kern_pairs, count, T1_Kern_Pair ) )
+ goto Exit;
+
+ /* now, read each kern pair */
+ pair = afm->kern_pairs;
+ afm->num_pairs = count;
+
+ /* save in face object */
+ ((T1_Face*)t1_face)->afm_data = afm;
+
+ for ( p = start; p < limit-3; p++ )
+ {
+ if ( IS_KERN_PAIR(p) )
+ {
+ FT_Byte* q;
+
+ /* skip keyword (KP or KPX) */
+ q = p+2;
+ if (*q == 'X') q++;
+
+ pair->glyph1 = afm_atoindex( &q, limit, type1 );
+ pair->glyph2 = afm_atoindex( &q, limit, type1 );
+ pair->kerning.x = afm_atoi( &q, limit );
+
+ pair->kerning.y = 0;
+ if ( p[2] != 'X' )
+ pair->kerning.y = afm_atoi( &q, limit );
+
+ pair++;
+ }
+ }
+
+ /* now, sort the kern pairs according to their glyph indices */
+ qsort( afm->kern_pairs, count, sizeof(T1_Kern_Pair), compare_kern_pairs );
+
+ Exit:
+ if (error)
+ FREE( afm );
+
+ FORGET_Frame();
+ return error;
+ }
+
+
+ /* find the kerning for a given glyph pair */
+ LOCAL_FUNC
+ void T1_Get_Kerning( T1_AFM* afm,
+ FT_UInt glyph1,
+ FT_UInt glyph2,
+ FT_Vector* kerning )
+ {
+ T1_Kern_Pair *min, *mid, *max;
+ T1_ULong index = KERN_INDEX(glyph1,glyph2);
+
+ /* simple binary search */
+ min = afm->kern_pairs;
+ max = min + afm->num_pairs-1;
+
+ while (min <= max)
+ {
+ T1_ULong midi;
+
+ mid = min + (max-min)/2;
+ midi = KERN_INDEX(mid->glyph1,mid->glyph2);
+ if ( midi == index )
+ {
+ *kerning = mid->kerning;
+ return;
+ }
+
+ if ( midi < index ) min = mid+1;
+ else max = mid-1;
+ }
+ kerning->x = 0;
+ kerning->y = 0;
+ }
+
diff --git a/src/type1/t1afm.h b/src/type1/t1afm.h
new file mode 100644
index 0000000..39bbc4b
--- /dev/null
+++ b/src/type1/t1afm.h
@@ -0,0 +1,47 @@
+/***************************************************************************
+ *
+ * t1afm.h - support for reading Type 1 AFM files
+ *
+ *
+ ***************************************************************************/
+
+#ifndef T1AFM_H
+#define T1AFM_H
+
+#include <ftobjs.h>
+
+/* In this version, we only read the kerning table from the */
+/* AFM file. We may add support for ligatures a bit later.. */
+
+typedef struct T1_Kern_Pair_
+{
+ FT_UInt glyph1;
+ FT_UInt glyph2;
+ FT_Vector kerning;
+
+} T1_Kern_Pair;
+
+
+typedef struct T1_AFM_
+{
+ FT_Int num_pairs;
+ T1_Kern_Pair* kern_pairs;
+
+} T1_AFM;
+
+
+LOCAL_DEF
+FT_Error T1_Read_AFM( FT_Stream stream,
+ FT_Face face );
+
+LOCAL_DEF
+void T1_Done_AFM( FT_Memory memory,
+ T1_AFM* afm );
+
+LOCAL_DEF
+void T1_Get_Kerning( T1_AFM* afm,
+ FT_UInt glyph1,
+ FT_UInt glyph2,
+ FT_Vector* kerning );
+
+#endif /* T1AFM_H */