aboutsummaryrefslogtreecommitdiffstats
path: root/unicode/src/base/UFont.pas
blob: 32764be37411d570a1afdbb5a0b9c895ea62ef4e (plain) (blame)
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
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
{* UltraStar Deluxe - Karaoke Game
 *
 * UltraStar Deluxe is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *}

unit UFont;

{$IFDEF FPC}
  {$MODE Delphi}
{$ENDIF}

{$I switches.inc}

interface

{$IFNDEF FREETYPE_DEMO}
  // Flip direction of y-axis.
  // Default is a cartesian coordinate system with y-axis in upper direction
  // but with USDX the y-axis is in lower direction.
  {$DEFINE FLIP_YAXIS}
  {$DEFINE BITMAP_FONT}
{$ENDIF}

uses
  FreeType,
  gl,
  glext,
  glu,
  sdl,
  Math,
  Classes,
  SysUtils,
  UUnicodeUtils,
  {$IFDEF BITMAP_FONT}
  UTexture,
  {$ENDIF}
  UPath;

type

  PGLubyteArray = ^TGLubyteArray;
  TGLubyteArray = array[0 .. (MaxInt div SizeOf(GLubyte))-1] of GLubyte;
  TGLubyteDynArray = array of GLubyte;

  TUCS4StringArray = array of UCS4String;

  TGLColor = packed record
    case byte of
      0: ( vals: array[0..3] of GLfloat; );
      1: ( r, g, b, a: GLfloat; );
  end;

  TBoundsDbl = record
    Left, Right: double;
    Bottom, Top: double;
  end;

  TPositionDbl = record
    X, Y: double;
  end;

  TTextureSize = record
    Width, Height: integer;
  end;

  TBitmapCoords = record
    Left, Top: double;
    Width, Height: integer;
  end;

  {**
   * Abstract base class representing a glyph.
   *}
  TGlyph = class
    protected
      function GetAdvance(): TPositionDbl; virtual; abstract;
      function GetBounds(): TBoundsDbl; virtual; abstract;
    public
      procedure Render(UseDisplayLists: boolean); virtual; abstract;
      procedure RenderReflection(); virtual; abstract;

      {** Distance to next glyph (in pixels) *}
      property Advance: TPositionDbl read GetAdvance;
      {** Glyph bounding box (in pixels) *}
      property Bounds: TBoundsDbl read GetBounds;
  end;

  {**
   * Font styles used by TFont.Style
   *}
  TFontStyle = set of (Italic, Underline, Reflect);

  {**
   * Base font class.
   *}
  TFont = class
    private
      {** Non-virtual reset-method used in Create() and Reset() }
      procedure ResetIntern();

    protected
      fStyle: TFontStyle;
      fUseKerning: boolean;       
      fLineSpacing: single;       // must be inited by subclass
      fReflectionSpacing: single; // must be inited by subclass to -2*Descender
      fGlyphSpacing: single;
      fReflectionPass: boolean;

      {**
       * Splits lines in Text seperated by newline (char-code #13).
       * @param Text   UTF-8 encoded string
       * @param Lines  splitted UCS4String lines
       *}
      procedure SplitLines(const Text: UCS4String; var Lines: TUCS4StringArray);

      {**
       * Print an array of UCS4Strings. Each array-item is a line of text.
       * Lines of text are seperated by the line-spacing.
       * This is the base function for all text drawing.
       *}
      procedure Print(const Text: TUCS4StringArray); overload; virtual;

      {**
       * Draws an underline.
       *}
      procedure DrawUnderline(const Text: UCS4String); virtual;

      {**
       * Renders (one) line of text.
       *}
      procedure Render(const Text: UCS4String); virtual; abstract;

      {**
       * Returns the bounds of text-lines contained in Text.
       * @param(Advance  if true the right bound is set to the advance instead
       *   of the minimal right bound.)
       *}
      function BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl; overload; virtual; abstract;

      {**
       * Resets all user settings to default values.
       * Override methods should always call the inherited version.
       *}
      procedure Reset(); virtual;

      function GetHeight(): single; virtual; abstract;
      function GetAscender(): single; virtual; abstract;
      function GetDescender(): single; virtual; abstract;
      procedure SetLineSpacing(Spacing: single); virtual;
      function GetLineSpacing(): single; virtual;
      procedure SetGlyphSpacing(Spacing: single); virtual;
      function GetGlyphSpacing(): single; virtual;
      procedure SetReflectionSpacing(Spacing: single); virtual;
      function GetReflectionSpacing(): single; virtual;
      procedure SetStyle(Style: TFontStyle); virtual;
      function GetStyle(): TFontStyle; virtual;
      function GetUnderlinePosition(): single; virtual; abstract;
      function GetUnderlineThickness(): single; virtual; abstract;
      procedure SetUseKerning(Enable: boolean); virtual;
      function GetUseKerning(): boolean; virtual;
      procedure SetReflectionPass(Enable: boolean); virtual;

      {** Returns true if the current render-pass is used to draw the reflection }
      property ReflectionPass: boolean read fReflectionPass write SetReflectionPass;

    public
      constructor Create();
      destructor Destroy(); override;

      {**
       * Prints a text.
       *}
      procedure Print(const Text: UCS4String); overload;
      {** UTF-16 version of @link(Print) }
      procedure Print(const Text: WideString); overload;
      {** UTF-8 version of @link(Print) }
      procedure Print(const Text: UTF8String); overload;

      {**
       * Calculates the bounding box (width and height) around Text.
       * Works with Italic and Underline styles but reflections created
       * with the Reflect style are not considered.
       * Note that the width might differ due to kerning with appended text,
       * e.g. Width('VA') <= Width('V') + Width('A').
       * @param Advance  if set to true, Result.Right is set to the advance of
       * the given text rather than the min. right border. The advance width is
       * bigger than the text's width as it additionally contains the advance
       * and glyph-spacing of the last character.
       *}
      function BBox(const Text: UCS4String; Advance: boolean = true): TBoundsDbl; overload;
      {** UTF-16 version of @link(BBox) }
      function BBox(const Text: WideString; Advance: boolean = true): TBoundsDbl; overload;
      {** UTF-8 version of @link(BBox) }
      function BBox(const Text: UTF8String; Advance: boolean = true): TBoundsDbl; overload;

      {** Font height }
      property Height: single read GetHeight;
      {** Vertical distance from baseline to top of glyph }
      property Ascender: single read GetAscender;
      {** Vertical distance from baseline to bottom of glyph }
      property Descender: single read GetDescender;
      {** Vertical distance between two baselines }
      property LineSpacing: single read GetLineSpacing write SetLineSpacing;
      {** Space between end and start of next glyph added to the advance width }
      property GlyphSpacing: single read GetGlyphSpacing write SetGlyphSpacing;
      {** Distance between normal baseline and baseline of the reflection }
      property ReflectionSpacing: single read GetReflectionSpacing write SetReflectionSpacing;
      {** Font style (italic/underline/...) }
      property Style: TFontStyle read GetStyle write SetStyle;
      {** If set to true (default) kerning will be used if available }
      property UseKerning: boolean read GetUseKerning write SetUseKerning;
  end;

const
  //** Max. number of mipmap levels that a TScalableFont can contain
  cMaxMipmapLevel = 5;

type
  {**
   * Wrapper around TFont to allow font size changes.
   * The font is scaled to the requested size by a modelview matrix
   * transformation (glScale) and not by rescaling the internal bitmap
   * representation. This way changing the size is really fast but the result
   * may lack quality on large or small scale factors.
   *}
  TScalableFont = class(TFont)
    private
      procedure ResetIntern();

    protected
      fScale: single;        //**< current height to base-font height ratio 
      fAspect: single;       //**< width to height aspect
      fBaseFont: TFont;      //**< shortcut for fMipmapFonts[0]
      fUseMipmaps: boolean;  //**< true if mipmap fonts are generated
      /// Mipmap fonts (size[level+1] = size[level]/2)
      fMipmapFonts: array[0..cMaxMipmapLevel] of TFont;

      procedure Render(const Text: UCS4String); override;
      procedure Print(const Text: TUCS4StringArray); override;
      function BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl; override;

      {**
       * Callback called for creation of each mipmap font.
       * Must be defined by the subclass.
       * Mipmaps created by this method are managed and freed by TScalableFont.
       *}
      function CreateMipmap(Level: integer; Scale: single): TFont; virtual; abstract;

      {**
       * Returns the mipmap level considering the current scale and projection
       * matrix.
       *}
      function GetMipmapLevel(): integer;

      {**
       * Returns the scale applied to the given mipmap font.
       * fScale * fBaseFont.Height / fMipmapFont[Level].Height
       *}
      function GetMipmapScale(Level: integer): single;

      {**
       * Chooses the mipmap that looks nicest with current scale and projection
       * matrix.
       *}
      function ChooseMipmapFont(): TFont;

      procedure SetHeight(Height: single); virtual;
      function GetHeight(): single; override;
      procedure SetAspect(Aspect: single); virtual;
      function GetAspect(): single; virtual;
      function GetAscender(): single; override;
      function GetDescender(): single; override;
      procedure SetLineSpacing(Spacing: single); override;
      function GetLineSpacing(): single; override;
      procedure SetGlyphSpacing(Spacing: single); override;
      function GetGlyphSpacing(): single; override;
      procedure SetReflectionSpacing(Spacing: single); override;
      function GetReflectionSpacing(): single; override;
      procedure SetStyle(Style: TFontStyle); override;
      function GetStyle(): TFontStyle; override;
      function GetUnderlinePosition(): single; override;
      function GetUnderlineThickness(): single; override;
      procedure SetUseKerning(Enable: boolean); override;

    public
      {**
       * Creates a wrapper to make the base-font Font scalable.
       * If UseMipmaps is set to true smaller fonts are created so that a
       * resized (Height property changed) font looks nicer.
       * The font passed is managed and freed by TScalableFont.
       *}
      constructor Create(Font: TFont; UseMipmaps: boolean); overload;

      {**
       * Frees memory. The fonts passed on Create() and mipmap creation
       * are freed too. 
       *}
      destructor Destroy(); override;

      {** @seealso TFont.Reset }
      procedure Reset(); override;

      {** Font height }
      property Height: single read GetHeight write SetHeight;
      {** Factor for font stretching (NewWidth = Width*Aspect), 1.0 by default }
      property Aspect: single read GetAspect write SetAspect;
  end;

  {**
   * Table for storage of max. 256 glyphs.
   * Used for the second cache level. Indexed by the LSB of the UCS4Char
   * char-code.
   *}
  PGlyphTable = ^TGlyphTable;
  TGlyphTable = array[0..255] of TGlyph;

  {**
   * Cache for glyphs of a single font.
   * The cached glyphs are stored inside a hash-list.
   * Hashing is performed in two steps:
   * 1. the least significant byte (LSB) of the UCS4Char character code
   * is removed (shr 8) and the result (we call it BaseCode here) looked up in
   * the hash-list.
   * 2. Each entry of the hash-list contains a table with max. 256 entries.
   * The LSB of the char-code of a glyph is the table-offset of that glyph.
   *}
  TGlyphCache = class
    private
      fHash: TList;

      {**
       * Finds a glyph-table storing cached glyphs with base-code BaseCode
       * (= upper char-code bytes) in the hash-list and returns the table and
       * its index.
       * @param(InsertPos  the position of the tyble in the list if it was found,
       *                   otherwise the position the table should be inserted)
       *}
      function FindGlyphTable(BaseCode: cardinal; out InsertPos: integer): PGlyphTable;

    public
      constructor Create();
      destructor Destroy(); override;

      {**
       * Add glyph Glyph with char-code ch to the cache.
       * @returns @true on success, @false otherwise
       *}
      function AddGlyph(ch: UCS4Char; const Glyph: TGlyph): boolean;

      {**
       * Removes the glyph with char-code ch from the cache.
       *}
      procedure DeleteGlyph(ch: UCS4Char);

      {**
       * Removes the glyph with char-code ch from the cache.
       *}
      function GetGlyph(ch: UCS4Char): TGlyph;

      {**
       * Checks if a glyph with char-code ch is cached.
       *}
      function HasGlyph(ch: UCS4Char): boolean;

      {**
       * Remove and free all cached glyphs. If KeepBaseSet is set to
       * true, cached characters in the range 0..255 will not be flushed.
       *}
      procedure FlushCache(KeepBaseSet: boolean);
  end;

  {**
   * Entry of a glyph-cache's (TGlyphCache) hash.
   * Stores a BaseCode (upper-bytes of a glyph's char-code) and a table
   * with all glyphs cached at the moment with that BaseCode.
   *}
  TGlyphCacheHashEntry = class
    private
      fBaseCode: cardinal;
    public
      GlyphTable: TGlyphTable;

      constructor Create(BaseCode: cardinal);

      {** Base-code (upper-bytes) of the glyphs stored in this entry's table }
      property BaseCode: cardinal read fBaseCode;
  end;

  TCachedFont = class(TFont)
    protected
      fCache: TGlyphCache;

      {**
       * Retrieves a cached glyph with char-code ch from cache.
       * If the glyph is not already cached, it is loaded with LoadGlyph().
       *}
      function GetGlyph(ch: UCS4Char): TGlyph;

      {**
       * Callback to create (load) a glyph with char-code ch.
       * Implemented by subclasses.
       *}
      function LoadGlyph(ch: UCS4Char): TGlyph; virtual; abstract;

    public
      constructor Create();
      destructor Destroy(); override;

      {**
       * Remove and free all cached glyphs. If KeepBaseSet is set to
       * true, the base glyphs are not be flushed.
       * @seealso TGlyphCache.FlushCache
       *}
      procedure FlushCache(KeepBaseSet: boolean);
  end;

  TFTFont = class;

  {**
   * Freetype glyph.
   * Each glyph stores a texture with the glyph's image.
   *}
  TFTGlyph = class(TGlyph)
    private
      fCharCode:  UCS4Char;     //**< Char code
      fCharIndex: FT_UInt;      //**< Freetype specific char-index (<> char-code)
      fDisplayList: GLuint;     //**< Display-list ID
      fTexture: GLuint;         //**< Texture ID
      fBitmapCoords: TBitmapCoords; //**< Left/Top offset and Width/Height of the bitmap (in pixels)
      fTexOffset: TPositionDbl; //**< Right and bottom texture offset for removal of power-of-2 padding
      fTexSize: TTextureSize;   //**< Texture size in pixels

      fFont: TFTFont;           //**< Font associated with this glyph
      fAdvance: TPositionDbl;   //**< Advance width of this glyph
      fBounds: TBoundsDbl;      //**< Glyph bounds
      fOutset: single;          //**< Extrusion outset

      {**
       * Extrudes the outline of a glyph's bitmap stored in TexBuffer with size
       * fTexSize by Outset pixels.
       * This is useful to create bold or outlined fonts.
       * TexBuffer must be 2*Ceil(Outset) pixels higher and wider than the
       * original glyph bitmap, otherwise the glyph borders cannot be extruded
       * correctly.
       * The bitmap must be 2* pixels wider and higher than the
       * original glyph's bitmap with the latter centered in it.
       *}
      procedure StrokeBorder(var Glyph: FT_Glyph);

      {**
       * Creates an OpenGL texture (and display list) for the glyph.
       * The glyph's and bitmap's metrics are set correspondingly.
       * @param  LoadFlags  flags passed to FT_Load_Glyph()
       * @raises Exception  if the glyph could not be initialized
       *}
      procedure CreateTexture(LoadFlags: FT_Int32);

    protected
      function GetAdvance(): TPositionDbl; override;
      function GetBounds(): TBoundsDbl; override;

    public
      {**
       * Creates a glyph with char-code ch from font Font.
       * @param LoadFlags  flags passed to FT_Load_Glyph()
       *}
      constructor Create(Font: TFTFont; ch: UCS4Char; Outset: single;
                         LoadFlags: FT_Int32);
      destructor Destroy(); override;

      {** Renders the glyph (normal render pass) }
      procedure Render(UseDisplayLists: boolean); override;
      {** Renders the glyph's reflection }
      procedure RenderReflection(); override;

      {** Freetype specific char-index (<> char-code) }
      property CharIndex: FT_UInt read fCharIndex;
  end;

  TFontPart = ( fpNone, fpInner, fpOutline );

  {**
   * Freetype font class.
   *}
  TFTFont = class(TCachedFont)
    private
      procedure ResetIntern();

    protected
      fFilename: IPath;             //**< filename of the font-file
      fSize: integer;               //**< Font base size (in pixels)
      fOutset: single;              //**< size of outset extrusion (in pixels)
      fFace: FT_Face;               //**< Holds the height of the font
      fLoadFlags: FT_Int32;         //**< FT glpyh load-flags
      fFontUnitScale: TPositionDbl; //**< FT font-units to pixel ratio
      fUseDisplayLists: boolean;    //**< true: use display-lists, false: direct drawing
      fPart: TFontPart;             //**< indicates the part of an outline font

      {** @seealso TCachedFont.LoadGlyph }
      function LoadGlyph(ch: UCS4Char): TGlyph; override;

      procedure Render(const Text: UCS4String); override;
      function BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl; override;

      function GetHeight(): single; override;
      function GetAscender(): single; override;
      function GetDescender(): single; override;
      function GetUnderlinePosition(): single; override;
      function GetUnderlineThickness(): single; override;

      property Face: FT_Face read fFace;

    public
      {**
       * Creates a font of size Size (in pixels) from the file Filename.
       * If Outset (in pixels) is set to a value > 0 the glyphs will be extruded
       * at their borders. Use it for e.g. a bold effect.
       * @param  LoadFlags  flags passed to FT_Load_Glyph()
       * @raises Exception  if the font-file could not be loaded
       *}
      constructor Create(const Filename: IPath;
                         Size: integer; Outset: single = 0.0;
                         LoadFlags: FT_Int32 = FT_LOAD_DEFAULT);

      {**
       * Frees all resources associated with the font.
       *}
      destructor Destroy(); override;

      {** @seealso TFont.Reset }
      procedure Reset(); override;
      
      {** Size of the base font }
      property Size: integer read fSize;
      {** Outset size }
      property Outset: single read fOutset;
  end;

  TFTScalableFont = class(TScalableFont)
    protected
      function GetOutset(): single; virtual;
      function CreateMipmap(Level: integer; Scale: single): TFont; override;

    public
      {**
       * Creates a scalable font of size Size (in pixels) from the file Filename.
       * OutsetAmount is the ratio of the glyph extrusion.
       * The extrusion in pixels is Size*OutsetAmount
       * (0.0 -> no extrusion, 0.1 -> 10%).
       *}
      constructor Create(const Filename: IPath;
                         Size: integer; OutsetAmount: single = 0.0;
                         UseMipmaps: boolean = true);

      {** @seealso TGlyphCache.FlushCache }
      procedure FlushCache(KeepBaseSet: boolean);

      {** Outset size (in pixels) of the scaled font }
      property Outset: single read GetOutset;
  end;

  
  {**
   * Represents a freetype font with an additional outline around its glyphs.
   * The outline size is passed on creation and cannot be changed later.
   *}
  TFTOutlineFont = class(TFont)
    private
      fFilename: IPath;
      fSize: integer;
      fOutset: single;
      fInnerFont, fOutlineFont: TFTFont;
      fOutlineColor: TGLColor;

      procedure ResetIntern();
      
  protected
      procedure DrawUnderline(const Text: UCS4String); override;
      procedure Render(const Text: UCS4String); override;
      function BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl; override;

      function GetHeight(): single; override;
      function GetAscender(): single; override;
      function GetDescender(): single; override;
      procedure SetLineSpacing(Spacing: single); override;
      procedure SetGlyphSpacing(Spacing: single); override;
      procedure SetReflectionSpacing(Spacing: single); override;
      procedure SetStyle(Style: TFontStyle); override;
      function GetStyle(): TFontStyle; override;
      function GetUnderlinePosition(): single; override;
      function GetUnderlineThickness(): single; override;
      procedure SetUseKerning(Enable: boolean); override;
      procedure SetReflectionPass(Enable: boolean); override;

    public
      constructor Create(const Filename: IPath;
                         Size: integer; Outset: single;
                         LoadFlags: FT_Int32 = FT_LOAD_DEFAULT);
      destructor Destroy; override;

      {**
       * Sets the color of the outline.
       * If the alpha component is < 0, OpenGL's current alpha value will be
       * used.
       *}
      procedure SetOutlineColor(r, g, b: GLfloat; a: GLfloat = -1.0);

      {** @seealso TGlyphCache.FlushCache }
      procedure FlushCache(KeepBaseSet: boolean);

      {** @seealso TFont.Reset }
      procedure Reset(); override;

      {** Size of the base font }
      property Size: integer read fSize;
      {** Outset size }
      property Outset: single read fOutset;
  end;

  {**
   * Wrapper around TOutlineFont to allow font resizing.
   * @seealso TScalableFont
   *}
  TFTScalableOutlineFont = class(TScalableFont)
    protected
      function GetOutset(): single; virtual;
      function CreateMipmap(Level: integer; Scale: single): TFont; override;

    public
      constructor Create(const Filename: IPath;
                         Size: integer; OutsetAmount: single;
                         UseMipmaps: boolean = true);

      {** @seealso TFTOutlineFont.SetOutlineColor }
      procedure SetOutlineColor(r, g, b: GLfloat; a: GLfloat = -1.0);

      {** @seealso TGlyphCache.FlushCache }
      procedure FlushCache(KeepBaseSet: boolean);

      {** Outset size }
      property Outset: single read GetOutset;
  end;

{$IFDEF BITMAP_FONT}

  {**
   * A bitmapped font loads it's glyphs from a bitmap and stores them in a
   * texture. Unicode characters are not supported (but could be by supporting
   * multiple textures each storing a subset of unicode glyphs).
   * For backward compatibility only.
   *}
  TBitmapFont = class(TFont)
    private
      fTex:       TTexture;
      fTexSize:   integer;
      fBaseline:  integer;
      fAscender:  integer;
      fDescender: integer;
      fWidths:    array[0..255] of byte; //**< half widths
      fOutline:   integer;
      fTempColor: TGLColor; //**< colours for the reflection

      procedure ResetIntern();

      procedure RenderChar(ch: UCS4Char; var AdvanceX: real);

      {**
       * Load font widths from an info file.
       * @param  InfoFile  the name of the info (.dat) file
       * @raises Exception if the file is corrupted
       *}
      procedure LoadFontInfo(const InfoFile: IPath);

    protected
      procedure Render(const Text: UCS4String); override;
      function BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl; override;

      function GetHeight(): single; override;
      function GetAscender(): single; override;
      function GetDescender(): single; override;
      function GetUnderlinePosition(): single; override;
      function GetUnderlineThickness(): single; override;

    public
      {**
       * Creates a bitmapped font from image Filename and font width info
       * loaded from the corresponding file with ending .dat.
       * @param(Baseline  y-coord of the baseline given in cartesian coords
       *        (y-axis up) and from the lower edge of the glyphs bounding box)
       * @param(Ascender  pixels from baseline to top of highest glyph)
       *}
      constructor Create(const Filename: IPath; Outline: integer;
                         Baseline, Ascender, Descender: integer);
      destructor Destroy(); override;

      {**
       * Corrects font widths provided by the info file.
       * NewWidth := Width * WidthMult + WidthAdd
       *}
      procedure CorrectWidths(WidthMult: real; WidthAdd: integer);

      {** @seealso TFont.Reset }
      procedure Reset(); override;
  end;

{$ENDIF BITMAP_FONT}

  TFreeType = class
    public
      {**
       * Returns a pointer to the freetype library singleton.
       * If non exists, freetype will be initialized.
       * @raises Exception if initialization failed
       *}
      class function GetLibrary(): FT_Library;
      class procedure FreeLibrary();
  end;


implementation

uses Types;

const
  //** shear factor used for the italic effect (bigger value -> more bending)
  cShearFactor = 0.25;
  cShearMatrix: array[0..15] of GLfloat = (
      1,            0, 0, 0,
      cShearFactor, 1, 0, 0,
      0,            0, 1, 0,
      0,            0, 0, 1
  );
  cShearMatrixInv: array[0..15] of GLfloat = (
      1,             0, 0, 0,
      -cShearFactor, 1, 0, 0,
      0,             0, 1, 0,
      0,             0, 0, 1
  );

var
  LibraryInst: FT_Library;

function NewGLColor(r, g, b, a: GLfloat): TGLColor;
begin
  Result.r := r;
  Result.g := g;
  Result.b := b;
  Result.a := a;
end;

{**
 * Returns the first power of 2 >= Value.
 *}
function NextPowerOf2(Value: integer): integer; {$IFDEF HasInline}inline;{$ENDIF}
begin
  Result := 1;
  while (Result < Value) do
    Result := Result shl 1;
end;


{*
 * TFont
 *}

constructor TFont.Create();
begin
  inherited;
  ResetIntern();
end;

destructor TFont.Destroy();
begin
  inherited;
end;

procedure TFont.ResetIntern();
begin
  fStyle := [];
  fUseKerning := true;
  fGlyphSpacing := 0.0;
  fReflectionPass := false;

  // must be set by subclasses
  fLineSpacing := 0.0;
  fReflectionSpacing := 0.0;
end;

procedure TFont.Reset();
begin
  ResetIntern();
end;

procedure TFont.SplitLines(const Text: UCS4String; var Lines: TUCS4StringArray);
var
  CharIndex: integer;
  LineStart: integer;
  LineLength: integer;
  EOT: boolean; // End-Of-Text
begin
  // split lines on newline (there is no UCS4String version of ExtractStrings)
  SetLength(Lines, 0);
  EOT := false;
  LineStart := 0;

  for CharIndex := 0 to High(Text) do
  begin
    // check for end of text (UCS4Strings are zero-terminated)
    if (CharIndex = High(Text)) then
      EOT := true;

    // check for newline (carriage return (#13)) or end of text
    if (Text[CharIndex] = 13) or EOT then
    begin
      LineLength := CharIndex - LineStart;
      // check if last character was a newline
      if (EOT and (LineLength = 0)) then
        Break;      

      // copy line (even if LineLength is 0)
      SetLength(Lines, Length(Lines)+1);
      Lines[High(Lines)] := UCS4Copy(Text, LineStart, LineLength);

      LineStart := CharIndex+1;
    end;
  end;
end;

function TFont.BBox(const Text: UCS4String; Advance: boolean): TBoundsDbl;
var
  LineArray: TUCS4StringArray;
begin
  SplitLines(Text, LineArray);
  Result := BBox(LineArray, Advance);
  SetLength(LineArray, 0);
end;

function TFont.BBox(const Text: UTF8String; Advance: boolean): TBoundsDbl;
begin
  Result := BBox(UTF8Decode(Text), Advance);
end;

function TFont.BBox(const Text: WideString; Advance: boolean): TBoundsDbl;
begin
  Result := BBox(WideStringToUCS4String(Text), Advance);
end;

procedure TFont.Print(const Text: TUCS4StringArray);
var
  LineIndex: integer;
begin
  // recursively call this function to draw reflected text
  if ((Reflect in Style) and not ReflectionPass) then
  begin
    ReflectionPass := true;
    Print(Text);
    ReflectionPass := false;
  end;

  // store current color, enable-flags, matrix-mode
  glPushAttrib(GL_CURRENT_BIT or GL_ENABLE_BIT or GL_TRANSFORM_BIT);

  // set OpenGL state
  glMatrixMode(GL_MODELVIEW);
  glDisable(GL_DEPTH_TEST);
  glEnable(GL_BLEND);
  glEnable(GL_TEXTURE_2D);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

  {
  // TODO: just draw texels with alpha > 0 to avoid setting z-buffer for them?
  glAlphaFunc(GL_GREATER, 0);
  glEnable(GL_ALPHA_TEST);

  //TODO: Do we need depth-testing?
  if (ReflectionPass) then
  begin
    glDepthMask(0);
    glEnable(GL_DEPTH_TEST);
  end;
  }

  {$IFDEF FLIP_YAXIS}
  glPushMatrix();
  glScalef(1, -1, 1);
  {$ENDIF}

  // display text
  for LineIndex := 0 to High(Text) do
  begin
    glPushMatrix();

    // move to baseline
    glTranslatef(0, -LineSpacing*LineIndex, 0);

    if ((Underline in Style) and not ReflectionPass) then
    begin
      glDisable(GL_TEXTURE_2D);
      DrawUnderline(Text[LineIndex]);
      glEnable(GL_TEXTURE_2D);
    end;

    // draw reflection
    if (ReflectionPass) then
    begin
      // set reflection spacing
      glTranslatef(0, -ReflectionSpacing, 0);
      // flip y-axis
      glScalef(1, -1, 1);
    end;

    // shear for italic effect
    if (Italic in Style) then
      glMultMatrixf(@cShearMatrix);

    // render text line
    Render(Text[LineIndex]);

    glPopMatrix();
  end;

  // restore settings
  {$IFDEF FLIP_YAXIS}
  glPopMatrix();
  {$ENDIF}
  glPopAttrib();
end;

procedure TFont.Print(const Text: UCS4String);
var
  LineArray: TUCS4StringArray;
begin
  SplitLines(Text, LineArray);
  Print(LineArray);
  SetLength(LineArray, 0);
end;

procedure TFont.Print(const Text: UTF8String);
begin
  Print(UTF8Decode(Text));
end;

procedure TFont.Print(const Text: WideString);
begin
  Print(WideStringToUCS4String(Text));
end;

procedure TFont.DrawUnderline(const Text: UCS4String);
var
  UnderlineY1, UnderlineY2: single;
  Bounds: TBoundsDbl;
begin
  UnderlineY1 := GetUnderlinePosition();
  UnderlineY2 := UnderlineY1 + GetUnderlineThickness();
  Bounds := BBox(Text, false);
  glRectf(Bounds.Left, UnderlineY1, Bounds.Right, UnderlineY2);
end;

procedure TFont.SetStyle(Style: TFontStyle);
begin
  fStyle := Style;
end;

function TFont.GetStyle(): TFontStyle;
begin
  Result := fStyle;
end;

procedure TFont.SetLineSpacing(Spacing: single);
begin
  fLineSpacing := Spacing;
end;

function TFont.GetLineSpacing(): single;
begin
  Result := fLineSpacing;
end;

procedure TFont.SetGlyphSpacing(Spacing: single);
begin
  fGlyphSpacing := Spacing;
end;

function TFont.GetGlyphSpacing(): single;
begin
  Result := fGlyphSpacing;
end;

procedure TFont.SetReflectionSpacing(Spacing: single);
begin
  fReflectionSpacing := Spacing;
end;

function TFont.GetReflectionSpacing(): single;
begin
  Result := fReflectionSpacing;
end;

procedure TFont.SetUseKerning(Enable: boolean);
begin
  fUseKerning := Enable;
end;

function TFont.GetUseKerning(): boolean;
begin
  Result := fUseKerning;
end;

procedure TFont.SetReflectionPass(Enable: boolean);
begin
  fReflectionPass := Enable;
end;


{*
 * TScalableFont
 *}

constructor TScalableFont.Create(Font: TFont; UseMipmaps: boolean);
var
  MipmapLevel: integer;
begin
  inherited Create();
  
  fBaseFont := Font;
  fMipmapFonts[0] := Font;
  fUseMipmaps := UseMipmaps;
  ResetIntern();

  // create mipmap fonts if requested
  if (UseMipmaps) then
  begin
    for MipmapLevel := 1 to cMaxMipmapLevel do
    begin
      fMipmapFonts[MipmapLevel] := CreateMipmap(MipmapLevel, 1/(1 shl MipmapLevel));
      // stop if no smaller mipmap font is returned
      if (fMipmapFonts[MipmapLevel] = nil) then
        Break;
    end;
  end;
end;

destructor TScalableFont.Destroy();
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    fMipmapFonts[Level].Free;
  inherited;
end;

procedure TScalableFont.ResetIntern();
begin
  fScale := 1.0;
  fAspect := 1.0;
end;

procedure TScalableFont.Reset();
var
  Level: integer;
begin
  inherited;
  ResetIntern();
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      fMipmapFonts[Level].Reset();
end;

{**
 * Returns the mipmap level to use with regard to the current projection
 * and modelview matrix, font scale and aspect.
 *
 * Note:
 * - for Freetype fonts, hinting and grid-fitting must be disabled, otherwise
 *   the glyph widths/heights ratios and advance widths of the mipmap fonts
 *   do not match as they are adjusted sligthly (e.g. an 'a' at size 12px has
 *   width 12px, but at size 6px width 8px).
 * - returned mipmap-level is used for all glyphs of the current text to print.
 *   This is faster, much easier to handle, since we just need to create
 *   multiple sized fonts and select the one we need for the mipmap-level and
 *   it avoids that neighbored glyphs use different mipmap-level which might
 *   look odd because one glyph might look blurry and the other sharp.
 *
 * Motivation:
 *   We do not use OpenGL for mipmapping as the results are very bad. At least
 *   with automatic mipmap generation (gluBuildMipmaps) the fonts look rather
 *   blurry.
 *   Defining our own mipmaps by creating multiple textures with
 *   for different mimap levels is a pain, as the font size passed to freetype
 *   is not the size of the bitmaps created and it does not guarantee that a
 *   glyph bitmap of a font with font-size s/2 is half the size of the font with
 *   font-size s. If the bitmap size is just a single pixel bigger than the half
 *   we might need a texture of the next power-of-2 and the texture would not be
 *   half of the size of the next bigger mipmap. In addition we use a fixed one
 *   pixel sized border to smooth the texture (see cTexSmoothBorder) and maybe
 *   an outset that is added to the font, so creating a glyph mipmap that is
 *   exactly half the size of the next bigger one is a very difficult task.
 *
 * Solution:
 *   Use mipmap textures that are not exactly half the size of the next mipmap
 *   level. OpenGL does not support this (at least not without extensions).
 *   The trickiest task is to determine the mipmap to use by calculating the
 *   amount of minification that is performed in this function.
 *}
function TScalableFont.GetMipmapLevel(): integer;
var
  ModelMatrix, ProjMatrix: T16dArray;
  WinCoords: array[0..2, 0..2] of GLdouble;
  ViewPortArray: TViewPortArray;
  Dist, Dist2: double;
  WidthScale, HeightScale: double;
const
  // width/height of square used for determining the scale
  cTestSize = 10.0;
  // an offset to the mipmap-level to adjust the change-over of two consecutive
  // mipmap levels. If for example the bias is 0.1 and unbiased level is 1.9
  // the result level will be 2. A bias of 0.5 is equal to rounding.
  // With bias=0.1 we prefer larger mipmaps over smaller ones.
  cBias = 0.2;
begin
  // 1. retrieve current transformation matrices for gluProject
  glGetDoublev(GL_MODELVIEW_MATRIX, @ModelMatrix);
  glGetDoublev(GL_PROJECTION_MATRIX, @ProjMatrix);
  glGetIntegerv(GL_VIEWPORT, @ViewPortArray);

  // 2. project three of the corner points of a square with size cTestSize
  // to window coordinates (the square is just a dummy for a glyph)

  // project point (x1, y1) to window corrdinates
  gluProject(0, 0, 0,
             ModelMatrix, ProjMatrix, ViewPortArray,
             @WinCoords[0][0], @WinCoords[0][1], @WinCoords[0][2]);
  // project point (x2, y1) to window corrdinates
  gluProject(cTestSize, 0, 0,
             ModelMatrix, ProjMatrix, ViewPortArray,
             @WinCoords[1][0], @WinCoords[1][1], @WinCoords[1][2]);
  // project point (x1, y2) to window corrdinates
  gluProject(0, cTestSize, 0,
             ModelMatrix, ProjMatrix, ViewPortArray,
             @WinCoords[2][0], @WinCoords[2][1], @WinCoords[2][2]);

  // 3. Lets see how much the width and height of the square changed.
  // Calculate the width and height as displayed on the screen in window
  // coordinates and calculate the ratio to the original coordinates in
  // modelview space so the ratio gives us the scale (minification here).

  // projected width ||(x1, y1) - (x2, y1)||
  Dist  := (WinCoords[0][0] - WinCoords[1][0]);
  Dist2 := (WinCoords[0][1] - WinCoords[1][1]);
  WidthScale := cTestSize / Sqrt(Dist*Dist + Dist2*Dist2);

  // projected height ||(x1, y1) - (x1, y2)||
  Dist  := (WinCoords[0][0] - WinCoords[2][0]);
  Dist2 := (WinCoords[0][1] - WinCoords[2][1]);
  HeightScale := cTestSize / Sqrt(Dist*Dist + Dist2*Dist2);

  //writeln(Format('Scale %f, %f', [WidthScale, HeightScale]));

  // 4. Now that we have got the scale, take the bigger minification scale
  // and get it to a logarithmic scale as each mipmap is 1/2 the size of its
  // predecessor (Mipmap_size[i] = Mipmap_size[i-1]/2).
  // The result is our mipmap-level = the index of the mipmap to use.

  // Level > 0: Minification; < 0: Magnification
  Result := Trunc(Log2(Max(WidthScale, HeightScale)) + cBias);

  // clamp to valid range
  if (Result < 0) then
    Result := 0;
  if (Result > High(fMipmapFonts)) then
    Result := High(fMipmapFonts);
end;

function TScalableFont.GetMipmapScale(Level: integer): single;
begin
  if (fMipmapFonts[Level] = nil) then
  begin
    Result := -1;
    Exit;
  end;

  Result := fScale * fMipmapFonts[0].Height / fMipmapFonts[Level].Height;
end;

{**
 * Returns the correct mipmap font for the current scale and projection
 * matrix. The modelview scale is adjusted to the mipmap level, so
 * Result.Print() will display the font in the correct size.
 *}
function TScalableFont.ChooseMipmapFont(): TFont;
var
  DesiredLevel: integer;
  Level: integer;
  MipmapScale: single;
begin
  Result := nil;
  DesiredLevel := GetMipmapLevel();

  // get the smallest mipmap available for the desired level
  // as not all levels must be assigned to a font.
  for Level := DesiredLevel downto 0 do
  begin
    if (fMipmapFonts[Level] <> nil) then
    begin
      Result := fMipmapFonts[Level];
      Break;
    end;
  end;

  // since the mipmap font (if level > 0) is smaller than the base-font
  // we have to scale to get its size right.
  MipmapScale := fMipmapFonts[0].Height/Result.Height;
  glScalef(MipmapScale, MipmapScale, 0);
end;

procedure TScalableFont.Print(const Text: TUCS4StringArray);
begin
  glPushMatrix();

  // set scale and stretching
  glScalef(fScale * fAspect, fScale, 0);

  // print text
  if (fUseMipmaps) then
    ChooseMipmapFont().Print(Text)
  else
    fBaseFont.Print(Text);

  glPopMatrix();
end;

procedure TScalableFont.Render(const Text: UCS4String);
begin
  Assert(false, 'Unused TScalableFont.Render() was called');
end;

function TScalableFont.BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl;
begin
  Result := fBaseFont.BBox(Text, Advance);
  Result.Left   := Result.Left * fScale * fAspect;
  Result.Right  := Result.Right * fScale * fAspect;
  Result.Top    := Result.Top * fScale;
  Result.Bottom := Result.Bottom * fScale;
end;

procedure TScalableFont.SetHeight(Height: single);
begin
  fScale := Height / fBaseFont.GetHeight();
end;

function TScalableFont.GetHeight(): single;
begin
  Result := fBaseFont.GetHeight() * fScale;
end;

procedure TScalableFont.SetAspect(Aspect: single);
begin
  fAspect := Aspect;
end;

function TScalableFont.GetAspect(): single;
begin
  Result := fAspect;
end;

function TScalableFont.GetAscender(): single;
begin
  Result := fBaseFont.GetAscender() * fScale;
end;

function TScalableFont.GetDescender(): single;
begin
  Result := fBaseFont.GetDescender() * fScale;
end;

procedure TScalableFont.SetLineSpacing(Spacing: single);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      fMipmapFonts[Level].SetLineSpacing(Spacing / GetMipmapScale(Level));
end;

function TScalableFont.GetLineSpacing(): single;
begin
  Result := fBaseFont.GetLineSpacing() * fScale;
end;

procedure TScalableFont.SetGlyphSpacing(Spacing: single);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      fMipmapFonts[Level].SetGlyphSpacing(Spacing / GetMipmapScale(Level));
end;

function TScalableFont.GetGlyphSpacing(): single;
begin
  Result := fBaseFont.GetGlyphSpacing() * fScale;
end;

procedure TScalableFont.SetReflectionSpacing(Spacing: single);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      fMipmapFonts[Level].SetReflectionSpacing(Spacing / GetMipmapScale(Level));
end;

function TScalableFont.GetReflectionSpacing(): single;
begin
  Result := fBaseFont.GetLineSpacing() * fScale;
end;

procedure TScalableFont.SetStyle(Style: TFontStyle);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      fMipmapFonts[Level].SetStyle(Style);
end;

function TScalableFont.GetStyle(): TFontStyle;
begin
  Result := fBaseFont.GetStyle();
end;

function TScalableFont.GetUnderlinePosition(): single;
begin
  Result := fBaseFont.GetUnderlinePosition();
end;

function TScalableFont.GetUnderlineThickness(): single;
begin
  Result := fBaseFont.GetUnderlinePosition();
end;

procedure TScalableFont.SetUseKerning(Enable: boolean);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      fMipmapFonts[Level].SetUseKerning(Enable);
end;


{*
 * TCachedFont
 *}

constructor TCachedFont.Create();
begin
  inherited;
  fCache := TGlyphCache.Create();
end;

destructor TCachedFont.Destroy();
begin
  fCache.Free;
  inherited;
end;

function TCachedFont.GetGlyph(ch: UCS4Char): TGlyph;
begin
  Result := fCache.GetGlyph(ch);
  if (Result = nil) then
  begin
    Result := LoadGlyph(ch);
    if (not fCache.AddGlyph(ch, Result)) then
      Result.Free;
  end;
end;

procedure TCachedFont.FlushCache(KeepBaseSet: boolean);
begin
  fCache.FlushCache(KeepBaseSet);
end;


{*
 * TFTFont
 *}

constructor TFTFont.Create(
    const Filename: IPath;
    Size: integer; Outset: single;
    LoadFlags: FT_Int32);
var
  ch: UCS4Char;
begin
  inherited Create();

  fFilename := Filename;
  fSize := Size;
  fOutset := Outset;
  fLoadFlags := LoadFlags;
  fUseDisplayLists := true;
  fPart := fpNone;

  // load font information
  if (FT_New_Face(TFreeType.GetLibrary(), PChar(Filename.ToNative), 0, fFace) <> 0) then
    raise Exception.Create('FT_New_Face: Could not load font '''  + Filename.ToNative + '''');

  // support scalable fonts only
  if (not FT_IS_SCALABLE(fFace)) then
    raise Exception.Create('Font is not scalable');

  if (FT_Set_Pixel_Sizes(fFace, 0, Size) <> 0) then
    raise Exception.Create('FT_Set_Pixel_Sizes failes');

  // get scale factor for font-unit to pixel-size transformation
  fFontUnitScale.X := fFace.size.metrics.x_ppem / fFace.units_per_EM;
  fFontUnitScale.Y := fFace.size.metrics.y_ppem / fFace.units_per_EM;

  ResetIntern();

  // pre-cache some commonly used glyphs (' ' - '~')
  for ch := 32 to 126 do
    fCache.AddGlyph(ch, TFTGlyph.Create(Self, ch, Outset, LoadFlags));
end;

destructor TFTFont.Destroy();
begin
  // free face
  FT_Done_Face(fFace);
  inherited;
end;

procedure TFTFont.ResetIntern();
begin
  // Note: outset and non outset fonts use same spacing
  fLineSpacing := fFace.height * fFontUnitScale.Y;
  fReflectionSpacing := -2*fFace.descender * fFontUnitScale.Y;
end;

procedure TFTFont.Reset();
begin
  inherited;
  ResetIntern();
end;

function TFTFont.LoadGlyph(ch: UCS4Char): TGlyph;
begin
  Result := TFTGlyph.Create(Self, ch, Outset, fLoadFlags);
end;

function TFTFont.BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl;
var
  Glyph, PrevGlyph: TFTGlyph;
  TextLine: UCS4String;
  LineYOffset: single;
  LineIndex, CharIndex: integer;
  LineBounds: TBoundsDbl;
  KernDelta: FT_Vector;
  UnderlinePos: double;
begin
  // Reset global bounds
  Result.Left   := Infinity;
  Result.Right  := 0;
  Result.Bottom := Infinity;
  Result.Top    := 0;

  // reset last glyph
  PrevGlyph := nil;

  // display text
  for LineIndex := 0 to High(Text) do
  begin
    // get next text line
    TextLine := Text[LineIndex];
    LineYOffset := -LineSpacing * LineIndex;

    // reset line bounds
    LineBounds.Left   := Infinity;
    LineBounds.Right  := 0;
    LineBounds.Bottom := Infinity;
    LineBounds.Top    := 0;

    // for each glyph image, compute its bounding box
    for CharIndex := 0 to LengthUCS4(TextLine)-1 do
    begin
      Glyph := TFTGlyph(GetGlyph(TextLine[CharIndex]));
      if (Glyph <> nil) then
      begin
        // get kerning
        if (fUseKerning and FT_HAS_KERNING(fFace) and (PrevGlyph <> nil)) then
        begin
          FT_Get_Kerning(fFace, PrevGlyph.CharIndex, Glyph.CharIndex,
                         FT_KERNING_UNSCALED, KernDelta);
          LineBounds.Right := LineBounds.Right + KernDelta.x * fFontUnitScale.X;
        end;

        // update left bound (must be done before right bound is updated)
        if (LineBounds.Right + Glyph.Bounds.Left < LineBounds.Left) then
          LineBounds.Left := LineBounds.Right + Glyph.Bounds.Left;

        // update right bound
        if (CharIndex < LengthUCS4(TextLine)-1) or  // not the last character
           (TextLine[CharIndex] = Ord(' ')) or      // on space char (Bounds.Right = 0)
           Advance then                             // or in advance mode
        begin
          // add advance and glyph spacing
          LineBounds.Right := LineBounds.Right + Glyph.Advance.x + GlyphSpacing
        end
        else
        begin
          // add glyph's right bound
          LineBounds.Right := LineBounds.Right + Glyph.Bounds.Right;
        end;

        // update bottom and top bounds
        if (Glyph.Bounds.Bottom < LineBounds.Bottom) then
          LineBounds.Bottom := Glyph.Bounds.Bottom;
        if (Glyph.Bounds.Top > LineBounds.Top) then
          LineBounds.Top := Glyph.Bounds.Top;
      end;

      PrevGlyph := Glyph;
    end;

    // handle italic font style
    if (Italic in Style) then
    begin
      LineBounds.Left := LineBounds.Left + LineBounds.Bottom * cShearFactor;
      LineBounds.Right := LineBounds.Right + LineBounds.Top * cShearFactor;
    end;

    // handle underlined font style
    if (Underline in Style) then
    begin
      UnderlinePos := GetUnderlinePosition();
      if (UnderlinePos < LineBounds.Bottom) then
        LineBounds.Bottom := UnderlinePos;
    end;

    // add line offset
    LineBounds.Bottom := LineBounds.Bottom + LineYOffset;
    LineBounds.Top := LineBounds.Top + LineYOffset;

    // adjust global bounds
    if (Result.Left > LineBounds.Left) then
      Result.Left := LineBounds.Left;
    if (Result.Right < LineBounds.Right) then
      Result.Right := LineBounds.Right;
    if (Result.Bottom > LineBounds.Bottom) then
      Result.Bottom := LineBounds.Bottom;
    if (Result.Top < LineBounds.Top) then
      Result.Top := LineBounds.Top;
  end;

  // if left or bottom bound was not set, set them to 0
  if (Result.Left = Infinity) then
    Result.Left := 0.0;
  if (Result.Bottom = Infinity) then
    Result.Bottom := 0.0;
end;

procedure TFTFont.Render(const Text: UCS4String);
var
  CharIndex: integer;
  Glyph, PrevGlyph: TFTGlyph;
  KernDelta: FT_Vector;
begin
  // reset last glyph
  PrevGlyph := nil;

  // draw current line
  for CharIndex := 0 to LengthUCS4(Text)-1 do
  begin
    Glyph := TFTGlyph(GetGlyph(Text[CharIndex]));
    if (Assigned(Glyph)) then
    begin
      // get kerning
      if (fUseKerning and FT_HAS_KERNING(fFace) and (PrevGlyph <> nil)) then
      begin
        FT_Get_Kerning(fFace, PrevGlyph.CharIndex, Glyph.CharIndex,
                       FT_KERNING_UNSCALED, KernDelta);
        glTranslatef(KernDelta.x * fFontUnitScale.X, 0, 0);
      end;

      if (ReflectionPass) then
        Glyph.RenderReflection()
      else
        Glyph.Render(fUseDisplayLists);

      glTranslatef(Glyph.Advance.x + fGlyphSpacing, 0, 0);
    end;

    PrevGlyph := Glyph;
  end;
end;

function TFTFont.GetHeight(): single;
begin
  Result := Ascender - Descender;
end;

function TFTFont.GetAscender(): single;
begin
  Result := fFace.ascender * fFontUnitScale.Y + Outset*2;
end;

function TFTFont.GetDescender(): single;
begin
  // Note: outset is not part of the descender as the baseline is lifted
  Result := fFace.descender * fFontUnitScale.Y;
end;

function TFTFont.GetUnderlinePosition(): single;
begin
  Result := fFace.underline_position * fFontUnitScale.Y - Outset;
end;

function TFTFont.GetUnderlineThickness(): single;
begin
  Result := fFace.underline_thickness * fFontUnitScale.Y + Outset*2;
end;


{*
 * TFTScalableFont
 *}

constructor TFTScalableFont.Create(const Filename: IPath;
                   Size: integer; OutsetAmount: single;
                   UseMipmaps: boolean);
var
  LoadFlags: FT_Int32;
begin
  LoadFlags := FT_LOAD_DEFAULT;
  // Disable hinting and grid-fitting to preserve font outlines at each font
  // size, otherwise the font widths/heights do not match resulting in ugly
  // text size changes during zooming.
  // A drawback is a reduced quality with smaller font sizes but it is not that
  // bad with gray-scaled rendering (at least it looks better than OpenGL's
  // linear downscaling on minification).
  if (UseMipmaps) then
    LoadFlags := LoadFlags or FT_LOAD_NO_HINTING;
  inherited Create(
      TFTFont.Create(Filename, Size, Size * OutsetAmount, LoadFlags),
      UseMipmaps);
end;

function TFTScalableFont.CreateMipmap(Level: integer; Scale: single): TFont;
var
  ScaledSize: integer;
  BaseFont: TFTFont;
begin
  Result := nil;
  BaseFont := TFTFont(fBaseFont);
  ScaledSize := Round(BaseFont.Size * Scale);
  // do not create mipmap fonts < 8 pixels
  if (ScaledSize < 8) then
    Exit;
  Result := TFTFont.Create(BaseFont.fFilename,
      ScaledSize, BaseFont.fOutset * Scale,
      FT_LOAD_DEFAULT or FT_LOAD_NO_HINTING);
end;

function TFTScalableFont.GetOutset(): single;
begin
  Result := TFTFont(fBaseFont).Outset * fScale;
end;

procedure TFTScalableFont.FlushCache(KeepBaseSet: boolean);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      TFTFont(fMipmapFonts[Level]).FlushCache(KeepBaseSet);
end;


{*
 * TOutlineFont
 *}

constructor TFTOutlineFont.Create(
    const Filename: IPath;
    Size: integer; Outset: single;
    LoadFlags: FT_Int32);
begin
  inherited Create();

  fFilename := Filename;
  fSize := Size;
  fOutset := Outset;

  fInnerFont := TFTFont.Create(Filename, Size, 0.0, LoadFlags);
  fInnerFont.fPart := fpInner;
  fOutlineFont := TFTFont.Create(Filename, Size, Outset, LoadFlags);
  fOutlineFont.fPart := fpOutline;

  ResetIntern();
end;

destructor TFTOutlineFont.Destroy;
begin
  fOutlineFont.Free;
  fInnerFont.Free;
  inherited;
end;

procedure TFTOutlineFont.ResetIntern();
begin
  // TODO: maybe swap fInnerFont/fOutlineFont.GlyphSpacing to use the spacing
  // of the outline font?
  //fInnerFont.GlyphSpacing := fOutset*2;
  fOutlineFont.GlyphSpacing := -fOutset*2;

  fLineSpacing := fOutlineFont.LineSpacing;
  fReflectionSpacing := fOutlineFont.ReflectionSpacing;
  fOutlineColor := NewGLColor(0, 0, 0, -1);
end;

procedure TFTOutlineFont.Reset();
begin
  inherited;
  fInnerFont.Reset();
  fOutlineFont.Reset();
  ResetIntern();
end;

procedure TFTOutlineFont.DrawUnderline(const Text: UCS4String);
var
  CurrentColor: TGLColor;
  OutlineColor: TGLColor;
begin
  // save current color
  glGetFloatv(GL_CURRENT_COLOR, @CurrentColor.vals);

  // if the outline's alpha component is < 0 use the current alpha
  OutlineColor := fOutlineColor;
  if (OutlineColor.a < 0) then
    OutlineColor.a := CurrentColor.a;

  // draw underline outline (in outline color)
  glColor4fv(@OutlineColor.vals);
  fOutlineFont.DrawUnderline(Text);
  glColor4fv(@CurrentColor.vals);

  // draw underline inner part (in current color)
  glPushMatrix();
  glTranslatef(fOutset, 0, 0);
  fInnerFont.DrawUnderline(Text);
  glPopMatrix();
end;

procedure TFTOutlineFont.Render(const Text: UCS4String);
var
  CurrentColor: TGLColor;
  OutlineColor: TGLColor;
begin
  // save current color
  glGetFloatv(GL_CURRENT_COLOR, @CurrentColor.vals);

  // if the outline's alpha component is < 0 use the current alpha
  OutlineColor := fOutlineColor;
  if (OutlineColor.a < 0) then
    OutlineColor.a := CurrentColor.a;

  { setup and render outline font }

  glColor4fv(@OutlineColor.vals);
  glPushMatrix();
  fOutlineFont.Render(Text);
  glPopMatrix();
  glColor4fv(@CurrentColor.vals);

  { setup and render inner font }

  glPushMatrix();
  glTranslatef(fOutset, fOutset, 0);
  fInnerFont.Render(Text);
  glPopMatrix();
end;

procedure TFTOutlineFont.SetOutlineColor(r, g, b: GLfloat; a: GLfloat);
begin
  fOutlineColor := NewGLColor(r, g, b, a);
end;

procedure TFTOutlineFont.FlushCache(KeepBaseSet: boolean);
begin
  fOutlineFont.FlushCache(KeepBaseSet);
  fInnerFont.FlushCache(KeepBaseSet);
end;

function TFTOutlineFont.BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl;
begin
  Result := fOutlineFont.BBox(Text, Advance);
end;

function TFTOutlineFont.GetHeight(): single;
begin
  Result := fOutlineFont.Height;
end;

function TFTOutlineFont.GetAscender(): single;
begin
  Result := fOutlineFont.Ascender;
end;

function TFTOutlineFont.GetDescender(): single;
begin
  Result := fOutlineFont.Descender;
end;

procedure TFTOutlineFont.SetLineSpacing(Spacing: single);
begin
  inherited SetLineSpacing(Spacing);
  fInnerFont.LineSpacing := Spacing;
  fOutlineFont.LineSpacing := Spacing;
end;

procedure TFTOutlineFont.SetGlyphSpacing(Spacing: single);
begin
  inherited SetGlyphSpacing(Spacing);
  fInnerFont.GlyphSpacing := Spacing;
  fOutlineFont.GlyphSpacing := Spacing - Outset*2;
end;

procedure TFTOutlineFont.SetReflectionSpacing(Spacing: single);
begin
  inherited SetReflectionSpacing(Spacing);
  fInnerFont.ReflectionSpacing := Spacing;
  fOutlineFont.ReflectionSpacing := Spacing;
end;

procedure TFTOutlineFont.SetStyle(Style: TFontStyle);
begin
  inherited SetStyle(Style);
  fInnerFont.Style := Style;
  fOutlineFont.Style := Style;
end;

function TFTOutlineFont.GetStyle(): TFontStyle;
begin
  Result := inherited GetStyle();
end;

function TFTOutlineFont.GetUnderlinePosition(): single;
begin
  Result := fOutlineFont.GetUnderlinePosition();
end;

function TFTOutlineFont.GetUnderlineThickness(): single;
begin
  Result := fOutlineFont.GetUnderlinePosition();
end;

procedure TFTOutlineFont.SetUseKerning(Enable: boolean);
begin
  inherited SetUseKerning(Enable);
  fInnerFont.fUseKerning := Enable;
  fOutlineFont.fUseKerning := Enable;
end;

procedure TFTOutlineFont.SetReflectionPass(Enable: boolean);
begin
  inherited SetReflectionPass(Enable);
  fInnerFont.fReflectionPass := Enable;
  fOutlineFont.fReflectionPass := Enable;
end;

{**
 * TScalableOutlineFont
 *}

constructor TFTScalableOutlineFont.Create(
    const Filename: IPath;
    Size: integer; OutsetAmount: single;
    UseMipmaps: boolean);
var
  LoadFlags: FT_Int32;
begin
  LoadFlags := FT_LOAD_DEFAULT;
  // Disable hinting and grid-fitting (see TFTScalableFont.Create)
  if (UseMipmaps) then
    LoadFlags := LoadFlags or FT_LOAD_NO_HINTING;
  inherited Create(
      TFTOutlineFont.Create(Filename, Size, Size*OutsetAmount, LoadFlags),
      UseMipmaps);
end;

function TFTScalableOutlineFont.CreateMipmap(Level: integer; Scale: single): TFont;
var
  ScaledSize: integer;
  BaseFont: TFTOutlineFont;
begin
  Result := nil;
  BaseFont := TFTOutlineFont(fBaseFont);
  ScaledSize := Round(BaseFont.Size*Scale);
  // do not create mipmap fonts < 8 pixels
  if (ScaledSize < 8) then
    Exit;
  Result := TFTOutlineFont.Create(BaseFont.fFilename,
      ScaledSize, BaseFont.fOutset*Scale,
      FT_LOAD_DEFAULT or FT_LOAD_NO_HINTING);
end;

function TFTScalableOutlineFont.GetOutset(): single;
begin
  Result := TFTOutlineFont(fBaseFont).Outset * fScale;
end;

procedure TFTScalableOutlineFont.SetOutlineColor(r, g, b: GLfloat; a: GLfloat);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      TFTOutlineFont(fMipmapFonts[Level]).SetOutlineColor(r, g, b, a);
end;

procedure TFTScalableOutlineFont.FlushCache(KeepBaseSet: boolean);
var
  Level: integer;
begin
  for Level := 0 to High(fMipmapFonts) do
    if (fMipmapFonts[Level] <> nil) then
      TFTOutlineFont(fMipmapFonts[Level]).FlushCache(KeepBaseSet);
end;


{*
 * TFTGlyph
 *}

const
  {**
   * Size of the transparent border surrounding the glyph image in the texture.
   * The border is necessary because OpenGL does not smooth texels at the
   * border of a texture with the GL_CLAMP or GL_CLAMP_TO_EDGE styles.
   * Without the border, magnified glyph textures look very ugly at their edges.
   * It looks edgy, as if some pixels are missing especially on the left edge
   * (just set cTexSmoothBorder to 0 to see what is meant by this).
   * With the border even the glyphs edges are blended to the border (transparent)
   * color and everything looks nice.
   *
   * Note:
   * OpenGL already supports texture border by setting the border parameter
   * of glTexImage*D() to 1 and using a texture size of 2^m+2b and setting the
   * border pixels to the border color. In some forums it is discouraged to use
   * the border parameter as only a few of the more modern graphics cards support
   * this feature. On an ATI Radeon 9700 card, the slowed down to 0.5 fps and
   * the glyph's background got black.  So instead of using this feature we
   * handle it on our own. The only drawback is that textures might get bigger
   * because the border might require a higher power of 2 size instead of just
   * two additional pixels.
   *}
  cTexSmoothBorder = 1;

procedure TFTGlyph.StrokeBorder(var Glyph: FT_Glyph);
var
  Outline: PFT_Outline;
  OuterStroker, InnerStroker:  FT_Stroker;
  OuterNumPoints, InnerNumPoints, GlyphNumPoints: FT_UInt;
  OuterNumContours, InnerNumContours, GlyphNumContours: FT_UInt;
  OuterBorder, InnerBorder: FT_StrokerBorder;
  OutlineFlags: FT_Int;
  UseStencil: boolean;
begin
  // It is possible to extrude the borders of a glyph with FT_Glyph_Stroke
  // but it will extrude the border to the outside and the inside of a glyph
  // although we just want to extrude to the outside.
  // FT_Glyph_StrokeBorder extrudes to the outside but also fills the interior
  // (this is what we need for bold fonts).
  // In both cases the inner font and outline font (border) will overlap.
  // Normally this does not matter but it does if alpha blending is active.
  // In this case if e.g. the inner color is set to white, the outline to red
  // and alpha to 0.5 the inner part will not be white it will be pink.

  InnerStroker := nil;
  OuterStroker := nil;

  // If we are to create the interior of an outlined font (fInner = true)
  // we have to create two borders:
  // - one extruded to the outside by fOutset pixels and
  // - one extruded to the inside by almost 0 zero pixels.
  // The second one is used as a stencil for the first one, clearing the
  // interiour of the glyph.
  // The stencil is not needed to create bold fonts.
  UseStencil := (fFont.fPart = fpInner);

  Outline := @FT_OutlineGlyph(Glyph).outline;

  OuterBorder := FT_Outline_GetOutsideBorder(Outline);
  if (OuterBorder = FT_STROKER_BORDER_LEFT) then
    InnerBorder := FT_STROKER_BORDER_RIGHT
  else
    InnerBorder := FT_STROKER_BORDER_LEFT;

  { extrude outer border }

  if (FT_Stroker_New(Glyph.library_, OuterStroker) <> 0) then
    raise Exception.Create('FT_Stroker_New failed!');
  FT_Stroker_Set(
      OuterStroker,
      Round(fOutset * 64),
      FT_STROKER_LINECAP_ROUND,
      FT_STROKER_LINEJOIN_BEVEL,
      0);

  // similar to FT_Glyph_StrokeBorder(inner = FT_FALSE) but it is possible to
  // use FT_Stroker_ExportBorder() afterwards to combine inner and outer borders
  if (FT_Stroker_ParseOutline(OuterStroker, Outline, FT_FALSE) <> 0) then
    raise Exception.Create('FT_Stroker_ParseOutline failed!');

  FT_Stroker_GetBorderCounts(OuterStroker, OuterBorder, OuterNumPoints, OuterNumContours);

  { extrude inner border (= stencil) }

  if (UseStencil) then
  begin
    if (FT_Stroker_New(Glyph.library_, InnerStroker) <> 0) then
      raise Exception.Create('FT_Stroker_New failed!');
    FT_Stroker_Set(
        InnerStroker,
        63, // extrude at most one pixel to avoid a black border
        FT_STROKER_LINECAP_ROUND,
        FT_STROKER_LINEJOIN_BEVEL,
        0);

    if (FT_Stroker_ParseOutline(InnerStroker, Outline, FT_FALSE) <> 0) then
      raise Exception.Create('FT_Stroker_ParseOutline failed!');

    FT_Stroker_GetBorderCounts(InnerStroker, InnerBorder, InnerNumPoints, InnerNumContours);
  end else begin
    InnerNumPoints := 0;
    InnerNumContours := 0;
  end;

  { combine borders (subtract: OuterBorder - InnerBorder) }

  GlyphNumPoints := InnerNumPoints + OuterNumPoints;
  GlyphNumContours := InnerNumContours + OuterNumContours;

  // save flags before deletion (TODO: set them on the resulting outline)
  OutlineFlags := Outline.flags;

  // resize glyph outline to hold inner and outer border
  FT_Outline_Done(Glyph.Library_, Outline);
  if (FT_Outline_New(Glyph.Library_, GlyphNumPoints, GlyphNumContours, Outline) <> 0) then
    raise Exception.Create('FT_Outline_New failed!');

  Outline.n_points := 0;
  Outline.n_contours := 0;

  // add points to outline. The inner-border is used as a stencil.
  FT_Stroker_ExportBorder(OuterStroker, OuterBorder, Outline);
  if (UseStencil) then
    FT_Stroker_ExportBorder(InnerStroker, InnerBorder, Outline);
  if (FT_Outline_Check(outline) <> 0) then
    raise Exception.Create('FT_Stroker_ExportBorder failed!');

  if (InnerStroker <> nil) then
    FT_Stroker_Done(InnerStroker);
  if (OuterStroker <> nil) then
    FT_Stroker_Done(OuterStroker);
end;

procedure TFTGlyph.CreateTexture(LoadFlags: FT_Int32);
var
  X, Y:          integer;
  Glyph:         FT_Glyph;
  BitmapGlyph:   FT_BitmapGlyph;
  Bitmap:        PFT_Bitmap;
  BitmapLine:    PByteArray;
  BitmapBuffer:  PByteArray;
  TexBuffer:     TGLubyteDynArray;
  TexLine:       PGLubyteArray;
  CBox:          FT_BBox;
begin
  // load the Glyph for our character
  if (FT_Load_Glyph(fFont.Face, fCharIndex, LoadFlags) <> 0) then
    raise Exception.Create('FT_Load_Glyph failed');

  // move the face's glyph into a Glyph object
  if (FT_Get_Glyph(fFont.Face^.glyph, Glyph) <> 0) then
    raise Exception.Create('FT_Get_Glyph failed');

  if (fOutset > 0) then
    StrokeBorder(Glyph);

  // store scaled advance width/height in glyph-object
  fAdvance.X := fFont.Face^.glyph^.advance.x / 64 + fOutset*2;
  fAdvance.Y := fFont.Face^.glyph^.advance.y / 64 + fOutset*2;

  // get the contour's bounding box (in 1/64th pixels, not font-units)
  FT_Glyph_Get_CBox(Glyph, FT_GLYPH_BBOX_UNSCALED, CBox);
  // convert 1/64th values to double values
  fBounds.Left   := CBox.xMin / 64;
  fBounds.Right  := CBox.xMax / 64 + fOutset*2;
  fBounds.Bottom := CBox.yMin / 64;
  fBounds.Top    := CBox.yMax / 64 + fOutset*2;

  // convert the glyph to a bitmap (and destroy original glyph image).
  // Request 8 bit gray level pixel mode. 
  FT_Glyph_To_Bitmap(Glyph, FT_RENDER_MODE_NORMAL, nil, 1);
  BitmapGlyph := FT_BitmapGlyph(Glyph);

  // get bitmap offsets
  fBitmapCoords.Left := BitmapGlyph^.left - cTexSmoothBorder;
  // Note: add 1*fOutset for lifting the baseline so outset fonts to not intersect
  // with the baseline; Ceil(fOutset) for the outset pixels added to the bitmap.
  fBitmapCoords.Top  := BitmapGlyph^.top + fOutset+Ceil(fOutset) + cTexSmoothBorder;

  // make accessing the bitmap easier
  Bitmap := @BitmapGlyph^.bitmap;
  // get bitmap dimensions
  fBitmapCoords.Width  := Bitmap.width + (Ceil(fOutset) + cTexSmoothBorder)*2;
  fBitmapCoords.Height := Bitmap.rows + (Ceil(fOutset) + cTexSmoothBorder)*2;

  // get power-of-2 bitmap widths
  fTexSize.Width  :=
      NextPowerOf2(Bitmap.width + (Ceil(fOutset) + cTexSmoothBorder)*2);
  fTexSize.Height :=
      NextPowerOf2(Bitmap.rows + (Ceil(fOutset) + cTexSmoothBorder)*2);

  // texture-widths ignoring empty (power-of-2) padding space
  fTexOffset.X := fBitmapCoords.Width / fTexSize.Width;
  fTexOffset.Y := fBitmapCoords.Height / fTexSize.Height;

  // allocate memory for texture data
  SetLength(TexBuffer, fTexSize.Width * fTexSize.Height);
  FillChar(TexBuffer[0], Length(TexBuffer), 0);

  // Freetype stores the bitmap with either upper (pitch is > 0) or lower
  // (pitch < 0) glyphs line first. Set the buffer to the upper line.
  // See http://freetype.sourceforge.net/freetype2/docs/glyphs/glyphs-7.html
  if (Bitmap.pitch > 0) then
    BitmapBuffer := @Bitmap.buffer[0]
  else
    BitmapBuffer := @Bitmap.buffer[(Bitmap.rows-1) * Abs(Bitmap.pitch)];

  // copy data to texture bitmap (upper line first).
  for Y := 0 to Bitmap.rows-1 do
  begin
    // set pointer to first pixel in line that holds bitmap data.
    // Each line starts with a cTexSmoothBorder pixel and multiple outset pixels
    // that are added by Extrude() later.
    TexLine := @TexBuffer[(Y + cTexSmoothBorder + Ceil(fOutset)) * fTexSize.Width +
                          cTexSmoothBorder + Ceil(fOutset)];
    // get next lower line offset, use pitch instead of width as it tells
    // us the storage direction of the lines. In addition a line might be padded.
    BitmapLine := @BitmapBuffer[Y * Bitmap.pitch];

    // check for pixel mode and copy pixels
    // Should be 8 bit gray, but even with FT_RENDER_MODE_NORMAL, freetype
    // sometimes (e.g. 16px sized japanese fonts) fallbacks to 1 bit pixels.
    case (Bitmap.pixel_mode) of
      FT_PIXEL_MODE_GRAY: begin  // 8 bit gray
        for X := 0 to Bitmap.width-1 do
          TexLine[X] := BitmapLine[X];
      end;
      FT_PIXEL_MODE_MONO: begin  // 1 bit mono
        for X := 0 to Bitmap.width-1 do
          TexLine[X] := High(GLubyte) * ((BitmapLine[X div 8] shr (7-(X mod 8))) and $1);
      end;
      else begin
        // unhandled pixel format
      end;
    end;
  end;

  // allocate resources for textures and display lists
  glGenTextures(1, @fTexture);

  // setup texture parameters
  glBindTexture(GL_TEXTURE_2D, fTexture);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  // create alpha-map (GL_ALPHA component only).
  // TexCoord (0,0) corresponds to the top left pixel of the glyph,
  // (1,1) to the bottom right pixel. So the glyph is flipped as OpenGL uses
  // a cartesian (y-axis up) coordinate system for textures.   
  // See the cTexSmoothBorder comment for info on texture borders.
  glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, fTexSize.Width, fTexSize.Height,
      0, GL_ALPHA, GL_UNSIGNED_BYTE, @TexBuffer[0]);

  // free expanded data
  SetLength(TexBuffer, 0);

  // create the display list
  fDisplayList := glGenLists(1);

  // render to display-list
  glNewList(fDisplayList, GL_COMPILE);
    Render(false);
  glEndList();

  // free glyph data (bitmap, etc.)
  FT_Done_Glyph(Glyph);
end;

constructor TFTGlyph.Create(Font: TFTFont; ch: UCS4Char; Outset: single;
    LoadFlags: FT_Int32);
begin
  inherited Create();

  fFont := Font;
  fOutset := Outset;
  fCharCode := ch;

  // get the Freetype char-index (use default UNICODE charmap)
  fCharIndex := FT_Get_Char_Index(Font.fFace, FT_ULONG(ch));

  CreateTexture(LoadFlags);
end;

destructor TFTGlyph.Destroy;
begin
  if (fDisplayList <> 0) then
    glDeleteLists(fDisplayList, 1);
  if (fTexture <> 0) then
    glDeleteTextures(1, @fTexture);
  inherited;
end;

procedure TFTGlyph.Render(UseDisplayLists: boolean);
begin
  // use display-lists if enabled and exit
  if (UseDisplayLists) then
  begin
    glCallList(fDisplayList);
    Exit;
  end;

  glBindTexture(GL_TEXTURE_2D, fTexture);
  glPushMatrix();

  // move to top left glyph position
  glTranslatef(fBitmapCoords.Left, fBitmapCoords.Top, 0);

  // draw glyph texture
  glBegin(GL_QUADS);
    // top right
    glTexCoord2f(fTexOffset.X, 0);
    glVertex2f(fBitmapCoords.Width, 0);

    // top left
    glTexCoord2f(0, 0);
    glVertex2f(0, 0);

    // bottom left
    glTexCoord2f(0, fTexOffset.Y);
    glVertex2f(0, -fBitmapCoords.Height);

    // bottom right
    glTexCoord2f(fTexOffset.X, fTexOffset.Y);
    glVertex2f(fBitmapCoords.Width, -fBitmapCoords.Height);
  glEnd();

  glPopMatrix();
end;

procedure TFTGlyph.RenderReflection();
var
  Color: TGLColor;
  TexUpperPos: single;
  TexLowerPos: single;
  UpperPos: single;
const
  CutOff = 0.6;
begin
  glPushMatrix();
  glBindTexture(GL_TEXTURE_2D, fTexture);
  glGetFloatv(GL_CURRENT_COLOR, @Color.vals);

  // add extra space to the left of the glyph
  glTranslatef(fBitmapCoords.Left, 0, 0);

  // The upper position of the glyph, if CutOff is 1.0, it is fFont.Ascender.
  // If CutOff is set to 0.5 only half of the glyph height is displayed.
  UpperPos := fFont.Descender + fFont.Height * CutOff;

  // the glyph texture's height is just the height of the glyph but not the font
  // height. Setting a color for the upper and lower bounds of the glyph results
  // in different color gradients. So we have to set the color values for the
  // descender and ascender (as we have a cutoff, for the upper-pos here) as
  // these positions are font but not glyph specific.

  // To get the texture positions we have to enhance the texture at the top and
  // bottom by the amount from the top to ascender (rather upper-pos here) and
  // from the bottom (Height-Top) to descender. Then we have to convert those
  // heights to texture coordinates by dividing by the bitmap Height and
  // removing the power-of-2 padding space by multiplying with fTexOffset.Y
  // (as fBitmapCoords.Height corresponds to fTexOffset.Y and not 1.0).
  TexUpperPos  := -(UpperPos - fBitmapCoords.Top) / fBitmapCoords.Height * fTexOffset.Y;
  TexLowerPos := (-(fFont.Descender + fBitmapCoords.Height - fBitmapCoords.Top) /
                    fBitmapCoords.Height + 1) * fTexOffset.Y;

  // draw glyph texture
  glBegin(GL_QUADS);
    // top right
    glColor4f(Color.r, Color.g, Color.b, 0);
    glTexCoord2f(fTexOffset.X, TexUpperPos);
    glVertex2f(fBitmapCoords.Width, UpperPos);

    // top left
    glTexCoord2f(0, TexUpperPos);
    glVertex2f(0, UpperPos);

    // bottom left
    glColor4f(Color.r, Color.g, Color.b, Color.a-0.3);
    glTexCoord2f(0, TexLowerPos);
    glVertex2f(0, fFont.Descender);

    // bottom right
    glTexCoord2f(fTexOffset.X, TexLowerPos);
    glVertex2f(fBitmapCoords.Width, fFont.Descender);
  glEnd();

  glPopMatrix();

  // restore old color
  // Note: glPopAttrib(GL_CURRENT_BIT)/glPopAttrib() is much slower then
  // glGetFloatv(GL_CURRENT_COLOR, ...)/glColor4fv(...)
  glColor4fv(@Color.vals);
end;

function TFTGlyph.GetAdvance(): TPositionDbl;
begin
  Result := fAdvance;
end;

function TFTGlyph.GetBounds(): TBoundsDbl;
begin
  Result := fBounds;
end;


{*
 * TGlyphCache
 *}

constructor TGlyphCache.Create();
begin
  inherited;
  fHash := TList.Create();
end;

destructor TGlyphCache.Destroy();
begin
  // free cached glyphs
  FlushCache(false);

  // destroy TList
  fHash.Free;
  
  inherited;
end;

function TGlyphCache.FindGlyphTable(BaseCode: cardinal; out InsertPos: integer): PGlyphTable;
var
  I: integer;
  Entry: TGlyphCacheHashEntry;
begin
  Result := nil;

  for I := 0 to fHash.Count-1 do
  begin
    Entry := TGlyphCacheHashEntry(fHash[I]);

    if (Entry.BaseCode > BaseCode) then
    begin
      InsertPos := I;
      Exit;
    end;

    if (Entry.BaseCode = BaseCode) then
    begin
      InsertPos := I;
      Result := @Entry.GlyphTable;
      Exit;
    end;
  end;

  InsertPos := fHash.Count;
end;

function TGlyphCache.AddGlyph(ch: UCS4Char; const Glyph: TGlyph): boolean;
var
  BaseCode:  cardinal;
  GlyphCode: integer;
  InsertPos: integer;
  GlyphTable: PGlyphTable;
  Entry: TGlyphCacheHashEntry;
begin
  Result := false;

  BaseCode := Ord(ch) shr 8;
  GlyphTable := FindGlyphTable(BaseCode, InsertPos);
  if (GlyphTable = nil) then
  begin
    Entry := TGlyphCacheHashEntry.Create(BaseCode);
    GlyphTable := @Entry.GlyphTable;
    fHash.Insert(InsertPos, Entry);
  end;

  // get glyph table offset
  GlyphCode := Ord(ch) and $FF;
  // insert glyph into table if not present
  if (GlyphTable[GlyphCode] = nil) then
  begin
    GlyphTable[GlyphCode] := Glyph;
    Result := true;
  end;
end;

procedure TGlyphCache.DeleteGlyph(ch: UCS4Char);
var
  Table: PGlyphTable;
  TableIndex, GlyphIndex: integer;
  TableEmpty: boolean;
begin
  // find table
  Table := FindGlyphTable(Ord(ch) shr 8, TableIndex);
  if (Table = nil) then
    Exit;

  // find glyph    
  GlyphIndex := Ord(ch) and $FF;
  if (Table[GlyphIndex] <> nil) then
  begin
    // destroy glyph
    FreeAndNil(Table[GlyphIndex]);

    // check if table is empty
    TableEmpty := true;
    for GlyphIndex := 0 to High(Table^) do
    begin
      if (Table[GlyphIndex] <> nil) then
      begin
        TableEmpty := false;
        Break;
      end;
    end;

    // free empty table
    if (TableEmpty) then
    begin
      fHash.Delete(TableIndex);
    end;
  end;
end;

function TGlyphCache.GetGlyph(ch: UCS4Char): TGlyph;
var
  InsertPos: integer;
  Table: PGlyphTable;
begin
  Table := FindGlyphTable(Ord(ch) shr 8, InsertPos);
  if (Table = nil) then
    Result := nil
  else
    Result := Table[Ord(ch) and $FF];
end;

function TGlyphCache.HasGlyph(ch: UCS4Char): boolean;
begin
  Result := (GetGlyph(ch) <> nil);
end;

procedure TGlyphCache.FlushCache(KeepBaseSet: boolean);
var
  EntryIndex, TableIndex: integer;
  Entry: TGlyphCacheHashEntry;
begin
  // destroy cached glyphs
  for EntryIndex := 0 to fHash.Count-1 do
  begin
    Entry := TGlyphCacheHashEntry(fHash[EntryIndex]);

    // the base set (0-255) has BaseCode 0 as the upper bytes are 0.
    if KeepBaseSet and (Entry.fBaseCode = 0) then
      Continue;

    for TableIndex := 0 to High(Entry.GlyphTable) do
    begin
      if (Entry.GlyphTable[TableIndex] <> nil) then
        FreeAndNil(Entry.GlyphTable[TableIndex]);
    end;
    FreeAndNil(Entry);
  end;
end;


{*
 * TGlyphCacheEntry
 *}

constructor TGlyphCacheHashEntry.Create(BaseCode: cardinal);
begin
  inherited Create();
  fBaseCode := BaseCode;
end;


{*
 * TFreeType
 *}

class function TFreeType.GetLibrary(): FT_Library;
begin
  if (LibraryInst = nil) then
  begin
    // initialize freetype
    if (FT_Init_FreeType(LibraryInst) <> 0) then
      raise Exception.Create('FT_Init_FreeType failed');
  end;
  Result := LibraryInst;
end;

class procedure TFreeType.FreeLibrary();
begin
  if (LibraryInst <> nil) then
    FT_Done_FreeType(LibraryInst);
  LibraryInst := nil;
end;


{$IFDEF BITMAP_FONT}
{*
 * TBitmapFont
 *}

constructor TBitmapFont.Create(const Filename: IPath; Outline: integer;
    Baseline, Ascender, Descender: integer);
begin
  inherited Create();

  fTex := Texture.LoadTexture(true, Filename, TEXTURE_TYPE_TRANSPARENT, 0);
  fTexSize := 1024;
  fOutline := Outline;
  fBaseline  := Baseline;
  fAscender  := Ascender;
  fDescender := Descender;

  LoadFontInfo(Filename.SetExtension('.dat'));

  ResetIntern();
end;

destructor TBitmapFont.Destroy();
begin
  glDeleteTextures(1, @fTex.TexNum);
  inherited;
end;

procedure TBitmapFont.ResetIntern();
begin
  fLineSpacing := Height;
end;

procedure TBitmapFont.Reset();
begin
  inherited;
  ResetIntern();
end;

procedure TBitmapFont.CorrectWidths(WidthMult: real; WidthAdd: integer);
var
  Count: integer;
begin
  for Count := 0 to 255 do
    fWidths[Count] := Round(fWidths[Count] * WidthMult) + WidthAdd;
end;

procedure TBitmapFont.LoadFontInfo(const InfoFile: IPath);
var
  Stream: TStream;
begin
  FillChar(fWidths[0], Length(fWidths), 0);

  Stream := nil;
  try
    Stream := TBinaryFileStream.Create(InfoFile, fmOpenRead);
    Stream.Read(fWidths, 256);
  except
    raise Exception.Create('Could not read font info file ''' +  InfoFile.ToNative + '''');
  end;
  Stream.Free;
end;

function TBitmapFont.BBox(const Text: TUCS4StringArray; Advance: boolean): TBoundsDbl;
var
  LineIndex, CharIndex: integer;
  CharCode: cardinal;
  Line: UCS4String;
  LineWidth: double;
begin
  Result.Left := 0;
  Result.Right := 0;
  Result.Top := Height;
  Result.Bottom := 0;

  for LineIndex := 0 to High(Text) do
  begin
    Line := Text[LineIndex];
    LineWidth := 0;
    for CharIndex := 0 to LengthUCS4(Line)-1 do
    begin
      CharCode := Ord(Line[CharIndex]);
      if (CharCode < Length(fWidths)) then
        LineWidth := LineWidth + fWidths[CharCode];
    end;
    if (LineWidth > Result.Right) then
      Result.Right := LineWidth;
  end;
end;

procedure TBitmapFont.RenderChar(ch: UCS4Char; var AdvanceX: real);
var
  TexX, TexY:        real;
  TexR, TexB:        real;
  GlyphWidth:        real;
  PL, PT:            real;
  PR, PB:            real;
  CharCode:          cardinal;
begin
  CharCode := Ord(ch);
  if (CharCode > High(fWidths)) then
    CharCode := 0;

  GlyphWidth := fWidths[CharCode];

  // set texture positions
  TexX := (CharCode mod 16) * 1/16 + 1/32 - (GlyphWidth/2 - fOutline)/fTexSize;
  TexY := (CharCode div 16) * 1/16 + {2 texels} 2/fTexSize;
  TexR := (CharCode mod 16) * 1/16 + 1/32 + (GlyphWidth/2 + fOutline)/fTexSize;
  TexB := (1 + CharCode div 16) * 1/16 - {2 texels} 2/fTexSize;

  // set vector positions
  PL := AdvanceX - fOutline;
  PR := PL + GlyphWidth + fOutline*2;
  PB := -fBaseline;
  PT := PB + fTexSize div 16;

  (*
  if (Font.Blend) then
  begin
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  end;
  *)

  glEnable(GL_TEXTURE_2D);
  glBindTexture(GL_TEXTURE_2D, fTex.TexNum);
  
  if (not ReflectionPass) then
  begin
    glBegin(GL_QUADS);
      glTexCoord2f(TexX, TexY); glVertex2f(PL, PT);
      glTexCoord2f(TexX, TexB); glVertex2f(PL, PB);
      glTexCoord2f(TexR, TexB); glVertex2f(PR, PB);
      glTexCoord2f(TexR, TexY); glVertex2f(PR, PT);
    glEnd;
  end
  else
  begin
    glDepthRange(0, 10);
    glDepthFunc(GL_LEQUAL);
    glEnable(GL_DEPTH_TEST);

    glBegin(GL_QUADS);
      glTexCoord2f(TexX, TexY); glVertex2f(PL, PT);
      glTexCoord2f(TexX, TexB); glVertex2f(PL, PB);
      glTexCoord2f(TexR, TexB); glVertex2f(PR, PB);
      glTexCoord2f(TexR, TexY); glVertex2f(PR, PT);
    glEnd;

    glBegin(GL_QUADS);
      glTexCoord2f(TexX, TexY); glVertex2f(PL, PT);
      glTexCoord2f(TexX, TexB); glVertex2f(PL, PB);
      glTexCoord2f(TexR, TexB); glVertex2f(PR, PB);
      glTexCoord2f(TexR, TexY); glVertex2f(PR, PT);

(*
      glColor4f(fTempColor.r, fTempColor.g, fTempColor.b, 0.7);
      glTexCoord2f(TexX, TexB); glVertex3f(PL, PB, 0);
      glTexCoord2f(TexR, TexB); glVertex3f(PR, PB, 0);

      glColor4f(fTempColor.r, fTempColor.g, fTempColor.b, 0);
      glTexCoord2f(TexR, (TexY + TexB)/2); glVertex3f(PR, (PT + PB)/2, 0);
      glTexCoord2f(TexX, (TexY + TexB)/2); glVertex3f(PL, (PT + PB)/2, 0);
*)
    glEnd;

    //write the colour back
    glColor4fv(@fTempColor);

    glDisable(GL_DEPTH_TEST);
  end; // reflection

  glDisable(GL_TEXTURE_2D);
  (*
  if (Font.Blend) then
    glDisable(GL_BLEND);
  *)

  AdvanceX := AdvanceX + GlyphWidth;
end;

procedure TBitmapFont.Render(const Text: UCS4String);
var
  CharIndex: integer;
  AdvanceX: real;
begin
  // if there is no text do nothing
  if (Text = nil) or (Text[0] = 0) then
    Exit;

  //Save the current color and alpha (for reflection)
  glGetFloatv(GL_CURRENT_COLOR, @fTempColor);

  AdvanceX := 0;
  for CharIndex := 0 to LengthUCS4(Text)-1 do
  begin
    RenderChar(Text[CharIndex], AdvanceX);
  end;
end;

function TBitmapFont.GetHeight(): single;
begin
  Result := fAscender - fDescender;
end;

function TBitmapFont.GetAscender(): single;
begin
  Result := fAscender;
end;

function TBitmapFont.GetDescender(): single;
begin
  Result := fDescender;
end;

function TBitmapFont.GetUnderlinePosition(): single;
begin
  Result := -2.0;
end;

function TBitmapFont.GetUnderlineThickness(): single;
begin
  Result := 1.0;
end;

{$ENDIF BITMAP_FONT}


initialization

finalization
  TFreeType.FreeLibrary();

end.