1 2 3 4 5<!doctype html> 6<html lang="en" class="no-js"> 7 <head> 8 9 <meta charset="utf-8"> 10 <meta name="viewport" content="width=device-width,initial-scale=1"> 11 <meta http-equiv="x-ua-compatible" content="ie=edge"> 12 13 <meta name="description" content="API Reference Documentation for FreeType-2.10.4"> 14 15 16 17 <meta name="author" content="FreeType Contributors"> 18 19 20 <meta name="lang:clipboard.copy" content="Copy to clipboard"> 21 22 <meta name="lang:clipboard.copied" content="Copied to clipboard"> 23 24 <meta name="lang:search.language" content="en"> 25 26 <meta name="lang:search.pipeline.stopwords" content="True"> 27 28 <meta name="lang:search.pipeline.trimmer" content="True"> 29 30 <meta name="lang:search.result.none" content="No matching documents"> 31 32 <meta name="lang:search.result.one" content="1 matching document"> 33 34 <meta name="lang:search.result.other" content="# matching documents"> 35 36 <meta name="lang:search.tokenizer" content="[\s\-]+"> 37 38 <link 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107 <div class="md-flex__cell md-flex__cell--shrink"> 108 <label class="md-icon md-icon--menu md-header-nav__button" for="__drawer"></label> 109 </div> 110 <div class="md-flex__cell md-flex__cell--stretch"> 111 <div class="md-flex__ellipsis md-header-nav__title" data-md-component="title"> 112 113 <span class="md-header-nav__topic"> 114 FreeType-2.10.4 API Reference 115 </span> 116 <span class="md-header-nav__topic"> 117 118 Incremental Loading 119 120 </span> 121 122 </div> 123 </div> 124 <div class="md-flex__cell md-flex__cell--shrink"> 125 126 <label class="md-icon md-icon--search md-header-nav__button" for="__search"></label> 127 128<div class="md-search" data-md-component="search" role="dialog"> 129 <label class="md-search__overlay" for="__search"></label> 130 <div class="md-search__inner" role="search"> 131 <form class="md-search__form" name="search"> 132 <input type="text" class="md-search__input" aria-label="search" name="query" placeholder="Search" autocapitalize="off" autocorrect="off" autocomplete="off" spellcheck="false" data-md-component="query" data-md-state="active"> 133 <label class="md-icon md-search__icon" for="__search"></label> 134 <button type="reset" class="md-icon md-search__icon" data-md-component="reset" tabindex="-1"> 135  136 </button> 137 </form> 138 <div class="md-search__output"> 139 <div class="md-search__scrollwrap" data-md-scrollfix> 140 <div class="md-search-result" data-md-component="result"> 141 <div class="md-search-result__meta"> 142 Type to start searching 143 </div> 144 <ol class="md-search-result__list"></ol> 145 </div> 146 </div> 147 </div> 148 </div> 149</div> 150 151 </div> 152 153 </div> 154 </nav> 155</header> 156 157 <div class="md-container"> 158 159 160 161 162 <main class="md-main" role="main"> 163 <div class="md-main__inner md-grid" data-md-component="container"> 164 165 166 <div class="md-sidebar md-sidebar--primary" data-md-component="navigation"> 167 <div class="md-sidebar__scrollwrap"> 168 <div class="md-sidebar__inner"> 169 <nav class="md-nav md-nav--primary" data-md-level="0"> 170 <label class="md-nav__title md-nav__title--site" for="__drawer"> 171 <a href="." title="FreeType-2.10.4 API Reference" class="md-nav__button md-logo"> 172 173 <img alt="logo" src="images/favico.ico" width="48" height="48"> 174 175 </a> 176 FreeType-2.10.4 API Reference 177 </label> 178 179 <ul class="md-nav__list" data-md-scrollfix> 180 181 182 183 184 185 186 <li class="md-nav__item"> 187 <a href="index.html" title="TOC" class="md-nav__link"> 188 TOC 189 </a> 190 </li> 191 192 193 194 195 196 197 198 <li class="md-nav__item"> 199 <a href="ft2-index.html" title="Index" class="md-nav__link"> 200 Index 201 </a> 202 </li> 203 204 205 206 207 208 209 210 <li class="md-nav__item md-nav__item--nested"> 211 212 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-3" type="checkbox" id="nav-3"> 213 214 <label class="md-nav__link" for="nav-3"> 215 General Remarks 216 </label> 217 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 218 <label class="md-nav__title" for="nav-3"> 219 General Remarks 220 </label> 221 <ul class="md-nav__list" data-md-scrollfix> 222 223 224 225 226 227 228 229 <li class="md-nav__item"> 230 <a href="ft2-header_inclusion.html" title="FreeType's header inclusion scheme" class="md-nav__link"> 231 FreeType's header inclusion scheme 232 </a> 233 </li> 234 235 236 237 238 239 240 241 <li class="md-nav__item"> 242 <a href="ft2-user_allocation.html" title="User allocation" class="md-nav__link"> 243 User allocation 244 </a> 245 </li> 246 247 248 </ul> 249 </nav> 250 </li> 251 252 253 254 255 256 257 258 <li class="md-nav__item md-nav__item--nested"> 259 260 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-4" type="checkbox" id="nav-4"> 261 262 <label class="md-nav__link" for="nav-4"> 263 Core API 264 </label> 265 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 266 <label class="md-nav__title" for="nav-4"> 267 Core API 268 </label> 269 <ul class="md-nav__list" data-md-scrollfix> 270 271 272 273 274 275 276 277 <li class="md-nav__item"> 278 <a href="ft2-version.html" title="FreeType Version" class="md-nav__link"> 279 FreeType Version 280 </a> 281 </li> 282 283 284 285 286 287 288 289 <li class="md-nav__item"> 290 <a href="ft2-basic_types.html" title="Basic Data Types" class="md-nav__link"> 291 Basic Data Types 292 </a> 293 </li> 294 295 296 297 298 299 300 301 <li class="md-nav__item"> 302 <a href="ft2-base_interface.html" title="Base Interface" class="md-nav__link"> 303 Base Interface 304 </a> 305 </li> 306 307 308 309 310 311 312 313 <li class="md-nav__item"> 314 <a href="ft2-glyph_variants.html" title="Unicode Variation Sequences" class="md-nav__link"> 315 Unicode Variation Sequences 316 </a> 317 </li> 318 319 320 321 322 323 324 325 <li class="md-nav__item"> 326 <a href="ft2-color_management.html" title="Glyph Color Management" class="md-nav__link"> 327 Glyph Color Management 328 </a> 329 </li> 330 331 332 333 334 335 336 337 <li class="md-nav__item"> 338 <a href="ft2-layer_management.html" title="Glyph Layer Management" class="md-nav__link"> 339 Glyph Layer Management 340 </a> 341 </li> 342 343 344 345 346 347 348 349 <li class="md-nav__item"> 350 <a href="ft2-glyph_management.html" title="Glyph Management" class="md-nav__link"> 351 Glyph Management 352 </a> 353 </li> 354 355 356 357 358 359 360 361 <li class="md-nav__item"> 362 <a href="ft2-mac_specific.html" title="Mac Specific Interface" class="md-nav__link"> 363 Mac Specific Interface 364 </a> 365 </li> 366 367 368 369 370 371 372 373 <li class="md-nav__item"> 374 <a href="ft2-sizes_management.html" title="Size Management" class="md-nav__link"> 375 Size Management 376 </a> 377 </li> 378 379 380 381 382 383 384 385 <li class="md-nav__item"> 386 <a href="ft2-header_file_macros.html" title="Header File Macros" class="md-nav__link"> 387 Header File Macros 388 </a> 389 </li> 390 391 392 </ul> 393 </nav> 394 </li> 395 396 397 398 399 400 401 402 <li class="md-nav__item md-nav__item--nested"> 403 404 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-5" type="checkbox" id="nav-5"> 405 406 <label class="md-nav__link" for="nav-5"> 407 Format-Specific API 408 </label> 409 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 410 <label class="md-nav__title" for="nav-5"> 411 Format-Specific API 412 </label> 413 <ul class="md-nav__list" data-md-scrollfix> 414 415 416 417 418 419 420 421 <li class="md-nav__item"> 422 <a href="ft2-multiple_masters.html" title="Multiple Masters" class="md-nav__link"> 423 Multiple Masters 424 </a> 425 </li> 426 427 428 429 430 431 432 433 <li class="md-nav__item"> 434 <a href="ft2-truetype_tables.html" title="TrueType Tables" class="md-nav__link"> 435 TrueType Tables 436 </a> 437 </li> 438 439 440 441 442 443 444 445 <li class="md-nav__item"> 446 <a href="ft2-type1_tables.html" title="Type 1 Tables" class="md-nav__link"> 447 Type 1 Tables 448 </a> 449 </li> 450 451 452 453 454 455 456 457 <li class="md-nav__item"> 458 <a href="ft2-sfnt_names.html" title="SFNT Names" class="md-nav__link"> 459 SFNT Names 460 </a> 461 </li> 462 463 464 465 466 467 468 469 <li class="md-nav__item"> 470 <a href="ft2-bdf_fonts.html" title="BDF and PCF Files" class="md-nav__link"> 471 BDF and PCF Files 472 </a> 473 </li> 474 475 476 477 478 479 480 481 <li class="md-nav__item"> 482 <a href="ft2-cid_fonts.html" title="CID Fonts" class="md-nav__link"> 483 CID Fonts 484 </a> 485 </li> 486 487 488 489 490 491 492 493 <li class="md-nav__item"> 494 <a href="ft2-pfr_fonts.html" title="PFR Fonts" class="md-nav__link"> 495 PFR Fonts 496 </a> 497 </li> 498 499 500 501 502 503 504 505 <li class="md-nav__item"> 506 <a href="ft2-winfnt_fonts.html" title="Window FNT Files" class="md-nav__link"> 507 Window FNT Files 508 </a> 509 </li> 510 511 512 513 514 515 516 517 <li class="md-nav__item"> 518 <a href="ft2-font_formats.html" title="Font Formats" class="md-nav__link"> 519 Font Formats 520 </a> 521 </li> 522 523 524 525 526 527 528 529 <li class="md-nav__item"> 530 <a href="ft2-gasp_table.html" title="Gasp Table" class="md-nav__link"> 531 Gasp Table 532 </a> 533 </li> 534 535 536 </ul> 537 </nav> 538 </li> 539 540 541 542 543 544 545 546 <li class="md-nav__item md-nav__item--nested"> 547 548 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-6" type="checkbox" id="nav-6"> 549 550 <label class="md-nav__link" for="nav-6"> 551 Controlling FreeType Modules 552 </label> 553 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 554 <label class="md-nav__title" for="nav-6"> 555 Controlling FreeType Modules 556 </label> 557 <ul class="md-nav__list" data-md-scrollfix> 558 559 560 561 562 563 564 565 <li class="md-nav__item"> 566 <a href="ft2-auto_hinter.html" title="The auto-hinter" class="md-nav__link"> 567 The auto-hinter 568 </a> 569 </li> 570 571 572 573 574 575 576 577 <li class="md-nav__item"> 578 <a href="ft2-cff_driver.html" title="The CFF driver" class="md-nav__link"> 579 The CFF driver 580 </a> 581 </li> 582 583 584 585 586 587 588 589 <li class="md-nav__item"> 590 <a href="ft2-t1_cid_driver.html" title="The Type 1 and CID drivers" class="md-nav__link"> 591 The Type 1 and CID drivers 592 </a> 593 </li> 594 595 596 597 598 599 600 601 <li class="md-nav__item"> 602 <a href="ft2-tt_driver.html" title="The TrueType driver" class="md-nav__link"> 603 The TrueType driver 604 </a> 605 </li> 606 607 608 609 610 611 612 613 <li class="md-nav__item"> 614 <a href="ft2-pcf_driver.html" title="The PCF driver" class="md-nav__link"> 615 The PCF driver 616 </a> 617 </li> 618 619 620 621 622 623 624 625 <li class="md-nav__item"> 626 <a href="ft2-properties.html" title="Driver properties" class="md-nav__link"> 627 Driver properties 628 </a> 629 </li> 630 631 632 633 634 635 636 637 <li class="md-nav__item"> 638 <a href="ft2-parameter_tags.html" title="Parameter Tags" class="md-nav__link"> 639 Parameter Tags 640 </a> 641 </li> 642 643 644 645 646 647 648 649 <li class="md-nav__item"> 650 <a href="ft2-lcd_rendering.html" title="Subpixel Rendering" class="md-nav__link"> 651 Subpixel Rendering 652 </a> 653 </li> 654 655 656 </ul> 657 </nav> 658 </li> 659 660 661 662 663 664 665 666 <li class="md-nav__item md-nav__item--nested"> 667 668 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-7" type="checkbox" id="nav-7"> 669 670 <label class="md-nav__link" for="nav-7"> 671 Cache Sub-System 672 </label> 673 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 674 <label class="md-nav__title" for="nav-7"> 675 Cache Sub-System 676 </label> 677 <ul class="md-nav__list" data-md-scrollfix> 678 679 680 681 682 683 684 685 <li class="md-nav__item"> 686 <a href="ft2-cache_subsystem.html" title="Cache Sub-System" class="md-nav__link"> 687 Cache Sub-System 688 </a> 689 </li> 690 691 692 </ul> 693 </nav> 694 </li> 695 696 697 698 699 700 701 702 <li class="md-nav__item md-nav__item--nested"> 703 704 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-8" type="checkbox" id="nav-8"> 705 706 <label class="md-nav__link" for="nav-8"> 707 Support API 708 </label> 709 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 710 <label class="md-nav__title" for="nav-8"> 711 Support API 712 </label> 713 <ul class="md-nav__list" data-md-scrollfix> 714 715 716 717 718 719 720 721 <li class="md-nav__item"> 722 <a href="ft2-computations.html" title="Computations" class="md-nav__link"> 723 Computations 724 </a> 725 </li> 726 727 728 729 730 731 732 733 <li class="md-nav__item"> 734 <a href="ft2-list_processing.html" title="List Processing" class="md-nav__link"> 735 List Processing 736 </a> 737 </li> 738 739 740 741 742 743 744 745 <li class="md-nav__item"> 746 <a href="ft2-outline_processing.html" title="Outline Processing" class="md-nav__link"> 747 Outline Processing 748 </a> 749 </li> 750 751 752 753 754 755 756 757 <li class="md-nav__item"> 758 <a href="ft2-quick_advance.html" title="Quick retrieval of advance values" class="md-nav__link"> 759 Quick retrieval of advance values 760 </a> 761 </li> 762 763 764 765 766 767 768 769 <li class="md-nav__item"> 770 <a href="ft2-bitmap_handling.html" title="Bitmap Handling" class="md-nav__link"> 771 Bitmap Handling 772 </a> 773 </li> 774 775 776 777 778 779 780 781 <li class="md-nav__item"> 782 <a href="ft2-raster.html" title="Scanline Converter" class="md-nav__link"> 783 Scanline Converter 784 </a> 785 </li> 786 787 788 789 790 791 792 793 <li class="md-nav__item"> 794 <a href="ft2-glyph_stroker.html" title="Glyph Stroker" class="md-nav__link"> 795 Glyph Stroker 796 </a> 797 </li> 798 799 800 801 802 803 804 805 <li class="md-nav__item"> 806 <a href="ft2-system_interface.html" title="System Interface" class="md-nav__link"> 807 System Interface 808 </a> 809 </li> 810 811 812 813 814 815 816 817 <li class="md-nav__item"> 818 <a href="ft2-module_management.html" title="Module Management" class="md-nav__link"> 819 Module Management 820 </a> 821 </li> 822 823 824 825 826 827 828 829 <li class="md-nav__item"> 830 <a href="ft2-gzip.html" title="GZIP Streams" class="md-nav__link"> 831 GZIP Streams 832 </a> 833 </li> 834 835 836 837 838 839 840 841 <li class="md-nav__item"> 842 <a href="ft2-lzw.html" title="LZW Streams" class="md-nav__link"> 843 LZW Streams 844 </a> 845 </li> 846 847 848 849 850 851 852 853 <li class="md-nav__item"> 854 <a href="ft2-bzip2.html" title="BZIP2 Streams" class="md-nav__link"> 855 BZIP2 Streams 856 </a> 857 </li> 858 859 860 </ul> 861 </nav> 862 </li> 863 864 865 866 867 868 869 870 <li class="md-nav__item md-nav__item--nested"> 871 872 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-9" type="checkbox" id="nav-9"> 873 874 <label class="md-nav__link" for="nav-9"> 875 Error Codes 876 </label> 877 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 878 <label class="md-nav__title" for="nav-9"> 879 Error Codes 880 </label> 881 <ul class="md-nav__list" data-md-scrollfix> 882 883 884 885 886 887 888 889 <li class="md-nav__item"> 890 <a href="ft2-error_enumerations.html" title="Error Enumerations" class="md-nav__link"> 891 Error Enumerations 892 </a> 893 </li> 894 895 896 897 898 899 900 901 <li class="md-nav__item"> 902 <a href="ft2-error_code_values.html" title="Error Code Values" class="md-nav__link"> 903 Error Code Values 904 </a> 905 </li> 906 907 908 </ul> 909 </nav> 910 </li> 911 912 913 914 915 916 917 918 919 920 <li class="md-nav__item md-nav__item--active md-nav__item--nested"> 921 922 <input class="md-toggle md-nav__toggle" data-md-toggle="nav-10" type="checkbox" id="nav-10" checked> 923 924 <label class="md-nav__link" for="nav-10"> 925 Miscellaneous 926 </label> 927 <nav class="md-nav" data-md-component="collapsible" data-md-level="1"> 928 <label class="md-nav__title" for="nav-10"> 929 Miscellaneous 930 </label> 931 <ul class="md-nav__list" data-md-scrollfix> 932 933 934 935 936 937 938 939 <li class="md-nav__item"> 940 <a href="ft2-gx_validation.html" title="TrueTypeGX/AAT Validation" class="md-nav__link"> 941 TrueTypeGX/AAT Validation 942 </a> 943 </li> 944 945 946 947 948 949 950 951 952 953 <li class="md-nav__item md-nav__item--active"> 954 955 <input class="md-toggle md-nav__toggle" data-md-toggle="toc" type="checkbox" id="__toc"> 956 957 958 959 960 <label class="md-nav__link md-nav__link--active" for="__toc"> 961 Incremental Loading 962 </label> 963 964 <a href="ft2-incremental.html" title="Incremental Loading" class="md-nav__link md-nav__link--active"> 965 Incremental Loading 966 </a> 967 968 969<nav class="md-nav md-nav--secondary"> 970 971 972 973 974 975 <label class="md-nav__title" for="__toc">Table of contents</label> 976 <ul class="md-nav__list" data-md-scrollfix> 977 978 <li class="md-nav__item"> 979 <a href="#synopsis" class="md-nav__link"> 980 Synopsis 981 </a> 982 983</li> 984 985 <li class="md-nav__item"> 986 <a href="#ft_incremental" class="md-nav__link"> 987 FT_Incremental 988 </a> 989 990</li> 991 992 <li class="md-nav__item"> 993 <a href="#ft_incremental_metricsrec" class="md-nav__link"> 994 FT_Incremental_MetricsRec 995 </a> 996 997</li> 998 999 <li class="md-nav__item"> 1000 <a href="#ft_incremental_metrics" class="md-nav__link"> 1001 FT_Incremental_Metrics 1002 </a> 1003 1004</li> 1005 1006 <li class="md-nav__item"> 1007 <a href="#ft_incremental_getglyphdatafunc" class="md-nav__link"> 1008 FT_Incremental_GetGlyphDataFunc 1009 </a> 1010 1011</li> 1012 1013 <li class="md-nav__item"> 1014 <a href="#ft_incremental_freeglyphdatafunc" class="md-nav__link"> 1015 FT_Incremental_FreeGlyphDataFunc 1016 </a> 1017 1018</li> 1019 1020 <li class="md-nav__item"> 1021 <a href="#ft_incremental_getglyphmetricsfunc" class="md-nav__link"> 1022 FT_Incremental_GetGlyphMetricsFunc 1023 </a> 1024 1025</li> 1026 1027 <li class="md-nav__item"> 1028 <a href="#ft_incremental_funcsrec" class="md-nav__link"> 1029 FT_Incremental_FuncsRec 1030 </a> 1031 1032</li> 1033 1034 <li class="md-nav__item"> 1035 <a href="#ft_incremental_interfacerec" class="md-nav__link"> 1036 FT_Incremental_InterfaceRec 1037 </a> 1038 1039</li> 1040 1041 <li class="md-nav__item"> 1042 <a href="#ft_incremental_interface" class="md-nav__link"> 1043 FT_Incremental_Interface 1044 </a> 1045 1046</li> 1047 1048 1049 1050 1051 1052 </ul> 1053 1054</nav> 1055 1056 </li> 1057 1058 1059 1060 1061 1062 1063 1064 <li class="md-nav__item"> 1065 <a href="ft2-truetype_engine.html" title="The TrueType Engine" class="md-nav__link"> 1066 The TrueType Engine 1067 </a> 1068 </li> 1069 1070 1071 1072 1073 1074 1075 1076 <li class="md-nav__item"> 1077 <a href="ft2-ot_validation.html" title="OpenType Validation" class="md-nav__link"> 1078 OpenType Validation 1079 </a> 1080 </li> 1081 1082 1083 </ul> 1084 </nav> 1085 </li> 1086 1087 1088 </ul> 1089</nav> 1090 </div> 1091 </div> 1092 </div> 1093 1094 1095 <div class="md-sidebar md-sidebar--secondary" data-md-component="toc"> 1096 <div class="md-sidebar__scrollwrap"> 1097 <div class="md-sidebar__inner"> 1098 1099<nav class="md-nav md-nav--secondary"> 1100 1101 1102 1103 1104 1105 <label class="md-nav__title" for="__toc">Table of contents</label> 1106 <ul class="md-nav__list" data-md-scrollfix> 1107 1108 <li class="md-nav__item"> 1109 <a href="#synopsis" class="md-nav__link"> 1110 Synopsis 1111 </a> 1112 1113</li> 1114 1115 <li class="md-nav__item"> 1116 <a href="#ft_incremental" class="md-nav__link"> 1117 FT_Incremental 1118 </a> 1119 1120</li> 1121 1122 <li class="md-nav__item"> 1123 <a href="#ft_incremental_metricsrec" class="md-nav__link"> 1124 FT_Incremental_MetricsRec 1125 </a> 1126 1127</li> 1128 1129 <li class="md-nav__item"> 1130 <a href="#ft_incremental_metrics" class="md-nav__link"> 1131 FT_Incremental_Metrics 1132 </a> 1133 1134</li> 1135 1136 <li class="md-nav__item"> 1137 <a href="#ft_incremental_getglyphdatafunc" class="md-nav__link"> 1138 FT_Incremental_GetGlyphDataFunc 1139 </a> 1140 1141</li> 1142 1143 <li class="md-nav__item"> 1144 <a href="#ft_incremental_freeglyphdatafunc" class="md-nav__link"> 1145 FT_Incremental_FreeGlyphDataFunc 1146 </a> 1147 1148</li> 1149 1150 <li class="md-nav__item"> 1151 <a href="#ft_incremental_getglyphmetricsfunc" class="md-nav__link"> 1152 FT_Incremental_GetGlyphMetricsFunc 1153 </a> 1154 1155</li> 1156 1157 <li class="md-nav__item"> 1158 <a href="#ft_incremental_funcsrec" class="md-nav__link"> 1159 FT_Incremental_FuncsRec 1160 </a> 1161 1162</li> 1163 1164 <li class="md-nav__item"> 1165 <a href="#ft_incremental_interfacerec" class="md-nav__link"> 1166 FT_Incremental_InterfaceRec 1167 </a> 1168 1169</li> 1170 1171 <li class="md-nav__item"> 1172 <a href="#ft_incremental_interface" class="md-nav__link"> 1173 FT_Incremental_Interface 1174 </a> 1175 1176</li> 1177 1178 1179 1180 1181 1182 </ul> 1183 1184</nav> 1185 </div> 1186 </div> 1187 </div> 1188 1189 1190 <div class="md-content"> 1191 <article class="md-content__inner md-typeset"> 1192 1193 1194 1195 <p><a href="https://www.freetype.org">FreeType</a> » <a href="../">Docs</a> » <a href="index.html#miscellaneous">Miscellaneous</a> » Incremental Loading</p> 1196<hr /> 1197<h1 id="incremental-loading">Incremental Loading<a class="headerlink" href="#incremental-loading" title="Permanent link">¶</a></h1> 1198<h2 id="synopsis">Synopsis<a class="headerlink" href="#synopsis" title="Permanent link">¶</a></h2> 1199<p>This section contains various functions used to perform so-called ‘incremental’ glyph loading. This is a mode where all glyphs loaded from a given <code><a href="ft2-base_interface.html#ft_face">FT_Face</a></code> are provided by the client application.</p> 1200<p>Apart from that, all other tables are loaded normally from the font file. This mode is useful when FreeType is used within another engine, e.g., a PostScript Imaging Processor.</p> 1201<p>To enable this mode, you must use <code><a href="ft2-base_interface.html#ft_open_face">FT_Open_Face</a></code>, passing an <code><a href="ft2-base_interface.html#ft_parameter">FT_Parameter</a></code> with the <code><a href="ft2-parameter_tags.html#ft_param_tag_incremental">FT_PARAM_TAG_INCREMENTAL</a></code> tag and an <code><a href="ft2-incremental.html#ft_incremental_interface">FT_Incremental_Interface</a></code> value. See the comments for <code><a href="ft2-incremental.html#ft_incremental_interfacerec">FT_Incremental_InterfaceRec</a></code> for an example.</p> 1202<h2 id="ft_incremental">FT_Incremental<a class="headerlink" href="#ft_incremental" title="Permanent link">¶</a></h2> 1203<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1204<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <span class="keyword">struct</span> FT_IncrementalRec_* <b>FT_Incremental</b>; 1205</code></pre></div> 1206 1207<p>An opaque type describing a user-provided object used to implement ‘incremental’ glyph loading within FreeType. This is used to support embedded fonts in certain environments (e.g., PostScript interpreters), where the glyph data isn't in the font file, or must be overridden by different values.</p> 1208<h4>note</h4> 1209 1210<p>It is up to client applications to create and implement <code><a href="ft2-incremental.html#ft_incremental">FT_Incremental</a></code> objects, as long as they provide implementations for the methods <code><a href="ft2-incremental.html#ft_incremental_getglyphdatafunc">FT_Incremental_GetGlyphDataFunc</a></code>, <code><a href="ft2-incremental.html#ft_incremental_freeglyphdatafunc">FT_Incremental_FreeGlyphDataFunc</a></code> and <code><a href="ft2-incremental.html#ft_incremental_getglyphmetricsfunc">FT_Incremental_GetGlyphMetricsFunc</a></code>.</p> 1211<p>See the description of <code><a href="ft2-incremental.html#ft_incremental_interfacerec">FT_Incremental_InterfaceRec</a></code> to understand how to use incremental objects with FreeType.</p> 1212<hr> 1213 1214<h2 id="ft_incremental_metricsrec">FT_Incremental_MetricsRec<a class="headerlink" href="#ft_incremental_metricsrec" title="Permanent link">¶</a></h2> 1215<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1216<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <span class="keyword">struct</span> FT_Incremental_MetricsRec_ 1217 { 1218 <a href="ft2-basic_types.html#ft_long">FT_Long</a> bearing_x; 1219 <a href="ft2-basic_types.html#ft_long">FT_Long</a> bearing_y; 1220 <a href="ft2-basic_types.html#ft_long">FT_Long</a> advance; 1221 <a href="ft2-basic_types.html#ft_long">FT_Long</a> advance_v; /* since 2.3.12 */ 1222 1223 } <b>FT_Incremental_MetricsRec</b>; 1224</code></pre></div> 1225 1226<p>A small structure used to contain the basic glyph metrics returned by the <code><a href="ft2-incremental.html#ft_incremental_getglyphmetricsfunc">FT_Incremental_GetGlyphMetricsFunc</a></code> method.</p> 1227<h4>fields</h4> 1228 1229<table class="fields"> 1230<tr><td class="val" id="bearing_x">bearing_x</td><td class="desc"> 1231<p>Left bearing, in font units.</p> 1232</td></tr> 1233<tr><td class="val" id="bearing_y">bearing_y</td><td class="desc"> 1234<p>Top bearing, in font units.</p> 1235</td></tr> 1236<tr><td class="val" id="advance">advance</td><td class="desc"> 1237<p>Horizontal component of glyph advance, in font units.</p> 1238</td></tr> 1239<tr><td class="val" id="advance_v">advance_v</td><td class="desc"> 1240<p>Vertical component of glyph advance, in font units.</p> 1241</td></tr> 1242</table> 1243 1244<h4>note</h4> 1245 1246<p>These correspond to horizontal or vertical metrics depending on the value of the <code>vertical</code> argument to the function <code><a href="ft2-incremental.html#ft_incremental_getglyphmetricsfunc">FT_Incremental_GetGlyphMetricsFunc</a></code>.</p> 1247<hr> 1248 1249<h2 id="ft_incremental_metrics">FT_Incremental_Metrics<a class="headerlink" href="#ft_incremental_metrics" title="Permanent link">¶</a></h2> 1250<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1251<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <span class="keyword">struct</span> FT_Incremental_MetricsRec_* <b>FT_Incremental_Metrics</b>; 1252</code></pre></div> 1253 1254<p>A handle to an <code><a href="ft2-incremental.html#ft_incremental_metricsrec">FT_Incremental_MetricsRec</a></code> structure.</p> 1255<hr> 1256 1257<h2 id="ft_incremental_getglyphdatafunc">FT_Incremental_GetGlyphDataFunc<a class="headerlink" href="#ft_incremental_getglyphdatafunc" title="Permanent link">¶</a></h2> 1258<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1259<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <a href="ft2-basic_types.html#ft_error">FT_Error</a> 1260 (*<b>FT_Incremental_GetGlyphDataFunc</b>)( <a href="ft2-incremental.html#ft_incremental">FT_Incremental</a> incremental, 1261 <a href="ft2-basic_types.html#ft_uint">FT_UInt</a> glyph_index, 1262 <a href="ft2-basic_types.html#ft_data">FT_Data</a>* adata ); 1263</code></pre></div> 1264 1265<p>A function called by FreeType to access a given glyph's data bytes during <code><a href="ft2-base_interface.html#ft_load_glyph">FT_Load_Glyph</a></code> or <code><a href="ft2-base_interface.html#ft_load_char">FT_Load_Char</a></code> if incremental loading is enabled.</p> 1266<p>Note that the format of the glyph's data bytes depends on the font file format. For TrueType, it must correspond to the raw bytes within the ‘glyf’ table. For PostScript formats, it must correspond to the <strong>unencrypted</strong> charstring bytes, without any <code>lenIV</code> header. It is undefined for any other format.</p> 1267<h4>input</h4> 1268 1269<table class="fields"> 1270<tr><td class="val" id="incremental">incremental</td><td class="desc"> 1271<p>Handle to an opaque <code><a href="ft2-incremental.html#ft_incremental">FT_Incremental</a></code> handle provided by the client application.</p> 1272</td></tr> 1273<tr><td class="val" id="glyph_index">glyph_index</td><td class="desc"> 1274<p>Index of relevant glyph.</p> 1275</td></tr> 1276</table> 1277 1278<h4>output</h4> 1279 1280<table class="fields"> 1281<tr><td class="val" id="adata">adata</td><td class="desc"> 1282<p>A structure describing the returned glyph data bytes (which will be accessed as a read-only byte block).</p> 1283</td></tr> 1284</table> 1285 1286<h4>return</h4> 1287 1288<p>FreeType error code. 0 means success.</p> 1289<h4>note</h4> 1290 1291<p>If this function returns successfully the method <code><a href="ft2-incremental.html#ft_incremental_freeglyphdatafunc">FT_Incremental_FreeGlyphDataFunc</a></code> will be called later to release the data bytes.</p> 1292<p>Nested calls to <code><a href="ft2-incremental.html#ft_incremental_getglyphdatafunc">FT_Incremental_GetGlyphDataFunc</a></code> can happen for compound glyphs.</p> 1293<hr> 1294 1295<h2 id="ft_incremental_freeglyphdatafunc">FT_Incremental_FreeGlyphDataFunc<a class="headerlink" href="#ft_incremental_freeglyphdatafunc" title="Permanent link">¶</a></h2> 1296<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1297<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <span class="keyword">void</span> 1298 (*<b>FT_Incremental_FreeGlyphDataFunc</b>)( <a href="ft2-incremental.html#ft_incremental">FT_Incremental</a> incremental, 1299 <a href="ft2-basic_types.html#ft_data">FT_Data</a>* data ); 1300</code></pre></div> 1301 1302<p>A function used to release the glyph data bytes returned by a successful call to <code><a href="ft2-incremental.html#ft_incremental_getglyphdatafunc">FT_Incremental_GetGlyphDataFunc</a></code>.</p> 1303<h4>input</h4> 1304 1305<table class="fields"> 1306<tr><td class="val" id="incremental">incremental</td><td class="desc"> 1307<p>A handle to an opaque <code><a href="ft2-incremental.html#ft_incremental">FT_Incremental</a></code> handle provided by the client application.</p> 1308</td></tr> 1309<tr><td class="val" id="data">data</td><td class="desc"> 1310<p>A structure describing the glyph data bytes (which will be accessed as a read-only byte block).</p> 1311</td></tr> 1312</table> 1313 1314<hr> 1315 1316<h2 id="ft_incremental_getglyphmetricsfunc">FT_Incremental_GetGlyphMetricsFunc<a class="headerlink" href="#ft_incremental_getglyphmetricsfunc" title="Permanent link">¶</a></h2> 1317<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1318<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <a href="ft2-basic_types.html#ft_error">FT_Error</a> 1319 (*<b>FT_Incremental_GetGlyphMetricsFunc</b>) 1320 ( <a href="ft2-incremental.html#ft_incremental">FT_Incremental</a> incremental, 1321 <a href="ft2-basic_types.html#ft_uint">FT_UInt</a> glyph_index, 1322 <a href="ft2-basic_types.html#ft_bool">FT_Bool</a> vertical, 1323 <a href="ft2-incremental.html#ft_incremental_metricsrec">FT_Incremental_MetricsRec</a> *ametrics ); 1324</code></pre></div> 1325 1326<p>A function used to retrieve the basic metrics of a given glyph index before accessing its data. This is necessary because, in certain formats like TrueType, the metrics are stored in a different place from the glyph images proper.</p> 1327<h4>input</h4> 1328 1329<table class="fields"> 1330<tr><td class="val" id="incremental">incremental</td><td class="desc"> 1331<p>A handle to an opaque <code><a href="ft2-incremental.html#ft_incremental">FT_Incremental</a></code> handle provided by the client application.</p> 1332</td></tr> 1333<tr><td class="val" id="glyph_index">glyph_index</td><td class="desc"> 1334<p>Index of relevant glyph.</p> 1335</td></tr> 1336<tr><td class="val" id="vertical">vertical</td><td class="desc"> 1337<p>If true, return vertical metrics.</p> 1338</td></tr> 1339<tr><td class="val" id="ametrics">ametrics</td><td class="desc"> 1340<p>This parameter is used for both input and output. The original glyph metrics, if any, in font units. If metrics are not available all the values must be set to zero.</p> 1341</td></tr> 1342</table> 1343 1344<h4>output</h4> 1345 1346<table class="fields"> 1347<tr><td class="val" id="ametrics">ametrics</td><td class="desc"> 1348<p>The replacement glyph metrics in font units.</p> 1349</td></tr> 1350</table> 1351 1352<hr> 1353 1354<h2 id="ft_incremental_funcsrec">FT_Incremental_FuncsRec<a class="headerlink" href="#ft_incremental_funcsrec" title="Permanent link">¶</a></h2> 1355<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1356<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <span class="keyword">struct</span> FT_Incremental_FuncsRec_ 1357 { 1358 <a href="ft2-incremental.html#ft_incremental_getglyphdatafunc">FT_Incremental_GetGlyphDataFunc</a> get_glyph_data; 1359 <a href="ft2-incremental.html#ft_incremental_freeglyphdatafunc">FT_Incremental_FreeGlyphDataFunc</a> free_glyph_data; 1360 <a href="ft2-incremental.html#ft_incremental_getglyphmetricsfunc">FT_Incremental_GetGlyphMetricsFunc</a> get_glyph_metrics; 1361 1362 } <b>FT_Incremental_FuncsRec</b>; 1363</code></pre></div> 1364 1365<p>A table of functions for accessing fonts that load data incrementally. Used in <code><a href="ft2-incremental.html#ft_incremental_interfacerec">FT_Incremental_InterfaceRec</a></code>.</p> 1366<h4>fields</h4> 1367 1368<table class="fields"> 1369<tr><td class="val" id="get_glyph_data">get_glyph_data</td><td class="desc"> 1370<p>The function to get glyph data. Must not be null.</p> 1371</td></tr> 1372<tr><td class="val" id="free_glyph_data">free_glyph_data</td><td class="desc"> 1373<p>The function to release glyph data. Must not be null.</p> 1374</td></tr> 1375<tr><td class="val" id="get_glyph_metrics">get_glyph_metrics</td><td class="desc"> 1376<p>The function to get glyph metrics. May be null if the font does not provide overriding glyph metrics.</p> 1377</td></tr> 1378</table> 1379 1380<hr> 1381 1382<h2 id="ft_incremental_interfacerec">FT_Incremental_InterfaceRec<a class="headerlink" href="#ft_incremental_interfacerec" title="Permanent link">¶</a></h2> 1383<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1384<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <span class="keyword">struct</span> FT_Incremental_InterfaceRec_ 1385 { 1386 <span class="keyword">const</span> <a href="ft2-incremental.html#ft_incremental_funcsrec">FT_Incremental_FuncsRec</a>* funcs; 1387 <a href="ft2-incremental.html#ft_incremental">FT_Incremental</a> object; 1388 1389 } <b>FT_Incremental_InterfaceRec</b>; 1390</code></pre></div> 1391 1392<p>A structure to be used with <code><a href="ft2-base_interface.html#ft_open_face">FT_Open_Face</a></code> to indicate that the user wants to support incremental glyph loading. You should use it with <code><a href="ft2-parameter_tags.html#ft_param_tag_incremental">FT_PARAM_TAG_INCREMENTAL</a></code> as in the following example: 1393<div class="highlight"><pre><span></span><code> FT_Incremental_InterfaceRec inc_int; 1394 FT_Parameter parameter; 1395 FT_Open_Args open_args; 1396 1397 1398 // set up incremental descriptor 1399 inc_int.funcs = my_funcs; 1400 inc_int.object = my_object; 1401 1402 // set up optional parameter 1403 parameter.tag = FT_PARAM_TAG_INCREMENTAL; 1404 parameter.data = &inc_int; 1405 1406 // set up FT_Open_Args structure 1407 open_args.flags = FT_OPEN_PATHNAME | FT_OPEN_PARAMS; 1408 open_args.pathname = my_font_pathname; 1409 open_args.num_params = 1; 1410 open_args.params = &parameter; // we use one optional argument 1411 1412 // open the font 1413 error = FT_Open_Face( library, &open_args, index, &face ); 1414 ... 1415</code></pre></div></p> 1416<hr> 1417 1418<h2 id="ft_incremental_interface">FT_Incremental_Interface<a class="headerlink" href="#ft_incremental_interface" title="Permanent link">¶</a></h2> 1419<p>Defined in FT_INCREMENTAL_H (freetype/ftincrem.h).</p> 1420<div class = "codehilite"><pre><code> <span class="keyword">typedef</span> <a href="ft2-incremental.html#ft_incremental_interfacerec">FT_Incremental_InterfaceRec</a>* <b>FT_Incremental_Interface</b>; 1421</code></pre></div> 1422 1423<p>A pointer to an <code><a href="ft2-incremental.html#ft_incremental_interfacerec">FT_Incremental_InterfaceRec</a></code> structure.</p> 1424<hr> 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 </article> 1436 </div> 1437 </div> 1438 </main> 1439 1440 1441<footer class="md-footer"> 1442 1443 <div class="md-footer-nav"> 1444 <nav class="md-footer-nav__inner md-grid"> 1445 1446 <a href="ft2-gx_validation.html" title="TrueTypeGX/AAT Validation" class="md-flex md-footer-nav__link md-footer-nav__link--prev" rel="prev"> 1447 <div class="md-flex__cell md-flex__cell--shrink"> 1448 <i class="md-icon md-icon--arrow-back md-footer-nav__button"></i> 1449 </div> 1450 <div class="md-flex__cell md-flex__cell--stretch md-footer-nav__title"> 1451 <span class="md-flex__ellipsis"> 1452 <span class="md-footer-nav__direction"> 1453 Previous 1454 </span> 1455 TrueTypeGX/AAT Validation 1456 </span> 1457 </div> 1458 </a> 1459 1460 1461 <a href="ft2-truetype_engine.html" title="The TrueType Engine" class="md-flex md-footer-nav__link md-footer-nav__link--next" rel="next"> 1462 <div class="md-flex__cell md-flex__cell--stretch md-footer-nav__title"> 1463 <span class="md-flex__ellipsis"> 1464 <span class="md-footer-nav__direction"> 1465 Next 1466 </span> 1467 The TrueType Engine 1468 </span> 1469 </div> 1470 <div class="md-flex__cell md-flex__cell--shrink"> 1471 <i class="md-icon md-icon--arrow-forward md-footer-nav__button"></i> 1472 </div> 1473 </a> 1474 1475 </nav> 1476 </div> 1477 1478 <div class="md-footer-meta md-typeset"> 1479 <div class="md-footer-meta__inner md-grid"> 1480 <div class="md-footer-copyright"> 1481 1482 <div class="md-footer-copyright__highlight"> 1483 Copyright 2020 <a href = "https://www.freetype.org/license.html">The FreeType Project</a>. 1484 </div> 1485 1486 powered by 1487 <a href="https://www.mkdocs.org" target="_blank" rel="noopener">MkDocs</a> 1488 and 1489 <a href="https://squidfunk.github.io/mkdocs-material/" target="_blank" rel="noopener"> 1490 Material for MkDocs</a> 1491 </div> 1492 1493 </div> 1494 </div> 1495</footer> 1496 1497 </div> 1498 1499 <script src="assets/javascripts/application.c33a9706.js"></script> 1500 1501 <script>app.initialize({version:"1.1",url:{base:"."}})</script> 1502 1503 <script src="javascripts/extra.js"></script> 1504 1505 1506 </body> 1507</html>