ftotval.h (5346B)
1 /**************************************************************************** 2 * 3 * ftotval.h 4 * 5 * FreeType API for validating OpenType tables (specification). 6 * 7 * Copyright (C) 2004-2025 by 8 * David Turner, Robert Wilhelm, and Werner Lemberg. 9 * 10 * This file is part of the FreeType project, and may only be used, 11 * modified, and distributed under the terms of the FreeType project 12 * license, LICENSE.TXT. By continuing to use, modify, or distribute 13 * this file you indicate that you have read the license and 14 * understand and accept it fully. 15 * 16 */ 17 18 19 /**************************************************************************** 20 * 21 * 22 * Warning: This module might be moved to a different library in the 23 * future to avoid a tight dependency between FreeType and the 24 * OpenType specification. 25 * 26 * 27 */ 28 29 30 #ifndef FTOTVAL_H_ 31 #define FTOTVAL_H_ 32 33 #include <freetype/freetype.h> 34 35 #ifdef FREETYPE_H 36 #error "freetype.h of FreeType 1 has been loaded!" 37 #error "Please fix the directory search order for header files" 38 #error "so that freetype.h of FreeType 2 is found first." 39 #endif 40 41 42 FT_BEGIN_HEADER 43 44 45 /************************************************************************** 46 * 47 * @section: 48 * ot_validation 49 * 50 * @title: 51 * OpenType Validation 52 * 53 * @abstract: 54 * An API to validate OpenType tables. 55 * 56 * @description: 57 * This section contains the declaration of functions to validate some 58 * OpenType tables (BASE, GDEF, GPOS, GSUB, JSTF, MATH). 59 * 60 * @order: 61 * FT_OpenType_Validate 62 * FT_OpenType_Free 63 * 64 * FT_VALIDATE_OTXXX 65 * 66 */ 67 68 69 /************************************************************************** 70 * 71 * @enum: 72 * FT_VALIDATE_OTXXX 73 * 74 * @description: 75 * A list of bit-field constants used with @FT_OpenType_Validate to 76 * indicate which OpenType tables should be validated. 77 * 78 * @values: 79 * FT_VALIDATE_BASE :: 80 * Validate BASE table. 81 * 82 * FT_VALIDATE_GDEF :: 83 * Validate GDEF table. 84 * 85 * FT_VALIDATE_GPOS :: 86 * Validate GPOS table. 87 * 88 * FT_VALIDATE_GSUB :: 89 * Validate GSUB table. 90 * 91 * FT_VALIDATE_JSTF :: 92 * Validate JSTF table. 93 * 94 * FT_VALIDATE_MATH :: 95 * Validate MATH table. 96 * 97 * FT_VALIDATE_OT :: 98 * Validate all OpenType tables (BASE, GDEF, GPOS, GSUB, JSTF, MATH). 99 * 100 */ 101 #define FT_VALIDATE_BASE 0x0100 102 #define FT_VALIDATE_GDEF 0x0200 103 #define FT_VALIDATE_GPOS 0x0400 104 #define FT_VALIDATE_GSUB 0x0800 105 #define FT_VALIDATE_JSTF 0x1000 106 #define FT_VALIDATE_MATH 0x2000 107 108 #define FT_VALIDATE_OT ( FT_VALIDATE_BASE | \ 109 FT_VALIDATE_GDEF | \ 110 FT_VALIDATE_GPOS | \ 111 FT_VALIDATE_GSUB | \ 112 FT_VALIDATE_JSTF | \ 113 FT_VALIDATE_MATH ) 114 115 116 /************************************************************************** 117 * 118 * @function: 119 * FT_OpenType_Validate 120 * 121 * @description: 122 * Validate various OpenType tables to assure that all offsets and 123 * indices are valid. The idea is that a higher-level library that 124 * actually does the text layout can access those tables without error 125 * checking (which can be quite time consuming). 126 * 127 * @input: 128 * face :: 129 * A handle to the input face. 130 * 131 * validation_flags :: 132 * A bit field that specifies the tables to be validated. See 133 * @FT_VALIDATE_OTXXX for possible values. 134 * 135 * @output: 136 * BASE_table :: 137 * A pointer to the BASE table. 138 * 139 * GDEF_table :: 140 * A pointer to the GDEF table. 141 * 142 * GPOS_table :: 143 * A pointer to the GPOS table. 144 * 145 * GSUB_table :: 146 * A pointer to the GSUB table. 147 * 148 * JSTF_table :: 149 * A pointer to the JSTF table. 150 * 151 * @return: 152 * FreeType error code. 0~means success. 153 * 154 * @note: 155 * This function only works with OpenType fonts, returning an error 156 * otherwise. 157 * 158 * After use, the application should deallocate the five tables with 159 * @FT_OpenType_Free. A `NULL` value indicates that the table either 160 * doesn't exist in the font, or the application hasn't asked for 161 * validation. 162 */ 163 FT_EXPORT( FT_Error ) 164 FT_OpenType_Validate( FT_Face face, 165 FT_UInt validation_flags, 166 FT_Bytes *BASE_table, 167 FT_Bytes *GDEF_table, 168 FT_Bytes *GPOS_table, 169 FT_Bytes *GSUB_table, 170 FT_Bytes *JSTF_table ); 171 172 173 /************************************************************************** 174 * 175 * @function: 176 * FT_OpenType_Free 177 * 178 * @description: 179 * Free the buffer allocated by OpenType validator. 180 * 181 * @input: 182 * face :: 183 * A handle to the input face. 184 * 185 * table :: 186 * The pointer to the buffer that is allocated by 187 * @FT_OpenType_Validate. 188 * 189 * @note: 190 * This function must be used to free the buffer allocated by 191 * @FT_OpenType_Validate only. 192 */ 193 FT_EXPORT( void ) 194 FT_OpenType_Free( FT_Face face, 195 FT_Bytes table ); 196 197 198 /* */ 199 200 201 FT_END_HEADER 202 203 #endif /* FTOTVAL_H_ */ 204 205 206 /* END */