1 | /***************************************************************************/
|
---|
2 | /* */
|
---|
3 | /* ftincrem.h */
|
---|
4 | /* */
|
---|
5 | /* FreeType incremental loading (specification). */
|
---|
6 | /* */
|
---|
7 | /* Copyright 2002, 2003 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 | #ifndef __FTINCREM_H__
|
---|
20 | #define __FTINCREM_H__
|
---|
21 |
|
---|
22 | #include <ft2build.h>
|
---|
23 | #include FT_FREETYPE_H
|
---|
24 |
|
---|
25 | #ifdef FREETYPE_H
|
---|
26 | #error "freetype.h of FreeType 1 has been loaded!"
|
---|
27 | #error "Please fix the directory search order for header files"
|
---|
28 | #error "so that freetype.h of FreeType 2 is found first."
|
---|
29 | #endif
|
---|
30 |
|
---|
31 |
|
---|
32 | FT_BEGIN_HEADER
|
---|
33 |
|
---|
34 |
|
---|
35 | /***************************************************************************
|
---|
36 | *
|
---|
37 | * @type:
|
---|
38 | * FT_Incremental
|
---|
39 | *
|
---|
40 | * @description:
|
---|
41 | * An opaque type describing a user-provided object used to implement
|
---|
42 | * "incremental" glyph loading within FreeType. This is used to support
|
---|
43 | * embedded fonts in certain environments (e.g. Postscript interpreters),
|
---|
44 | * where the glyph data isn't in the font file, or must be overridden by
|
---|
45 | * different values.
|
---|
46 | *
|
---|
47 | * @note:
|
---|
48 | * It is up to client applications to create and implement @FT_Incremental
|
---|
49 | * objects, as long as they provide implementations for the methods
|
---|
50 | * @FT_Incremental_GetGlyphDataFunc, @FT_Incremental_FreeGlyphDataFunc
|
---|
51 | * and @FT_Incremental_GetGlyphMetricsFunc.
|
---|
52 | *
|
---|
53 | * See the description of @FT_Incremental_InterfaceRec to understand how
|
---|
54 | * to use incremental objects with FreeType.
|
---|
55 | */
|
---|
56 | typedef struct FT_IncrementalRec_* FT_Incremental;
|
---|
57 |
|
---|
58 |
|
---|
59 | /***************************************************************************
|
---|
60 | *
|
---|
61 | * @struct:
|
---|
62 | * FT_Incremental_Metrics
|
---|
63 | *
|
---|
64 | * @description:
|
---|
65 | * A small structure used to contain the basic glyph metrics returned
|
---|
66 | * by the @FT_Incremental_GetGlyphMetricsFunc method.
|
---|
67 | *
|
---|
68 | * @fields:
|
---|
69 | * bearing_x ::
|
---|
70 | * Left bearing, in font units.
|
---|
71 | *
|
---|
72 | * bearing_y ::
|
---|
73 | * Top bearing, in font units.
|
---|
74 | *
|
---|
75 | * advance ::
|
---|
76 | * Glyph advance, in font units.
|
---|
77 | *
|
---|
78 | * @note:
|
---|
79 | * These correspond to horizontal or vertical metrics depending on the
|
---|
80 | * value of the 'vertical' argument to the function
|
---|
81 | * @FT_Incremental_GetGlyphMetricsFunc.
|
---|
82 | */
|
---|
83 | typedef struct FT_Incremental_MetricsRec_
|
---|
84 | {
|
---|
85 | FT_Long bearing_x;
|
---|
86 | FT_Long bearing_y;
|
---|
87 | FT_Long advance;
|
---|
88 |
|
---|
89 | } FT_Incremental_MetricsRec, *FT_Incremental_Metrics;
|
---|
90 |
|
---|
91 |
|
---|
92 | /***************************************************************************
|
---|
93 | *
|
---|
94 | * @type:
|
---|
95 | * FT_Incremental_GetGlyphDataFunc
|
---|
96 | *
|
---|
97 | * @description:
|
---|
98 | * A function called by FreeType to access a given glyph's data bytes
|
---|
99 | * during @FT_Load_Glyph or @FT_Load_Char if incremental loading is
|
---|
100 | * enabled.
|
---|
101 | *
|
---|
102 | * Note that the format of the glyph's data bytes depends on the font
|
---|
103 | * file format. For TrueType, it must correspond to the raw bytes within
|
---|
104 | * the 'glyf' table. For Postscript formats, it must correspond to the
|
---|
105 | * *unencrypted* charstring bytes, without any 'lenIV' header. It is
|
---|
106 | * undefined for any other format.
|
---|
107 | *
|
---|
108 | * @input:
|
---|
109 | * incremental ::
|
---|
110 | * Handle to an opaque @FT_Incremental handle provided by the client
|
---|
111 | * application.
|
---|
112 | *
|
---|
113 | * glyph_index ::
|
---|
114 | * Index of relevant glyph.
|
---|
115 | *
|
---|
116 | * @output:
|
---|
117 | * adata ::
|
---|
118 | * A structure describing the returned glyph data bytes (which will be
|
---|
119 | * accessed as a read-only byte block).
|
---|
120 | *
|
---|
121 | * @return:
|
---|
122 | * FreeType error code. 0 means success.
|
---|
123 | *
|
---|
124 | * @note:
|
---|
125 | * If this function returns succesfully the method
|
---|
126 | * @FT_Incremental_FreeGlyphDataFunc will be called later to release
|
---|
127 | * the data bytes.
|
---|
128 | *
|
---|
129 | * Nested calls to @FT_Incremental_GetGlyphDataFunc can happen for
|
---|
130 | * compound glyphs.
|
---|
131 | */
|
---|
132 | typedef FT_Error
|
---|
133 | (*FT_Incremental_GetGlyphDataFunc)( FT_Incremental incremental,
|
---|
134 | FT_UInt glyph_index,
|
---|
135 | FT_Data* adata );
|
---|
136 |
|
---|
137 |
|
---|
138 | /***************************************************************************
|
---|
139 | *
|
---|
140 | * @type:
|
---|
141 | * FT_Incremental_FreeGlyphDataFunc
|
---|
142 | *
|
---|
143 | * @description:
|
---|
144 | * A function used to release the glyph data bytes returned by a
|
---|
145 | * successful call to @FT_Incremental_GetGlyphDataFunc.
|
---|
146 | *
|
---|
147 | * @input:
|
---|
148 | * incremental ::
|
---|
149 | * A handle to an opaque @FT_Incremental handle provided by the client
|
---|
150 | * application.
|
---|
151 | *
|
---|
152 | * data ::
|
---|
153 | * A structure describing the glyph data bytes (which will be accessed
|
---|
154 | * as a read-only byte block).
|
---|
155 | */
|
---|
156 | typedef void
|
---|
157 | (*FT_Incremental_FreeGlyphDataFunc)( FT_Incremental incremental,
|
---|
158 | FT_Data* data );
|
---|
159 |
|
---|
160 |
|
---|
161 | /***************************************************************************
|
---|
162 | *
|
---|
163 | * @type:
|
---|
164 | * FT_Incremental_GetGlyphMetricsFunc
|
---|
165 | *
|
---|
166 | * @description:
|
---|
167 | * A function used to retrieve the basic metrics of a given glyph index
|
---|
168 | * before accessing its data. This is necessary because, in certain
|
---|
169 | * formats like TrueType, the metrics are stored in a different place from
|
---|
170 | * the glyph images proper.
|
---|
171 | *
|
---|
172 | * @input:
|
---|
173 | * incremental ::
|
---|
174 | * A handle to an opaque @FT_Incremental handle provided by the client
|
---|
175 | * application.
|
---|
176 | *
|
---|
177 | * glyph_index ::
|
---|
178 | * Index of relevant glyph.
|
---|
179 | *
|
---|
180 | * vertical ::
|
---|
181 | * If true, return vertical metrics.
|
---|
182 | *
|
---|
183 | * ametrics ::
|
---|
184 | * This parameter is used for both input and output.
|
---|
185 | * The original glyph metrics, if any, in font units. If metrics are
|
---|
186 | * not available all the values must be set to zero.
|
---|
187 | *
|
---|
188 | * @output:
|
---|
189 | * ametrics ::
|
---|
190 | * The replacement glyph metrics in font units.
|
---|
191 | *
|
---|
192 | */
|
---|
193 | typedef FT_Error
|
---|
194 | (*FT_Incremental_GetGlyphMetricsFunc)
|
---|
195 | ( FT_Incremental incremental,
|
---|
196 | FT_UInt glyph_index,
|
---|
197 | FT_Bool vertical,
|
---|
198 | FT_Incremental_MetricsRec *ametrics );
|
---|
199 |
|
---|
200 |
|
---|
201 | /**************************************************************************
|
---|
202 | *
|
---|
203 | * @struct:
|
---|
204 | * FT_Incremental_FuncsRec
|
---|
205 | *
|
---|
206 | * @description:
|
---|
207 | * A table of functions for accessing fonts that load data
|
---|
208 | * incrementally. Used in @FT_Incremental_InterfaceRec.
|
---|
209 | *
|
---|
210 | * @fields:
|
---|
211 | * get_glyph_data ::
|
---|
212 | * The function to get glyph data. Must not be null.
|
---|
213 | *
|
---|
214 | * free_glyph_data ::
|
---|
215 | * The function to release glyph data. Must not be null.
|
---|
216 | *
|
---|
217 | * get_glyph_metrics ::
|
---|
218 | * The function to get glyph metrics. May be null if the font does
|
---|
219 | * not provide overriding glyph metrics.
|
---|
220 | */
|
---|
221 | typedef struct FT_Incremental_FuncsRec_
|
---|
222 | {
|
---|
223 | FT_Incremental_GetGlyphDataFunc get_glyph_data;
|
---|
224 | FT_Incremental_FreeGlyphDataFunc free_glyph_data;
|
---|
225 | FT_Incremental_GetGlyphMetricsFunc get_glyph_metrics;
|
---|
226 |
|
---|
227 | } FT_Incremental_FuncsRec;
|
---|
228 |
|
---|
229 |
|
---|
230 | /***************************************************************************
|
---|
231 | *
|
---|
232 | * @struct:
|
---|
233 | * FT_Incremental_InterfaceRec
|
---|
234 | *
|
---|
235 | * @description:
|
---|
236 | * A structure to be used with @FT_Open_Face to indicate that the user
|
---|
237 | * wants to support incremental glyph loading. You should use it with
|
---|
238 | * @FT_PARAM_TAG_INCREMENTAL as in the following example:
|
---|
239 | *
|
---|
240 | * {
|
---|
241 | * FT_Incremental_InterfaceRec inc_int;
|
---|
242 | * FT_Parameter parameter;
|
---|
243 | * FT_Open_Args open_args;
|
---|
244 | *
|
---|
245 | *
|
---|
246 | * // set up incremental descriptor
|
---|
247 | * inc_int.funcs = my_funcs;
|
---|
248 | * inc_int.object = my_object;
|
---|
249 | *
|
---|
250 | * // set up optional parameter
|
---|
251 | * parameter.tag = FT_PARAM_TAG_INCREMENTAL;
|
---|
252 | * parameter.data = &inc_int;
|
---|
253 | *
|
---|
254 | * // set up FT_Open_Args structure
|
---|
255 | * open_args.flags = FT_OPEN_PATHNAME | FT_OPEN_PARAMS;
|
---|
256 | * open_args.pathname = my_font_pathname;
|
---|
257 | * open_args.num_params = 1;
|
---|
258 | * open_args.params = ¶meter; // we use one optional argument
|
---|
259 | *
|
---|
260 | * // open the font
|
---|
261 | * error = FT_Open_Face( library, &open_args, index, &face );
|
---|
262 | * ...
|
---|
263 | * }
|
---|
264 | */
|
---|
265 | typedef struct FT_Incremental_InterfaceRec_
|
---|
266 | {
|
---|
267 | const FT_Incremental_FuncsRec* funcs;
|
---|
268 | FT_Incremental object;
|
---|
269 |
|
---|
270 | } FT_Incremental_InterfaceRec;
|
---|
271 |
|
---|
272 |
|
---|
273 | /***************************************************************************
|
---|
274 | *
|
---|
275 | * @constant:
|
---|
276 | * FT_PARAM_TAG_INCREMENTAL
|
---|
277 | *
|
---|
278 | * @description:
|
---|
279 | * A constant used as the tag of @FT_Parameter structures to indicate
|
---|
280 | * an incremental loading object to be used by FreeType.
|
---|
281 | *
|
---|
282 | */
|
---|
283 | #define FT_PARAM_TAG_INCREMENTAL FT_MAKE_TAG( 'i', 'n', 'c', 'r' )
|
---|
284 |
|
---|
285 | /* */
|
---|
286 |
|
---|
287 | FT_END_HEADER
|
---|
288 |
|
---|
289 | #endif /* __FTINCREM_H__ */
|
---|
290 |
|
---|
291 |
|
---|
292 | /* END */
|
---|