/src/freetype/include/freetype/ftoutln.h
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1/***************************************************************************/ 2/* */ 3/* ftoutln.h */ 4/* */ 5/* Support for the FT_Outline type used to store glyph shapes of */ 6/* most scalable font formats (specification). */ 7/* */ 8/* Copyright 1996-2003, 2005-2011 by */ 9/* David Turner, Robert Wilhelm, and Werner Lemberg. */ 10/* */ 11/* This file is part of the FreeType project, and may only be used, */ 12/* modified, and distributed under the terms of the FreeType project */ 13/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 14/* this file you indicate that you have read the license and */ 15/* understand and accept it fully. */ 16/* */ 17/***************************************************************************/ 18 19 20#ifndef __FTOUTLN_H__ 21#define __FTOUTLN_H__ 22 23 24#include <ft2build.h> 25#include FT_FREETYPE_H 26 27#ifdef FREETYPE_H 28#error "freetype.h of FreeType 1 has been loaded!" 29#error "Please fix the directory search order for header files" 30#error "so that freetype.h of FreeType 2 is found first." 31#endif 32 33 34FT_BEGIN_HEADER 35 36 37 /*************************************************************************/ 38 /* */ 39 /* <Section> */ 40 /* outline_processing */ 41 /* */ 42 /* <Title> */ 43 /* Outline Processing */ 44 /* */ 45 /* <Abstract> */ 46 /* Functions to create, transform, and render vectorial glyph images. */ 47 /* */ 48 /* <Description> */ 49 /* This section contains routines used to create and destroy scalable */ 50 /* glyph images known as `outlines'. These can also be measured, */ 51 /* transformed, and converted into bitmaps and pixmaps. */ 52 /* */ 53 /* <Order> */ 54 /* FT_Outline */ 55 /* FT_OUTLINE_FLAGS */ 56 /* FT_Outline_New */ 57 /* FT_Outline_Done */ 58 /* FT_Outline_Copy */ 59 /* FT_Outline_Translate */ 60 /* FT_Outline_Transform */ 61 /* FT_Outline_Embolden */ 62 /* FT_Outline_Reverse */ 63 /* FT_Outline_Check */ 64 /* */ 65 /* FT_Outline_Get_CBox */ 66 /* FT_Outline_Get_BBox */ 67 /* */ 68 /* FT_Outline_Get_Bitmap */ 69 /* FT_Outline_Render */ 70 /* */ 71 /* FT_Outline_Decompose */ 72 /* FT_Outline_Funcs */ 73 /* FT_Outline_MoveTo_Func */ 74 /* FT_Outline_LineTo_Func */ 75 /* FT_Outline_ConicTo_Func */ 76 /* FT_Outline_CubicTo_Func */ 77 /* */ 78 /*************************************************************************/ 79 80 81 /*************************************************************************/ 82 /* */ 83 /* <Function> */ 84 /* FT_Outline_Decompose */ 85 /* */ 86 /* <Description> */ 87 /* Walk over an outline's structure to decompose it into individual */ 88 /* segments and Bézier arcs. This function also emits `move to' */ 89 /* operations to indicate the start of new contours in the outline. */ 90 /* */ 91 /* <Input> */ 92 /* outline :: A pointer to the source target. */ 93 /* */ 94 /* func_interface :: A table of `emitters', i.e., function pointers */ 95 /* called during decomposition to indicate path */ 96 /* operations. */ 97 /* */ 98 /* <InOut> */ 99 /* user :: A typeless pointer which is passed to each */ 100 /* emitter during the decomposition. It can be */ 101 /* used to store the state during the */ 102 /* decomposition. */ 103 /* */ 104 /* <Return> */ 105 /* FreeType error code. 0~means success. */ 106 /* */ 107 FT_EXPORT( FT_Error ) 108 FT_Outline_Decompose( FT_Outline* outline, 109 const FT_Outline_Funcs* func_interface, 110 void* user ); 111 112 113 /*************************************************************************/ 114 /* */ 115 /* <Function> */ 116 /* FT_Outline_New */ 117 /* */ 118 /* <Description> */ 119 /* Create a new outline of a given size. */ 120 /* */ 121 /* <Input> */ 122 /* library :: A handle to the library object from where the */ 123 /* outline is allocated. Note however that the new */ 124 /* outline will *not* necessarily be *freed*, when */ 125 /* destroying the library, by @FT_Done_FreeType. */ 126 /* */ 127 /* numPoints :: The maximal number of points within the outline. */ 128 /* */ 129 /* numContours :: The maximal number of contours within the outline. */ 130 /* */ 131 /* <Output> */ 132 /* anoutline :: A handle to the new outline. */ 133 /* */ 134 /* <Return> */ 135 /* FreeType error code. 0~means success. */ 136 /* */ 137 /* <Note> */ 138 /* The reason why this function takes a `library' parameter is simply */ 139 /* to use the library's memory allocator. */ 140 /* */ 141 FT_EXPORT( FT_Error ) 142 FT_Outline_New( FT_Library library, 143 FT_UInt numPoints, 144 FT_Int numContours, 145 FT_Outline *anoutline ); 146 147 148 FT_EXPORT( FT_Error ) 149 FT_Outline_New_Internal( FT_Memory memory, 150 FT_UInt numPoints, 151 FT_Int numContours, 152 FT_Outline *anoutline ); 153 154 155 /*************************************************************************/ 156 /* */ 157 /* <Function> */ 158 /* FT_Outline_Done */ 159 /* */ 160 /* <Description> */ 161 /* Destroy an outline created with @FT_Outline_New. */ 162 /* */ 163 /* <Input> */ 164 /* library :: A handle of the library object used to allocate the */ 165 /* outline. */ 166 /* */ 167 /* outline :: A pointer to the outline object to be discarded. */ 168 /* */ 169 /* <Return> */ 170 /* FreeType error code. 0~means success. */ 171 /* */ 172 /* <Note> */ 173 /* If the outline's `owner' field is not set, only the outline */ 174 /* descriptor will be released. */ 175 /* */ 176 /* The reason why this function takes an `library' parameter is */ 177 /* simply to use ft_mem_free(). */ 178 /* */ 179 FT_EXPORT( FT_Error ) 180 FT_Outline_Done( FT_Library library, 181 FT_Outline* outline ); 182 183 184 FT_EXPORT( FT_Error ) 185 FT_Outline_Done_Internal( FT_Memory memory, 186 FT_Outline* outline ); 187 188 189 /*************************************************************************/ 190 /* */ 191 /* <Function> */ 192 /* FT_Outline_Check */ 193 /* */ 194 /* <Description> */ 195 /* Check the contents of an outline descriptor. */ 196 /* */ 197 /* <Input> */ 198 /* outline :: A handle to a source outline. */ 199 /* */ 200 /* <Return> */ 201 /* FreeType error code. 0~means success. */ 202 /* */ 203 FT_EXPORT( FT_Error ) 204 FT_Outline_Check( FT_Outline* outline ); 205 206 207 /*************************************************************************/ 208 /* */ 209 /* <Function> */ 210 /* FT_Outline_Get_CBox */ 211 /* */ 212 /* <Description> */ 213 /* Return an outline's `control box'. The control box encloses all */ 214 /* the outline's points, including Bézier control points. Though it */ 215 /* coincides with the exact bounding box for most glyphs, it can be */ 216 /* slightly larger in some situations (like when rotating an outline */ 217 /* which contains Bézier outside arcs). */ 218 /* */ 219 /* Computing the control box is very fast, while getting the bounding */ 220 /* box can take much more time as it needs to walk over all segments */ 221 /* and arcs in the outline. To get the latter, you can use the */ 222 /* `ftbbox' component which is dedicated to this single task. */ 223 /* */ 224 /* <Input> */ 225 /* outline :: A pointer to the source outline descriptor. */ 226 /* */ 227 /* <Output> */ 228 /* acbox :: The outline's control box. */ 229 /* */ 230 /* <Note> */ 231 /* See @FT_Glyph_Get_CBox for a discussion of tricky fonts. */ 232 /* */ 233 FT_EXPORT( void ) 234 FT_Outline_Get_CBox( const FT_Outline* outline, 235 FT_BBox *acbox ); 236 237 238 /*************************************************************************/ 239 /* */ 240 /* <Function> */ 241 /* FT_Outline_Translate */ 242 /* */ 243 /* <Description> */ 244 /* Apply a simple translation to the points of an outline. */ 245 /* */ 246 /* <InOut> */ 247 /* outline :: A pointer to the target outline descriptor. */ 248 /* */ 249 /* <Input> */ 250 /* xOffset :: The horizontal offset. */ 251 /* */ 252 /* yOffset :: The vertical offset. */ 253 /* */ 254 FT_EXPORT( void ) 255 FT_Outline_Translate( const FT_Outline* outline, 256 FT_Pos xOffset, 257 FT_Pos yOffset ); 258 259 260 /*************************************************************************/ 261 /* */ 262 /* <Function> */ 263 /* FT_Outline_Copy */ 264 /* */ 265 /* <Description> */ 266 /* Copy an outline into another one. Both objects must have the */ 267 /* same sizes (number of points & number of contours) when this */ 268 /* function is called. */ 269 /* */ 270 /* <Input> */ 271 /* source :: A handle to the source outline. */ 272 /* */ 273 /* <Output> */ 274 /* target :: A handle to the target outline. */ 275 /* */ 276 /* <Return> */ 277 /* FreeType error code. 0~means success. */ 278 /* */ 279 FT_EXPORT( FT_Error ) 280 FT_Outline_Copy( const FT_Outline* source, 281 FT_Outline *target ); 282 283 284 /*************************************************************************/ 285 /* */ 286 /* <Function> */ 287 /* FT_Outline_Transform */ 288 /* */ 289 /* <Description> */ 290 /* Apply a simple 2x2 matrix to all of an outline's points. Useful */ 291 /* for applying rotations, slanting, flipping, etc. */ 292 /* */ 293 /* <InOut> */ 294 /* outline :: A pointer to the target outline descriptor. */ 295 /* */ 296 /* <Input> */ 297 /* matrix :: A pointer to the transformation matrix. */ 298 /* */ 299 /* <Note> */ 300 /* You can use @FT_Outline_Translate if you need to translate the */ 301 /* outline's points. */ 302 /* */ 303 FT_EXPORT( void ) 304 FT_Outline_Transform( const FT_Outline* outline, 305 const FT_Matrix* matrix ); 306 307 308 /*************************************************************************/ 309 /* */ 310 /* <Function> */ 311 /* FT_Outline_Embolden */ 312 /* */ 313 /* <Description> */ 314 /* Embolden an outline. The new outline will be at most 4~times */ 315 /* `strength' pixels wider and higher. You may think of the left and */ 316 /* bottom borders as unchanged. */ 317 /* */ 318 /* Negative `strength' values to reduce the outline thickness are */ 319 /* possible also. */ 320 /* */ 321 /* <InOut> */ 322 /* outline :: A handle to the target outline. */ 323 /* */ 324 /* <Input> */ 325 /* strength :: How strong the glyph is emboldened. Expressed in */ 326 /* 26.6 pixel format. */ 327 /* */ 328 /* <Return> */ 329 /* FreeType error code. 0~means success. */ 330 /* */ 331 /* <Note> */ 332 /* The used algorithm to increase or decrease the thickness of the */ 333 /* glyph doesn't change the number of points; this means that certain */ 334 /* situations like acute angles or intersections are sometimes */ 335 /* handled incorrectly. */ 336 /* */ 337 /* If you need `better' metrics values you should call */ 338 /* @FT_Outline_Get_CBox or @FT_Outline_Get_BBox. */ 339 /* */ 340 /* Example call: */ 341 /* */ 342 /* { */ 343 /* FT_Load_Glyph( face, index, FT_LOAD_DEFAULT ); */ 344 /* if ( face->slot->format == FT_GLYPH_FORMAT_OUTLINE ) */ 345 /* FT_Outline_Embolden( &face->slot->outline, strength ); */ 346 /* } */ 347 /* */ 348 FT_EXPORT( FT_Error ) 349 FT_Outline_Embolden( FT_Outline* outline, 350 FT_Pos strength ); 351 352 353 /*************************************************************************/ 354 /* */ 355 /* <Function> */ 356 /* FT_Outline_Reverse */ 357 /* */ 358 /* <Description> */ 359 /* Reverse the drawing direction of an outline. This is used to */ 360 /* ensure consistent fill conventions for mirrored glyphs. */ 361 /* */ 362 /* <InOut> */ 363 /* outline :: A pointer to the target outline descriptor. */ 364 /* */ 365 /* <Note> */ 366 /* This function toggles the bit flag @FT_OUTLINE_REVERSE_FILL in */ 367 /* the outline's `flags' field. */ 368 /* */ 369 /* It shouldn't be used by a normal client application, unless it */ 370 /* knows what it is doing. */ 371 /* */ 372 FT_EXPORT( void ) 373 FT_Outline_Reverse( FT_Outline* outline ); 374 375 376 /*************************************************************************/ 377 /* */ 378 /* <Function> */ 379 /* FT_Outline_Get_Bitmap */ 380 /* */ 381 /* <Description> */ 382 /* Render an outline within a bitmap. The outline's image is simply */ 383 /* OR-ed to the target bitmap. */ 384 /* */ 385 /* <Input> */ 386 /* library :: A handle to a FreeType library object. */ 387 /* */ 388 /* outline :: A pointer to the source outline descriptor. */ 389 /* */ 390 /* <InOut> */ 391 /* abitmap :: A pointer to the target bitmap descriptor. */ 392 /* */ 393 /* <Return> */ 394 /* FreeType error code. 0~means success. */ 395 /* */ 396 /* <Note> */ 397 /* This function does NOT CREATE the bitmap, it only renders an */ 398 /* outline image within the one you pass to it! Consequently, the */ 399 /* various fields in `abitmap' should be set accordingly. */ 400 /* */ 401 /* It will use the raster corresponding to the default glyph format. */ 402 /* */ 403 /* The value of the `num_grays' field in `abitmap' is ignored. If */ 404 /* you select the gray-level rasterizer, and you want less than 256 */ 405 /* gray levels, you have to use @FT_Outline_Render directly. */ 406 /* */ 407 FT_EXPORT( FT_Error ) 408 FT_Outline_Get_Bitmap( FT_Library library, 409 FT_Outline* outline, 410 const FT_Bitmap *abitmap ); 411 412 413 /*************************************************************************/ 414 /* */ 415 /* <Function> */ 416 /* FT_Outline_Render */ 417 /* */ 418 /* <Description> */ 419 /* Render an outline within a bitmap using the current scan-convert. */ 420 /* This function uses an @FT_Raster_Params structure as an argument, */ 421 /* allowing advanced features like direct composition, translucency, */ 422 /* etc. */ 423 /* */ 424 /* <Input> */ 425 /* library :: A handle to a FreeType library object. */ 426 /* */ 427 /* outline :: A pointer to the source outline descriptor. */ 428 /* */ 429 /* <InOut> */ 430 /* params :: A pointer to an @FT_Raster_Params structure used to */ 431 /* describe the rendering operation. */ 432 /* */ 433 /* <Return> */ 434 /* FreeType error code. 0~means success. */ 435 /* */ 436 /* <Note> */ 437 /* You should know what you are doing and how @FT_Raster_Params works */ 438 /* to use this function. */ 439 /* */ 440 /* The field `params.source' will be set to `outline' before the scan */ 441 /* converter is called, which means that the value you give to it is */ 442 /* actually ignored. */ 443 /* */ 444 /* The gray-level rasterizer always uses 256 gray levels. If you */ 445 /* want less gray levels, you have to provide your own span callback. */ 446 /* See the @FT_RASTER_FLAG_DIRECT value of the `flags' field in the */ 447 /* @FT_Raster_Params structure for more details. */ 448 /* */ 449 FT_EXPORT( FT_Error ) 450 FT_Outline_Render( FT_Library library, 451 FT_Outline* outline, 452 FT_Raster_Params* params ); 453 454 455 /************************************************************************** 456 * 457 * @enum: 458 * FT_Orientation 459 * 460 * @description: 461 * A list of values used to describe an outline's contour orientation. 462 * 463 * The TrueType and PostScript specifications use different conventions 464 * to determine whether outline contours should be filled or unfilled. 465 * 466 * @values: 467 * FT_ORIENTATION_TRUETYPE :: 468 * According to the TrueType specification, clockwise contours must 469 * be filled, and counter-clockwise ones must be unfilled. 470 * 471 * FT_ORIENTATION_POSTSCRIPT :: 472 * According to the PostScript specification, counter-clockwise contours 473 * must be filled, and clockwise ones must be unfilled. 474 * 475 * FT_ORIENTATION_FILL_RIGHT :: 476 * This is identical to @FT_ORIENTATION_TRUETYPE, but is used to 477 * remember that in TrueType, everything that is to the right of 478 * the drawing direction of a contour must be filled. 479 * 480 * FT_ORIENTATION_FILL_LEFT :: 481 * This is identical to @FT_ORIENTATION_POSTSCRIPT, but is used to 482 * remember that in PostScript, everything that is to the left of 483 * the drawing direction of a contour must be filled. 484 * 485 * FT_ORIENTATION_NONE :: 486 * The orientation cannot be determined. That is, different parts of 487 * the glyph have different orientation. 488 * 489 */ 490 typedef enum FT_Orientation_ 491 { 492 FT_ORIENTATION_TRUETYPE = 0, 493 FT_ORIENTATION_POSTSCRIPT = 1, 494 FT_ORIENTATION_FILL_RIGHT = FT_ORIENTATION_TRUETYPE, 495 FT_ORIENTATION_FILL_LEFT = FT_ORIENTATION_POSTSCRIPT, 496 FT_ORIENTATION_NONE 497 498 } FT_Orientation; 499 500 501 /************************************************************************** 502 * 503 * @function: 504 * FT_Outline_Get_Orientation 505 * 506 * @description: 507 * This function analyzes a glyph outline and tries to compute its 508 * fill orientation (see @FT_Orientation). This is done by computing 509 * the direction of each global horizontal and/or vertical extrema 510 * within the outline. 511 * 512 * Note that this will return @FT_ORIENTATION_TRUETYPE for empty 513 * outlines. 514 * 515 * @input: 516 * outline :: 517 * A handle to the source outline. 518 * 519 * @return: 520 * The orientation. 521 * 522 */ 523 FT_EXPORT( FT_Orientation ) 524 FT_Outline_Get_Orientation( FT_Outline* outline ); 525 526 527 /* */ 528 529 530FT_END_HEADER 531 532#endif /* __FTOUTLN_H__ */ 533 534 535/* END */ 536 537 538/* Local Variables: */ 539/* coding: utf-8 */ 540/* End: */