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, 2005-2014 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 34 FT_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_EmboldenXY */ 63 /* FT_Outline_Reverse */ 64 /* FT_Outline_Check */ 65 /* */ 66 /* FT_Outline_Get_CBox */ 67 /* FT_Outline_Get_BBox */ 68 /* */ 69 /* FT_Outline_Get_Bitmap */ 70 /* FT_Outline_Render */ 71 /* */ 72 /* FT_Outline_Decompose */ 73 /* FT_Outline_Funcs */ 74 /* FT_Outline_MoveTo_Func */ 75 /* FT_Outline_LineTo_Func */ 76 /* FT_Outline_ConicTo_Func */ 77 /* FT_Outline_CubicTo_Func */ 78 /* */ 79 /*************************************************************************/ 80 81 82 /*************************************************************************/ 83 /* */ 84 /* <Function> */ 85 /* FT_Outline_Decompose */ 86 /* */ 87 /* <Description> */ 88 /* Walk over an outline's structure to decompose it into individual */ 89 /* segments and Bzier arcs. This function also emits `move to' */ 90 /* operations to indicate the start of new contours in the outline. */ 91 /* */ 92 /* <Input> */ 93 /* outline :: A pointer to the source target. */ 94 /* */ 95 /* func_interface :: A table of `emitters', i.e., function pointers */ 96 /* called during decomposition to indicate path */ 97 /* operations. */ 98 /* */ 99 /* <InOut> */ 100 /* user :: A typeless pointer that is passed to each */ 101 /* emitter during the decomposition. It can be */ 102 /* used to store the state during the */ 103 /* decomposition. */ 104 /* */ 105 /* <Return> */ 106 /* FreeType error code. 0~means success. */ 107 /* */ 108 /* <Note> */ 109 /* A contour that contains a single point only is represented by a */ 110 /* `move to' operation followed by `line to' to the same point. In */ 111 /* most cases, it is best to filter this out before using the */ 112 /* outline for stroking purposes (otherwise it would result in a */ 113 /* visible dot when round caps are used). */ 114 /* */ 115 FT_EXPORT( FT_Error ) 116 FT_Outline_Decompose( FT_Outline* outline, 117 const FT_Outline_Funcs* func_interface, 118 void* user ); 119 120 121 /*************************************************************************/ 122 /* */ 123 /* <Function> */ 124 /* FT_Outline_New */ 125 /* */ 126 /* <Description> */ 127 /* Create a new outline of a given size. */ 128 /* */ 129 /* <Input> */ 130 /* library :: A handle to the library object from where the */ 131 /* outline is allocated. Note however that the new */ 132 /* outline will *not* necessarily be *freed*, when */ 133 /* destroying the library, by @FT_Done_FreeType. */ 134 /* */ 135 /* numPoints :: The maximum number of points within the outline. */ 136 /* Must be smaller than or equal to 0xFFFF (65535). */ 137 /* */ 138 /* numContours :: The maximum number of contours within the outline. */ 139 /* This value must be in the range 0 to `numPoints'. */ 140 /* */ 141 /* <Output> */ 142 /* anoutline :: A handle to the new outline. */ 143 /* */ 144 /* <Return> */ 145 /* FreeType error code. 0~means success. */ 146 /* */ 147 /* <Note> */ 148 /* The reason why this function takes a `library' parameter is simply */ 149 /* to use the library's memory allocator. */ 150 /* */ 151 FT_EXPORT( FT_Error ) 152 FT_Outline_New( FT_Library library, 153 FT_UInt numPoints, 154 FT_Int numContours, 155 FT_Outline *anoutline ); 156 157 158 FT_EXPORT( FT_Error ) 159 FT_Outline_New_Internal( FT_Memory memory, 160 FT_UInt numPoints, 161 FT_Int numContours, 162 FT_Outline *anoutline ); 163 164 165 /*************************************************************************/ 166 /* */ 167 /* <Function> */ 168 /* FT_Outline_Done */ 169 /* */ 170 /* <Description> */ 171 /* Destroy an outline created with @FT_Outline_New. */ 172 /* */ 173 /* <Input> */ 174 /* library :: A handle of the library object used to allocate the */ 175 /* outline. */ 176 /* */ 177 /* outline :: A pointer to the outline object to be discarded. */ 178 /* */ 179 /* <Return> */ 180 /* FreeType error code. 0~means success. */ 181 /* */ 182 /* <Note> */ 183 /* If the outline's `owner' field is not set, only the outline */ 184 /* descriptor will be released. */ 185 /* */ 186 /* The reason why this function takes an `library' parameter is */ 187 /* simply to use ft_mem_free(). */ 188 /* */ 189 FT_EXPORT( FT_Error ) 190 FT_Outline_Done( FT_Library library, 191 FT_Outline* outline ); 192 193 194 FT_EXPORT( FT_Error ) 195 FT_Outline_Done_Internal( FT_Memory memory, 196 FT_Outline* outline ); 197 198 199 /*************************************************************************/ 200 /* */ 201 /* <Function> */ 202 /* FT_Outline_Check */ 203 /* */ 204 /* <Description> */ 205 /* Check the contents of an outline descriptor. */ 206 /* */ 207 /* <Input> */ 208 /* outline :: A handle to a source outline. */ 209 /* */ 210 /* <Return> */ 211 /* FreeType error code. 0~means success. */ 212 /* */ 213 FT_EXPORT( FT_Error ) 214 FT_Outline_Check( FT_Outline* outline ); 215 216 217 /*************************************************************************/ 218 /* */ 219 /* <Function> */ 220 /* FT_Outline_Get_CBox */ 221 /* */ 222 /* <Description> */ 223 /* Return an outline's `control box'. The control box encloses all */ 224 /* the outline's points, including Bzier control points. Though it */ 225 /* coincides with the exact bounding box for most glyphs, it can be */ 226 /* slightly larger in some situations (like when rotating an outline */ 227 /* that contains Bzier outside arcs). */ 228 /* */ 229 /* Computing the control box is very fast, while getting the bounding */ 230 /* box can take much more time as it needs to walk over all segments */ 231 /* and arcs in the outline. To get the latter, you can use the */ 232 /* `ftbbox' component, which is dedicated to this single task. */ 233 /* */ 234 /* <Input> */ 235 /* outline :: A pointer to the source outline descriptor. */ 236 /* */ 237 /* <Output> */ 238 /* acbox :: The outline's control box. */ 239 /* */ 240 /* <Note> */ 241 /* See @FT_Glyph_Get_CBox for a discussion of tricky fonts. */ 242 /* */ 243 FT_EXPORT( void ) 244 FT_Outline_Get_CBox( const FT_Outline* outline, 245 FT_BBox *acbox ); 246 247 248 /*************************************************************************/ 249 /* */ 250 /* <Function> */ 251 /* FT_Outline_Translate */ 252 /* */ 253 /* <Description> */ 254 /* Apply a simple translation to the points of an outline. */ 255 /* */ 256 /* <InOut> */ 257 /* outline :: A pointer to the target outline descriptor. */ 258 /* */ 259 /* <Input> */ 260 /* xOffset :: The horizontal offset. */ 261 /* */ 262 /* yOffset :: The vertical offset. */ 263 /* */ 264 FT_EXPORT( void ) 265 FT_Outline_Translate( const FT_Outline* outline, 266 FT_Pos xOffset, 267 FT_Pos yOffset ); 268 269 270 /*************************************************************************/ 271 /* */ 272 /* <Function> */ 273 /* FT_Outline_Copy */ 274 /* */ 275 /* <Description> */ 276 /* Copy an outline into another one. Both objects must have the */ 277 /* same sizes (number of points & number of contours) when this */ 278 /* function is called. */ 279 /* */ 280 /* <Input> */ 281 /* source :: A handle to the source outline. */ 282 /* */ 283 /* <Output> */ 284 /* target :: A handle to the target outline. */ 285 /* */ 286 /* <Return> */ 287 /* FreeType error code. 0~means success. */ 288 /* */ 289 FT_EXPORT( FT_Error ) 290 FT_Outline_Copy( const FT_Outline* source, 291 FT_Outline *target ); 292 293 294 /*************************************************************************/ 295 /* */ 296 /* <Function> */ 297 /* FT_Outline_Transform */ 298 /* */ 299 /* <Description> */ 300 /* Apply a simple 2x2 matrix to all of an outline's points. Useful */ 301 /* for applying rotations, slanting, flipping, etc. */ 302 /* */ 303 /* <InOut> */ 304 /* outline :: A pointer to the target outline descriptor. */ 305 /* */ 306 /* <Input> */ 307 /* matrix :: A pointer to the transformation matrix. */ 308 /* */ 309 /* <Note> */ 310 /* You can use @FT_Outline_Translate if you need to translate the */ 311 /* outline's points. */ 312 /* */ 313 FT_EXPORT( void ) 314 FT_Outline_Transform( const FT_Outline* outline, 315 const FT_Matrix* matrix ); 316 317 318 /*************************************************************************/ 319 /* */ 320 /* <Function> */ 321 /* FT_Outline_Embolden */ 322 /* */ 323 /* <Description> */ 324 /* Embolden an outline. The new outline will be at most 4~times */ 325 /* `strength' pixels wider and higher. You may think of the left and */ 326 /* bottom borders as unchanged. */ 327 /* */ 328 /* Negative `strength' values to reduce the outline thickness are */ 329 /* possible also. */ 330 /* */ 331 /* <InOut> */ 332 /* outline :: A handle to the target outline. */ 333 /* */ 334 /* <Input> */ 335 /* strength :: How strong the glyph is emboldened. Expressed in */ 336 /* 26.6 pixel format. */ 337 /* */ 338 /* <Return> */ 339 /* FreeType error code. 0~means success. */ 340 /* */ 341 /* <Note> */ 342 /* The used algorithm to increase or decrease the thickness of the */ 343 /* glyph doesn't change the number of points; this means that certain */ 344 /* situations like acute angles or intersections are sometimes */ 345 /* handled incorrectly. */ 346 /* */ 347 /* If you need `better' metrics values you should call */ 348 /* @FT_Outline_Get_CBox or @FT_Outline_Get_BBox. */ 349 /* */ 350 /* Example call: */ 351 /* */ 352 /* { */ 353 /* FT_Load_Glyph( face, index, FT_LOAD_DEFAULT ); */ 354 /* if ( face->slot->format == FT_GLYPH_FORMAT_OUTLINE ) */ 355 /* FT_Outline_Embolden( &face->slot->outline, strength ); */ 356 /* } */ 357 /* */ 358 /* To get meaningful results, font scaling values must be set with */ 359 /* functions like @FT_Set_Char_Size before calling FT_Render_Glyph. */ 360 /* */ 361 FT_EXPORT( FT_Error ) 362 FT_Outline_Embolden( FT_Outline* outline, 363 FT_Pos strength ); 364 365 366 /*************************************************************************/ 367 /* */ 368 /* <Function> */ 369 /* FT_Outline_EmboldenXY */ 370 /* */ 371 /* <Description> */ 372 /* Embolden an outline. The new outline will be `xstrength' pixels */ 373 /* wider and `ystrength' pixels higher. Otherwise, it is similar to */ 374 /* @FT_Outline_Embolden, which uses the same strength in both */ 375 /* directions. */ 376 /* */ 377 FT_EXPORT( FT_Error ) 378 FT_Outline_EmboldenXY( FT_Outline* outline, 379 FT_Pos xstrength, 380 FT_Pos ystrength ); 381 382 383 /*************************************************************************/ 384 /* */ 385 /* <Function> */ 386 /* FT_Outline_Reverse */ 387 /* */ 388 /* <Description> */ 389 /* Reverse the drawing direction of an outline. This is used to */ 390 /* ensure consistent fill conventions for mirrored glyphs. */ 391 /* */ 392 /* <InOut> */ 393 /* outline :: A pointer to the target outline descriptor. */ 394 /* */ 395 /* <Note> */ 396 /* This function toggles the bit flag @FT_OUTLINE_REVERSE_FILL in */ 397 /* the outline's `flags' field. */ 398 /* */ 399 /* It shouldn't be used by a normal client application, unless it */ 400 /* knows what it is doing. */ 401 /* */ 402 FT_EXPORT( void ) 403 FT_Outline_Reverse( FT_Outline* outline ); 404 405 406 /*************************************************************************/ 407 /* */ 408 /* <Function> */ 409 /* FT_Outline_Get_Bitmap */ 410 /* */ 411 /* <Description> */ 412 /* Render an outline within a bitmap. The outline's image is simply */ 413 /* OR-ed to the target bitmap. */ 414 /* */ 415 /* <Input> */ 416 /* library :: A handle to a FreeType library object. */ 417 /* */ 418 /* outline :: A pointer to the source outline descriptor. */ 419 /* */ 420 /* <InOut> */ 421 /* abitmap :: A pointer to the target bitmap descriptor. */ 422 /* */ 423 /* <Return> */ 424 /* FreeType error code. 0~means success. */ 425 /* */ 426 /* <Note> */ 427 /* This function does NOT CREATE the bitmap, it only renders an */ 428 /* outline image within the one you pass to it! Consequently, the */ 429 /* various fields in `abitmap' should be set accordingly. */ 430 /* */ 431 /* It will use the raster corresponding to the default glyph format. */ 432 /* */ 433 /* The value of the `num_grays' field in `abitmap' is ignored. If */ 434 /* you select the gray-level rasterizer, and you want less than 256 */ 435 /* gray levels, you have to use @FT_Outline_Render directly. */ 436 /* */ 437 FT_EXPORT( FT_Error ) 438 FT_Outline_Get_Bitmap( FT_Library library, 439 FT_Outline* outline, 440 const FT_Bitmap *abitmap ); 441 442 443 /*************************************************************************/ 444 /* */ 445 /* <Function> */ 446 /* FT_Outline_Render */ 447 /* */ 448 /* <Description> */ 449 /* Render an outline within a bitmap using the current scan-convert. */ 450 /* This function uses an @FT_Raster_Params structure as an argument, */ 451 /* allowing advanced features like direct composition, translucency, */ 452 /* etc. */ 453 /* */ 454 /* <Input> */ 455 /* library :: A handle to a FreeType library object. */ 456 /* */ 457 /* outline :: A pointer to the source outline descriptor. */ 458 /* */ 459 /* <InOut> */ 460 /* params :: A pointer to an @FT_Raster_Params structure used to */ 461 /* describe the rendering operation. */ 462 /* */ 463 /* <Return> */ 464 /* FreeType error code. 0~means success. */ 465 /* */ 466 /* <Note> */ 467 /* You should know what you are doing and how @FT_Raster_Params works */ 468 /* to use this function. */ 469 /* */ 470 /* The field `params.source' will be set to `outline' before the scan */ 471 /* converter is called, which means that the value you give to it is */ 472 /* actually ignored. */ 473 /* */ 474 /* The gray-level rasterizer always uses 256 gray levels. If you */ 475 /* want less gray levels, you have to provide your own span callback. */ 476 /* See the @FT_RASTER_FLAG_DIRECT value of the `flags' field in the */ 477 /* @FT_Raster_Params structure for more details. */ 478 /* */ 479 FT_EXPORT( FT_Error ) 480 FT_Outline_Render( FT_Library library, 481 FT_Outline* outline, 482 FT_Raster_Params* params ); 483 484 485 /************************************************************************** 486 * 487 * @enum: 488 * FT_Orientation 489 * 490 * @description: 491 * A list of values used to describe an outline's contour orientation. 492 * 493 * The TrueType and PostScript specifications use different conventions 494 * to determine whether outline contours should be filled or unfilled. 495 * 496 * @values: 497 * FT_ORIENTATION_TRUETYPE :: 498 * According to the TrueType specification, clockwise contours must 499 * be filled, and counter-clockwise ones must be unfilled. 500 * 501 * FT_ORIENTATION_POSTSCRIPT :: 502 * According to the PostScript specification, counter-clockwise contours 503 * must be filled, and clockwise ones must be unfilled. 504 * 505 * FT_ORIENTATION_FILL_RIGHT :: 506 * This is identical to @FT_ORIENTATION_TRUETYPE, but is used to 507 * remember that in TrueType, everything that is to the right of 508 * the drawing direction of a contour must be filled. 509 * 510 * FT_ORIENTATION_FILL_LEFT :: 511 * This is identical to @FT_ORIENTATION_POSTSCRIPT, but is used to 512 * remember that in PostScript, everything that is to the left of 513 * the drawing direction of a contour must be filled. 514 * 515 * FT_ORIENTATION_NONE :: 516 * The orientation cannot be determined. That is, different parts of 517 * the glyph have different orientation. 518 * 519 */ 520 typedef enum FT_Orientation_ 521 { 522 FT_ORIENTATION_TRUETYPE = 0, 523 FT_ORIENTATION_POSTSCRIPT = 1, 524 FT_ORIENTATION_FILL_RIGHT = FT_ORIENTATION_TRUETYPE, 525 FT_ORIENTATION_FILL_LEFT = FT_ORIENTATION_POSTSCRIPT, 526 FT_ORIENTATION_NONE 527 528 } FT_Orientation; 529 530 531 /************************************************************************** 532 * 533 * @function: 534 * FT_Outline_Get_Orientation 535 * 536 * @description: 537 * This function analyzes a glyph outline and tries to compute its 538 * fill orientation (see @FT_Orientation). This is done by integrating 539 * the total area covered by the outline. The positive integral 540 * corresponds to the clockwise orientation and @FT_ORIENTATION_POSTSCRIPT 541 * is returned. The negative integral corresponds to the counter-clockwise 542 * orientation and @FT_ORIENTATION_TRUETYPE is returned. 543 * 544 * Note that this will return @FT_ORIENTATION_TRUETYPE for empty 545 * outlines. 546 * 547 * @input: 548 * outline :: 549 * A handle to the source outline. 550 * 551 * @return: 552 * The orientation. 553 * 554 */ 555 FT_EXPORT( FT_Orientation ) 556 FT_Outline_Get_Orientation( FT_Outline* outline ); 557 558 559 /* */ 560 561 562 FT_END_HEADER 563 564 #endif /* __FTOUTLN_H__ */ 565 566 567 /* END */ 568 569 570 /* Local Variables: */ 571 /* coding: utf-8 */ 572 /* End: */ 573
