src/third_party/freetype2/src/include/freetype/ftoutln.h

   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
  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_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
 530 FT_END_HEADER
 531
 532 #endif /* __FTOUTLN_H__ */
 533
 534
 535 /* END */
 536
 537
 538 /* Local Variables: */
 539 /* coding: utf-8    */
 540 /* End:             */