extension/SDL2_ttf-2.0.14/external/freetype-2.4.12/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, 2005-2012 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 Bézier 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 which 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   FT_EXPORT( FT_Error )
 109   FT_Outline_Decompose( FT_Outline*              outline,
 110                         const FT_Outline_Funcs*  func_interface,
 111                         void*                    user );
 112
 113
 114   /*************************************************************************/
 115   /*                                                                       */
 116   /* <Function>                                                            */
 117   /*    FT_Outline_New                                                     */
 118   /*                                                                       */
 119   /* <Description>                                                         */
 120   /*    Create a new outline of a given size.                              */
 121   /*                                                                       */
 122   /* <Input>                                                               */
 123   /*    library     :: A handle to the library object from where the       */
 124   /*                   outline is allocated.  Note however that the new    */
 125   /*                   outline will *not* necessarily be *freed*, when     */
 126   /*                   destroying the library, by @FT_Done_FreeType.       */
 127   /*                                                                       */
 128   /*    numPoints   :: The maximum number of points within the outline.    */
 129   /*                   Must be smaller than or equal to 0xFFFF (65535).    */
 130   /*                                                                       */
 131   /*    numContours :: The maximum number of contours within the outline.  */
 132   /*                   This value must be in the range 0 to `numPoints'.   */
 133   /*                                                                       */
 134   /* <Output>                                                              */
 135   /*    anoutline   :: A handle to the new outline.                        */
 136   /*                                                                       */
 137   /* <Return>                                                              */
 138   /*    FreeType error code.  0~means success.                             */
 139   /*                                                                       */
 140   /* <Note>                                                                */
 141   /*    The reason why this function takes a `library' parameter is simply */
 142   /*    to use the library's memory allocator.                             */
 143   /*                                                                       */
 144   FT_EXPORT( FT_Error )
 145   FT_Outline_New( FT_Library   library,
 146                   FT_UInt      numPoints,
 147                   FT_Int       numContours,
 148                   FT_Outline  *anoutline );
 149
 150
 151   FT_EXPORT( FT_Error )
 152   FT_Outline_New_Internal( FT_Memory    memory,
 153                            FT_UInt      numPoints,
 154                            FT_Int       numContours,
 155                            FT_Outline  *anoutline );
 156
 157
 158   /*************************************************************************/
 159   /*                                                                       */
 160   /* <Function>                                                            */
 161   /*    FT_Outline_Done                                                    */
 162   /*                                                                       */
 163   /* <Description>                                                         */
 164   /*    Destroy an outline created with @FT_Outline_New.                   */
 165   /*                                                                       */
 166   /* <Input>                                                               */
 167   /*    library :: A handle of the library object used to allocate the     */
 168   /*               outline.                                                */
 169   /*                                                                       */
 170   /*    outline :: A pointer to the outline object to be discarded.        */
 171   /*                                                                       */
 172   /* <Return>                                                              */
 173   /*    FreeType error code.  0~means success.                             */
 174   /*                                                                       */
 175   /* <Note>                                                                */
 176   /*    If the outline's `owner' field is not set, only the outline        */
 177   /*    descriptor will be released.                                       */
 178   /*                                                                       */
 179   /*    The reason why this function takes an `library' parameter is       */
 180   /*    simply to use ft_mem_free().                                       */
 181   /*                                                                       */
 182   FT_EXPORT( FT_Error )
 183   FT_Outline_Done( FT_Library   library,
 184                    FT_Outline*  outline );
 185
 186
 187   FT_EXPORT( FT_Error )
 188   FT_Outline_Done_Internal( FT_Memory    memory,
 189                             FT_Outline*  outline );
 190
 191
 192   /*************************************************************************/
 193   /*                                                                       */
 194   /* <Function>                                                            */
 195   /*    FT_Outline_Check                                                   */
 196   /*                                                                       */
 197   /* <Description>                                                         */
 198   /*    Check the contents of an outline descriptor.                       */
 199   /*                                                                       */
 200   /* <Input>                                                               */
 201   /*    outline :: A handle to a source outline.                           */
 202   /*                                                                       */
 203   /* <Return>                                                              */
 204   /*    FreeType error code.  0~means success.                             */
 205   /*                                                                       */
 206   FT_EXPORT( FT_Error )
 207   FT_Outline_Check( FT_Outline*  outline );
 208
 209
 210   /*************************************************************************/
 211   /*                                                                       */
 212   /* <Function>                                                            */
 213   /*    FT_Outline_Get_CBox                                                */
 214   /*                                                                       */
 215   /* <Description>                                                         */
 216   /*    Return an outline's `control box'.  The control box encloses all   */
 217   /*    the outline's points, including Bézier control points.  Though it  */
 218   /*    coincides with the exact bounding box for most glyphs, it can be   */
 219   /*    slightly larger in some situations (like when rotating an outline  */
 220   /*    which contains Bézier outside arcs).                               */
 221   /*                                                                       */
 222   /*    Computing the control box is very fast, while getting the bounding */
 223   /*    box can take much more time as it needs to walk over all segments  */
 224   /*    and arcs in the outline.  To get the latter, you can use the       */
 225   /*    `ftbbox' component which is dedicated to this single task.         */
 226   /*                                                                       */
 227   /* <Input>                                                               */
 228   /*    outline :: A pointer to the source outline descriptor.             */
 229   /*                                                                       */
 230   /* <Output>                                                              */
 231   /*    acbox   :: The outline's control box.                              */
 232   /*                                                                       */
 233   /* <Note>                                                                */
 234   /*    See @FT_Glyph_Get_CBox for a discussion of tricky fonts.           */
 235   /*                                                                       */
 236   FT_EXPORT( void )
 237   FT_Outline_Get_CBox( const FT_Outline*  outline,
 238                        FT_BBox           *acbox );
 239
 240
 241   /*************************************************************************/
 242   /*                                                                       */
 243   /* <Function>                                                            */
 244   /*    FT_Outline_Translate                                               */
 245   /*                                                                       */
 246   /* <Description>                                                         */
 247   /*    Apply a simple translation to the points of an outline.            */
 248   /*                                                                       */
 249   /* <InOut>                                                               */
 250   /*    outline :: A pointer to the target outline descriptor.             */
 251   /*                                                                       */
 252   /* <Input>                                                               */
 253   /*    xOffset :: The horizontal offset.                                  */
 254   /*                                                                       */
 255   /*    yOffset :: The vertical offset.                                    */
 256   /*                                                                       */
 257   FT_EXPORT( void )
 258   FT_Outline_Translate( const FT_Outline*  outline,
 259                         FT_Pos             xOffset,
 260                         FT_Pos             yOffset );
 261
 262
 263   /*************************************************************************/
 264   /*                                                                       */
 265   /* <Function>                                                            */
 266   /*    FT_Outline_Copy                                                    */
 267   /*                                                                       */
 268   /* <Description>                                                         */
 269   /*    Copy an outline into another one.  Both objects must have the      */
 270   /*    same sizes (number of points & number of contours) when this       */
 271   /*    function is called.                                                */
 272   /*                                                                       */
 273   /* <Input>                                                               */
 274   /*    source :: A handle to the source outline.                          */
 275   /*                                                                       */
 276   /* <Output>                                                              */
 277   /*    target :: A handle to the target outline.                          */
 278   /*                                                                       */
 279   /* <Return>                                                              */
 280   /*    FreeType error code.  0~means success.                             */
 281   /*                                                                       */
 282   FT_EXPORT( FT_Error )
 283   FT_Outline_Copy( const FT_Outline*  source,
 284                    FT_Outline        *target );
 285
 286
 287   /*************************************************************************/
 288   /*                                                                       */
 289   /* <Function>                                                            */
 290   /*    FT_Outline_Transform                                               */
 291   /*                                                                       */
 292   /* <Description>                                                         */
 293   /*    Apply a simple 2x2 matrix to all of an outline's points.  Useful   */
 294   /*    for applying rotations, slanting, flipping, etc.                   */
 295   /*                                                                       */
 296   /* <InOut>                                                               */
 297   /*    outline :: A pointer to the target outline descriptor.             */
 298   /*                                                                       */
 299   /* <Input>                                                               */
 300   /*    matrix  :: A pointer to the transformation matrix.                 */
 301   /*                                                                       */
 302   /* <Note>                                                                */
 303   /*    You can use @FT_Outline_Translate if you need to translate the     */
 304   /*    outline's points.                                                  */
 305   /*                                                                       */
 306   FT_EXPORT( void )
 307   FT_Outline_Transform( const FT_Outline*  outline,
 308                         const FT_Matrix*   matrix );
 309
 310
 311   /*************************************************************************/
 312   /*                                                                       */
 313   /* <Function>                                                            */
 314   /*    FT_Outline_Embolden                                                */
 315   /*                                                                       */
 316   /* <Description>                                                         */
 317   /*    Embolden an outline.  The new outline will be at most 4~times      */
 318   /*    `strength' pixels wider and higher.  You may think of the left and */
 319   /*    bottom borders as unchanged.                                       */
 320   /*                                                                       */
 321   /*    Negative `strength' values to reduce the outline thickness are     */
 322   /*    possible also.                                                     */
 323   /*                                                                       */
 324   /* <InOut>                                                               */
 325   /*    outline  :: A handle to the target outline.                        */
 326   /*                                                                       */
 327   /* <Input>                                                               */
 328   /*    strength :: How strong the glyph is emboldened.  Expressed in      */
 329   /*                26.6 pixel format.                                     */
 330   /*                                                                       */
 331   /* <Return>                                                              */
 332   /*    FreeType error code.  0~means success.                             */
 333   /*                                                                       */
 334   /* <Note>                                                                */
 335   /*    The used algorithm to increase or decrease the thickness of the    */
 336   /*    glyph doesn't change the number of points; this means that certain */
 337   /*    situations like acute angles or intersections are sometimes        */
 338   /*    handled incorrectly.                                               */
 339   /*                                                                       */
 340   /*    If you need `better' metrics values you should call                */
 341   /*    @FT_Outline_Get_CBox or @FT_Outline_Get_BBox.                      */
 342   /*                                                                       */
 343   /*    Example call:                                                      */
 344   /*                                                                       */
 345   /*    {                                                                  */
 346   /*      FT_Load_Glyph( face, index, FT_LOAD_DEFAULT );                   */
 347   /*      if ( face->slot->format == FT_GLYPH_FORMAT_OUTLINE )             */
 348   /*        FT_Outline_Embolden( &face->slot->outline, strength );         */
 349   /*    }                                                                  */
 350   /*                                                                       */
 351   FT_EXPORT( FT_Error )
 352   FT_Outline_Embolden( FT_Outline*  outline,
 353                        FT_Pos       strength );
 354
 355
 356   /*************************************************************************/
 357   /*                                                                       */
 358   /* <Function>                                                            */
 359   /*    FT_Outline_EmboldenXY                                              */
 360   /*                                                                       */
 361   /* <Description>                                                         */
 362   /*    Embolden an outline.  The new outline will be `xstrength' pixels   */
 363   /*    wider and `ystrength' pixels higher.  Otherwise, it is similar to  */
 364   /*    @FT_Outline_Embolden, which uses the same strength in both         */
 365   /*    directions.                                                        */
 366   /*                                                                       */
 367   FT_EXPORT( FT_Error )
 368   FT_Outline_EmboldenXY( FT_Outline*  outline,
 369                          FT_Pos       xstrength,
 370                          FT_Pos       ystrength );
 371
 372
 373   /*************************************************************************/
 374   /*                                                                       */
 375   /* <Function>                                                            */
 376   /*    FT_Outline_Reverse                                                 */
 377   /*                                                                       */
 378   /* <Description>                                                         */
 379   /*    Reverse the drawing direction of an outline.  This is used to      */
 380   /*    ensure consistent fill conventions for mirrored glyphs.            */
 381   /*                                                                       */
 382   /* <InOut>                                                               */
 383   /*    outline :: A pointer to the target outline descriptor.             */
 384   /*                                                                       */
 385   /* <Note>                                                                */
 386   /*    This function toggles the bit flag @FT_OUTLINE_REVERSE_FILL in     */
 387   /*    the outline's `flags' field.                                       */
 388   /*                                                                       */
 389   /*    It shouldn't be used by a normal client application, unless it     */
 390   /*    knows what it is doing.                                            */
 391   /*                                                                       */
 392   FT_EXPORT( void )
 393   FT_Outline_Reverse( FT_Outline*  outline );
 394
 395
 396   /*************************************************************************/
 397   /*                                                                       */
 398   /* <Function>                                                            */
 399   /*    FT_Outline_Get_Bitmap                                              */
 400   /*                                                                       */
 401   /* <Description>                                                         */
 402   /*    Render an outline within a bitmap.  The outline's image is simply  */
 403   /*    OR-ed to the target bitmap.                                        */
 404   /*                                                                       */
 405   /* <Input>                                                               */
 406   /*    library :: A handle to a FreeType library object.                  */
 407   /*                                                                       */
 408   /*    outline :: A pointer to the source outline descriptor.             */
 409   /*                                                                       */
 410   /* <InOut>                                                               */
 411   /*    abitmap :: A pointer to the target bitmap descriptor.              */
 412   /*                                                                       */
 413   /* <Return>                                                              */
 414   /*    FreeType error code.  0~means success.                             */
 415   /*                                                                       */
 416   /* <Note>                                                                */
 417   /*    This function does NOT CREATE the bitmap, it only renders an       */
 418   /*    outline image within the one you pass to it!  Consequently, the    */
 419   /*    various fields in `abitmap' should be set accordingly.             */
 420   /*                                                                       */
 421   /*    It will use the raster corresponding to the default glyph format.  */
 422   /*                                                                       */
 423   /*    The value of the `num_grays' field in `abitmap' is ignored.  If    */
 424   /*    you select the gray-level rasterizer, and you want less than 256   */
 425   /*    gray levels, you have to use @FT_Outline_Render directly.          */
 426   /*                                                                       */
 427   FT_EXPORT( FT_Error )
 428   FT_Outline_Get_Bitmap( FT_Library        library,
 429                          FT_Outline*       outline,
 430                          const FT_Bitmap  *abitmap );
 431
 432
 433   /*************************************************************************/
 434   /*                                                                       */
 435   /* <Function>                                                            */
 436   /*    FT_Outline_Render                                                  */
 437   /*                                                                       */
 438   /* <Description>                                                         */
 439   /*    Render an outline within a bitmap using the current scan-convert.  */
 440   /*    This function uses an @FT_Raster_Params structure as an argument,  */
 441   /*    allowing advanced features like direct composition, translucency,  */
 442   /*    etc.                                                               */
 443   /*                                                                       */
 444   /* <Input>                                                               */
 445   /*    library :: A handle to a FreeType library object.                  */
 446   /*                                                                       */
 447   /*    outline :: A pointer to the source outline descriptor.             */
 448   /*                                                                       */
 449   /* <InOut>                                                               */
 450   /*    params  :: A pointer to an @FT_Raster_Params structure used to     */
 451   /*               describe the rendering operation.                       */
 452   /*                                                                       */
 453   /* <Return>                                                              */
 454   /*    FreeType error code.  0~means success.                             */
 455   /*                                                                       */
 456   /* <Note>                                                                */
 457   /*    You should know what you are doing and how @FT_Raster_Params works */
 458   /*    to use this function.                                              */
 459   /*                                                                       */
 460   /*    The field `params.source' will be set to `outline' before the scan */
 461   /*    converter is called, which means that the value you give to it is  */
 462   /*    actually ignored.                                                  */
 463   /*                                                                       */
 464   /*    The gray-level rasterizer always uses 256 gray levels.  If you     */
 465   /*    want less gray levels, you have to provide your own span callback. */
 466   /*    See the @FT_RASTER_FLAG_DIRECT value of the `flags' field in the   */
 467   /*    @FT_Raster_Params structure for more details.                      */
 468   /*                                                                       */
 469   FT_EXPORT( FT_Error )
 470   FT_Outline_Render( FT_Library         library,
 471                      FT_Outline*        outline,
 472                      FT_Raster_Params*  params );
 473
 474
 475  /**************************************************************************
 476   *
 477   * @enum:
 478   *   FT_Orientation
 479   *
 480   * @description:
 481   *   A list of values used to describe an outline's contour orientation.
 482   *
 483   *   The TrueType and PostScript specifications use different conventions
 484   *   to determine whether outline contours should be filled or unfilled.
 485   *
 486   * @values:
 487   *   FT_ORIENTATION_TRUETYPE ::
 488   *     According to the TrueType specification, clockwise contours must
 489   *     be filled, and counter-clockwise ones must be unfilled.
 490   *
 491   *   FT_ORIENTATION_POSTSCRIPT ::
 492   *     According to the PostScript specification, counter-clockwise contours
 493   *     must be filled, and clockwise ones must be unfilled.
 494   *
 495   *   FT_ORIENTATION_FILL_RIGHT ::
 496   *     This is identical to @FT_ORIENTATION_TRUETYPE, but is used to
 497   *     remember that in TrueType, everything that is to the right of
 498   *     the drawing direction of a contour must be filled.
 499   *
 500   *   FT_ORIENTATION_FILL_LEFT ::
 501   *     This is identical to @FT_ORIENTATION_POSTSCRIPT, but is used to
 502   *     remember that in PostScript, everything that is to the left of
 503   *     the drawing direction of a contour must be filled.
 504   *
 505   *   FT_ORIENTATION_NONE ::
 506   *     The orientation cannot be determined.  That is, different parts of
 507   *     the glyph have different orientation.
 508   *
 509   */
 510   typedef enum  FT_Orientation_
 511   {
 512     FT_ORIENTATION_TRUETYPE   = 0,
 513     FT_ORIENTATION_POSTSCRIPT = 1,
 514     FT_ORIENTATION_FILL_RIGHT = FT_ORIENTATION_TRUETYPE,
 515     FT_ORIENTATION_FILL_LEFT  = FT_ORIENTATION_POSTSCRIPT,
 516     FT_ORIENTATION_NONE
 517
 518   } FT_Orientation;
 519
 520
 521  /**************************************************************************
 522   *
 523   * @function:
 524   *   FT_Outline_Get_Orientation
 525   *
 526   * @description:
 527   *   This function analyzes a glyph outline and tries to compute its
 528   *   fill orientation (see @FT_Orientation).  This is done by computing
 529   *   the direction of each global horizontal and/or vertical extrema
 530   *   within the outline.
 531   *
 532   *   Note that this will return @FT_ORIENTATION_TRUETYPE for empty
 533   *   outlines.
 534   *
 535   * @input:
 536   *   outline ::
 537   *     A handle to the source outline.
 538   *
 539   * @return:
 540   *   The orientation.
 541   *
 542   */
 543   FT_EXPORT( FT_Orientation )
 544   FT_Outline_Get_Orientation( FT_Outline*  outline );
 545
 546
 547   /* */
 548
 549
 550 FT_END_HEADER
 551
 552 #endif /* __FTOUTLN_H__ */
 553
 554
 555 /* END */
 556
 557
 558 /* Local Variables: */
 559 /* coding: utf-8    */
 560 /* End:             */