subsys/win32k/freetype/include/freetype/ftimage.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ftimage.h                                                              */
   4 /*                                                                         */
   5 /*    FreeType glyph image formats and default raster interface            */
   6 /*    (specification).                                                     */
   7 /*                                                                         */
   8 /*  Copyright 1996-2000 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   /*                                                                       */
  21   /* Note: A `raster' is simply a scan-line converter, used to render      */
  22   /*       FT_Outlines into FT_Bitmaps.                                    */
  23   /*                                                                       */
  24   /*************************************************************************/
  25
  26
  27 #ifndef FTIMAGE_H
  28 #define FTIMAGE_H
  29
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35
  36   /*************************************************************************/
  37   /*                                                                       */
  38   /* <Type>                                                                */
  39   /*    FT_Pos                                                             */
  40   /*                                                                       */
  41   /* <Description>                                                         */
  42   /*    The type FT_Pos is a 32-bit integer used to store vectorial        */
  43   /*    coordinates.  Depending on the context, these can represent        */
  44   /*    distances in integer font units, or 26.6 fixed float pixel         */
  45   /*    coordinates.                                                       */
  46   /*                                                                       */
  47   typedef signed long  FT_Pos;
  48
  49
  50   /*************************************************************************/
  51   /*                                                                       */
  52   /* <Struct>                                                              */
  53   /*    FT_Vector                                                          */
  54   /*                                                                       */
  55   /* <Description>                                                         */
  56   /*    A simple structure used to store a 2D vector; coordinates are of   */
  57   /*    the FT_Pos type.                                                   */
  58   /*                                                                       */
  59   /* <Fields>                                                              */
  60   /*    x :: The horizontal coordinate.                                    */
  61   /*    y :: The vertical coordinate.                                      */
  62   /*                                                                       */
  63   typedef struct  FT_Vector_
  64   {
  65     FT_Pos  x;
  66     FT_Pos  y;
  67
  68   } FT_Vector;
  69
  70
  71   /*************************************************************************/
  72   /*                                                                       */
  73   /* <Enum>                                                                */
  74   /*    FT_Pixel_Mode                                                      */
  75   /*                                                                       */
  76   /* <Description>                                                         */
  77   /*    An enumeration type used to describe the format of pixels in a     */
  78   /*    given bitmap.  Note that additional formats may be added in the    */
  79   /*    future.                                                            */
  80   /*                                                                       */
  81   /* <Fields>                                                              */
  82   /*    ft_pixel_mode_mono  :: A monochrome bitmap (1 bit/pixel).          */
  83   /*                                                                       */
  84   /*    ft_pixel_mode_grays :: An 8-bit gray-levels bitmap.  Note that the */
  85   /*                           total number of gray levels is given in the */
  86   /*                           `num_grays' field of the FT_Bitmap          */
  87   /*                           structure.                                  */
  88   /*                                                                       */
  89   /*    ft_pixel_mode_pal2  :: A 2-bit paletted bitmap.                    */
  90   /*                           Currently unused by FreeType.               */
  91   /*                                                                       */
  92   /*    ft_pixel_mode_pal4  :: A 4-bit paletted bitmap.                    */
  93   /*                           Currently unused by FreeType.               */
  94   /*                                                                       */
  95   /*    ft_pixel_mode_pal8  :: An 8-bit paletted bitmap.                   */
  96   /*                           Currently unused by FreeType.               */
  97   /*                                                                       */
  98   /*    ft_pixel_mode_rgb15 :: A 15-bit RGB bitmap.  Uses 5:5:5 encoding.  */
  99   /*                           Currently unused by FreeType.               */
 100   /*                                                                       */
 101   /*    ft_pixel_mode_rgb16 :: A 16-bit RGB bitmap.  Uses 5:6:5 encoding.  */
 102   /*                           Currently unused by FreeType.               */
 103   /*                                                                       */
 104   /*    ft_pixel_mode_rgb24 :: A 24-bit RGB bitmap.                        */
 105   /*                           Currently unused by FreeType.               */
 106   /*                                                                       */
 107   /*    ft_pixel_mode_rgb32 :: A 32-bit RGB bitmap.                        */
 108   /*                           Currently unused by FreeType.               */
 109   /*                                                                       */
 110   /* <Note>                                                                */
 111   /*    Some anti-aliased bitmaps might be embedded in TrueType fonts      */
 112   /*    using formats pal2 or pal4, though no fonts presenting those have  */
 113   /*    been found to date.                                                */
 114   /*                                                                       */
 115   typedef enum  FT_Pixel_Mode_
 116   {
 117     ft_pixel_mode_none = 0,
 118     ft_pixel_mode_mono,
 119     ft_pixel_mode_grays,
 120     ft_pixel_mode_pal2,
 121     ft_pixel_mode_pal4,
 122     ft_pixel_mode_pal8,
 123     ft_pixel_mode_rgb15,
 124     ft_pixel_mode_rgb16,
 125     ft_pixel_mode_rgb24,
 126     ft_pixel_mode_rgb32,
 127
 128     ft_pixel_mode_max      /* do not remove */
 129
 130   } FT_Pixel_Mode;
 131
 132
 133   /*************************************************************************/
 134   /*                                                                       */
 135   /* <Enum>                                                                */
 136   /*    FT_Palette_Mode                                                    */
 137   /*                                                                       */
 138   /* <Description>                                                         */
 139   /*    An enumeration type used to describe the format of a bitmap        */
 140   /*    palette, used with ft_pixel_mode_pal4 and ft_pixel_mode_pal8.      */
 141   /*                                                                       */
 142   /* <Fields>                                                              */
 143   /*    ft_palette_mode_rgb  :: The palette is an array of 3-bytes RGB     */
 144   /*                            records.                                   */
 145   /*                                                                       */
 146   /*    ft_palette_mode_rgba :: The palette is an array of 4-bytes RGBA    */
 147   /*                            records.                                   */
 148   /*                                                                       */
 149   /* <Note>                                                                */
 150   /*    As ft_pixel_mode_pal2, pal4 and pal8 are currently unused by       */
 151   /*    FreeType, these types are not handled by the library itself.       */
 152   /*                                                                       */
 153   typedef enum  FT_Palette_Mode_
 154   {
 155     ft_palette_mode_rgb = 0,
 156     ft_palette_mode_rgba,
 157
 158     ft_palettte_mode_max   /* do not remove */
 159
 160   } FT_Palette_Mode;
 161
 162
 163   /*************************************************************************/
 164   /*                                                                       */
 165   /* <Struct>                                                              */
 166   /*    FT_Bitmap                                                          */
 167   /*                                                                       */
 168   /* <Description>                                                         */
 169   /*    A structure used to describe a bitmap or pixmap to the raster.     */
 170   /*    Note that we now manage pixmaps of various depths through the      */
 171   /*    `pixel_mode' field.                                                */
 172   /*                                                                       */
 173   /* <Fields>                                                              */
 174   /*    rows         :: The number of bitmap rows.                         */
 175   /*                                                                       */
 176   /*    width        :: The number of pixels in bitmap row.                */
 177   /*                                                                       */
 178   /*    pitch        :: The pitch's absolute value is the number of bytes  */
 179   /*                    taken by one bitmap row, including padding.        */
 180   /*                    However, the pitch is positive when the bitmap has */
 181   /*                    a `down' flow, and negative when it has an `up'    */
 182   /*                    flow.  In all cases, the pitch is an offset to add */
 183   /*                    to a bitmap pointer in order to go down one row.   */
 184   /*                                                                       */
 185   /*    buffer       :: A typeless pointer to the bitmap buffer.  This     */
 186   /*                    value should be aligned on 32-bit boundaries in    */
 187   /*                    most cases.                                        */
 188   /*                                                                       */
 189   /*    num_grays    :: This field is only used with                       */
 190   /*                    `ft_pixel_mode_grays'; it gives the number of gray */
 191   /*                    levels used in the bitmap.                         */
 192   /*                                                                       */
 193   /*    pixel_mode   :: The pixel_mode, i.e., how pixel bits are stored.   */
 194   /*                                                                       */
 195   /*    palette_mode :: This field is only used with paletted pixel modes; */
 196   /*                    it indicates how the palette is stored.            */
 197   /*                                                                       */
 198   /*    palette      :: A typeless pointer to the bitmap palette; only     */
 199   /*                    used for paletted pixel modes.                     */
 200   /*                                                                       */
 201   /* <Note>                                                                */
 202   /*   For now, the only pixel mode supported by FreeType are mono and     */
 203   /*   grays.  However, drivers might be added in the future to support    */
 204   /*   more `colorful' options.                                            */
 205   /*                                                                       */
 206   /*   When using pixel modes pal2, pal4 and pal8 with a void `palette'    */
 207   /*   field, a gray pixmap with respectively 4, 16, and 256 levels of     */
 208   /*   gray is assumed.  This, in order to be compatible with some         */
 209   /*   embedded bitmap formats defined in the TrueType specification.      */
 210   /*                                                                       */
 211   /*   Note that no font was found presenting such embedded bitmaps, so    */
 212   /*   this is currently completely unhandled by the library.              */
 213   /*                                                                       */
 214   typedef struct  FT_Bitmap_
 215   {
 216     int             rows;
 217     int             width;
 218     int             pitch;
 219     unsigned char*  buffer;
 220     short           num_grays;
 221     char            pixel_mode;
 222     char            palette_mode;
 223     void*           palette;
 224
 225   } FT_Bitmap;
 226
 227
 228   /*************************************************************************/
 229   /*                                                                       */
 230   /* <Struct>                                                              */
 231   /*    FT_Outline                                                         */
 232   /*                                                                       */
 233   /* <Description>                                                         */
 234   /*    This structure is used to describe an outline to the scan-line     */
 235   /*    converter.                                                         */
 236   /*                                                                       */
 237   /* <Fields>                                                              */
 238   /*    n_contours :: The number of contours in the outline.               */
 239   /*                                                                       */
 240   /*    n_points   :: The number of points in the outline.                 */
 241   /*                                                                       */
 242   /*    points     :: A pointer to an array of `n_points' FT_Vector        */
 243   /*                  elements, giving the outline's point coordinates.    */
 244   /*                                                                       */
 245   /*    tags       :: A pointer to an array of `n_points' chars, giving    */
 246   /*                  giving each outline point's type.  If bit 0 is       */
 247   /*                  unset, the point is 'off' the curve, i.e. a Bezier   */
 248   /*                  control point, while it is `on' when unset.          */
 249   /*                                                                       */
 250   /*                  Bit 1 is meaningful for `off' points only.  If set,  */
 251   /*                  it indicates a third-order Bezier arc control point; */
 252   /*                  and a second-order control point if unset.           */
 253   /*                                                                       */
 254   /*    contours   :: An array of `n_contours' shorts, giving the end      */
 255   /*                  point of each contour within the outline.  For       */
 256   /*                  example, the first contour is defined by the points  */
 257   /*                  `0' to `contours[0]', the second one is defined by   */
 258   /*                  the points `contours[0]+1' to `contours[1]', etc.    */
 259   /*                                                                       */
 260   /*    flags      :: A set of bit flags used to characterize the outline  */
 261   /*                  and give hints to the scan-converter and hinter on   */
 262   /*                  how to convert/grid-fit it.  See FT_Outline_Flags.   */
 263   /*                                                                       */
 264   typedef struct  FT_Outline_
 265   {
 266     short       n_contours;      /* number of contours in glyph        */
 267     short       n_points;        /* number of points in the glyph      */
 268
 269     FT_Vector*  points;          /* the outline's points               */
 270     char*       tags;            /* the points flags                   */
 271     short*      contours;        /* the contour end points             */
 272
 273     int         flags;           /* outline masks                      */
 274
 275   } FT_Outline;
 276
 277
 278   /*************************************************************************/
 279   /*                                                                       */
 280   /* <Enum>                                                                */
 281   /*   FT_Outline_Flags                                                    */
 282   /*                                                                       */
 283   /* <Description>                                                         */
 284   /*    A simple type used to enumerates the flags in an outline's         */
 285   /*    `outline_flags' field.                                             */
 286   /*                                                                       */
 287   /* <Fields>                                                              */
 288   /*    ft_outline_owner          :: If set, this flag indicates that the  */
 289   /*                                 outline's field arrays (i.e.          */
 290   /*                                 `points', `flags' & `contours') are   */
 291   /*                                 `owned' by the outline object, and    */
 292   /*                                 should thus be freed when it is       */
 293   /*                                 destroyed.                            */
 294   /*                                                                       */
 295   /*   ft_outline_even_odd_fill   :: By default, outlines are filled using */
 296   /*                                 the non-zero winding rule.  If set to */
 297   /*                                 1, the outline will be filled using   */
 298   /*                                 the even-odd fill rule (only works    */
 299   /*                                 with the smooth raster).              */
 300   /*                                                                       */
 301   /*   ft_outline_reverse_fill    :: By default, outside contours of an    */
 302   /*                                 outline are oriented in clock-wise    */
 303   /*                                 direction, as defined in the TrueType */
 304   /*                                 specification.  This flag is set if   */
 305   /*                                 the outline uses the opposite         */
 306   /*                                 direction (typically for Type 1       */
 307   /*                                 fonts).  This flag is ignored by the  */
 308   /*                                 scan-converter.  However, it is very  */
 309   /*                                 important for the auto-hinter.        */
 310   /*                                                                       */
 311   /*   ft_outline_ignore_dropouts :: By default, the scan converter will   */
 312   /*                                 try to detect drop-outs in an outline */
 313   /*                                 and correct the glyph bitmap to       */
 314   /*                                 ensure consistent shape continuity.   */
 315   /*                                 If set, this flag hints the scan-line */
 316   /*                                 converter to ignore such cases.       */
 317   /*                                                                       */
 318   /*   ft_outline_high_precision  :: This flag indicates that the          */
 319   /*                                 scan-line converter should try to     */
 320   /*                                 convert this outline to bitmaps with  */
 321   /*                                 the highest possible quality.  It is  */
 322   /*                                 typically set for small character     */
 323   /*                                 sizes.  Note that this is only a      */
 324   /*                                 hint, that might be completely        */
 325   /*                                 ignored by a given scan-converter.    */
 326   /*                                                                       */
 327   /*   ft_outline_single_pass     :: This flag is set to force a given     */
 328   /*                                 scan-converter to only use a single   */
 329   /*                                 pass over the outline to render a     */
 330   /*                                 bitmap glyph image.  Normally, it is  */
 331   /*                                 set for very large character sizes.   */
 332   /*                                 It is only a hint, that might be      */
 333   /*                                 completely ignored by a given         */
 334   /*                                 scan-converter.                       */
 335   /*                                                                       */
 336   typedef enum  FT_Outline_Flags_
 337   {
 338     ft_outline_none            = 0,
 339     ft_outline_owner           = 1,
 340     ft_outline_even_odd_fill   = 2,
 341     ft_outline_reverse_fill    = 4,
 342     ft_outline_ignore_dropouts = 8,
 343     ft_outline_high_precision  = 256,
 344     ft_outline_single_pass     = 512
 345
 346   } FT_Outline_Flags;
 347
 348
 349 #define FT_CURVE_TAG( flag )  ( flag & 3 )
 350
 351 #define FT_Curve_Tag_On           1
 352 #define FT_Curve_Tag_Conic        0
 353 #define FT_Curve_Tag_Cubic        2
 354
 355 #define FT_Curve_Tag_Touch_X      8  /* reserved for the TrueType hinter */
 356 #define FT_Curve_Tag_Touch_Y     16  /* reserved for the TrueType hinter */
 357
 358 #define FT_Curve_Tag_Touch_Both  ( FT_Curve_Tag_Touch_X | \
 359                                    FT_Curve_Tag_Touch_Y )
 360
 361
 362   /*************************************************************************/
 363   /*                                                                       */
 364   /* <FuncType>                                                            */
 365   /*    FT_Outline_MoveTo_Func                                             */
 366   /*                                                                       */
 367   /* <Description>                                                         */
 368   /*    A function pointer type used to describe the signature of a `move  */
 369   /*    to' function during outline walking/decomposition.                 */
 370   /*                                                                       */
 371   /*    A `move to' is emitted to start a new contour in an outline.       */
 372   /*                                                                       */
 373   /* <Input>                                                               */
 374   /*    to   :: A pointer to the target point of the `move to'.            */
 375   /*                                                                       */
 376   /*    user :: A typeless pointer which is passed from the caller of the  */
 377   /*            decomposition function.                                    */
 378   /*                                                                       */
 379   /* <Return>                                                              */
 380   /*    Error code.  0 means success.                                      */
 381   /*                                                                       */
 382   typedef int  (*FT_Outline_MoveTo_Func)( FT_Vector*  to,
 383                                           void*       user );
 384
 385
 386   /*************************************************************************/
 387   /*                                                                       */
 388   /* <FuncType>                                                            */
 389   /*    FT_Outline_LineTo_Func                                             */
 390   /*                                                                       */
 391   /* <Description>                                                         */
 392   /*    A function pointer type used to describe the signature of a `line  */
 393   /*    to' function during outline walking/decomposition.                 */
 394   /*                                                                       */
 395   /*    A `line to' is emitted to indicate a segment in the outline.       */
 396   /*                                                                       */
 397   /* <Input>                                                               */
 398   /*    to   :: A pointer to the target point of the `line to'.            */
 399   /*                                                                       */
 400   /*    user :: A typeless pointer which is passed from the caller of the  */
 401   /*            decomposition function.                                    */
 402   /*                                                                       */
 403   /* <Return>                                                              */
 404   /*    Error code.  0 means success.                                      */
 405   /*                                                                       */
 406   typedef int  (*FT_Outline_LineTo_Func)( FT_Vector*  to,
 407                                           void*       user );
 408
 409
 410   /*************************************************************************/
 411   /*                                                                       */
 412   /* <FuncType>                                                            */
 413   /*    FT_Outline_ConicTo_Func                                            */
 414   /*                                                                       */
 415   /* <Description>                                                         */
 416   /*    A function pointer type use to describe the signature of a `conic  */
 417   /*    to' function during outline walking/decomposition.                 */
 418   /*                                                                       */
 419   /*    A `conic to' is emitted to indicate a second-order Bezier arc in   */
 420   /*    the outline.                                                       */
 421   /*                                                                       */
 422   /* <Input>                                                               */
 423   /*    control :: An intermediate control point between the last position */
 424   /*               and the new target in `to'.                             */
 425   /*                                                                       */
 426   /*    to      :: A pointer to the target end point of the conic arc.     */
 427   /*                                                                       */
 428   /*    user    :: A typeless pointer which is passed from the caller of   */
 429   /*               the decomposition function.                             */
 430   /*                                                                       */
 431   /* <Return>                                                              */
 432   /*    Error code.  0 means success.                                      */
 433   /*                                                                       */
 434   typedef int  (*FT_Outline_ConicTo_Func)( FT_Vector*  control,
 435                                            FT_Vector*  to,
 436                                            void*       user );
 437
 438
 439   /*************************************************************************/
 440   /*                                                                       */
 441   /* <FuncType>                                                            */
 442   /*    FT_Outline_CubicTo_Func                                            */
 443   /*                                                                       */
 444   /* <Description>                                                         */
 445   /*    A function pointer type used to describe the signature of a `cubic */
 446   /*    to' function during outline walking/decomposition.                 */
 447   /*                                                                       */
 448   /*    A `cubic to' is emitted to indicate a third-order Bezier arc.      */
 449   /*                                                                       */
 450   /* <Input>                                                               */
 451   /*    control1 :: A pointer to the first Bezier control point.           */
 452   /*                                                                       */
 453   /*    control2 :: A pointer to the second Bezier control point.          */
 454   /*                                                                       */
 455   /*    to       :: A pointer to the target end point.                     */
 456   /*                                                                       */
 457   /*    user     :: A typeless pointer which is passed from the caller of  */
 458   /*                the decomposition function.                            */
 459   /*                                                                       */
 460   /* <Return>                                                              */
 461   /*    Error code.  0 means success.                                      */
 462   /*                                                                       */
 463   typedef int  (*FT_Outline_CubicTo_Func)( FT_Vector*  control1,
 464                                            FT_Vector*  control2,
 465                                            FT_Vector*  to,
 466                                            void*       user );
 467
 468
 469   /*************************************************************************/
 470   /*                                                                       */
 471   /* <Struct>                                                              */
 472   /*    FT_Outline_Funcs                                                   */
 473   /*                                                                       */
 474   /* <Description>                                                         */
 475   /*    A structure to hold various function pointers used during outline  */
 476   /*    decomposition in order to emit segments, conic, and cubic Beziers, */
 477   /*    as well as `move to' and `close to' operations.                    */
 478   /*                                                                       */
 479   /* <Fields>                                                              */
 480   /*    move_to  :: The `move to' emitter.                                 */
 481   /*                                                                       */
 482   /*    line_to  :: The segment emitter.                                   */
 483   /*                                                                       */
 484   /*    conic_to :: The second-order Bezier arc emitter.                   */
 485   /*                                                                       */
 486   /*    cubic_to :: The third-order Bezier arc emitter.                    */
 487   /*                                                                       */
 488   /*    shift    :: The shift that is applied to coordinates before they   */
 489   /*                are sent to the emitter.                               */
 490   /*                                                                       */
 491   /*    delta    :: The delta that is applied to coordinates before they   */
 492   /*                are sent to the emitter, but after the shift.          */
 493   /*                                                                       */
 494   /* <Note>                                                                */
 495   /*    The point coordinates sent to the emitters are the transformed     */
 496   /*    version of the original coordinates (this is important for high    */
 497   /*    accuracy during scan-conversion).  The transformation is simple:   */
 498   /*                                                                       */
 499   /*      x' = (x << shift) - delta                                        */
 500   /*      y' = (x << shift) - delta                                        */
 501   /*                                                                       */
 502   /*    Set the value of `shift' and `delta' to 0 to get the original      */
 503   /*    point coordinates.                                                 */
 504   /*                                                                       */
 505   typedef struct  FT_Outline_Funcs_
 506   {
 507     FT_Outline_MoveTo_Func   move_to;
 508     FT_Outline_LineTo_Func   line_to;
 509     FT_Outline_ConicTo_Func  conic_to;
 510     FT_Outline_CubicTo_Func  cubic_to;
 511
 512     int                      shift;
 513     FT_Pos                   delta;
 514
 515   } FT_Outline_Funcs;
 516
 517
 518   /*************************************************************************/
 519   /*                                                                       */
 520   /* <Macro>                                                               */
 521   /*    FT_IMAGE_TAG                                                       */
 522   /*                                                                       */
 523   /* <Description>                                                         */
 524   /*    This macro converts four letter tags into an unsigned long.        */
 525   /*                                                                       */
 526 #define FT_IMAGE_TAG( _x1, _x2, _x3, _x4 ) \
 527           ( ( (unsigned long)_x1 << 24 ) | \
 528             ( (unsigned long)_x2 << 16 ) | \
 529             ( (unsigned long)_x3 << 8  ) | \
 530               (unsigned long)_x4         )
 531
 532
 533   /*************************************************************************/
 534   /*                                                                       */
 535   /* <Enum>                                                                */
 536   /*    FT_Glyph_Format                                                    */
 537   /*                                                                       */
 538   /* <Description>                                                         */
 539   /*    An enumeration type used to describe the format of a given glyph   */
 540   /*    image.  Note that this version of FreeType only supports two image */
 541   /*    formats, even though future font drivers will be able to register  */
 542   /*    their own format.                                                  */
 543   /*                                                                       */
 544   /* <Fields>                                                              */
 545   /*    ft_glyph_format_composite :: The glyph image is a composite of     */
 546   /*                                 several other images.  This glyph     */
 547   /*                                 format is _only_ used with the        */
 548   /*                                 FT_LOAD_FLAG_NO_RECURSE flag (XXX:    */
 549   /*                                 Which is currently unimplemented).    */
 550   /*                                                                       */
 551   /*    ft_glyph_format_bitmap    :: The glyph image is a bitmap, and can  */
 552   /*                                 be described as a FT_Bitmap.          */
 553   /*                                                                       */
 554   /*    ft_glyph_format_outline   :: The glyph image is a vectorial image  */
 555   /*                                 made of bezier control points, and    */
 556   /*                                 can be described as a FT_Outline.     */
 557   /*                                                                       */
 558   /*    ft_glyph_format_plotter   :: The glyph image is a vectorial image  */
 559   /*                                 made of plotter lines (some T1 fonts  */
 560   /*                                 like Hershey contain glyph in this    */
 561   /*                                 format).                              */
 562   /*                                                                       */
 563   typedef enum  FT_Glyph_Format_
 564   {
 565     ft_glyph_format_none      = 0,
 566     ft_glyph_format_composite = FT_IMAGE_TAG( 'c', 'o', 'm', 'p' ),
 567     ft_glyph_format_bitmap    = FT_IMAGE_TAG( 'b', 'i', 't', 's' ),
 568     ft_glyph_format_outline   = FT_IMAGE_TAG( 'o', 'u', 't', 'l' ),
 569     ft_glyph_format_plotter   = FT_IMAGE_TAG( 'p', 'l', 'o', 't' )
 570
 571   } FT_Glyph_Format;
 572
 573
 574   /*************************************************************************/
 575   /*************************************************************************/
 576   /*************************************************************************/
 577   /*****                                                               *****/
 578   /*****            R A S T E R   D E F I N I T I O N S                *****/
 579   /*****                                                               *****/
 580   /*************************************************************************/
 581   /*************************************************************************/
 582   /*************************************************************************/
 583
 584
 585   /*************************************************************************/
 586   /*                                                                       */
 587   /* A raster is a scan converter, in charge of rendering an outline into  */
 588   /* a a bitmap.  This section contains the public API for rasters.        */
 589   /*                                                                       */
 590   /* Note that in FreeType 2, all rasters are now encapsulated within      */
 591   /* specific modules called `renderers'.  See `freetype/ftrender.h' for   */
 592   /* more details on renderers.                                            */
 593   /*                                                                       */
 594   /*************************************************************************/
 595
 596
 597   /*************************************************************************/
 598   /*                                                                       */
 599   /* <Type>                                                                */
 600   /*    FT_Raster                                                          */
 601   /*                                                                       */
 602   /* <Description>                                                         */
 603   /*    A handle (pointer) to a raster object.  Each object can be used    */
 604   /*    independently to convert an outline into a bitmap or pixmap.       */
 605   /*                                                                       */
 606   typedef struct FT_RasterRec_*  FT_Raster;
 607
 608
 609   /*************************************************************************/
 610   /*                                                                       */
 611   /* <Struct>                                                              */
 612   /*    FT_Span                                                            */
 613   /*                                                                       */
 614   /* <Description>                                                         */
 615   /*    A structure used to model a single span of gray (or black) pixels  */
 616   /*    when rendering a monochrome or anti-aliased bitmap.                */
 617   /*                                                                       */
 618   /* <Fields>                                                              */
 619   /*    x        :: The span's horizontal start position.                  */
 620   /*                                                                       */
 621   /*    len      :: The span's length in pixels.                           */
 622   /*                                                                       */
 623   /*    coverage :: The span color/coverage, ranging from 0 (background)   */
 624   /*                to 255 (foreground).  Only used for anti-aliased       */
 625   /*                rendering.                                             */
 626   /*                                                                       */
 627   /* <Note>                                                                */
 628   /*    This structure is used by the span drawing callback type named     */
 629   /*    FT_Raster_Span_Func(), which takes the y-coordinate of the span as */
 630   /*    a parameter.                                                       */
 631   /*                                                                       */
 632   /*    The coverage value is always between 0 and 255, even if the number */
 633   /*    of gray levels have been set through FT_Set_Gray_Levels().         */
 634   /*                                                                       */
 635   typedef struct  FT_Span_
 636   {
 637     short          x;
 638     unsigned short len;
 639     unsigned char  coverage;
 640
 641   } FT_Span;
 642
 643
 644   /*************************************************************************/
 645   /*                                                                       */
 646   /* <FuncType>                                                            */
 647   /*    FT_Raster_Span_Func                                                */
 648   /*                                                                       */
 649   /* <Description>                                                         */
 650   /*    A function used as a call-back by the anti-aliased renderer in     */
 651   /*    order to let client applications draw themselves the gray pixel    */
 652   /*    spans on each scan line.                                           */
 653   /*                                                                       */
 654   /* <Input>                                                               */
 655   /*    y     :: The scanline's y-coordinate.                              */
 656   /*                                                                       */
 657   /*    count :: The number of spans to draw on this scanline.             */
 658   /*                                                                       */
 659   /*    spans :: A table of `count' spans to draw on the scanline.         */
 660   /*                                                                       */
 661   /*    user  :: User-supplied data that is passed to the callback.        */
 662   /*                                                                       */
 663   /* <Note>                                                                */
 664   /*    This callback allows client applications to directly render the    */
 665   /*    gray spans of the anti-aliased bitmap to any kind of surfaces.     */
 666   /*                                                                       */
 667   /*    This can be used to write anti-aliased outlines directly to a      */
 668   /*    given background bitmap, and even perform translucency.            */
 669   /*                                                                       */
 670   /*    Note that the `count' field cannot be greater than a fixed value   */
 671   /*    defined by the FT_MAX_GRAY_SPANS configuration macro in            */
 672   /*    ftoption.h.  By default, this value is set to 32, which means that */
 673   /*    if there are more than 32 spans on a given scanline, the callback  */
 674   /*    will be called several times with the same `y' parameter in order  */
 675   /*    to draw all callbacks.                                             */
 676   /*                                                                       */
 677   /*    Otherwise, the callback is only called once per scan-line, and     */
 678   /*    only for those scanlines that do have `gray' pixels on them.       */
 679   /*                                                                       */
 680   typedef void  (*FT_Raster_Span_Func)( int       y,
 681                                         int       count,
 682                                         FT_Span*  spans,
 683                                         void*     user );
 684
 685
 686   /*************************************************************************/
 687   /*                                                                       */
 688   /* <FuncType>                                                            */
 689   /*    FT_Raster_BitTest_Func                                             */
 690   /*                                                                       */
 691   /* <Description>                                                         */
 692   /*    A function used as a call-back by the monochrome scan-converter    */
 693   /*    to test whether a given target pixel is already set to the drawing */
 694   /*    `color'.  These tests are crucial to implement drop-out control    */
 695   /*    per-se the TrueType spec.                                          */
 696   /*                                                                       */
 697   /* <Input>                                                               */
 698   /*    y     :: The pixel's y-coordinate.                                 */
 699   /*                                                                       */
 700   /*    x     :: The pixel's x-coordinate.                                 */
 701   /*                                                                       */
 702   /*    user  :: User-supplied data that is passed to the callback.        */
 703   /*                                                                       */
 704   /* <Return>                                                              */
 705   /*   1 if the pixel is `set', 0 otherwise.                               */
 706   /*                                                                       */
 707   typedef int  (*FT_Raster_BitTest_Func)( int    y,
 708                                           int    x,
 709                                           void*  user );
 710
 711
 712   /*************************************************************************/
 713   /*                                                                       */
 714   /* <FuncType>                                                            */
 715   /*    FT_Raster_BitSet_Func                                              */
 716   /*                                                                       */
 717   /* <Description>                                                         */
 718   /*    A function used as a call-back by the monochrome scan-converter    */
 719   /*    to set an individual target pixel.  This is crucial to implement   */
 720   /*    drop-out control according to the TrueType specification.          */
 721   /*                                                                       */
 722   /* <Input>                                                               */
 723   /*    y     :: The pixel's y-coordinate.                                 */
 724   /*                                                                       */
 725   /*    x     :: The pixel's x-coordinate.                                 */
 726   /*                                                                       */
 727   /*    user  :: User-supplied data that is passed to the callback.        */
 728   /*                                                                       */
 729   /* <Return>                                                              */
 730   /*    1 if the pixel is `set', 0 otherwise.                              */
 731   /*                                                                       */
 732   typedef void  (*FT_Raster_BitSet_Func)( int    y,
 733                                           int    x,
 734                                           void*  user );
 735
 736
 737   /*************************************************************************/
 738   /*                                                                       */
 739   /* <Enum>                                                                */
 740   /*    FT_Raster_Flag                                                     */
 741   /*                                                                       */
 742   /* <Description>                                                         */
 743   /*    An enumeration to list the bit flags as used in the `flags' field  */
 744   /*    of a FT_Raster_Params structure.                                   */
 745   /*                                                                       */
 746   /* <Fields>                                                              */
 747   /*    ft_raster_flag_default :: This value is 0.                         */
 748   /*                                                                       */
 749   /*    ft_raster_flag_aa      :: Requests the rendering of an             */
 750   /*                              anti-aliased glyph bitmap.  If unset, a  */
 751   /*                              monchrome bitmap will be rendered.       */
 752   /*                                                                       */
 753   /*    ft_raster_flag_direct  :: Requests direct rendering over the       */
 754   /*                              target bitmap.  Direct rendering uses    */
 755   /*                              user-provided callbacks in order to      */
 756   /*                              perform direct drawing or composition    */
 757   /*                              over an existing bitmap.  If this bit is */
 758   /*                              unset, the content of the target bitmap  */
 759   /*                              *must be zeroed*!                        */
 760   /*                                                                       */
 761   typedef  enum
 762   {
 763     ft_raster_flag_default = 0,
 764     ft_raster_flag_aa      = 1,
 765     ft_raster_flag_direct  = 2
 766
 767   } FT_Raster_Flag;
 768
 769
 770   /*************************************************************************/
 771   /*                                                                       */
 772   /* <Struct>                                                              */
 773   /*    FT_Raster_Params                                                   */
 774   /*                                                                       */
 775   /* <Description>                                                         */
 776   /*    A structure to hold the arguments used by a raster's render        */
 777   /*    function.                                                          */
 778   /*                                                                       */
 779   /* <Fields>                                                              */
 780   /*    target      :: The target bitmap.                                  */
 781   /*                                                                       */
 782   /*    source      :: A pointer to the source glyph image (e.g. an        */
 783   /*                   FT_Outline).                                        */
 784   /*                                                                       */
 785   /*    flags       :: The rendering flags.                                */
 786   /*                                                                       */
 787   /*    gray_spans  :: The gray span drawing callback.                     */
 788   /*                                                                       */
 789   /*    black_spans :: The black span drawing callback.                    */
 790   /*                                                                       */
 791   /*    bit_test    :: The bit test callback.                              */
 792   /*                                                                       */
 793   /*    bit_set     :: The bit set callback.                               */
 794   /*                                                                       */
 795   /*    user        :: User-supplied data that is passed to each drawing   */
 796   /*                   callback.                                           */
 797   /*                                                                       */
 798   /* <Note>                                                                */
 799   /*    An anti-aliased glyph bitmap is drawn if the ft_raster_flag_aa bit */
 800   /*    flag is set in the `flags' field, otherwise a monochrome bitmap    */
 801   /*    will be generated.                                                 */
 802   /*                                                                       */
 803   /*    If the ft_raster_flag_direct bit flag is set in `flags', the       */
 804   /*    raster will call the `gray_spans' callback to draw gray pixel      */
 805   /*    spans, in the case of an aa glyph bitmap, it will call             */
 806   /*    `black_spans', and `bit_test' and `bit_set' in the case of a       */
 807   /*    monochrome bitmap.  This allows direct composition over a          */
 808   /*    pre-existing bitmap through user-provided callbacks to perform the */
 809   /*    span drawing/composition.                                          */
 810   /*                                                                       */
 811   /*    Note that the `bit_test' and `bit_set' callbacks are required when */
 812   /*    rendering a monochrome bitmap, as they are crucial to implement    */
 813   /*    correct drop-out control as defined in the TrueType specification. */
 814   /*                                                                       */
 815   typedef struct  FT_Raster_Params_
 816   {
 817     FT_Bitmap*              target;
 818     void*                   source;
 819     int                     flags;
 820     FT_Raster_Span_Func     gray_spans;
 821     FT_Raster_Span_Func     black_spans;
 822     FT_Raster_BitTest_Func  bit_test;
 823     FT_Raster_BitSet_Func   bit_set;
 824     void*                   user;
 825
 826   } FT_Raster_Params;
 827
 828
 829   /*************************************************************************/
 830   /*                                                                       */
 831   /* <FuncType>                                                            */
 832   /*    FT_Raster_New_Func                                                 */
 833   /*                                                                       */
 834   /* <Description>                                                         */
 835   /*    A function used to create a new raster object.                     */
 836   /*                                                                       */
 837   /* <Input>                                                               */
 838   /*    memory :: A handle to the memory allocator.                        */
 839   /*                                                                       */
 840   /* <Output>                                                              */
 841   /*    raster :: A handle to the new raster object.                       */
 842   /*                                                                       */
 843   /* <Return>                                                              */
 844   /*    Error code.  0 means success.                                      */
 845   /*                                                                       */
 846   /* <Note>                                                                */
 847   /*    The `memory' parameter is a typeless pointer in order to avoid     */
 848   /*    un-wanted dependencies on the rest of the FreeType code.  In       */
 849   /*    practice, it is a FT_Memory, i.e., a handle to the standard        */
 850   /*    FreeType memory allocator.  However, this field can be completely  */
 851   /*    ignored by a given raster implementation.                          */
 852   /*                                                                       */
 853   typedef int  (*FT_Raster_New_Func)( void*       memory,
 854                                       FT_Raster*  raster );
 855
 856
 857   /*************************************************************************/
 858   /*                                                                       */
 859   /* <FuncType>                                                            */
 860   /*    FT_Raster_Done_Func                                                */
 861   /*                                                                       */
 862   /* <Description>                                                         */
 863   /*    A function used to destroy a given raster object.                  */
 864   /*                                                                       */
 865   /* <Input>                                                               */
 866   /*    raster :: A handle to the raster object.                           */
 867   /*                                                                       */
 868   typedef void  (*FT_Raster_Done_Func)( FT_Raster  raster );
 869
 870
 871   /*************************************************************************/
 872   /*                                                                       */
 873   /* <FuncType>                                                            */
 874   /*    FT_Raster_Reset_Func                                               */
 875   /*                                                                       */
 876   /* <Description>                                                         */
 877   /*    FreeType provides an area of memory called the `render pool',      */
 878   /*    available to all registered rasters.  This pool can be freely used */
 879   /*    during a given scan-conversion but is shared by all rasters.  Its  */
 880   /*    content is thus transient.                                         */
 881   /*                                                                       */
 882   /*    This function is called each time the render pool changes, or just */
 883   /*    after a new raster object is created.                              */
 884   /*                                                                       */
 885   /* <Input>                                                               */
 886   /*    raster    :: A handle to the new raster object.                    */
 887   /*                                                                       */
 888   /*    pool_base :: The address in memory of the render pool.             */
 889   /*                                                                       */
 890   /*    pool_size :: The size in bytes of the render pool.                 */
 891   /*                                                                       */
 892   /* <Note>                                                                */
 893   /*    Rasters can ignore the render pool and rely on dynamic memory      */
 894   /*    allocation if they want to (a handle to the memory allocator is    */
 895   /*    passed to the raster constructor).  However, this is not           */
 896   /*    recommended for efficiency purposes.                               */
 897   /*                                                                       */
 898   typedef void  (*FT_Raster_Reset_Func)( FT_Raster       raster,
 899                                          unsigned char*  pool_base,
 900                                          unsigned long   pool_size );
 901
 902
 903   /*************************************************************************/
 904   /*                                                                       */
 905   /* <FuncType>                                                            */
 906   /*    FT_Raster_Set_Mode_Func                                            */
 907   /*                                                                       */
 908   /* <Description>                                                         */
 909   /*    This function is a generic facility to change modes or attributes  */
 910   /*    in a given raster.  This can be used for debugging purposes, or    */
 911   /*    simply to allow implementation-specific `features' in a given      */
 912   /*    raster module.                                                     */
 913   /*                                                                       */
 914   /* <Input>                                                               */
 915   /*    raster :: A handle to the new raster object.                       */
 916   /*                                                                       */
 917   /*    mode   :: A 4-byte tag used to name the mode or property.          */
 918   /*                                                                       */
 919   /*    args   :: A pointer to the new mode/property to use.               */
 920   /*                                                                       */
 921   typedef int  (*FT_Raster_Set_Mode_Func)( FT_Raster      raster,
 922                                            unsigned long  mode,
 923                                            void*          args );
 924
 925
 926   /*************************************************************************/
 927   /*                                                                       */
 928   /* <FuncType>                                                            */
 929   /*    FT_Raster_Render_Func                                              */
 930   /*                                                                       */
 931   /* <Description>                                                         */
 932   /*   Invokes a given raster to scan-convert a given glyph image into a   */
 933   /*   target bitmap.                                                      */
 934   /*                                                                       */
 935   /* <Input>                                                               */
 936   /*    raster :: A handle to the raster object.                           */
 937   /*                                                                       */
 938   /*    params :: A pointer to a FT_Raster_Params structure used to store  */
 939   /*              the rendering parameters.                                */
 940   /*                                                                       */
 941   /* <Return>                                                              */
 942   /*    Error code.  0 means success.                                      */
 943   /*                                                                       */
 944   /* <Note>                                                                */
 945   /*    The exact format of the source image depends on the raster's glyph */
 946   /*    format defined in its FT_Raster_Funcs structure.  It can be an     */
 947   /*    FT_Outline or anything else in order to support a large array of   */
 948   /*    glyph formats.                                                     */
 949   /*                                                                       */
 950   /*    Note also that the render function can fail and return a           */
 951   /*    FT_Err_Unimplemented_Feature error code if the raster used does    */
 952   /*    not support direct composition.                                    */
 953   /*                                                                       */
 954   /*    XXX: For now, the standard raster doesn't support direct           */
 955   /*         composition but this should change for the final release (see */
 956   /*         the files demos/src/ftgrays.c and demos/src/ftgrays2.c for    */
 957   /*         examples of distinct implementations which support direct     */
 958   /*         composition).                                                 */
 959   /*                                                                       */
 960   typedef int  (*FT_Raster_Render_Func)( FT_Raster          raster,
 961                                          FT_Raster_Params*  params );
 962
 963
 964   /*************************************************************************/
 965   /*                                                                       */
 966   /* <Struct>                                                              */
 967   /*    FT_Raster_Funcs                                                    */
 968   /*                                                                       */
 969   /* <Description>                                                         */
 970   /*   A structure used to describe a given raster class to the library.   */
 971   /*                                                                       */
 972   /* <Fields>                                                              */
 973   /*    glyph_format  :: The supported glyph format for this raster.       */
 974   /*                                                                       */
 975   /*    raster_new    :: The raster constructor.                           */
 976   /*                                                                       */
 977   /*    raster_reset  :: Used to reset the render pool within the raster.  */
 978   /*                                                                       */
 979   /*    raster_render :: A function to render a glyph into a given bitmap. */
 980   /*                                                                       */
 981   /*    raster_done   :: The raster destructor.                            */
 982   /*                                                                       */
 983   typedef struct  FT_Raster_Funcs_
 984   {
 985     FT_Glyph_Format          glyph_format;
 986     FT_Raster_New_Func       raster_new;
 987     FT_Raster_Reset_Func     raster_reset;
 988     FT_Raster_Set_Mode_Func  raster_set_mode;
 989     FT_Raster_Render_Func    raster_render;
 990     FT_Raster_Done_Func      raster_done;
 991
 992   } FT_Raster_Funcs;
 993
 994
 995 #ifdef __cplusplus
 996   }
 997 #endif
 998
 999
1000 #endif /* FTIMAGE_H */
1001
1002
1003 /* END */