include/ftimage.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ftimage.h                                                              */
   4 /*                                                                         */
   5 /*    FreeType glyph image formats and default raster interface            */
   6 /*    (specification).                                                     */
   7 /*                                                                         */
   8 /*  Copyright 1996-2010, 2013, 2014 by                                     */
   9 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
  10 /*                                                                         */
  11 /*  This file is part of the FreeType project, and may only be used,       */
  12 /*  modified, and distributed under the terms of the FreeType project      */
  13 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
  14 /*  this file you indicate that you have read the license and              */
  15 /*  understand and accept it fully.                                        */
  16 /*                                                                         */
  17 /***************************************************************************/
  18
  19   /*************************************************************************/
  20   /*                                                                       */
  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   /* _STANDALONE_ is from ftgrays.c */
  32 #ifndef _STANDALONE_
  33 #include <ft2build.h>
  34 #endif
  35
  36
  37 FT_BEGIN_HEADER
  38
  39
  40   /*************************************************************************/
  41   /*                                                                       */
  42   /* <Section>                                                             */
  43   /*    basic_types                                                        */
  44   /*                                                                       */
  45   /*************************************************************************/
  46
  47
  48   /*************************************************************************/
  49   /*                                                                       */
  50   /* <Type>                                                                */
  51   /*    FT_Pos                                                             */
  52   /*                                                                       */
  53   /* <Description>                                                         */
  54   /*    The type FT_Pos is used to store vectorial coordinates.  Depending */
  55   /*    on the context, these can represent distances in integer font      */
  56   /*    units, or 16.16, or 26.6 fixed-point pixel coordinates.            */
  57   /*                                                                       */
  58   typedef signed long  FT_Pos;
  59
  60
  61   /*************************************************************************/
  62   /*                                                                       */
  63   /* <Struct>                                                              */
  64   /*    FT_Vector                                                          */
  65   /*                                                                       */
  66   /* <Description>                                                         */
  67   /*    A simple structure used to store a 2D vector; coordinates are of   */
  68   /*    the FT_Pos type.                                                   */
  69   /*                                                                       */
  70   /* <Fields>                                                              */
  71   /*    x :: The horizontal coordinate.                                    */
  72   /*    y :: The vertical coordinate.                                      */
  73   /*                                                                       */
  74   typedef struct  FT_Vector_
  75   {
  76     FT_Pos  x;
  77     FT_Pos  y;
  78
  79   } FT_Vector;
  80
  81
  82   /*************************************************************************/
  83   /*                                                                       */
  84   /* <Struct>                                                              */
  85   /*    FT_BBox                                                            */
  86   /*                                                                       */
  87   /* <Description>                                                         */
  88   /*    A structure used to hold an outline's bounding box, i.e., the      */
  89   /*    coordinates of its extrema in the horizontal and vertical          */
  90   /*    directions.                                                        */
  91   /*                                                                       */
  92   /* <Fields>                                                              */
  93   /*    xMin :: The horizontal minimum (left-most).                        */
  94   /*                                                                       */
  95   /*    yMin :: The vertical minimum (bottom-most).                        */
  96   /*                                                                       */
  97   /*    xMax :: The horizontal maximum (right-most).                       */
  98   /*                                                                       */
  99   /*    yMax :: The vertical maximum (top-most).                           */
 100   /*                                                                       */
 101   /* <Note>                                                                */
 102   /*    The bounding box is specified with the coordinates of the lower    */
 103   /*    left and the upper right corner.  In PostScript, those values are  */
 104   /*    often called (llx,lly) and (urx,ury), respectively.                */
 105   /*                                                                       */
 106   /*    If `yMin' is negative, this value gives the glyph's descender.     */
 107   /*    Otherwise, the glyph doesn't descend below the baseline.           */
 108   /*    Similarly, if `ymax' is positive, this value gives the glyph's     */
 109   /*    ascender.                                                          */
 110   /*                                                                       */
 111   /*    `xMin' gives the horizontal distance from the glyph's origin to    */
 112   /*    the left edge of the glyph's bounding box.  If `xMin' is negative, */
 113   /*    the glyph extends to the left of the origin.                       */
 114   /*                                                                       */
 115   typedef struct  FT_BBox_
 116   {
 117     FT_Pos  xMin, yMin;
 118     FT_Pos  xMax, yMax;
 119
 120   } FT_BBox;
 121
 122
 123   /*************************************************************************/
 124   /*                                                                       */
 125   /* <Enum>                                                                */
 126   /*    FT_Pixel_Mode                                                      */
 127   /*                                                                       */
 128   /* <Description>                                                         */
 129   /*    An enumeration type used to describe the format of pixels in a     */
 130   /*    given bitmap.  Note that additional formats may be added in the    */
 131   /*    future.                                                            */
 132   /*                                                                       */
 133   /* <Values>                                                              */
 134   /*    FT_PIXEL_MODE_NONE ::                                              */
 135   /*      Value~0 is reserved.                                             */
 136   /*                                                                       */
 137   /*    FT_PIXEL_MODE_MONO ::                                              */
 138   /*      A monochrome bitmap, using 1~bit per pixel.  Note that pixels    */
 139   /*      are stored in most-significant order (MSB), which means that     */
 140   /*      the left-most pixel in a byte has value 128.                     */
 141   /*                                                                       */
 142   /*    FT_PIXEL_MODE_GRAY ::                                              */
 143   /*      An 8-bit bitmap, generally used to represent anti-aliased glyph  */
 144   /*      images.  Each pixel is stored in one byte.  Note that the number */
 145   /*      of `gray' levels is stored in the `num_grays' field of the       */
 146   /*      @FT_Bitmap structure (it generally is 256).                      */
 147   /*                                                                       */
 148   /*    FT_PIXEL_MODE_GRAY2 ::                                             */
 149   /*      A 2-bit per pixel bitmap, used to represent embedded             */
 150   /*      anti-aliased bitmaps in font files according to the OpenType     */
 151   /*      specification.  We haven't found a single font using this        */
 152   /*      format, however.                                                 */
 153   /*                                                                       */
 154   /*    FT_PIXEL_MODE_GRAY4 ::                                             */
 155   /*      A 4-bit per pixel bitmap, representing embedded anti-aliased     */
 156   /*      bitmaps in font files according to the OpenType specification.   */
 157   /*      We haven't found a single font using this format, however.       */
 158   /*                                                                       */
 159   /*    FT_PIXEL_MODE_LCD ::                                               */
 160   /*      An 8-bit bitmap, representing RGB or BGR decimated glyph images  */
 161   /*      used for display on LCD displays; the bitmap is three times      */
 162   /*      wider than the original glyph image.  See also                   */
 163   /*      @FT_RENDER_MODE_LCD.                                             */
 164   /*                                                                       */
 165   /*    FT_PIXEL_MODE_LCD_V ::                                             */
 166   /*      An 8-bit bitmap, representing RGB or BGR decimated glyph images  */
 167   /*      used for display on rotated LCD displays; the bitmap is three    */
 168   /*      times taller than the original glyph image.  See also            */
 169   /*      @FT_RENDER_MODE_LCD_V.                                           */
 170   /*                                                                       */
 171   /*    FT_PIXEL_MODE_BGRA ::                                              */
 172   /*      An image with four 8-bit channels per pixel, representing a      */
 173   /*      color image (such as emoticons) with alpha channel.  For each    */
 174   /*      pixel, the format is BGRA, which means, the blue channel comes   */
 175   /*      first in memory.  The color channels are pre-multiplied and in   */
 176   /*      the sRGB colorspace.  For example, full red at half-translucent  */
 177   /*      opacity will be represented as `00,00,80,80', not `00,00,FF,80'. */
 178   /*      See also @FT_LOAD_COLOR.                                         */
 179   /*                                                                       */
 180   typedef enum  FT_Pixel_Mode_
 181   {
 182     FT_PIXEL_MODE_NONE = 0,
 183     FT_PIXEL_MODE_MONO,
 184     FT_PIXEL_MODE_GRAY,
 185     FT_PIXEL_MODE_GRAY2,
 186     FT_PIXEL_MODE_GRAY4,
 187     FT_PIXEL_MODE_LCD,
 188     FT_PIXEL_MODE_LCD_V,
 189     FT_PIXEL_MODE_BGRA,
 190
 191     FT_PIXEL_MODE_MAX      /* do not remove */
 192
 193   } FT_Pixel_Mode;
 194
 195
 196   /* these constants are deprecated; use the corresponding `FT_Pixel_Mode' */
 197   /* values instead.                                                       */
 198 #define ft_pixel_mode_none   FT_PIXEL_MODE_NONE
 199 #define ft_pixel_mode_mono   FT_PIXEL_MODE_MONO
 200 #define ft_pixel_mode_grays  FT_PIXEL_MODE_GRAY
 201 #define ft_pixel_mode_pal2   FT_PIXEL_MODE_GRAY2
 202 #define ft_pixel_mode_pal4   FT_PIXEL_MODE_GRAY4
 203
 204
 205   /*************************************************************************/
 206   /*                                                                       */
 207   /* <Struct>                                                              */
 208   /*    FT_Bitmap                                                          */
 209   /*                                                                       */
 210   /* <Description>                                                         */
 211   /*    A structure used to describe a bitmap or pixmap to the raster.     */
 212   /*    Note that we now manage pixmaps of various depths through the      */
 213   /*    `pixel_mode' field.                                                */
 214   /*                                                                       */
 215   /* <Fields>                                                              */
 216   /*    rows         :: The number of bitmap rows.                         */
 217   /*                                                                       */
 218   /*    width        :: The number of pixels in bitmap row.                */
 219   /*                                                                       */
 220   /*    pitch        :: The pitch's absolute value is the number of bytes  */
 221   /*                    taken by one bitmap row, including padding.        */
 222   /*                    However, the pitch is positive when the bitmap has */
 223   /*                    a `down' flow, and negative when it has an `up'    */
 224   /*                    flow.  In all cases, the pitch is an offset to add */
 225   /*                    to a bitmap pointer in order to go down one row.   */
 226   /*                                                                       */
 227   /*                    Note that `padding' means the alignment of a       */
 228   /*                    bitmap to a byte border, and FreeType functions    */
 229   /*                    normally align to the smallest possible integer    */
 230   /*                    value.                                             */
 231   /*                                                                       */
 232   /*                    For the B/W rasterizer, `pitch' is always an even  */
 233   /*                    number.                                            */
 234   /*                                                                       */
 235   /*                    To change the pitch of a bitmap (say, to make it a */
 236   /*                    multiple of 4), use @FT_Bitmap_Convert.            */
 237   /*                    Alternatively, you might use callback functions to */
 238   /*                    directly render to the application's surface; see  */
 239   /*                    the file `example2.cpp' in the tutorial for a      */
 240   /*                    demonstration.                                     */
 241   /*                                                                       */
 242   /*    buffer       :: A typeless pointer to the bitmap buffer.  This     */
 243   /*                    value should be aligned on 32-bit boundaries in    */
 244   /*                    most cases.                                        */
 245   /*                                                                       */
 246   /*    num_grays    :: This field is only used with                       */
 247   /*                    @FT_PIXEL_MODE_GRAY; it gives the number of gray   */
 248   /*                    levels used in the bitmap.                         */
 249   /*                                                                       */
 250   /*    pixel_mode   :: The pixel mode, i.e., how pixel bits are stored.   */
 251   /*                    See @FT_Pixel_Mode for possible values.            */
 252   /*                                                                       */
 253   /*    palette_mode :: This field is intended for paletted pixel modes;   */
 254   /*                    it indicates how the palette is stored.  Not       */
 255   /*                    used currently.                                    */
 256   /*                                                                       */
 257   /*    palette      :: A typeless pointer to the bitmap palette; this     */
 258   /*                    field is intended for paletted pixel modes.  Not   */
 259   /*                    used currently.                                    */
 260   /*                                                                       */
 261   /* <Note>                                                                */
 262   /*   For now, the only pixel modes supported by FreeType are mono and    */
 263   /*   grays.  However, drivers might be added in the future to support    */
 264   /*   more `colorful' options.                                            */
 265   /*                                                                       */
 266   typedef struct  FT_Bitmap_
 267   {
 268     unsigned int    rows;
 269     unsigned int    width;
 270     int             pitch;
 271     unsigned char*  buffer;
 272     unsigned short  num_grays;
 273     unsigned char   pixel_mode;
 274     unsigned char   palette_mode;
 275     void*           palette;
 276
 277   } FT_Bitmap;
 278
 279
 280   /*************************************************************************/
 281   /*                                                                       */
 282   /* <Section>                                                             */
 283   /*    outline_processing                                                 */
 284   /*                                                                       */
 285   /*************************************************************************/
 286
 287
 288   /*************************************************************************/
 289   /*                                                                       */
 290   /* <Struct>                                                              */
 291   /*    FT_Outline                                                         */
 292   /*                                                                       */
 293   /* <Description>                                                         */
 294   /*    This structure is used to describe an outline to the scan-line     */
 295   /*    converter.                                                         */
 296   /*                                                                       */
 297   /* <Fields>                                                              */
 298   /*    n_contours :: The number of contours in the outline.               */
 299   /*                                                                       */
 300   /*    n_points   :: The number of points in the outline.                 */
 301   /*                                                                       */
 302   /*    points     :: A pointer to an array of `n_points' @FT_Vector       */
 303   /*                  elements, giving the outline's point coordinates.    */
 304   /*                                                                       */
 305   /*    tags       :: A pointer to an array of `n_points' chars, giving    */
 306   /*                  each outline point's type.                           */
 307   /*                                                                       */
 308   /*                  If bit~0 is unset, the point is `off' the curve,     */
 309   /*                  i.e., a Bézier control point, while it is `on' if    */
 310   /*                  set.                                                 */
 311   /*                                                                       */
 312   /*                  Bit~1 is meaningful for `off' points only.  If set,  */
 313   /*                  it indicates a third-order Bézier arc control point; */
 314   /*                  and a second-order control point if unset.           */
 315   /*                                                                       */
 316   /*                  If bit~2 is set, bits 5-7 contain the drop-out mode  */
 317   /*                  (as defined in the OpenType specification; the value */
 318   /*                  is the same as the argument to the SCANMODE          */
 319   /*                  instruction).                                        */
 320   /*                                                                       */
 321   /*                  Bits 3 and~4 are reserved for internal purposes.     */
 322   /*                                                                       */
 323   /*    contours   :: An array of `n_contours' shorts, giving the end      */
 324   /*                  point of each contour within the outline.  For       */
 325   /*                  example, the first contour is defined by the points  */
 326   /*                  `0' to `contours[0]', the second one is defined by   */
 327   /*                  the points `contours[0]+1' to `contours[1]', etc.    */
 328   /*                                                                       */
 329   /*    flags      :: A set of bit flags used to characterize the outline  */
 330   /*                  and give hints to the scan-converter and hinter on   */
 331   /*                  how to convert/grid-fit it.  See @FT_OUTLINE_XXX.    */
 332   /*                                                                       */
 333   /* <Note>                                                                */
 334   /*    The B/W rasterizer only checks bit~2 in the `tags' array for the   */
 335   /*    first point of each contour.  The drop-out mode as given with      */
 336   /*    @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and       */
 337   /*    @FT_OUTLINE_INCLUDE_STUBS in `flags' is then overridden.           */
 338   /*                                                                       */
 339   typedef struct  FT_Outline_
 340   {
 341     short       n_contours;      /* number of contours in glyph        */
 342     short       n_points;        /* number of points in the glyph      */
 343
 344     FT_Vector*  points;          /* the outline's points               */
 345     char*       tags;            /* the points flags                   */
 346     short*      contours;        /* the contour end points             */
 347
 348     int         flags;           /* outline masks                      */
 349
 350   } FT_Outline;
 351
 352   /* */
 353
 354   /* Following limits must be consistent with */
 355   /* FT_Outline.{n_contours,n_points}         */
 356 #define FT_OUTLINE_CONTOURS_MAX  SHRT_MAX
 357 #define FT_OUTLINE_POINTS_MAX    SHRT_MAX
 358
 359
 360   /*************************************************************************/
 361   /*                                                                       */
 362   /* <Enum>                                                                */
 363   /*    FT_OUTLINE_XXX                                                     */
 364   /*                                                                       */
 365   /* <Description>                                                         */
 366   /*    A list of bit-field constants use for the flags in an outline's    */
 367   /*    `flags' field.                                                     */
 368   /*                                                                       */
 369   /* <Values>                                                              */
 370   /*    FT_OUTLINE_NONE ::                                                 */
 371   /*      Value~0 is reserved.                                             */
 372   /*                                                                       */
 373   /*    FT_OUTLINE_OWNER ::                                                */
 374   /*      If set, this flag indicates that the outline's field arrays      */
 375   /*      (i.e., `points', `flags', and `contours') are `owned' by the     */
 376   /*      outline object, and should thus be freed when it is destroyed.   */
 377   /*                                                                       */
 378   /*    FT_OUTLINE_EVEN_ODD_FILL ::                                        */
 379   /*      By default, outlines are filled using the non-zero winding rule. */
 380   /*      If set to 1, the outline will be filled using the even-odd fill  */
 381   /*      rule (only works with the smooth rasterizer).                    */
 382   /*                                                                       */
 383   /*    FT_OUTLINE_REVERSE_FILL ::                                         */
 384   /*      By default, outside contours of an outline are oriented in       */
 385   /*      clock-wise direction, as defined in the TrueType specification.  */
 386   /*      This flag is set if the outline uses the opposite direction      */
 387   /*      (typically for Type~1 fonts).  This flag is ignored by the scan  */
 388   /*      converter.                                                       */
 389   /*                                                                       */
 390   /*    FT_OUTLINE_IGNORE_DROPOUTS ::                                      */
 391   /*      By default, the scan converter will try to detect drop-outs in   */
 392   /*      an outline and correct the glyph bitmap to ensure consistent     */
 393   /*      shape continuity.  If set, this flag hints the scan-line         */
 394   /*      converter to ignore such cases.  See below for more information. */
 395   /*                                                                       */
 396   /*    FT_OUTLINE_SMART_DROPOUTS ::                                       */
 397   /*      Select smart dropout control.  If unset, use simple dropout      */
 398   /*      control.  Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set.  See    */
 399   /*      below for more information.                                      */
 400   /*                                                                       */
 401   /*    FT_OUTLINE_INCLUDE_STUBS ::                                        */
 402   /*      If set, turn pixels on for `stubs', otherwise exclude them.      */
 403   /*      Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set.  See below for    */
 404   /*      more information.                                                */
 405   /*                                                                       */
 406   /*    FT_OUTLINE_HIGH_PRECISION ::                                       */
 407   /*      This flag indicates that the scan-line converter should try to   */
 408   /*      convert this outline to bitmaps with the highest possible        */
 409   /*      quality.  It is typically set for small character sizes.  Note   */
 410   /*      that this is only a hint that might be completely ignored by a   */
 411   /*      given scan-converter.                                            */
 412   /*                                                                       */
 413   /*    FT_OUTLINE_SINGLE_PASS ::                                          */
 414   /*      This flag is set to force a given scan-converter to only use a   */
 415   /*      single pass over the outline to render a bitmap glyph image.     */
 416   /*      Normally, it is set for very large character sizes.  It is only  */
 417   /*      a hint that might be completely ignored by a given               */
 418   /*      scan-converter.                                                  */
 419   /*                                                                       */
 420   /* <Note>                                                                */
 421   /*    The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */
 422   /*    and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth            */
 423   /*    rasterizer.                                                        */
 424   /*                                                                       */
 425   /*    There exists a second mechanism to pass the drop-out mode to the   */
 426   /*    B/W rasterizer; see the `tags' field in @FT_Outline.               */
 427   /*                                                                       */
 428   /*    Please refer to the description of the `SCANTYPE' instruction in   */
 429   /*    the OpenType specification (in file `ttinst1.doc') how simple      */
 430   /*    drop-outs, smart drop-outs, and stubs are defined.                 */
 431   /*                                                                       */
 432 #define FT_OUTLINE_NONE             0x0
 433 #define FT_OUTLINE_OWNER            0x1
 434 #define FT_OUTLINE_EVEN_ODD_FILL    0x2
 435 #define FT_OUTLINE_REVERSE_FILL     0x4
 436 #define FT_OUTLINE_IGNORE_DROPOUTS  0x8
 437 #define FT_OUTLINE_SMART_DROPOUTS   0x10
 438 #define FT_OUTLINE_INCLUDE_STUBS    0x20
 439
 440 #define FT_OUTLINE_HIGH_PRECISION   0x100
 441 #define FT_OUTLINE_SINGLE_PASS      0x200
 442
 443
 444   /* these constants are deprecated; use the corresponding */
 445   /* `FT_OUTLINE_XXX' values instead                       */
 446 #define ft_outline_none             FT_OUTLINE_NONE
 447 #define ft_outline_owner            FT_OUTLINE_OWNER
 448 #define ft_outline_even_odd_fill    FT_OUTLINE_EVEN_ODD_FILL
 449 #define ft_outline_reverse_fill     FT_OUTLINE_REVERSE_FILL
 450 #define ft_outline_ignore_dropouts  FT_OUTLINE_IGNORE_DROPOUTS
 451 #define ft_outline_high_precision   FT_OUTLINE_HIGH_PRECISION
 452 #define ft_outline_single_pass      FT_OUTLINE_SINGLE_PASS
 453
 454   /* */
 455
 456 #define FT_CURVE_TAG( flag )  ( flag & 3 )
 457
 458 #define FT_CURVE_TAG_ON            1
 459 #define FT_CURVE_TAG_CONIC         0
 460 #define FT_CURVE_TAG_CUBIC         2
 461
 462 #define FT_CURVE_TAG_HAS_SCANMODE  4
 463
 464 #define FT_CURVE_TAG_TOUCH_X       8  /* reserved for the TrueType hinter */
 465 #define FT_CURVE_TAG_TOUCH_Y      16  /* reserved for the TrueType hinter */
 466
 467 #define FT_CURVE_TAG_TOUCH_BOTH    ( FT_CURVE_TAG_TOUCH_X | \
 468                                      FT_CURVE_TAG_TOUCH_Y )
 469
 470 #define FT_Curve_Tag_On       FT_CURVE_TAG_ON
 471 #define FT_Curve_Tag_Conic    FT_CURVE_TAG_CONIC
 472 #define FT_Curve_Tag_Cubic    FT_CURVE_TAG_CUBIC
 473 #define FT_Curve_Tag_Touch_X  FT_CURVE_TAG_TOUCH_X
 474 #define FT_Curve_Tag_Touch_Y  FT_CURVE_TAG_TOUCH_Y
 475
 476
 477   /*************************************************************************/
 478   /*                                                                       */
 479   /* <FuncType>                                                            */
 480   /*    FT_Outline_MoveToFunc                                              */
 481   /*                                                                       */
 482   /* <Description>                                                         */
 483   /*    A function pointer type used to describe the signature of a `move  */
 484   /*    to' function during outline walking/decomposition.                 */
 485   /*                                                                       */
 486   /*    A `move to' is emitted to start a new contour in an outline.       */
 487   /*                                                                       */
 488   /* <Input>                                                               */
 489   /*    to   :: A pointer to the target point of the `move to'.            */
 490   /*                                                                       */
 491   /*    user :: A typeless pointer, which is passed from the caller of the */
 492   /*            decomposition function.                                    */
 493   /*                                                                       */
 494   /* <Return>                                                              */
 495   /*    Error code.  0~means success.                                      */
 496   /*                                                                       */
 497   typedef int
 498   (*FT_Outline_MoveToFunc)( const FT_Vector*  to,
 499                             void*             user );
 500
 501 #define FT_Outline_MoveTo_Func  FT_Outline_MoveToFunc
 502
 503
 504   /*************************************************************************/
 505   /*                                                                       */
 506   /* <FuncType>                                                            */
 507   /*    FT_Outline_LineToFunc                                              */
 508   /*                                                                       */
 509   /* <Description>                                                         */
 510   /*    A function pointer type used to describe the signature of a `line  */
 511   /*    to' function during outline walking/decomposition.                 */
 512   /*                                                                       */
 513   /*    A `line to' is emitted to indicate a segment in the outline.       */
 514   /*                                                                       */
 515   /* <Input>                                                               */
 516   /*    to   :: A pointer to the target point of the `line to'.            */
 517   /*                                                                       */
 518   /*    user :: A typeless pointer, which is passed from the caller of the */
 519   /*            decomposition function.                                    */
 520   /*                                                                       */
 521   /* <Return>                                                              */
 522   /*    Error code.  0~means success.                                      */
 523   /*                                                                       */
 524   typedef int
 525   (*FT_Outline_LineToFunc)( const FT_Vector*  to,
 526                             void*             user );
 527
 528 #define FT_Outline_LineTo_Func  FT_Outline_LineToFunc
 529
 530
 531   /*************************************************************************/
 532   /*                                                                       */
 533   /* <FuncType>                                                            */
 534   /*    FT_Outline_ConicToFunc                                             */
 535   /*                                                                       */
 536   /* <Description>                                                         */
 537   /*    A function pointer type used to describe the signature of a `conic */
 538   /*    to' function during outline walking or decomposition.              */
 539   /*                                                                       */
 540   /*    A `conic to' is emitted to indicate a second-order Bézier arc in   */
 541   /*    the outline.                                                       */
 542   /*                                                                       */
 543   /* <Input>                                                               */
 544   /*    control :: An intermediate control point between the last position */
 545   /*               and the new target in `to'.                             */
 546   /*                                                                       */
 547   /*    to      :: A pointer to the target end point of the conic arc.     */
 548   /*                                                                       */
 549   /*    user    :: A typeless pointer, which is passed from the caller of  */
 550   /*               the decomposition function.                             */
 551   /*                                                                       */
 552   /* <Return>                                                              */
 553   /*    Error code.  0~means success.                                      */
 554   /*                                                                       */
 555   typedef int
 556   (*FT_Outline_ConicToFunc)( const FT_Vector*  control,
 557                              const FT_Vector*  to,
 558                              void*             user );
 559
 560 #define FT_Outline_ConicTo_Func  FT_Outline_ConicToFunc
 561
 562
 563   /*************************************************************************/
 564   /*                                                                       */
 565   /* <FuncType>                                                            */
 566   /*    FT_Outline_CubicToFunc                                             */
 567   /*                                                                       */
 568   /* <Description>                                                         */
 569   /*    A function pointer type used to describe the signature of a `cubic */
 570   /*    to' function during outline walking or decomposition.              */
 571   /*                                                                       */
 572   /*    A `cubic to' is emitted to indicate a third-order Bézier arc.      */
 573   /*                                                                       */
 574   /* <Input>                                                               */
 575   /*    control1 :: A pointer to the first Bézier control point.           */
 576   /*                                                                       */
 577   /*    control2 :: A pointer to the second Bézier control point.          */
 578   /*                                                                       */
 579   /*    to       :: A pointer to the target end point.                     */
 580   /*                                                                       */
 581   /*    user     :: A typeless pointer, which is passed from the caller of */
 582   /*                the decomposition function.                            */
 583   /*                                                                       */
 584   /* <Return>                                                              */
 585   /*    Error code.  0~means success.                                      */
 586   /*                                                                       */
 587   typedef int
 588   (*FT_Outline_CubicToFunc)( const FT_Vector*  control1,
 589                              const FT_Vector*  control2,
 590                              const FT_Vector*  to,
 591                              void*             user );
 592
 593 #define FT_Outline_CubicTo_Func  FT_Outline_CubicToFunc
 594
 595
 596   /*************************************************************************/
 597   /*                                                                       */
 598   /* <Struct>                                                              */
 599   /*    FT_Outline_Funcs                                                   */
 600   /*                                                                       */
 601   /* <Description>                                                         */
 602   /*    A structure to hold various function pointers used during outline  */
 603   /*    decomposition in order to emit segments, conic, and cubic Béziers. */
 604   /*                                                                       */
 605   /* <Fields>                                                              */
 606   /*    move_to  :: The `move to' emitter.                                 */
 607   /*                                                                       */
 608   /*    line_to  :: The segment emitter.                                   */
 609   /*                                                                       */
 610   /*    conic_to :: The second-order Bézier arc emitter.                   */
 611   /*                                                                       */
 612   /*    cubic_to :: The third-order Bézier arc emitter.                    */
 613   /*                                                                       */
 614   /*    shift    :: The shift that is applied to coordinates before they   */
 615   /*                are sent to the emitter.                               */
 616   /*                                                                       */
 617   /*    delta    :: The delta that is applied to coordinates before they   */
 618   /*                are sent to the emitter, but after the shift.          */
 619   /*                                                                       */
 620   /* <Note>                                                                */
 621   /*    The point coordinates sent to the emitters are the transformed     */
 622   /*    version of the original coordinates (this is important for high    */
 623   /*    accuracy during scan-conversion).  The transformation is simple:   */
 624   /*                                                                       */
 625   /*    {                                                                  */
 626   /*      x' = (x << shift) - delta                                        */
 627   /*      y' = (x << shift) - delta                                        */
 628   /*    }                                                                  */
 629   /*                                                                       */
 630   /*    Set the values of `shift' and `delta' to~0 to get the original     */
 631   /*    point coordinates.                                                 */
 632   /*                                                                       */
 633   typedef struct  FT_Outline_Funcs_
 634   {
 635     FT_Outline_MoveToFunc   move_to;
 636     FT_Outline_LineToFunc   line_to;
 637     FT_Outline_ConicToFunc  conic_to;
 638     FT_Outline_CubicToFunc  cubic_to;
 639
 640     int                     shift;
 641     FT_Pos                  delta;
 642
 643   } FT_Outline_Funcs;
 644
 645
 646   /*************************************************************************/
 647   /*                                                                       */
 648   /* <Section>                                                             */
 649   /*    basic_types                                                        */
 650   /*                                                                       */
 651   /*************************************************************************/
 652
 653
 654   /*************************************************************************/
 655   /*                                                                       */
 656   /* <Macro>                                                               */
 657   /*    FT_IMAGE_TAG                                                       */
 658   /*                                                                       */
 659   /* <Description>                                                         */
 660   /*    This macro converts four-letter tags to an unsigned long type.     */
 661   /*                                                                       */
 662   /* <Note>                                                                */
 663   /*    Since many 16-bit compilers don't like 32-bit enumerations, you    */
 664   /*    should redefine this macro in case of problems to something like   */
 665   /*    this:                                                              */
 666   /*                                                                       */
 667   /*    {                                                                  */
 668   /*      #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  value         */
 669   /*    }                                                                  */
 670   /*                                                                       */
 671   /*    to get a simple enumeration without assigning special numbers.     */
 672   /*                                                                       */
 673 #ifndef FT_IMAGE_TAG
 674 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  \
 675           value = ( ( (unsigned long)_x1 << 24 ) | \
 676                     ( (unsigned long)_x2 << 16 ) | \
 677                     ( (unsigned long)_x3 << 8  ) | \
 678                       (unsigned long)_x4         )
 679 #endif /* FT_IMAGE_TAG */
 680
 681
 682   /*************************************************************************/
 683   /*                                                                       */
 684   /* <Enum>                                                                */
 685   /*    FT_Glyph_Format                                                    */
 686   /*                                                                       */
 687   /* <Description>                                                         */
 688   /*    An enumeration type used to describe the format of a given glyph   */
 689   /*    image.  Note that this version of FreeType only supports two image */
 690   /*    formats, even though future font drivers will be able to register  */
 691   /*    their own format.                                                  */
 692   /*                                                                       */
 693   /* <Values>                                                              */
 694   /*    FT_GLYPH_FORMAT_NONE ::                                            */
 695   /*      The value~0 is reserved.                                         */
 696   /*                                                                       */
 697   /*    FT_GLYPH_FORMAT_COMPOSITE ::                                       */
 698   /*      The glyph image is a composite of several other images.  This    */
 699   /*      format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to   */
 700   /*      report compound glyphs (like accented characters).               */
 701   /*                                                                       */
 702   /*    FT_GLYPH_FORMAT_BITMAP ::                                          */
 703   /*      The glyph image is a bitmap, and can be described as an          */
 704   /*      @FT_Bitmap.  You generally need to access the `bitmap' field of  */
 705   /*      the @FT_GlyphSlotRec structure to read it.                       */
 706   /*                                                                       */
 707   /*    FT_GLYPH_FORMAT_OUTLINE ::                                         */
 708   /*      The glyph image is a vectorial outline made of line segments     */
 709   /*      and Bézier arcs; it can be described as an @FT_Outline; you      */
 710   /*      generally want to access the `outline' field of the              */
 711   /*      @FT_GlyphSlotRec structure to read it.                           */
 712   /*                                                                       */
 713   /*    FT_GLYPH_FORMAT_PLOTTER ::                                         */
 714   /*      The glyph image is a vectorial path with no inside and outside   */
 715   /*      contours.  Some Type~1 fonts, like those in the Hershey family,  */
 716   /*      contain glyphs in this format.  These are described as           */
 717   /*      @FT_Outline, but FreeType isn't currently capable of rendering   */
 718   /*      them correctly.                                                  */
 719   /*                                                                       */
 720   typedef enum  FT_Glyph_Format_
 721   {
 722     FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ),
 723
 724     FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
 725     FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP,    'b', 'i', 't', 's' ),
 726     FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE,   'o', 'u', 't', 'l' ),
 727     FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER,   'p', 'l', 'o', 't' )
 728
 729   } FT_Glyph_Format;
 730
 731
 732   /* these constants are deprecated; use the corresponding */
 733   /* `FT_Glyph_Format' values instead.                     */
 734 #define ft_glyph_format_none       FT_GLYPH_FORMAT_NONE
 735 #define ft_glyph_format_composite  FT_GLYPH_FORMAT_COMPOSITE
 736 #define ft_glyph_format_bitmap     FT_GLYPH_FORMAT_BITMAP
 737 #define ft_glyph_format_outline    FT_GLYPH_FORMAT_OUTLINE
 738 #define ft_glyph_format_plotter    FT_GLYPH_FORMAT_PLOTTER
 739
 740
 741   /*************************************************************************/
 742   /*************************************************************************/
 743   /*************************************************************************/
 744   /*****                                                               *****/
 745   /*****            R A S T E R   D E F I N I T I O N S                *****/
 746   /*****                                                               *****/
 747   /*************************************************************************/
 748   /*************************************************************************/
 749   /*************************************************************************/
 750
 751
 752   /*************************************************************************/
 753   /*                                                                       */
 754   /* A raster is a scan converter, in charge of rendering an outline into  */
 755   /* a a bitmap.  This section contains the public API for rasters.        */
 756   /*                                                                       */
 757   /* Note that in FreeType 2, all rasters are now encapsulated within      */
 758   /* specific modules called `renderers'.  See `ftrender.h' for more       */
 759   /* details on renderers.                                                 */
 760   /*                                                                       */
 761   /*************************************************************************/
 762
 763
 764   /*************************************************************************/
 765   /*                                                                       */
 766   /* <Section>                                                             */
 767   /*    raster                                                             */
 768   /*                                                                       */
 769   /* <Title>                                                               */
 770   /*    Scanline Converter                                                 */
 771   /*                                                                       */
 772   /* <Abstract>                                                            */
 773   /*    How vectorial outlines are converted into bitmaps and pixmaps.     */
 774   /*                                                                       */
 775   /* <Description>                                                         */
 776   /*    This section contains technical definitions.                       */
 777   /*                                                                       */
 778   /* <Order>                                                               */
 779   /*    FT_Raster                                                          */
 780   /*    FT_Span                                                            */
 781   /*    FT_SpanFunc                                                        */
 782   /*                                                                       */
 783   /*    FT_Raster_Params                                                   */
 784   /*    FT_RASTER_FLAG_XXX                                                 */
 785   /*                                                                       */
 786   /*    FT_Raster_NewFunc                                                  */
 787   /*    FT_Raster_DoneFunc                                                 */
 788   /*    FT_Raster_ResetFunc                                                */
 789   /*    FT_Raster_SetModeFunc                                              */
 790   /*    FT_Raster_RenderFunc                                               */
 791   /*    FT_Raster_Funcs                                                    */
 792   /*                                                                       */
 793   /*************************************************************************/
 794
 795
 796   /*************************************************************************/
 797   /*                                                                       */
 798   /* <Type>                                                                */
 799   /*    FT_Raster                                                          */
 800   /*                                                                       */
 801   /* <Description>                                                         */
 802   /*    An opaque handle (pointer) to a raster object.  Each object can be */
 803   /*    used independently to convert an outline into a bitmap or pixmap.  */
 804   /*                                                                       */
 805   typedef struct FT_RasterRec_*  FT_Raster;
 806
 807
 808   /*************************************************************************/
 809   /*                                                                       */
 810   /* <Struct>                                                              */
 811   /*    FT_Span                                                            */
 812   /*                                                                       */
 813   /* <Description>                                                         */
 814   /*    A structure used to model a single span of gray pixels when        */
 815   /*    rendering an anti-aliased bitmap.                                  */
 816   /*                                                                       */
 817   /* <Fields>                                                              */
 818   /*    x        :: The span's horizontal start position.                  */
 819   /*                                                                       */
 820   /*    len      :: The span's length in pixels.                           */
 821   /*                                                                       */
 822   /*    coverage :: The span color/coverage, ranging from 0 (background)   */
 823   /*                to 255 (foreground).                                   */
 824   /*                                                                       */
 825   /* <Note>                                                                */
 826   /*    This structure is used by the span drawing callback type named     */
 827   /*    @FT_SpanFunc that takes the y~coordinate of the span as a          */
 828   /*    parameter.                                                         */
 829   /*                                                                       */
 830   /*    The coverage value is always between 0 and 255.  If you want less  */
 831   /*    gray values, the callback function has to reduce them.             */
 832   /*                                                                       */
 833   typedef struct  FT_Span_
 834   {
 835     short           x;
 836     unsigned short  len;
 837     unsigned char   coverage;
 838
 839   } FT_Span;
 840
 841
 842   /*************************************************************************/
 843   /*                                                                       */
 844   /* <FuncType>                                                            */
 845   /*    FT_SpanFunc                                                        */
 846   /*                                                                       */
 847   /* <Description>                                                         */
 848   /*    A function used as a call-back by the anti-aliased renderer in     */
 849   /*    order to let client applications draw themselves the gray pixel    */
 850   /*    spans on each scan line.                                           */
 851   /*                                                                       */
 852   /* <Input>                                                               */
 853   /*    y     :: The scanline's y~coordinate.                              */
 854   /*                                                                       */
 855   /*    count :: The number of spans to draw on this scanline.             */
 856   /*                                                                       */
 857   /*    spans :: A table of `count' spans to draw on the scanline.         */
 858   /*                                                                       */
 859   /*    user  :: User-supplied data that is passed to the callback.        */
 860   /*                                                                       */
 861   /* <Note>                                                                */
 862   /*    This callback allows client applications to directly render the    */
 863   /*    gray spans of the anti-aliased bitmap to any kind of surfaces.     */
 864   /*                                                                       */
 865   /*    This can be used to write anti-aliased outlines directly to a      */
 866   /*    given background bitmap, and even perform translucency.            */
 867   /*                                                                       */
 868   /*    Note that the `count' field cannot be greater than a fixed value   */
 869   /*    defined by the `FT_MAX_GRAY_SPANS' configuration macro in          */
 870   /*    `ftoption.h'.  By default, this value is set to~32, which means    */
 871   /*    that if there are more than 32~spans on a given scanline, the      */
 872   /*    callback is called several times with the same `y' parameter in    */
 873   /*    order to draw all callbacks.                                       */
 874   /*                                                                       */
 875   /*    Otherwise, the callback is only called once per scan-line, and     */
 876   /*    only for those scanlines that do have `gray' pixels on them.       */
 877   /*                                                                       */
 878   typedef void
 879   (*FT_SpanFunc)( int             y,
 880                   int             count,
 881                   const FT_Span*  spans,
 882                   void*           user );
 883
 884 #define FT_Raster_Span_Func  FT_SpanFunc
 885
 886
 887   /*************************************************************************/
 888   /*                                                                       */
 889   /* <FuncType>                                                            */
 890   /*    FT_Raster_BitTest_Func                                             */
 891   /*                                                                       */
 892   /* <Description>                                                         */
 893   /*    Deprecated, unimplemented.                                         */
 894   /*                                                                       */
 895   typedef int
 896   (*FT_Raster_BitTest_Func)( int    y,
 897                              int    x,
 898                              void*  user );
 899
 900
 901   /*************************************************************************/
 902   /*                                                                       */
 903   /* <FuncType>                                                            */
 904   /*    FT_Raster_BitSet_Func                                              */
 905   /*                                                                       */
 906   /* <Description>                                                         */
 907   /*    Deprecated, unimplemented.                                         */
 908   /*                                                                       */
 909   typedef void
 910   (*FT_Raster_BitSet_Func)( int    y,
 911                             int    x,
 912                             void*  user );
 913
 914
 915   /*************************************************************************/
 916   /*                                                                       */
 917   /* <Enum>                                                                */
 918   /*    FT_RASTER_FLAG_XXX                                                 */
 919   /*                                                                       */
 920   /* <Description>                                                         */
 921   /*    A list of bit flag constants as used in the `flags' field of a     */
 922   /*    @FT_Raster_Params structure.                                       */
 923   /*                                                                       */
 924   /* <Values>                                                              */
 925   /*    FT_RASTER_FLAG_DEFAULT :: This value is 0.                         */
 926   /*                                                                       */
 927   /*    FT_RASTER_FLAG_AA      :: This flag is set to indicate that an     */
 928   /*                              anti-aliased glyph image should be       */
 929   /*                              generated.  Otherwise, it will be        */
 930   /*                              monochrome (1-bit).                      */
 931   /*                                                                       */
 932   /*    FT_RASTER_FLAG_DIRECT  :: This flag is set to indicate direct      */
 933   /*                              rendering.  In this mode, client         */
 934   /*                              applications must provide their own span */
 935   /*                              callback.  This lets them directly       */
 936   /*                              draw or compose over an existing bitmap. */
 937   /*                              If this bit is not set, the target       */
 938   /*                              pixmap's buffer _must_ be zeroed before  */
 939   /*                              rendering.                               */
 940   /*                                                                       */
 941   /*                              Direct rendering is only possible with   */
 942   /*                              anti-aliased glyphs.                     */
 943   /*                                                                       */
 944   /*    FT_RASTER_FLAG_CLIP    :: This flag is only used in direct         */
 945   /*                              rendering mode.  If set, the output will */
 946   /*                              be clipped to a box specified in the     */
 947   /*                              `clip_box' field of the                  */
 948   /*                              @FT_Raster_Params structure.             */
 949   /*                                                                       */
 950   /*                              Note that by default, the glyph bitmap   */
 951   /*                              is clipped to the target pixmap, except  */
 952   /*                              in direct rendering mode where all spans */
 953   /*                              are generated if no clipping box is set. */
 954   /*                                                                       */
 955 #define FT_RASTER_FLAG_DEFAULT  0x0
 956 #define FT_RASTER_FLAG_AA       0x1
 957 #define FT_RASTER_FLAG_DIRECT   0x2
 958 #define FT_RASTER_FLAG_CLIP     0x4
 959
 960   /* these constants are deprecated; use the corresponding */
 961   /* `FT_RASTER_FLAG_XXX' values instead                   */
 962 #define ft_raster_flag_default  FT_RASTER_FLAG_DEFAULT
 963 #define ft_raster_flag_aa       FT_RASTER_FLAG_AA
 964 #define ft_raster_flag_direct   FT_RASTER_FLAG_DIRECT
 965 #define ft_raster_flag_clip     FT_RASTER_FLAG_CLIP
 966
 967
 968   /*************************************************************************/
 969   /*                                                                       */
 970   /* <Struct>                                                              */
 971   /*    FT_Raster_Params                                                   */
 972   /*                                                                       */
 973   /* <Description>                                                         */
 974   /*    A structure to hold the arguments used by a raster's render        */
 975   /*    function.                                                          */
 976   /*                                                                       */
 977   /* <Fields>                                                              */
 978   /*    target      :: The target bitmap.                                  */
 979   /*                                                                       */
 980   /*    source      :: A pointer to the source glyph image (e.g., an       */
 981   /*                   @FT_Outline).                                       */
 982   /*                                                                       */
 983   /*    flags       :: The rendering flags.                                */
 984   /*                                                                       */
 985   /*    gray_spans  :: The gray span drawing callback.                     */
 986   /*                                                                       */
 987   /*    black_spans :: Unused.                                             */
 988   /*                                                                       */
 989   /*    bit_test    :: Unused.                                             */
 990   /*                                                                       */
 991   /*    bit_set     :: Unused.                                             */
 992   /*                                                                       */
 993   /*    user        :: User-supplied data that is passed to each drawing   */
 994   /*                   callback.                                           */
 995   /*                                                                       */
 996   /*    clip_box    :: An optional clipping box.  It is only used in       */
 997   /*                   direct rendering mode.  Note that coordinates here  */
 998   /*                   should be expressed in _integer_ pixels (and not in */
 999   /*                   26.6 fixed-point units).                            */
1000   /*                                                                       */
1001   /* <Note>                                                                */
1002   /*    An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA    */
1003   /*    bit flag is set in the `flags' field, otherwise a monochrome       */
1004   /*    bitmap is generated.                                               */
1005   /*                                                                       */
1006   /*    If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the      */
1007   /*    raster will call the `gray_spans' callback to draw gray pixel      */
1008   /*    spans.  This allows direct composition over a pre-existing bitmap  */
1009   /*    through user-provided callbacks to perform the span drawing and    */
1010   /*    composition.    Not supported by the monochrome rasterizer.        */
1011   /*                                                                       */
1012   typedef struct  FT_Raster_Params_
1013   {
1014     const FT_Bitmap*        target;
1015     const void*             source;
1016     int                     flags;
1017     FT_SpanFunc             gray_spans;
1018     FT_SpanFunc             black_spans;  /* unused */
1019     FT_Raster_BitTest_Func  bit_test;     /* unused */
1020     FT_Raster_BitSet_Func   bit_set;      /* unused */
1021     void*                   user;
1022     FT_BBox                 clip_box;
1023
1024   } FT_Raster_Params;
1025
1026
1027   /*************************************************************************/
1028   /*                                                                       */
1029   /* <FuncType>                                                            */
1030   /*    FT_Raster_NewFunc                                                  */
1031   /*                                                                       */
1032   /* <Description>                                                         */
1033   /*    A function used to create a new raster object.                     */
1034   /*                                                                       */
1035   /* <Input>                                                               */
1036   /*    memory :: A handle to the memory allocator.                        */
1037   /*                                                                       */
1038   /* <Output>                                                              */
1039   /*    raster :: A handle to the new raster object.                       */
1040   /*                                                                       */
1041   /* <Return>                                                              */
1042   /*    Error code.  0~means success.                                      */
1043   /*                                                                       */
1044   /* <Note>                                                                */
1045   /*    The `memory' parameter is a typeless pointer in order to avoid     */
1046   /*    un-wanted dependencies on the rest of the FreeType code.  In       */
1047   /*    practice, it is an @FT_Memory object, i.e., a handle to the        */
1048   /*    standard FreeType memory allocator.  However, this field can be    */
1049   /*    completely ignored by a given raster implementation.               */
1050   /*                                                                       */
1051   typedef int
1052   (*FT_Raster_NewFunc)( void*       memory,
1053                         FT_Raster*  raster );
1054
1055 #define FT_Raster_New_Func  FT_Raster_NewFunc
1056
1057
1058   /*************************************************************************/
1059   /*                                                                       */
1060   /* <FuncType>                                                            */
1061   /*    FT_Raster_DoneFunc                                                 */
1062   /*                                                                       */
1063   /* <Description>                                                         */
1064   /*    A function used to destroy a given raster object.                  */
1065   /*                                                                       */
1066   /* <Input>                                                               */
1067   /*    raster :: A handle to the raster object.                           */
1068   /*                                                                       */
1069   typedef void
1070   (*FT_Raster_DoneFunc)( FT_Raster  raster );
1071
1072 #define FT_Raster_Done_Func  FT_Raster_DoneFunc
1073
1074
1075   /*************************************************************************/
1076   /*                                                                       */
1077   /* <FuncType>                                                            */
1078   /*    FT_Raster_ResetFunc                                                */
1079   /*                                                                       */
1080   /* <Description>                                                         */
1081   /*    FreeType provides an area of memory called the `render pool',      */
1082   /*    available to all registered rasters.  This pool can be freely used */
1083   /*    during a given scan-conversion but is shared by all rasters.  Its  */
1084   /*    content is thus transient.                                         */
1085   /*                                                                       */
1086   /*    This function is called each time the render pool changes, or just */
1087   /*    after a new raster object is created.                              */
1088   /*                                                                       */
1089   /* <Input>                                                               */
1090   /*    raster    :: A handle to the new raster object.                    */
1091   /*                                                                       */
1092   /*    pool_base :: The address in memory of the render pool.             */
1093   /*                                                                       */
1094   /*    pool_size :: The size in bytes of the render pool.                 */
1095   /*                                                                       */
1096   /* <Note>                                                                */
1097   /*    Rasters can ignore the render pool and rely on dynamic memory      */
1098   /*    allocation if they want to (a handle to the memory allocator is    */
1099   /*    passed to the raster constructor).  However, this is not           */
1100   /*    recommended for efficiency purposes.                               */
1101   /*                                                                       */
1102   typedef void
1103   (*FT_Raster_ResetFunc)( FT_Raster       raster,
1104                           unsigned char*  pool_base,
1105                           unsigned long   pool_size );
1106
1107 #define FT_Raster_Reset_Func  FT_Raster_ResetFunc
1108
1109
1110   /*************************************************************************/
1111   /*                                                                       */
1112   /* <FuncType>                                                            */
1113   /*    FT_Raster_SetModeFunc                                              */
1114   /*                                                                       */
1115   /* <Description>                                                         */
1116   /*    This function is a generic facility to change modes or attributes  */
1117   /*    in a given raster.  This can be used for debugging purposes, or    */
1118   /*    simply to allow implementation-specific `features' in a given      */
1119   /*    raster module.                                                     */
1120   /*                                                                       */
1121   /* <Input>                                                               */
1122   /*    raster :: A handle to the new raster object.                       */
1123   /*                                                                       */
1124   /*    mode   :: A 4-byte tag used to name the mode or property.          */
1125   /*                                                                       */
1126   /*    args   :: A pointer to the new mode/property to use.               */
1127   /*                                                                       */
1128   typedef int
1129   (*FT_Raster_SetModeFunc)( FT_Raster      raster,
1130                             unsigned long  mode,
1131                             void*          args );
1132
1133 #define FT_Raster_Set_Mode_Func  FT_Raster_SetModeFunc
1134
1135
1136   /*************************************************************************/
1137   /*                                                                       */
1138   /* <FuncType>                                                            */
1139   /*    FT_Raster_RenderFunc                                               */
1140   /*                                                                       */
1141   /* <Description>                                                         */
1142   /*    Invoke a given raster to scan-convert a given glyph image into a   */
1143   /*    target bitmap.                                                     */
1144   /*                                                                       */
1145   /* <Input>                                                               */
1146   /*    raster :: A handle to the raster object.                           */
1147   /*                                                                       */
1148   /*    params :: A pointer to an @FT_Raster_Params structure used to      */
1149   /*              store the rendering parameters.                          */
1150   /*                                                                       */
1151   /* <Return>                                                              */
1152   /*    Error code.  0~means success.                                      */
1153   /*                                                                       */
1154   /* <Note>                                                                */
1155   /*    The exact format of the source image depends on the raster's glyph */
1156   /*    format defined in its @FT_Raster_Funcs structure.  It can be an    */
1157   /*    @FT_Outline or anything else in order to support a large array of  */
1158   /*    glyph formats.                                                     */
1159   /*                                                                       */
1160   /*    Note also that the render function can fail and return a           */
1161   /*    `FT_Err_Unimplemented_Feature' error code if the raster used does  */
1162   /*    not support direct composition.                                    */
1163   /*                                                                       */
1164   /*    XXX: For now, the standard raster doesn't support direct           */
1165   /*         composition but this should change for the final release (see */
1166   /*         the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c'    */
1167   /*         for examples of distinct implementations that support direct  */
1168   /*         composition).                                                 */
1169   /*                                                                       */
1170   typedef int
1171   (*FT_Raster_RenderFunc)( FT_Raster                raster,
1172                            const FT_Raster_Params*  params );
1173
1174 #define FT_Raster_Render_Func  FT_Raster_RenderFunc
1175
1176
1177   /*************************************************************************/
1178   /*                                                                       */
1179   /* <Struct>                                                              */
1180   /*    FT_Raster_Funcs                                                    */
1181   /*                                                                       */
1182   /* <Description>                                                         */
1183   /*   A structure used to describe a given raster class to the library.   */
1184   /*                                                                       */
1185   /* <Fields>                                                              */
1186   /*    glyph_format  :: The supported glyph format for this raster.       */
1187   /*                                                                       */
1188   /*    raster_new    :: The raster constructor.                           */
1189   /*                                                                       */
1190   /*    raster_reset  :: Used to reset the render pool within the raster.  */
1191   /*                                                                       */
1192   /*    raster_render :: A function to render a glyph into a given bitmap. */
1193   /*                                                                       */
1194   /*    raster_done   :: The raster destructor.                            */
1195   /*                                                                       */
1196   typedef struct  FT_Raster_Funcs_
1197   {
1198     FT_Glyph_Format        glyph_format;
1199     FT_Raster_NewFunc      raster_new;
1200     FT_Raster_ResetFunc    raster_reset;
1201     FT_Raster_SetModeFunc  raster_set_mode;
1202     FT_Raster_RenderFunc   raster_render;
1203     FT_Raster_DoneFunc     raster_done;
1204
1205   } FT_Raster_Funcs;
1206
1207   /* */
1208
1209
1210 FT_END_HEADER
1211
1212 #endif /* __FTIMAGE_H__ */
1213
1214
1215 /* END */
1216
1217
1218 /* Local Variables: */
1219 /* coding: utf-8    */
1220 /* End:             */