ftraster.c

qt-embedded-2.3.8.tar.gz源码

#define TRUNC( x )    ( (signed long)(x) >> ras.precision_bits )
#define FRAC( x )     ( (x) & ( ras.precision - 1 ) )
#define SCALED( x )   ( ( (x) << ras.scale_shift ) - ras.precision_half )

  /* Note that I have moved the location of some fields in the */
  /* structure to ensure that the most used variables are used */
  /* at the top.  Thus, their offset can be coded with less    */
  /* opcodes, and it results in a smaller executable.          */

  struct  TRaster_Instance_
  {
    Int       precision_bits;       /* precision related variables         */
    Int       precision;
    Int       precision_half;
    Long      precision_mask;
    Int       precision_shift;
    Int       precision_step;
    Int       precision_jitter;

    Int       scale_shift;          /* == precision_shift   for bitmaps    */
                                    /* == precision_shift+1 for pixmaps    */

    PLong     buff;                 /* The profiles buffer                 */
    PLong     sizeBuff;             /* Render pool size                    */
    PLong     maxBuff;              /* Profiles buffer size                */
    PLong     top;                  /* Current cursor in buffer            */

    FT_Error  error;

    Int       numTurns;             /* number of Y-turns in outline        */

    TPoint*   arc;                  /* current Bezier arc pointer          */

    UShort    bWidth;               /* target bitmap width                 */
    PByte     bTarget;              /* target bitmap buffer                */
    PByte     gTarget;              /* target pixmap buffer                */

    Long      lastX, lastY, minY, maxY;

    UShort    num_Profs;            /* current number of profiles          */

    Bool      fresh;                /* signals a fresh new profile which   */
                                    /* 'start' field must be completed     */
    Bool      joint;                /* signals that the last arc ended     */
                                    /* exactly on a scanline.  Allows      */
                                    /* removal of doublets                 */
    PProfile  cProfile;             /* current profile                     */
    PProfile  fProfile;             /* head of linked list of profiles     */
    PProfile  gProfile;             /* contour's first profile in case     */
                                    /* of impact                           */

    TStates   state;                /* rendering state                     */

    FT_Bitmap   target;             /* description of target bit/pixmap    */
    FT_Outline  outline;

    Long      traceOfs;             /* current offset in target bitmap     */
    Long      traceG;               /* current offset in target pixmap     */

    Short     traceIncr;            /* sweep's increment in target bitmap  */

    Short     gray_min_x;           /* current min x during gray rendering */
    Short     gray_max_x;           /* current max x during gray rendering */

    /* dispatch variables */

    Function_Sweep_Init*  Proc_Sweep_Init;
    Function_Sweep_Span*  Proc_Sweep_Span;
    Function_Sweep_Span*  Proc_Sweep_Drop;
    Function_Sweep_Step*  Proc_Sweep_Step;

    Byte      dropOutControl;       /* current drop_out control method     */

    Bool      second_pass;          /* indicates wether a horizontal pass  */
                                    /* should be performed to control      */
                                    /* drop-out accurately when calling    */
                                    /* Render_Glyph.  Note that there is   */
                                    /* no horizontal pass during gray      */
                                    /* rendering.                          */

    TPoint    arcs[2 * MaxBezier + 1]; /* The Bezier stack                 */

    TBand     band_stack[16];       /* band stack used for sub-banding     */
    Int       band_top;             /* band stack top                      */

    Int       count_table[256];     /* Look-up table used to quickly count */
                                    /* set bits in a gray 2x2 cell         */

    void*     memory;

#ifdef FT_RASTER_OPTION_ANTI_ALIASING

    Byte      grays[5];             /* Palette of gray levels used for     */
                                    /* render.                             */

    Byte      gray_lines[RASTER_GRAY_LINES];
                                /* Intermediate table used to render the   */
                                /* graylevels pixmaps.                     */
                                /* gray_lines is a buffer holding two      */
                                /* monochrome scanlines                    */

    Short     gray_width;       /* width in bytes of one monochrome        */
                                /* intermediate scanline of gray_lines.    */
                                /* Each gray pixel takes 2 bits long there */

                       /* The gray_lines must hold 2 lines, thus with size */
                       /* in bytes of at least `gray_width*2'.             */

#endif /* FT_RASTER_ANTI_ALIASING */

#if 0
    PByte       flags;              /* current flags table                 */
    PUShort     outs;               /* current outlines table              */
    FT_Vector*  coords;

    UShort      nPoints;            /* number of points in current glyph   */
    Short       nContours;          /* number of contours in current glyph */
#endif

  };


#ifdef FT_CONFIG_OPTION_STATIC_RASTER

  static TRaster_Instance  cur_ras;
#define ras  cur_ras

#else

#define ras  (*raster)

#endif /* FT_CONFIG_OPTION_STATIC_RASTER */


  /*************************************************************************/
  /*************************************************************************/
  /**                                                                     **/
  /**  PROFILES COMPUTATION                                               **/
  /**                                                                     **/
  /*************************************************************************/
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Set_High_Precision                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Sets precision variables according to param flag.                  */
  /*                                                                       */
  /* <Input>                                                               */
  /*    High :: Set to True for high precision (typically for ppem < 18),  */
  /*            false otherwise.                                           */
  /*                                                                       */
  static
  void  Set_High_Precision( RAS_ARGS Int  High )
  {
    if ( High )
    {
      ras.precision_bits   = 10;
      ras.precision_step   = 128;
      ras.precision_jitter = 24;
    }
    else
    {
      ras.precision_bits   = 6;
      ras.precision_step   = 32;
      ras.precision_jitter = 2;
    }

    FT_TRACE6(( "Set_High_Precision(%s)\n", High ? "true" : "false" ));

    ras.precision       = 1L << ras.precision_bits;
    ras.precision_half  = ras.precision / 2;
    ras.precision_shift = ras.precision_bits - Pixel_Bits;
    ras.precision_mask  = -ras.precision;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    New_Profile                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Creates a new profile in the render pool.                          */
  /*                                                                       */
  /* <Input>                                                               */
  /*    aState :: The state/orientation of the new profile.                */
  /*                                                                       */
  /* <Return>                                                              */
  /*   SUCCESS on success.  FAILURE in case of overflow or of incoherent   */
  /*   profile.                                                            */
  /*                                                                       */
  static
  Bool  New_Profile( RAS_ARGS TStates  aState )
  {
    if ( !ras.fProfile )
    {
      ras.cProfile  = (PProfile)ras.top;
      ras.fProfile  = ras.cProfile;
      ras.top      += AlignProfileSize;
    }

    if ( ras.top >= ras.maxBuff )
    {
      ras.error = Raster_Err_Overflow;
      return FAILURE;
    }

    switch ( aState )
    {
    case Ascending:
      ras.cProfile->flow = Flow_Up;
      FT_TRACE6(( "New ascending profile = %lx\n", (long)ras.cProfile ));
      break;

    case Descending:
      ras.cProfile->flow = Flow_Down;
      FT_TRACE6(( "New descending profile = %lx\n", (long)ras.cProfile ));
      break;

    default:
      FT_ERROR(( "New_Profile: invalid profile direction!\n" ));
      ras.error = Raster_Err_Invalid;
      return FAILURE;
    }

    ras.cProfile->start  = 0;
    ras.cProfile->height = 0;
    ras.cProfile->offset = ras.top;
    ras.cProfile->link   = (PProfile)0;
    ras.cProfile->next   = (PProfile)0;

    if ( !ras.gProfile )
      ras.gProfile = ras.cProfile;

    ras.state = aState;
    ras.fresh = TRUE;
    ras.joint = FALSE;

    return SUCCESS;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    End_Profile                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Finalizes the current profile.                                     */
  /*                                                                       */
  /* <Return>                                                              */
  /*    SUCCESS on success.  FAILURE in case of overflow or incoherency.   */
  /*                                                                       */
  static
  Bool  End_Profile( RAS_ARG )
  {
    Long      h;
    PProfile  oldProfile;


    h = ras.top - ras.cProfile->offset;

    if ( h < 0 )
    {
      FT_ERROR(( "End_Profile: negative height encountered!\n" ));
      ras.error = Raster_Err_Neg_Height;
      return FAILURE;
    }

    if ( h > 0 )
    {
      FT_TRACE6(( "Ending profile %lx, start = %ld, height = %ld\n",
                  (long)ras.cProfile, ras.cProfile->start, h ));

      oldProfile           = ras.cProfile;
      ras.cProfile->height = h;
      ras.cProfile         = (PProfile)ras.top;

      ras.top             += AlignProfileSize;

      ras.cProfile->height = 0;
      ras.cProfile->offset = ras.top;
      oldProfile->next     = ras.cProfile;
      ras.num_Profs++;
    }

    if ( ras.top >= ras.maxBuff )
    {
      FT_TRACE1(( "overflow in End_Profile\n" ));
      ras.error = Raster_Err_Overflow;
      return FAILURE;
    }

    ras.joint = FALSE;

    return SUCCESS;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Insert_Y_Turn                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Inserts a salient into the sorted list placed on top of the render */
  /*    pool.                                                              */
  /*                                                                       */
  /* <Input>                                                               */
  /*    New y scanline position.                                           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    SUCCESS on success.  FAILURE in case of overflow.                  */
  /*                                                                       */
  static
  Bool  Insert_Y_Turn( RAS_ARGS Int  y )
  {
    PLong     y_turns;
    Int       y2, n;


    n       = ras.numTurns - 1;
    y_turns = ras.sizeBuff - ras.numTurns;

    /* look for first y value that is <= */
    while ( n >= 0 && y < y_turns[n] )
      n--;

    /* if it is <, simply insert it, ignore if == */
    if ( n >= 0 && y > y_turns[n] )
      while ( n >= 0 )
      {
        y2 = y_turns[n];
        y_turns[n] = y;
        y = y2;
        n--;
      }

    if ( n < 0 )
    {
      if ( ras.maxBuff <= ras.top )
      {
        ras.error = Raster_Err_Overflow;
        return FAILURE;
      }
      ras.maxBuff--;
      ras.numTurns++;
      ras.sizeBuff[-ras.numTurns] = y;
    }

    return SUCCESS;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */