ftraster.c

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/****************************************************************************
 *
 * ftraster.c
 *
 *   The FreeType glyph rasterizer (body).
 *
 * Copyright (C) 1996-2020 by
 * David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */
 
  /**************************************************************************
   *
   * This file can be compiled without the rest of the FreeType engine, by
   * defining the STANDALONE_ macro when compiling it.  You also need to
   * put the files `ftimage.h' and `ftmisc.h' into the $(incdir)
   * directory.  Typically, you should do something like
   *
   * - copy `src/raster/ftraster.c' (this file) to your current directory
   *
   * - copy `include/freetype/ftimage.h' and `src/raster/ftmisc.h' to your
   *   current directory
   *
   * - compile `ftraster' with the STANDALONE_ macro defined, as in
   *
   *     cc -c -DSTANDALONE_ ftraster.c
   *
   * The renderer can be initialized with a call to
   * `ft_standard_raster.raster_new'; a bitmap can be generated
   * with a call to `ft_standard_raster.raster_render'.
   *
   * See the comments and documentation in the file `ftimage.h' for more
   * details on how the raster works.
   *
   */
 
 
  /**************************************************************************
   *
   * This is a rewrite of the FreeType 1.x scan-line converter
   *
   */
 
#ifdef STANDALONE_
 
  /* The size in bytes of the render pool used by the scan-line converter  */
  /* to do all of its work.                                                */
#define FT_RENDER_POOL_SIZE  16384L
 
#define FT_CONFIG_STANDARD_LIBRARY_H  <stdlib.h>
 
#include <string.h>           /* for memset */
 
#include "ftmisc.h"
#include "ftimage.h"
 
#else /* !STANDALONE_ */
 
#include "ftraster.h"
#include <freetype/internal/ftcalc.h> /* for FT_MulDiv and FT_MulDiv_No_Round */
#include <freetype/ftoutln.h>         /* for FT_Outline_Get_CBox              */
 
#endif /* !STANDALONE_ */
 
 
  /**************************************************************************
   *
   * A simple technical note on how the raster works
   * -----------------------------------------------
   *
   *   Converting an outline into a bitmap is achieved in several steps:
   *
   *   1 - Decomposing the outline into successive `profiles'.  Each
   *       profile is simply an array of scanline intersections on a given
   *       dimension.  A profile's main attributes are
   *
   *       o its scanline position boundaries, i.e. `Ymin' and `Ymax'
   *
   *       o an array of intersection coordinates for each scanline
   *         between `Ymin' and `Ymax'
   *
   *       o a direction, indicating whether it was built going `up' or
   *         `down', as this is very important for filling rules
   *
   *       o its drop-out mode
   *
   *   2 - Sweeping the target map's scanlines in order to compute segment
   *       `spans' which are then filled.  Additionally, this pass
   *       performs drop-out control.
   *
   *   The outline data is parsed during step 1 only.  The profiles are
   *   built from the bottom of the render pool, used as a stack.  The
   *   following graphics shows the profile list under construction:
   *
   *    __________________________________________________________ _ _
   *   |         |                 |         |                 |
   *   | profile | coordinates for | profile | coordinates for |-->
   *   |    1    |  profile 1      |    2    |  profile 2      |-->
   *   |_________|_________________|_________|_________________|__ _ _
   *
   *   ^                                                       ^
   *   |                                                       |
   * start of render pool                                      top
   *
   *   The top of the profile stack is kept in the `top' variable.
   *
   *   As you can see, a profile record is pushed on top of the render
   *   pool, which is then followed by its coordinates/intersections.  If
   *   a change of direction is detected in the outline, a new profile is
   *   generated until the end of the outline.
   *
   *   Note that when all profiles have been generated, the function
   *   Finalize_Profile_Table() is used to record, for each profile, its
   *   bottom-most scanline as well as the scanline above its upmost
   *   boundary.  These positions are called `y-turns' because they (sort
   *   of) correspond to local extrema.  They are stored in a sorted list
   *   built from the top of the render pool as a downwards stack:
   *
   *     _ _ _______________________________________
   *                           |                    |
   *                        <--| sorted list of     |
   *                        <--|  extrema scanlines |
   *     _ _ __________________|____________________|
   *
   *                           ^                    ^
   *                           |                    |
   *                         maxBuff           sizeBuff = end of pool
   *
   *   This list is later used during the sweep phase in order to
   *   optimize performance (see technical note on the sweep below).
   *
   *   Of course, the raster detects whether the two stacks collide and
   *   handles the situation properly.
   *
   */
 
 
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
 
  /* define DEBUG_RASTER if you want to compile a debugging version */
/* #define DEBUG_RASTER */
 
 
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
 
  /**************************************************************************
   *
   * The macro FT_COMPONENT is used in trace mode.  It is an implicit
   * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
   * messages during execution.
   */
#undef  FT_COMPONENT
#define FT_COMPONENT  raster
 
 
#ifdef STANDALONE_
 
  /* Auxiliary macros for token concatenation. */
#define FT_ERR_XCAT( x, y )  x ## y
#define FT_ERR_CAT( x, y )   FT_ERR_XCAT( x, y )
 
  /* This macro is used to indicate that a function parameter is unused. */
  /* Its purpose is simply to reduce compiler warnings.  Note also that  */
  /* simply defining it as `(void)x' doesn't avoid warnings with certain */
  /* ANSI compilers (e.g. LCC).                                          */
#define FT_UNUSED( x )  (x) = (x)
 
  /* Disable the tracing mechanism for simplicity -- developers can      */
  /* activate it easily by redefining these macros.                      */
#ifndef FT_ERROR
#define FT_ERROR( x )  do { } while ( 0 )     /* nothing */
#endif
 
#ifndef FT_TRACE
#define FT_TRACE( x )   do { } while ( 0 )    /* nothing */
#define FT_TRACE1( x )  do { } while ( 0 )    /* nothing */
#define FT_TRACE6( x )  do { } while ( 0 )    /* nothing */
#define FT_TRACE7( x )  do { } while ( 0 )    /* nothing */
#endif
 
#ifndef FT_THROW
#define FT_THROW( e )  FT_ERR_CAT( Raster_Err_, e )
#endif
 
#define Raster_Err_None          0
#define Raster_Err_Not_Ini      -1
#define Raster_Err_Overflow     -2
#define Raster_Err_Neg_Height   -3
#define Raster_Err_Invalid      -4
#define Raster_Err_Unsupported  -5
 
#define ft_memset  memset
 
#define FT_DEFINE_RASTER_FUNCS( class_, glyph_format_, raster_new_, \
                                raster_reset_, raster_set_mode_,    \
                                raster_render_, raster_done_ )      \
          const FT_Raster_Funcs class_ =                            \
          {                                                         \
            glyph_format_,                                          \
            raster_new_,                                            \
            raster_reset_,                                          \
            raster_set_mode_,                                       \
            raster_render_,                                         \
            raster_done_                                            \
         };
 
#else /* !STANDALONE_ */
 
 
#include <freetype/internal/ftobjs.h>
#include <freetype/internal/ftdebug.h> /* for FT_TRACE, FT_ERROR, and FT_THROW */
 
#include "rasterrs.h"
 
#define Raster_Err_None         FT_Err_Ok
#define Raster_Err_Not_Ini      Raster_Err_Raster_Uninitialized
#define Raster_Err_Overflow     Raster_Err_Raster_Overflow
#define Raster_Err_Neg_Height   Raster_Err_Raster_Negative_Height
#define Raster_Err_Invalid      Raster_Err_Invalid_Outline
#define Raster_Err_Unsupported  Raster_Err_Cannot_Render_Glyph
 
 
#endif /* !STANDALONE_ */
 
 
#ifndef FT_MEM_SET
#define FT_MEM_SET( d, s, c )  ft_memset( d, s, c )
#endif
 
#ifndef FT_MEM_ZERO
#define FT_MEM_ZERO( dest, count )  FT_MEM_SET( dest, 0, count )
#endif
 
#ifndef FT_ZERO
#define FT_ZERO( p )  FT_MEM_ZERO( p, sizeof ( *(p) ) )
#endif
 
  /* FMulDiv means `Fast MulDiv'; it is used in case where `b' is       */
  /* typically a small value and the result of a*b is known to fit into */
  /* 32 bits.                                                           */
#define FMulDiv( a, b, c )  ( (a) * (b) / (c) )
 
  /* On the other hand, SMulDiv means `Slow MulDiv', and is used typically */
  /* for clipping computations.  It simply uses the FT_MulDiv() function   */
  /* defined in `ftcalc.h'.                                                */
#define SMulDiv           FT_MulDiv
#define SMulDiv_No_Round  FT_MulDiv_No_Round
 
  /* The rasterizer is a very general purpose component; please leave */
  /* the following redefinitions there (you never know your target    */
  /* environment).                                                    */
 
#ifndef TRUE
#define TRUE   1
#endif
 
#ifndef FALSE
#define FALSE  0
#endif
 
#ifndef NULL
#define NULL  (void*)0
#endif
 
#ifndef SUCCESS
#define SUCCESS  0
#endif
 
#ifndef FAILURE
#define FAILURE  1
#endif
 
 
#define MaxBezier  32   /* The maximum number of stacked Bezier curves. */
                        /* Setting this constant to more than 32 is a   */
                        /* pure waste of space.                         */
 
#define Pixel_Bits  6   /* fractional bits of *input* coordinates */
 
 
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
 
  typedef int             Int;
  typedef unsigned int    UInt;
  typedef short           Short;
  typedef unsigned short  UShort, *PUShort;
  typedef long            Long, *PLong;
  typedef unsigned long   ULong;
 
  typedef unsigned char   Byte, *PByte;
  typedef char            Bool;
 
 
  typedef union  Alignment_
  {
    Long    l;
    void*   p;
    void  (*f)(void);
 
  } Alignment, *PAlignment;
 
 
  typedef struct  TPoint_
  {
    Long  x;
    Long  y;
 
  } TPoint;
 
 
  /* values for the `flags' bit field */
#define Flow_Up           0x08U
#define Overshoot_Top     0x10U
#define Overshoot_Bottom  0x20U
 
 
  /* States of each line, arc, and profile */
  typedef enum  TStates_
  {
    Unknown_State,
    Ascending_State,
    Descending_State,
    Flat_State
 
  } TStates;
 
 
  typedef struct TProfile_  TProfile;
  typedef TProfile*         PProfile;
 
  struct  TProfile_
  {
    FT_F26Dot6  X;           /* current coordinate during sweep          */
    PProfile    link;        /* link to next profile (various purposes)  */
    PLong       offset;      /* start of profile's data in render pool   */
    UShort      flags;       /* Bit 0-2: drop-out mode                   */
                             /* Bit 3: profile orientation (up/down)     */
                             /* Bit 4: is top profile?                   */
                             /* Bit 5: is bottom profile?                */
    Long        height;      /* profile's height in scanlines            */
    Long        start;       /* profile's starting scanline              */
 
    Int         countL;      /* number of lines to step before this      */
                             /* profile becomes drawable                 */
 
    PProfile    next;        /* next profile in same contour, used       */
                             /* during drop-out control                  */
  };
 
  typedef PProfile   TProfileList;
  typedef PProfile*  PProfileList;
 
 
  /* Simple record used to implement a stack of bands, required */
  /* by the sub-banding mechanism                               */
  typedef struct  black_TBand_
  {
    Short  y_min;   /* band's minimum */
    Short  y_max;   /* band's maximum */
 
  } black_TBand;
 
 
#define AlignProfileSize \
  ( ( sizeof ( TProfile ) + sizeof ( Alignment ) - 1 ) / sizeof ( Long ) )
 
 
#undef RAS_ARG
#undef RAS_ARGS
#undef RAS_VAR
#undef RAS_VARS
 
#ifdef FT_STATIC_RASTER
 
 
#define RAS_ARGS       /* void */
#define RAS_ARG        void
 
#define RAS_VARS       /* void */
#define RAS_VAR        /* void */
 
#define FT_UNUSED_RASTER  do { } while ( 0 )
 
 
#else /* !FT_STATIC_RASTER */
 
 
#define RAS_ARGS       black_PWorker  worker,
#define RAS_ARG        black_PWorker  worker
 
#define RAS_VARS       worker,
#define RAS_VAR        worker
 
#define FT_UNUSED_RASTER  FT_UNUSED( worker )
 
 
#endif /* !FT_STATIC_RASTER */
 
 
  typedef struct black_TWorker_  black_TWorker, *black_PWorker;
 
 
  /* prototypes used for sweep function dispatch */
  typedef void
  Function_Sweep_Init( RAS_ARGS Short*  min,
                                Short*  max );
 
  typedef void
  Function_Sweep_Span( RAS_ARGS Short       y,
                                FT_F26Dot6  x1,
                                FT_F26Dot6  x2,
                                PProfile    left,
                                PProfile    right );
 
  typedef void
  Function_Sweep_Step( RAS_ARG );
 
 
  /* NOTE: These operations are only valid on 2's complement processors */
#undef FLOOR
#undef CEILING
#undef TRUNC
#undef SCALED
 
#define FLOOR( x )    ( (x) & -ras.precision )
#define CEILING( x )  ( ( (x) + ras.precision - 1 ) & -ras.precision )
#define TRUNC( x )    ( (Long)(x) >> ras.precision_bits )
#define FRAC( x )     ( (x) & ( ras.precision - 1 ) )
 
  /* scale and shift grid to pixel centers */
#define SCALED( x )   ( (x) * ras.precision_scale - ras.precision_half )
 
#define IS_BOTTOM_OVERSHOOT( x ) \
          (Bool)( CEILING( x ) - x >= ras.precision_half )
#define IS_TOP_OVERSHOOT( x )    \
          (Bool)( x - FLOOR( x ) >= ras.precision_half )
 
  /* Smart dropout rounding to find which pixel is closer to span ends. */
  /* To mimick Windows, symmetric cases break down indepenently of the  */
  /* precision.                                                         */
#define SMART( p, q )  FLOOR( ( (p) + (q) + ras.precision * 63 / 64 ) >> 1 )
 
#if FT_RENDER_POOL_SIZE > 2048
#define FT_MAX_BLACK_POOL  ( FT_RENDER_POOL_SIZE / sizeof ( Long ) )
#else
#define FT_MAX_BLACK_POOL  ( 2048 / sizeof ( Long ) )
#endif
 
  /* The most used variables are positioned at the top of the structure. */
  /* Thus, their offset can be coded with less opcodes, resulting in a   */
  /* smaller executable.                                                 */
 
  struct  black_TWorker_
  {
    Int         precision_bits;     /* precision related variables         */
    Int         precision;
    Int         precision_half;
    Int         precision_scale;
    Int         precision_step;
    Int         precision_jitter;
 
    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       bOrigin;            /* target bitmap bottom-left origin    */
 
    Long        lastX, lastY;
    Long        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     */
    Short       traceIncr;          /* sweep's increment in target bitmap  */
 
    /* 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 whether a horizontal pass */
                                    /* should be performed to control      */
                                    /* drop-out accurately when calling    */
                                    /* Render_Glyph.                       */
 
    TPoint      arcs[3 * MaxBezier + 1]; /* The Bezier stack               */
 
    black_TBand  band_stack[16];    /* band stack used for sub-banding     */
    Int          band_top;          /* band stack top                      */
 
  };
 
 
  typedef struct  black_TRaster_
  {
    void*          memory;
 
  } black_TRaster, *black_PRaster;
 
#ifdef FT_STATIC_RASTER
 
  static black_TWorker  ras;
 
#else /* !FT_STATIC_RASTER */
 
#define ras  (*worker)
 
#endif /* !FT_STATIC_RASTER */
 
 
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
 
 
  /**************************************************************************
   *
   * @Function:
   *   Set_High_Precision
   *
   * @Description:
   *   Set precision variables according to param flag.
   *
   * @Input:
   *   High ::
   *     Set to True for high precision (typically for ppem < 24),
   *     false otherwise.
   */
  static void
  Set_High_Precision( RAS_ARGS Int  High )
  {
    /*
     * `precision_step' is used in `Bezier_Up' to decide when to split a
     * given y-monotonous Bezier arc that crosses a scanline before
     * approximating it as a straight segment.  The default value of 32 (for
     * low accuracy) corresponds to
     *
     *   32 / 64 == 0.5 pixels,
     *
     * while for the high accuracy case we have
     *
     *   256 / (1 << 12) = 0.0625 pixels.
     *
     * `precision_jitter' is an epsilon threshold used in
     * `Vertical_Sweep_Span' to deal with small imperfections in the Bezier
     * decomposition (after all, we are working with approximations only);
     * it avoids switching on additional pixels which would cause artifacts
     * otherwise.
     *
     * The value of `precision_jitter' has been determined heuristically.
     *
     */
 
    if ( High )
    {
      ras.precision_bits   = 12;
      ras.precision_step   = 256;
      ras.precision_jitter = 30;
    }
    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       = 1 << ras.precision_bits;
    ras.precision_half  = ras.precision >> 1;
    ras.precision_scale = ras.precision >> Pixel_Bits;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   New_Profile
   *
   * @Description:
   *   Create a new profile in the render pool.
   *
   * @Input:
   *   aState ::
   *     The state/orientation of the new profile.
   *
   *   overshoot ::
   *     Whether the profile's unrounded start position
   *     differs by at least a half pixel.
   *
   * @Return:
   *  SUCCESS on success.  FAILURE in case of overflow or of incoherent
   *  profile.
   */
  static Bool
  New_Profile( RAS_ARGS TStates  aState,
                        Bool     overshoot )
  {
    if ( !ras.fProfile )
    {
      ras.cProfile  = (PProfile)ras.top;
      ras.fProfile  = ras.cProfile;
      ras.top      += AlignProfileSize;
    }
 
    if ( ras.top >= ras.maxBuff )
    {
      ras.error = FT_THROW( Overflow );
      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;
    ras.cProfile->flags  = ras.dropOutControl;
 
    switch ( aState )
    {
    case Ascending_State:
      ras.cProfile->flags |= Flow_Up;
      if ( overshoot )
        ras.cProfile->flags |= Overshoot_Bottom;
 
      FT_TRACE6(( "  new ascending profile = %p\n", (void *)ras.cProfile ));
      break;
 
    case Descending_State:
      if ( overshoot )
        ras.cProfile->flags |= Overshoot_Top;
      FT_TRACE6(( "  new descending profile = %p\n", (void *)ras.cProfile ));
      break;
 
    default:
      FT_ERROR(( "New_Profile: invalid profile direction\n" ));
      ras.error = FT_THROW( Invalid );
      return FAILURE;
    }
 
    if ( !ras.gProfile )
      ras.gProfile = ras.cProfile;
 
    ras.state = aState;
    ras.fresh = TRUE;
    ras.joint = FALSE;
 
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   End_Profile
   *
   * @Description:
   *   Finalize the current profile.
   *
   * @Input:
   *   overshoot ::
   *     Whether the profile's unrounded end position differs
   *     by at least a half pixel.
   *
   * @Return:
   *   SUCCESS on success.  FAILURE in case of overflow or incoherency.
   */
  static Bool
  End_Profile( RAS_ARGS Bool  overshoot )
  {
    Long  h;
 
 
    h = (Long)( ras.top - ras.cProfile->offset );
 
    if ( h < 0 )
    {
      FT_ERROR(( "End_Profile: negative height encountered\n" ));
      ras.error = FT_THROW( Neg_Height );
      return FAILURE;
    }
 
    if ( h > 0 )
    {
      PProfile  oldProfile;
 
 
      FT_TRACE6(( "  ending profile %p, start = %ld, height = %ld\n",
                  (void *)ras.cProfile, ras.cProfile->start, h ));
 
      ras.cProfile->height = h;
      if ( overshoot )
      {
        if ( ras.cProfile->flags & Flow_Up )
          ras.cProfile->flags |= Overshoot_Top;
        else
          ras.cProfile->flags |= Overshoot_Bottom;
      }
 
      oldProfile   = ras.cProfile;
      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 = FT_THROW( Overflow );
      return FAILURE;
    }
 
    ras.joint = FALSE;
 
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Insert_Y_Turn
   *
   * @Description:
   *   Insert 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    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] )
      do
      {
        Int  y2 = (Int)y_turns[n];
 
 
        y_turns[n] = y;
        y = y2;
      } while ( --n >= 0 );
 
    if ( n < 0 )
    {
      ras.maxBuff--;
      if ( ras.maxBuff <= ras.top )
      {
        ras.error = FT_THROW( Overflow );
        return FAILURE;
      }
      ras.numTurns++;
      ras.sizeBuff[-ras.numTurns] = y;
    }
 
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Finalize_Profile_Table
   *
   * @Description:
   *   Adjust all links in the profiles list.
   *
   * @Return:
   *   SUCCESS on success.  FAILURE in case of overflow.
   */
  static Bool
  Finalize_Profile_Table( RAS_ARG )
  {
    UShort    n;
    PProfile  p;
 
 
    n = ras.num_Profs;
    p = ras.fProfile;
 
    if ( n > 1 && p )
    {
      do
      {
        Int  bottom, top;
 
 
        if ( n > 1 )
          p->link = (PProfile)( p->offset + p->height );
        else
          p->link = NULL;
 
        if ( p->flags & Flow_Up )
        {
          bottom = (Int)p->start;
          top    = (Int)( p->start + p->height - 1 );
        }
        else
        {
          bottom     = (Int)( p->start - p->height + 1 );
          top        = (Int)p->start;
          p->start   = bottom;
          p->offset += p->height - 1;
        }
 
        if ( Insert_Y_Turn( RAS_VARS bottom )  ||
             Insert_Y_Turn( RAS_VARS top + 1 ) )
          return FAILURE;
 
        p = p->link;
      } while ( --n );
    }
    else
      ras.fProfile = NULL;
 
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Split_Conic
   *
   * @Description:
   *   Subdivide one conic Bezier into two joint sub-arcs in the Bezier
   *   stack.
   *
   * @Input:
   *   None (subdivided Bezier is taken from the top of the stack).
   *
   * @Note:
   *   This routine is the `beef' of this component.  It is  _the_ inner
   *   loop that should be optimized to hell to get the best performance.
   */
  static void
  Split_Conic( TPoint*  base )
  {
    Long  a, b;
 
 
    base[4].x = base[2].x;
    a = base[0].x + base[1].x;
    b = base[1].x + base[2].x;
    base[3].x = b >> 1;
    base[2].x = ( a + b ) >> 2;
    base[1].x = a >> 1;
 
    base[4].y = base[2].y;
    a = base[0].y + base[1].y;
    b = base[1].y + base[2].y;
    base[3].y = b >> 1;
    base[2].y = ( a + b ) >> 2;
    base[1].y = a >> 1;
 
    /* hand optimized.  gcc doesn't seem to be too good at common      */
    /* expression substitution and instruction scheduling ;-)          */
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Split_Cubic
   *
   * @Description:
   *   Subdivide a third-order Bezier arc into two joint sub-arcs in the
   *   Bezier stack.
   *
   * @Note:
   *   This routine is the `beef' of the component.  It is one of _the_
   *   inner loops that should be optimized like hell to get the best
   *   performance.
   */
  static void
  Split_Cubic( TPoint*  base )
  {
    Long  a, b, c;
 
 
    base[6].x = base[3].x;
    a = base[0].x + base[1].x;
    b = base[1].x + base[2].x;
    c = base[2].x + base[3].x;
    base[5].x = c >> 1;
    c += b;
    base[4].x = c >> 2;
    base[1].x = a >> 1;
    a += b;
    base[2].x = a >> 2;
    base[3].x = ( a + c ) >> 3;
 
    base[6].y = base[3].y;
    a = base[0].y + base[1].y;
    b = base[1].y + base[2].y;
    c = base[2].y + base[3].y;
    base[5].y = c >> 1;
    c += b;
    base[4].y = c >> 2;
    base[1].y = a >> 1;
    a += b;
    base[2].y = a >> 2;
    base[3].y = ( a + c ) >> 3;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Line_Up
   *
   * @Description:
   *   Compute the x-coordinates of an ascending line segment and store
   *   them in the render pool.
   *
   * @Input:
   *   x1 ::
   *     The x-coordinate of the segment's start point.
   *
   *   y1 ::
   *     The y-coordinate of the segment's start point.
   *
   *   x2 ::
   *     The x-coordinate of the segment's end point.
   *
   *   y2 ::
   *     The y-coordinate of the segment's end point.
   *
   *   miny ::
   *     A lower vertical clipping bound value.
   *
   *   maxy ::
   *     An upper vertical clipping bound value.
   *
   * @Return:
   *   SUCCESS on success, FAILURE on render pool overflow.
   */
  static Bool
  Line_Up( RAS_ARGS Long  x1,
                    Long  y1,
                    Long  x2,
                    Long  y2,
                    Long  miny,
                    Long  maxy )
  {
    Long   Dx, Dy;
    Int    e1, e2, f1, f2, size;     /* XXX: is `Short' sufficient? */
    Long   Ix, Rx, Ax;
 
    PLong  top;
 
 
    Dx = x2 - x1;
    Dy = y2 - y1;
 
    if ( Dy <= 0 || y2 < miny || y1 > maxy )
      return SUCCESS;
 
    if ( y1 < miny )
    {
      /* Take care: miny-y1 can be a very large value; we use     */
      /*            a slow MulDiv function to avoid clipping bugs */
      x1 += SMulDiv( Dx, miny - y1, Dy );
      e1  = (Int)TRUNC( miny );
      f1  = 0;
    }
    else
    {
      e1 = (Int)TRUNC( y1 );
      f1 = (Int)FRAC( y1 );
    }
 
    if ( y2 > maxy )
    {
      /* x2 += FMulDiv( Dx, maxy - y2, Dy );  UNNECESSARY */
      e2  = (Int)TRUNC( maxy );
      f2  = 0;
    }
    else
    {
      e2 = (Int)TRUNC( y2 );
      f2 = (Int)FRAC( y2 );
    }
 
    if ( f1 > 0 )
    {
      if ( e1 == e2 )
        return SUCCESS;
      else
      {
        x1 += SMulDiv( Dx, ras.precision - f1, Dy );
        e1 += 1;
      }
    }
    else
      if ( ras.joint )
      {
        ras.top--;
        ras.joint = FALSE;
      }
 
    ras.joint = (char)( f2 == 0 );
 
    if ( ras.fresh )
    {
      ras.cProfile->start = e1;
      ras.fresh           = FALSE;
    }
 
    size = e2 - e1 + 1;
    if ( ras.top + size >= ras.maxBuff )
    {
      ras.error = FT_THROW( Overflow );
      return FAILURE;
    }
 
    if ( Dx > 0 )
    {
      Ix = SMulDiv_No_Round( ras.precision, Dx, Dy );
      Rx = ( ras.precision * Dx ) % Dy;
      Dx = 1;
    }
    else
    {
      Ix = -SMulDiv_No_Round( ras.precision, -Dx, Dy );
      Rx = ( ras.precision * -Dx ) % Dy;
      Dx = -1;
    }
 
    Ax  = -Dy;
    top = ras.top;
 
    while ( size > 0 )
    {
      *top++ = x1;
 
      x1 += Ix;
      Ax += Rx;
      if ( Ax >= 0 )
      {
        Ax -= Dy;
        x1 += Dx;
      }
      size--;
    }
 
    ras.top = top;
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Line_Down
   *
   * @Description:
   *   Compute the x-coordinates of an descending line segment and store
   *   them in the render pool.
   *
   * @Input:
   *   x1 ::
   *     The x-coordinate of the segment's start point.
   *
   *   y1 ::
   *     The y-coordinate of the segment's start point.
   *
   *   x2 ::
   *     The x-coordinate of the segment's end point.
   *
   *   y2 ::
   *     The y-coordinate of the segment's end point.
   *
   *   miny ::
   *     A lower vertical clipping bound value.
   *
   *   maxy ::
   *     An upper vertical clipping bound value.
   *
   * @Return:
   *   SUCCESS on success, FAILURE on render pool overflow.
   */
  static Bool
  Line_Down( RAS_ARGS Long  x1,
                      Long  y1,
                      Long  x2,
                      Long  y2,
                      Long  miny,
                      Long  maxy )
  {
    Bool  result, fresh;
 
 
    fresh  = ras.fresh;
 
    result = Line_Up( RAS_VARS x1, -y1, x2, -y2, -maxy, -miny );
 
    if ( fresh && !ras.fresh )
      ras.cProfile->start = -ras.cProfile->start;
 
    return result;
  }
 
 
  /* A function type describing the functions used to split Bezier arcs */
  typedef void  (*TSplitter)( TPoint*  base );
 
 
  /**************************************************************************
   *
   * @Function:
   *   Bezier_Up
   *
   * @Description:
   *   Compute the x-coordinates of an ascending Bezier arc and store
   *   them in the render pool.
   *
   * @Input:
   *   degree ::
   *     The degree of the Bezier arc (either 2 or 3).
   *
   *   splitter ::
   *     The function to split Bezier arcs.
   *
   *   miny ::
   *     A lower vertical clipping bound value.
   *
   *   maxy ::
   *     An upper vertical clipping bound value.
   *
   * @Return:
   *   SUCCESS on success, FAILURE on render pool overflow.
   */
  static Bool
  Bezier_Up( RAS_ARGS Int        degree,
                      TSplitter  splitter,
                      Long       miny,
                      Long       maxy )
  {
    Long   y1, y2, e, e2, e0;
    Short  f1;
 
    TPoint*  arc;
    TPoint*  start_arc;
 
    PLong top;
 
 
    arc = ras.arc;
    y1  = arc[degree].y;
    y2  = arc[0].y;
    top = ras.top;
 
    if ( y2 < miny || y1 > maxy )
      goto Fin;
 
    e2 = FLOOR( y2 );
 
    if ( e2 > maxy )
      e2 = maxy;
 
    e0 = miny;
 
    if ( y1 < miny )
      e = miny;
    else
    {
      e  = CEILING( y1 );
      f1 = (Short)( FRAC( y1 ) );
      e0 = e;
 
      if ( f1 == 0 )
      {
        if ( ras.joint )
        {
          top--;
          ras.joint = FALSE;
        }
 
        *top++ = arc[degree].x;
 
        e += ras.precision;
      }
    }
 
    if ( ras.fresh )
    {
      ras.cProfile->start = TRUNC( e0 );
      ras.fresh = FALSE;
    }
 
    if ( e2 < e )
      goto Fin;
 
    if ( ( top + TRUNC( e2 - e ) + 1 ) >= ras.maxBuff )
    {
      ras.top   = top;
      ras.error = FT_THROW( Overflow );
      return FAILURE;
    }
 
    start_arc = arc;
 
    do
    {
      ras.joint = FALSE;
 
      y2 = arc[0].y;
 
      if ( y2 > e )
      {
        y1 = arc[degree].y;
        if ( y2 - y1 >= ras.precision_step )
        {
          splitter( arc );
          arc += degree;
        }
        else
        {
          *top++ = arc[degree].x + FMulDiv( arc[0].x - arc[degree].x,
                                            e - y1, y2 - y1 );
          arc -= degree;
          e   += ras.precision;
        }
      }
      else
      {
        if ( y2 == e )
        {
          ras.joint  = TRUE;
          *top++     = arc[0].x;
 
          e += ras.precision;
        }
        arc -= degree;
      }
    } while ( arc >= start_arc && e <= e2 );
 
  Fin:
    ras.top  = top;
    ras.arc -= degree;
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Bezier_Down
   *
   * @Description:
   *   Compute the x-coordinates of an descending Bezier arc and store
   *   them in the render pool.
   *
   * @Input:
   *   degree ::
   *     The degree of the Bezier arc (either 2 or 3).
   *
   *   splitter ::
   *     The function to split Bezier arcs.
   *
   *   miny ::
   *     A lower vertical clipping bound value.
   *
   *   maxy ::
   *     An upper vertical clipping bound value.
   *
   * @Return:
   *   SUCCESS on success, FAILURE on render pool overflow.
   */
  static Bool
  Bezier_Down( RAS_ARGS Int        degree,
                        TSplitter  splitter,
                        Long       miny,
                        Long       maxy )
  {
    TPoint*  arc = ras.arc;
    Bool     result, fresh;
 
 
    arc[0].y = -arc[0].y;
    arc[1].y = -arc[1].y;
    arc[2].y = -arc[2].y;
    if ( degree > 2 )
      arc[3].y = -arc[3].y;
 
    fresh = ras.fresh;
 
    result = Bezier_Up( RAS_VARS degree, splitter, -maxy, -miny );
 
    if ( fresh && !ras.fresh )
      ras.cProfile->start = -ras.cProfile->start;
 
    arc[0].y = -arc[0].y;
    return result;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Line_To
   *
   * @Description:
   *   Inject a new line segment and adjust the Profiles list.
   *
   * @Input:
   *  x ::
   *    The x-coordinate of the segment's end point (its start point
   *    is stored in `lastX').
   *
   *  y ::
   *    The y-coordinate of the segment's end point (its start point
   *    is stored in `lastY').
   *
   * @Return:
   *  SUCCESS on success, FAILURE on render pool overflow or incorrect
   *  profile.
   */
  static Bool
  Line_To( RAS_ARGS Long  x,
                    Long  y )
  {
    /* First, detect a change of direction */
 
    switch ( ras.state )
    {
    case Unknown_State:
      if ( y > ras.lastY )
      {
        if ( New_Profile( RAS_VARS Ascending_State,
                                   IS_BOTTOM_OVERSHOOT( ras.lastY ) ) )
          return FAILURE;
      }
      else
      {
        if ( y < ras.lastY )
          if ( New_Profile( RAS_VARS Descending_State,
                                     IS_TOP_OVERSHOOT( ras.lastY ) ) )
            return FAILURE;
      }
      break;
 
    case Ascending_State:
      if ( y < ras.lastY )
      {
        if ( End_Profile( RAS_VARS IS_TOP_OVERSHOOT( ras.lastY ) ) ||
             New_Profile( RAS_VARS Descending_State,
                                   IS_TOP_OVERSHOOT( ras.lastY ) ) )
          return FAILURE;
      }
      break;
 
    case Descending_State:
      if ( y > ras.lastY )
      {
        if ( End_Profile( RAS_VARS IS_BOTTOM_OVERSHOOT( ras.lastY ) ) ||
             New_Profile( RAS_VARS Ascending_State,
                                   IS_BOTTOM_OVERSHOOT( ras.lastY ) ) )
          return FAILURE;
      }
      break;
 
    default:
      ;
    }
 
    /* Then compute the lines */
 
    switch ( ras.state )
    {
    case Ascending_State:
      if ( Line_Up( RAS_VARS ras.lastX, ras.lastY,
                             x, y, ras.minY, ras.maxY ) )
        return FAILURE;
      break;
 
    case Descending_State:
      if ( Line_Down( RAS_VARS ras.lastX, ras.lastY,
                               x, y, ras.minY, ras.maxY ) )
        return FAILURE;
      break;
 
    default:
      ;
    }
 
    ras.lastX = x;
    ras.lastY = y;
 
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Conic_To
   *
   * @Description:
   *   Inject a new conic arc and adjust the profile list.
   *
   * @Input:
   *  cx ::
   *    The x-coordinate of the arc's new control point.
   *
   *  cy ::
   *    The y-coordinate of the arc's new control point.
   *
   *  x ::
   *    The x-coordinate of the arc's end point (its start point is
   *    stored in `lastX').
   *
   *  y ::
   *    The y-coordinate of the arc's end point (its start point is
   *    stored in `lastY').
   *
   * @Return:
   *  SUCCESS on success, FAILURE on render pool overflow or incorrect
   *  profile.
   */
  static Bool
  Conic_To( RAS_ARGS Long  cx,
                     Long  cy,
                     Long  x,
                     Long  y )
  {
    Long     y1, y2, y3, x3, ymin, ymax;
    TStates  state_bez;
 
 
    ras.arc      = ras.arcs;
    ras.arc[2].x = ras.lastX;
    ras.arc[2].y = ras.lastY;
    ras.arc[1].x = cx;
    ras.arc[1].y = cy;
    ras.arc[0].x = x;
    ras.arc[0].y = y;
 
    do
    {
      y1 = ras.arc[2].y;
      y2 = ras.arc[1].y;
      y3 = ras.arc[0].y;
      x3 = ras.arc[0].x;
 
      /* first, categorize the Bezier arc */
 
      if ( y1 <= y3 )
      {
        ymin = y1;
        ymax = y3;
      }
      else
      {
        ymin = y3;
        ymax = y1;
      }
 
      if ( y2 < ymin || y2 > ymax )
      {
        /* this arc has no given direction, split it! */
        Split_Conic( ras.arc );
        ras.arc += 2;
      }
      else if ( y1 == y3 )
      {
        /* this arc is flat, ignore it and pop it from the Bezier stack */
        ras.arc -= 2;
      }
      else
      {
        /* the arc is y-monotonous, either ascending or descending */
        /* detect a change of direction                            */
        state_bez = y1 < y3 ? Ascending_State : Descending_State;
        if ( ras.state != state_bez )
        {
          Bool  o = ( state_bez == Ascending_State )
                      ? IS_BOTTOM_OVERSHOOT( y1 )
                      : IS_TOP_OVERSHOOT( y1 );
 
 
          /* finalize current profile if any */
          if ( ras.state != Unknown_State &&
               End_Profile( RAS_VARS o )  )
            goto Fail;
 
          /* create a new profile */
          if ( New_Profile( RAS_VARS state_bez, o ) )
            goto Fail;
        }
 
        /* now call the appropriate routine */
        if ( state_bez == Ascending_State )
        {
          if ( Bezier_Up( RAS_VARS 2, Split_Conic, ras.minY, ras.maxY ) )
            goto Fail;
        }
        else
          if ( Bezier_Down( RAS_VARS 2, Split_Conic, ras.minY, ras.maxY ) )
            goto Fail;
      }
 
    } while ( ras.arc >= ras.arcs );
 
    ras.lastX = x3;
    ras.lastY = y3;
 
    return SUCCESS;
 
  Fail:
    return FAILURE;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Cubic_To
   *
   * @Description:
   *   Inject a new cubic arc and adjust the profile list.
   *
   * @Input:
   *  cx1 ::
   *    The x-coordinate of the arc's first new control point.
   *
   *  cy1 ::
   *    The y-coordinate of the arc's first new control point.
   *
   *  cx2 ::
   *    The x-coordinate of the arc's second new control point.
   *
   *  cy2 ::
   *    The y-coordinate of the arc's second new control point.
   *
   *  x ::
   *    The x-coordinate of the arc's end point (its start point is
   *    stored in `lastX').
   *
   *  y ::
   *    The y-coordinate of the arc's end point (its start point is
   *    stored in `lastY').
   *
   * @Return:
   *  SUCCESS on success, FAILURE on render pool overflow or incorrect
   *  profile.
   */
  static Bool
  Cubic_To( RAS_ARGS Long  cx1,
                     Long  cy1,
                     Long  cx2,
                     Long  cy2,
                     Long  x,
                     Long  y )
  {
    Long     y1, y2, y3, y4, x4, ymin1, ymax1, ymin2, ymax2;
    TStates  state_bez;
 
 
    ras.arc      = ras.arcs;
    ras.arc[3].x = ras.lastX;
    ras.arc[3].y = ras.lastY;
    ras.arc[2].x = cx1;
    ras.arc[2].y = cy1;
    ras.arc[1].x = cx2;
    ras.arc[1].y = cy2;
    ras.arc[0].x = x;
    ras.arc[0].y = y;
 
    do
    {
      y1 = ras.arc[3].y;
      y2 = ras.arc[2].y;
      y3 = ras.arc[1].y;
      y4 = ras.arc[0].y;
      x4 = ras.arc[0].x;
 
      /* first, categorize the Bezier arc */
 
      if ( y1 <= y4 )
      {
        ymin1 = y1;
        ymax1 = y4;
      }
      else
      {
        ymin1 = y4;
        ymax1 = y1;
      }
 
      if ( y2 <= y3 )
      {
        ymin2 = y2;
        ymax2 = y3;
      }
      else
      {
        ymin2 = y3;
        ymax2 = y2;
      }
 
      if ( ymin2 < ymin1 || ymax2 > ymax1 )
      {
        /* this arc has no given direction, split it! */
        Split_Cubic( ras.arc );
        ras.arc += 3;
      }
      else if ( y1 == y4 )
      {
        /* this arc is flat, ignore it and pop it from the Bezier stack */
        ras.arc -= 3;
      }
      else
      {
        state_bez = ( y1 <= y4 ) ? Ascending_State : Descending_State;
 
        /* detect a change of direction */
        if ( ras.state != state_bez )
        {
          Bool  o = ( state_bez == Ascending_State )
                      ? IS_BOTTOM_OVERSHOOT( y1 )
                      : IS_TOP_OVERSHOOT( y1 );
 
 
          /* finalize current profile if any */
          if ( ras.state != Unknown_State &&
               End_Profile( RAS_VARS o )  )
            goto Fail;
 
          if ( New_Profile( RAS_VARS state_bez, o ) )
            goto Fail;
        }
 
        /* compute intersections */
        if ( state_bez == Ascending_State )
        {
          if ( Bezier_Up( RAS_VARS 3, Split_Cubic, ras.minY, ras.maxY ) )
            goto Fail;
        }
        else
          if ( Bezier_Down( RAS_VARS 3, Split_Cubic, ras.minY, ras.maxY ) )
            goto Fail;
      }
 
    } while ( ras.arc >= ras.arcs );
 
    ras.lastX = x4;
    ras.lastY = y4;
 
    return SUCCESS;
 
  Fail:
    return FAILURE;
  }
 
 
#undef  SWAP_
#define SWAP_( x, y )  do                \
                       {                 \
                         Long  swap = x; \
                                         \
                                         \
                         x = y;          \
                         y = swap;       \
                       } while ( 0 )
 
 
  /**************************************************************************
   *
   * @Function:
   *   Decompose_Curve
   *
   * @Description:
   *   Scan the outline arrays in order to emit individual segments and
   *   Beziers by calling Line_To() and Bezier_To().  It handles all
   *   weird cases, like when the first point is off the curve, or when
   *   there are simply no `on' points in the contour!
   *
   * @Input:
   *   first ::
   *     The index of the first point in the contour.
   *
   *   last ::
   *     The index of the last point in the contour.
   *
   *   flipped ::
   *     If set, flip the direction of the curve.
   *
   * @Return:
   *   SUCCESS on success, FAILURE on error.
   */
  static Bool
  Decompose_Curve( RAS_ARGS UShort  first,
                            UShort  last,
                            Int     flipped )
  {
    FT_Vector   v_last;
    FT_Vector   v_control;
    FT_Vector   v_start;
 
    FT_Vector*  points;
    FT_Vector*  point;
    FT_Vector*  limit;
    char*       tags;
 
    UInt        tag;       /* current point's state           */
 
 
    points = ras.outline.points;
    limit  = points + last;
 
    v_start.x = SCALED( points[first].x );
    v_start.y = SCALED( points[first].y );
    v_last.x  = SCALED( points[last].x );
    v_last.y  = SCALED( points[last].y );
 
    if ( flipped )
    {
      SWAP_( v_start.x, v_start.y );
      SWAP_( v_last.x, v_last.y );
    }
 
    v_control = v_start;
 
    point = points + first;
    tags  = ras.outline.tags + first;
 
    /* set scan mode if necessary */
    if ( tags[0] & FT_CURVE_TAG_HAS_SCANMODE )
      ras.dropOutControl = (Byte)tags[0] >> 5;
 
    tag = FT_CURVE_TAG( tags[0] );
 
    /* A contour cannot start with a cubic control point! */
    if ( tag == FT_CURVE_TAG_CUBIC )
      goto Invalid_Outline;
 
    /* check first point to determine origin */
    if ( tag == FT_CURVE_TAG_CONIC )
    {
      /* first point is conic control.  Yes, this happens. */
      if ( FT_CURVE_TAG( ras.outline.tags[last] ) == FT_CURVE_TAG_ON )
      {
        /* start at last point if it is on the curve */
        v_start = v_last;
        limit--;
      }
      else
      {
        /* if both first and last points are conic,         */
        /* start at their middle and record its position    */
        /* for closure                                      */
        v_start.x = ( v_start.x + v_last.x ) / 2;
        v_start.y = ( v_start.y + v_last.y ) / 2;
 
     /* v_last = v_start; */
      }
      point--;
      tags--;
    }
 
    ras.lastX = v_start.x;
    ras.lastY = v_start.y;
 
    while ( point < limit )
    {
      point++;
      tags++;
 
      tag = FT_CURVE_TAG( tags[0] );
 
      switch ( tag )
      {
      case FT_CURVE_TAG_ON:  /* emit a single line_to */
        {
          Long  x, y;
 
 
          x = SCALED( point->x );
          y = SCALED( point->y );
          if ( flipped )
            SWAP_( x, y );
 
          if ( Line_To( RAS_VARS x, y ) )
            goto Fail;
          continue;
        }
 
      case FT_CURVE_TAG_CONIC:  /* consume conic arcs */
        v_control.x = SCALED( point[0].x );
        v_control.y = SCALED( point[0].y );
 
        if ( flipped )
          SWAP_( v_control.x, v_control.y );
 
      Do_Conic:
        if ( point < limit )
        {
          FT_Vector  v_middle;
          Long       x, y;
 
 
          point++;
          tags++;
          tag = FT_CURVE_TAG( tags[0] );
 
          x = SCALED( point[0].x );
          y = SCALED( point[0].y );
 
          if ( flipped )
            SWAP_( x, y );
 
          if ( tag == FT_CURVE_TAG_ON )
          {
            if ( Conic_To( RAS_VARS v_control.x, v_control.y, x, y ) )
              goto Fail;
            continue;
          }
 
          if ( tag != FT_CURVE_TAG_CONIC )
            goto Invalid_Outline;
 
          v_middle.x = ( v_control.x + x ) / 2;
          v_middle.y = ( v_control.y + y ) / 2;
 
          if ( Conic_To( RAS_VARS v_control.x, v_control.y,
                                  v_middle.x,  v_middle.y ) )
            goto Fail;
 
          v_control.x = x;
          v_control.y = y;
 
          goto Do_Conic;
        }
 
        if ( Conic_To( RAS_VARS v_control.x, v_control.y,
                                v_start.x,   v_start.y ) )
          goto Fail;
 
        goto Close;
 
      default:  /* FT_CURVE_TAG_CUBIC */
        {
          Long  x1, y1, x2, y2, x3, y3;
 
 
          if ( point + 1 > limit                             ||
               FT_CURVE_TAG( tags[1] ) != FT_CURVE_TAG_CUBIC )
            goto Invalid_Outline;
 
          point += 2;
          tags  += 2;
 
          x1 = SCALED( point[-2].x );
          y1 = SCALED( point[-2].y );
          x2 = SCALED( point[-1].x );
          y2 = SCALED( point[-1].y );
 
          if ( flipped )
          {
            SWAP_( x1, y1 );
            SWAP_( x2, y2 );
          }
 
          if ( point <= limit )
          {
            x3 = SCALED( point[0].x );
            y3 = SCALED( point[0].y );
 
            if ( flipped )
              SWAP_( x3, y3 );
 
            if ( Cubic_To( RAS_VARS x1, y1, x2, y2, x3, y3 ) )
              goto Fail;
            continue;
          }
 
          if ( Cubic_To( RAS_VARS x1, y1, x2, y2, v_start.x, v_start.y ) )
            goto Fail;
          goto Close;
        }
      }
    }
 
    /* close the contour with a line segment */
    if ( Line_To( RAS_VARS v_start.x, v_start.y ) )
      goto Fail;
 
  Close:
    return SUCCESS;
 
  Invalid_Outline:
    ras.error = FT_THROW( Invalid );
 
  Fail:
    return FAILURE;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Convert_Glyph
   *
   * @Description:
   *   Convert a glyph into a series of segments and arcs and make a
   *   profiles list with them.
   *
   * @Input:
   *   flipped ::
   *     If set, flip the direction of curve.
   *
   * @Return:
   *   SUCCESS on success, FAILURE if any error was encountered during
   *   rendering.
   */
  static Bool
  Convert_Glyph( RAS_ARGS Int  flipped )
  {
    Int   i;
    UInt  start;
 
 
    ras.fProfile = NULL;
    ras.joint    = FALSE;
    ras.fresh    = FALSE;
 
    ras.maxBuff  = ras.sizeBuff - AlignProfileSize;
 
    ras.numTurns = 0;
 
    ras.cProfile         = (PProfile)ras.top;
    ras.cProfile->offset = ras.top;
    ras.num_Profs        = 0;
 
    start = 0;
 
    for ( i = 0; i < ras.outline.n_contours; i++ )
    {
      PProfile  lastProfile;
      Bool      o;
 
 
      ras.state    = Unknown_State;
      ras.gProfile = NULL;
 
      if ( Decompose_Curve( RAS_VARS (UShort)start,
                                     (UShort)ras.outline.contours[i],
                                     flipped ) )
        return FAILURE;
 
      start = (UShort)ras.outline.contours[i] + 1;
 
      /* we must now check whether the extreme arcs join or not */
      if ( FRAC( ras.lastY ) == 0 &&
           ras.lastY >= ras.minY  &&
           ras.lastY <= ras.maxY  )
        if ( ras.gProfile                        &&
             ( ras.gProfile->flags & Flow_Up ) ==
               ( ras.cProfile->flags & Flow_Up ) )
          ras.top--;
        /* Note that ras.gProfile can be nil if the contour was too small */
        /* to be drawn.                                                   */
 
      lastProfile = ras.cProfile;
      if ( ras.top != ras.cProfile->offset &&
           ( ras.cProfile->flags & Flow_Up ) )
        o = IS_TOP_OVERSHOOT( ras.lastY );
      else
        o = IS_BOTTOM_OVERSHOOT( ras.lastY );
      if ( End_Profile( RAS_VARS o ) )
        return FAILURE;
 
      /* close the `next profile in contour' linked list */
      if ( ras.gProfile )
        lastProfile->next = ras.gProfile;
    }
 
    if ( Finalize_Profile_Table( RAS_VAR ) )
      return FAILURE;
 
    return (Bool)( ras.top < ras.maxBuff ? SUCCESS : FAILURE );
  }
 
 
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
 
 
  /**************************************************************************
   *
   * Init_Linked
   *
   *   Initializes an empty linked list.
   */
  static void
  Init_Linked( TProfileList*  l )
  {
    *l = NULL;
  }
 
 
  /**************************************************************************
   *
   * InsNew
   *
   *   Inserts a new profile in a linked list.
   */
  static void
  InsNew( PProfileList  list,
          PProfile      profile )
  {
    PProfile  *old, current;
    Long       x;
 
 
    old     = list;
    current = *old;
    x       = profile->X;
 
    while ( current )
    {
      if ( x < current->X )
        break;
      old     = &current->link;
      current = *old;
    }
 
    profile->link = current;
    *old          = profile;
  }
 
 
  /**************************************************************************
   *
   * DelOld
   *
   *   Removes an old profile from a linked list.
   */
  static void
  DelOld( PProfileList  list,
          PProfile      profile )
  {
    PProfile  *old, current;
 
 
    old     = list;
    current = *old;
 
    while ( current )
    {
      if ( current == profile )
      {
        *old = current->link;
        return;
      }
 
      old     = &current->link;
      current = *old;
    }
 
    /* we should never get there, unless the profile was not part of */
    /* the list.                                                     */
  }
 
 
  /**************************************************************************
   *
   * Sort
   *
   *   Sorts a trace list.  In 95%, the list is already sorted.  We need
   *   an algorithm which is fast in this case.  Bubble sort is enough
   *   and simple.
   */
  static void
  Sort( PProfileList  list )
  {
    PProfile  *old, current, next;
 
 
    /* First, set the new X coordinate of each profile */
    current = *list;
    while ( current )
    {
      current->X       = *current->offset;
      current->offset += ( current->flags & Flow_Up ) ? 1 : -1;
      current->height--;
      current = current->link;
    }
 
    /* Then sort them */
    old     = list;
    current = *old;
 
    if ( !current )
      return;
 
    next = current->link;
 
    while ( next )
    {
      if ( current->X <= next->X )
      {
        old     = &current->link;
        current = *old;
 
        if ( !current )
          return;
      }
      else
      {
        *old          = next;
        current->link = next->link;
        next->link    = current;
 
        old     = list;
        current = *old;
      }
 
      next = current->link;
    }
  }
 
 
  /**************************************************************************
   *
   * Vertical Sweep Procedure Set
   *
   * These four routines are used during the vertical black/white sweep
   * phase by the generic Draw_Sweep() function.
   *
   */
 
  static void
  Vertical_Sweep_Init( RAS_ARGS Short*  min,
                                Short*  max )
  {
    Long  pitch = ras.target.pitch;
 
    FT_UNUSED( max );
 
 
    ras.traceIncr = (Short)-pitch;
    ras.traceOfs  = -*min * pitch;
  }
 
 
  static void
  Vertical_Sweep_Span( RAS_ARGS Short       y,
                                FT_F26Dot6  x1,
                                FT_F26Dot6  x2,
                                PProfile    left,
                                PProfile    right )
  {
    Long   e1, e2;
    Byte*  target;
 
    Int  dropOutControl = left->flags & 7;
 
    FT_UNUSED( y );
    FT_UNUSED( left );
    FT_UNUSED( right );
 
 
    /* in high-precision mode, we need 12 digits after the comma to */
    /* represent multiples of 1/(1<<12) = 1/4096                    */
    FT_TRACE7(( "  y=%d x=[% .12f;% .12f]",
                y,
                x1 / (double)ras.precision,
                x2 / (double)ras.precision ));
 
    /* Drop-out control */
 
    e1 = CEILING( x1 );
    e2 = FLOOR( x2 );
 
    /* take care of the special case where both the left */
    /* and right contour lie exactly on pixel centers    */
    if ( dropOutControl != 2                             &&
         x2 - x1 - ras.precision <= ras.precision_jitter &&
         e1 != x1 && e2 != x2                            )
      e2 = e1;
 
    e1 = TRUNC( e1 );
    e2 = TRUNC( e2 );
 
    if ( e2 >= 0 && e1 < ras.bWidth )
    {
      Int   c1, c2;
      Byte  f1, f2;
 
 
      if ( e1 < 0 )
        e1 = 0;
      if ( e2 >= ras.bWidth )
        e2 = ras.bWidth - 1;
 
      FT_TRACE7(( " -> x=[%ld;%ld]", e1, e2 ));
 
      c1 = (Short)( e1 >> 3 );
      c2 = (Short)( e2 >> 3 );
 
      f1 = (Byte)  ( 0xFF >> ( e1 & 7 ) );
      f2 = (Byte) ~( 0x7F >> ( e2 & 7 ) );
 
      target = ras.bOrigin + ras.traceOfs + c1;
      c2 -= c1;
 
      if ( c2 > 0 )
      {
        target[0] |= f1;
 
        /* memset() is slower than the following code on many platforms. */
        /* This is due to the fact that, in the vast majority of cases,  */
        /* the span length in bytes is relatively small.                 */
        while ( --c2 > 0 )
          *(++target) = 0xFF;
 
        target[1] |= f2;
      }
      else
        *target |= ( f1 & f2 );
    }
 
    FT_TRACE7(( "\n" ));
  }
 
 
  static void
  Vertical_Sweep_Drop( RAS_ARGS Short       y,
                                FT_F26Dot6  x1,
                                FT_F26Dot6  x2,
                                PProfile    left,
                                PProfile    right )
  {
    Long   e1, e2, pxl;
    Short  c1, f1;
 
 
    FT_TRACE7(( "  y=%d x=[% .12f;% .12f]",
                y,
                x1 / (double)ras.precision,
                x2 / (double)ras.precision ));
 
    /* Drop-out control */
 
    /*   e2            x2                    x1           e1   */
    /*                                                         */
    /*                 ^                     |                 */
    /*                 |                     |                 */
    /*   +-------------+---------------------+------------+    */
    /*                 |                     |                 */
    /*                 |                     v                 */
    /*                                                         */
    /* pixel         contour              contour       pixel  */
    /* center                                           center */
 
    /* drop-out mode    scan conversion rules (as defined in OpenType) */
    /* --------------------------------------------------------------- */
    /*  0                1, 2, 3                                       */
    /*  1                1, 2, 4                                       */
    /*  2                1, 2                                          */
    /*  3                same as mode 2                                */
    /*  4                1, 2, 5                                       */
    /*  5                1, 2, 6                                       */
    /*  6, 7             same as mode 2                                */
 
    e1  = CEILING( x1 );
    e2  = FLOOR  ( x2 );
    pxl = e1;
 
    if ( e1 > e2 )
    {
      Int  dropOutControl = left->flags & 7;
 
 
      if ( e1 == e2 + ras.precision )
      {
        switch ( dropOutControl )
        {
        case 0: /* simple drop-outs including stubs */
          pxl = e2;
          break;
 
        case 4: /* smart drop-outs including stubs */
          pxl = SMART( x1, x2 );
          break;
 
        case 1: /* simple drop-outs excluding stubs */
        case 5: /* smart drop-outs excluding stubs  */
 
          /* Drop-out Control Rules #4 and #6 */
 
          /* The specification neither provides an exact definition */
          /* of a `stub' nor gives exact rules to exclude them.     */
          /*                                                        */
          /* Here the constraints we use to recognize a stub.       */
          /*                                                        */
          /*  upper stub:                                           */
          /*                                                        */
          /*   - P_Left and P_Right are in the same contour         */
          /*   - P_Right is the successor of P_Left in that contour */
          /*   - y is the top of P_Left and P_Right                 */
          /*                                                        */
          /*  lower stub:                                           */
          /*                                                        */
          /*   - P_Left and P_Right are in the same contour         */
          /*   - P_Left is the successor of P_Right in that contour */
          /*   - y is the bottom of P_Left                          */
          /*                                                        */
          /* We draw a stub if the following constraints are met.   */
          /*                                                        */
          /*   - for an upper or lower stub, there is top or bottom */
          /*     overshoot, respectively                            */
          /*   - the covered interval is greater or equal to a half */
          /*     pixel                                              */
 
          /* upper stub test */
          if ( left->next == right                &&
               left->height <= 0                  &&
               !( left->flags & Overshoot_Top   &&
                  x2 - x1 >= ras.precision_half ) )
            goto Exit;
 
          /* lower stub test */
          if ( right->next == left                 &&
               left->start == y                    &&
               !( left->flags & Overshoot_Bottom &&
                  x2 - x1 >= ras.precision_half  ) )
            goto Exit;
 
          if ( dropOutControl == 1 )
            pxl = e2;
          else
            pxl = SMART( x1, x2 );
          break;
 
        default: /* modes 2, 3, 6, 7 */
          goto Exit;  /* no drop-out control */
        }
 
        /* undocumented but confirmed: If the drop-out would result in a  */
        /* pixel outside of the bounding box, use the pixel inside of the */
        /* bounding box instead                                           */
        if ( pxl < 0 )
          pxl = e1;
        else if ( TRUNC( pxl ) >= ras.bWidth )
          pxl = e2;
 
        /* check that the other pixel isn't set */
        e1 = ( pxl == e1 ) ? e2 : e1;
 
        e1 = TRUNC( e1 );
 
        c1 = (Short)( e1 >> 3 );
        f1 = (Short)( e1 &  7 );
 
        if ( e1 >= 0 && e1 < ras.bWidth                      &&
             ras.bOrigin[ras.traceOfs + c1] & ( 0x80 >> f1 ) )
          goto Exit;
      }
      else
        goto Exit;
    }
 
    e1 = TRUNC( pxl );
 
    if ( e1 >= 0 && e1 < ras.bWidth )
    {
      FT_TRACE7(( " -> x=%ld", e1 ));
 
      c1 = (Short)( e1 >> 3 );
      f1 = (Short)( e1 & 7 );
 
      ras.bOrigin[ras.traceOfs + c1] |= (char)( 0x80 >> f1 );
    }
 
  Exit:
    FT_TRACE7(( " dropout=%d\n", left->flags & 7 ));
  }
 
 
  static void
  Vertical_Sweep_Step( RAS_ARG )
  {
    ras.traceOfs += ras.traceIncr;
  }
 
 
  /************************************************************************
   *
   * Horizontal Sweep Procedure Set
   *
   * These four routines are used during the horizontal black/white
   * sweep phase by the generic Draw_Sweep() function.
   *
   */
 
  static void
  Horizontal_Sweep_Init( RAS_ARGS Short*  min,
                                  Short*  max )
  {
    /* nothing, really */
    FT_UNUSED_RASTER;
    FT_UNUSED( min );
    FT_UNUSED( max );
  }
 
 
  static void
  Horizontal_Sweep_Span( RAS_ARGS Short       y,
                                  FT_F26Dot6  x1,
                                  FT_F26Dot6  x2,
                                  PProfile    left,
                                  PProfile    right )
  {
    Long  e1, e2;
 
    FT_UNUSED( left );
    FT_UNUSED( right );
 
 
    FT_TRACE7(( "  x=%d y=[% .12f;% .12f]",
                y,
                x1 / (double)ras.precision,
                x2 / (double)ras.precision ));
 
    /* We should not need this procedure but the vertical sweep   */
    /* mishandles horizontal lines through pixel centers.  So we  */
    /* have to check perfectly aligned span edges here.           */
    /*                                                            */
    /* XXX: Can we handle horizontal lines better and drop this?  */
 
    e1 = CEILING( x1 );
 
    if ( x1 == e1 )
    {
      e1 = TRUNC( e1 );
 
      if ( e1 >= 0 && (ULong)e1 < ras.target.rows )
      {
        Byte   f1;
        PByte  bits;
 
 
        bits = ras.bOrigin + ( y >> 3 ) - e1 * ras.target.pitch;
        f1   = (Byte)( 0x80 >> ( y & 7 ) );
 
        FT_TRACE7(( bits[0] & f1 ? " redundant"
                                 : " -> y=%ld edge", e1 ));
 
        bits[0] |= f1;
      }
    }
 
    e2 = FLOOR  ( x2 );
 
    if ( x2 == e2 )
    {
      e2 = TRUNC( e2 );
 
      if ( e2 >= 0 && (ULong)e2 < ras.target.rows )
      {
        Byte   f1;
        PByte  bits;
 
 
        bits = ras.bOrigin + ( y >> 3 ) - e2 * ras.target.pitch;
        f1   = (Byte)( 0x80 >> ( y & 7 ) );
 
        FT_TRACE7(( bits[0] & f1 ? " redundant"
                                 : " -> y=%ld edge", e2 ));
 
        bits[0] |= f1;
      }
    }
 
    FT_TRACE7(( "\n" ));
  }
 
 
  static void
  Horizontal_Sweep_Drop( RAS_ARGS Short       y,
                                  FT_F26Dot6  x1,
                                  FT_F26Dot6  x2,
                                  PProfile    left,
                                  PProfile    right )
  {
    Long   e1, e2, pxl;
    PByte  bits;
    Byte   f1;
 
 
    FT_TRACE7(( "  x=%d y=[% .12f;% .12f]",
                y,
                x1 / (double)ras.precision,
                x2 / (double)ras.precision ));
 
    /* During the horizontal sweep, we only take care of drop-outs */
 
    /* e1     +       <-- pixel center */
    /*        |                        */
    /* x1  ---+-->    <-- contour      */
    /*        |                        */
    /*        |                        */
    /* x2  <--+---    <-- contour      */
    /*        |                        */
    /*        |                        */
    /* e2     +       <-- pixel center */
 
    e1  = CEILING( x1 );
    e2  = FLOOR  ( x2 );
    pxl = e1;
 
    if ( e1 > e2 )
    {
      Int  dropOutControl = left->flags & 7;
 
 
      if ( e1 == e2 + ras.precision )
      {
        switch ( dropOutControl )
        {
        case 0: /* simple drop-outs including stubs */
          pxl = e2;
          break;
 
        case 4: /* smart drop-outs including stubs */
          pxl = SMART( x1, x2 );
          break;
 
        case 1: /* simple drop-outs excluding stubs */
        case 5: /* smart drop-outs excluding stubs  */
          /* see Vertical_Sweep_Drop for details */
 
          /* rightmost stub test */
          if ( left->next == right                &&
               left->height <= 0                  &&
               !( left->flags & Overshoot_Top   &&
                  x2 - x1 >= ras.precision_half ) )
            goto Exit;
 
          /* leftmost stub test */
          if ( right->next == left                 &&
               left->start == y                    &&
               !( left->flags & Overshoot_Bottom &&
                  x2 - x1 >= ras.precision_half  ) )
            goto Exit;
 
          if ( dropOutControl == 1 )
            pxl = e2;
          else
            pxl = SMART( x1, x2 );
          break;
 
        default: /* modes 2, 3, 6, 7 */
          goto Exit;  /* no drop-out control */
        }
 
        /* undocumented but confirmed: If the drop-out would result in a  */
        /* pixel outside of the bounding box, use the pixel inside of the */
        /* bounding box instead                                           */
        if ( pxl < 0 )
          pxl = e1;
        else if ( (ULong)( TRUNC( pxl ) ) >= ras.target.rows )
          pxl = e2;
 
        /* check that the other pixel isn't set */
        e1 = ( pxl == e1 ) ? e2 : e1;
 
        e1 = TRUNC( e1 );
 
        bits = ras.bOrigin + ( y >> 3 ) - e1 * ras.target.pitch;
        f1   = (Byte)( 0x80 >> ( y & 7 ) );
 
        if ( e1 >= 0                     &&
             (ULong)e1 < ras.target.rows &&
             *bits & f1                  )
          goto Exit;
      }
      else
        goto Exit;
    }
 
    e1 = TRUNC( pxl );
 
    if ( e1 >= 0 && (ULong)e1 < ras.target.rows )
    {
      FT_TRACE7(( " -> y=%ld", e1 ));
 
      bits  = ras.bOrigin + ( y >> 3 ) - e1 * ras.target.pitch;
      f1    = (Byte)( 0x80 >> ( y & 7 ) );
 
      bits[0] |= f1;
    }
 
  Exit:
    FT_TRACE7(( " dropout=%d\n", left->flags & 7 ));
  }
 
 
  static void
  Horizontal_Sweep_Step( RAS_ARG )
  {
    /* Nothing, really */
    FT_UNUSED_RASTER;
  }
 
 
  /**************************************************************************
   *
   * Generic Sweep Drawing routine
   *
   */
 
  static Bool
  Draw_Sweep( RAS_ARG )
  {
    Short         y, y_change, y_height;
 
    PProfile      P, Q, P_Left, P_Right;
 
    Short         min_Y, max_Y, top, bottom, dropouts;
 
    Long          x1, x2, xs, e1, e2;
 
    TProfileList  waiting;
    TProfileList  draw_left, draw_right;
 
 
    /* initialize empty linked lists */
 
    Init_Linked( &waiting );
 
    Init_Linked( &draw_left  );
    Init_Linked( &draw_right );
 
    /* first, compute min and max Y */
 
    P     = ras.fProfile;
    max_Y = (Short)TRUNC( ras.minY );
    min_Y = (Short)TRUNC( ras.maxY );
 
    while ( P )
    {
      Q = P->link;
 
      bottom = (Short)P->start;
      top    = (Short)( P->start + P->height - 1 );
 
      if ( min_Y > bottom )
        min_Y = bottom;
      if ( max_Y < top )
        max_Y = top;
 
      P->X = 0;
      InsNew( &waiting, P );
 
      P = Q;
    }
 
    /* check the Y-turns */
    if ( ras.numTurns == 0 )
    {
      ras.error = FT_THROW( Invalid );
      return FAILURE;
    }
 
    /* now initialize the sweep */
 
    ras.Proc_Sweep_Init( RAS_VARS &min_Y, &max_Y );
 
    /* then compute the distance of each profile from min_Y */
 
    P = waiting;
 
    while ( P )
    {
      P->countL = P->start - min_Y;
      P = P->link;
    }
 
    /* let's go */
 
    y        = min_Y;
    y_height = 0;
 
    if ( ras.numTurns > 0                     &&
         ras.sizeBuff[-ras.numTurns] == min_Y )
      ras.numTurns--;
 
    while ( ras.numTurns > 0 )
    {
      /* check waiting list for new activations */
 
      P = waiting;
 
      while ( P )
      {
        Q = P->link;
        P->countL -= y_height;
        if ( P->countL == 0 )
        {
          DelOld( &waiting, P );
 
          if ( P->flags & Flow_Up )
            InsNew( &draw_left,  P );
          else
            InsNew( &draw_right, P );
        }
 
        P = Q;
      }
 
      /* sort the drawing lists */
 
      Sort( &draw_left );
      Sort( &draw_right );
 
      y_change = (Short)ras.sizeBuff[-ras.numTurns--];
      y_height = (Short)( y_change - y );
 
      while ( y < y_change )
      {
        /* let's trace */
 
        dropouts = 0;
 
        P_Left  = draw_left;
        P_Right = draw_right;
 
        while ( P_Left && P_Right )
        {
          x1 = P_Left ->X;
          x2 = P_Right->X;
 
          if ( x1 > x2 )
          {
            xs = x1;
            x1 = x2;
            x2 = xs;
          }
 
          e1 = FLOOR( x1 );
          e2 = CEILING( x2 );
 
          if ( x2 - x1 <= ras.precision &&
               e1 != x1 && e2 != x2     )
          {
            if ( e1 > e2 || e2 == e1 + ras.precision )
            {
              Int  dropOutControl = P_Left->flags & 7;
 
 
              if ( dropOutControl != 2 )
              {
                /* a drop-out was detected */
 
                P_Left ->X = x1;
                P_Right->X = x2;
 
                /* mark profile for drop-out processing */
                P_Left->countL = 1;
                dropouts++;
              }
 
              goto Skip_To_Next;
            }
          }
 
          ras.Proc_Sweep_Span( RAS_VARS y, x1, x2, P_Left, P_Right );
 
        Skip_To_Next:
 
          P_Left  = P_Left->link;
          P_Right = P_Right->link;
        }
 
        /* handle drop-outs _after_ the span drawing --       */
        /* drop-out processing has been moved out of the loop */
        /* for performance tuning                             */
        if ( dropouts > 0 )
          goto Scan_DropOuts;
 
      Next_Line:
 
        ras.Proc_Sweep_Step( RAS_VAR );
 
        y++;
 
        if ( y < y_change )
        {
          Sort( &draw_left  );
          Sort( &draw_right );
        }
      }
 
      /* now finalize the profiles that need it */
 
      P = draw_left;
      while ( P )
      {
        Q = P->link;
        if ( P->height == 0 )
          DelOld( &draw_left, P );
        P = Q;
      }
 
      P = draw_right;
      while ( P )
      {
        Q = P->link;
        if ( P->height == 0 )
          DelOld( &draw_right, P );
        P = Q;
      }
    }
 
    /* for gray-scaling, flush the bitmap scanline cache */
    while ( y <= max_Y )
    {
      ras.Proc_Sweep_Step( RAS_VAR );
      y++;
    }
 
    return SUCCESS;
 
  Scan_DropOuts:
 
    P_Left  = draw_left;
    P_Right = draw_right;
 
    while ( P_Left && P_Right )
    {
      if ( P_Left->countL )
      {
        P_Left->countL = 0;
#if 0
        dropouts--;  /* -- this is useful when debugging only */
#endif
        ras.Proc_Sweep_Drop( RAS_VARS y,
                                      P_Left->X,
                                      P_Right->X,
                                      P_Left,
                                      P_Right );
      }
 
      P_Left  = P_Left->link;
      P_Right = P_Right->link;
    }
 
    goto Next_Line;
  }
 
 
#ifdef STANDALONE_
 
  /**************************************************************************
   *
   * The following functions should only compile in stand-alone mode,
   * i.e., when building this component without the rest of FreeType.
   *
   */
 
  /**************************************************************************
   *
   * @Function:
   *   FT_Outline_Get_CBox
   *
   * @Description:
   *   Return an outline's `control box'.  The control box encloses all
   *   the outline's points, including Bézier control points.  Though it
   *   coincides with the exact bounding box for most glyphs, it can be
   *   slightly larger in some situations (like when rotating an outline
   *   that contains Bézier outside arcs).
   *
   *   Computing the control box is very fast, while getting the bounding
   *   box can take much more time as it needs to walk over all segments
   *   and arcs in the outline.  To get the latter, you can use the
   *   `ftbbox' component, which is dedicated to this single task.
   *
   * @Input:
   *   outline ::
   *     A pointer to the source outline descriptor.
   *
   * @Output:
   *   acbox ::
   *     The outline's control box.
   *
   * @Note:
   *   See @FT_Glyph_Get_CBox for a discussion of tricky fonts.
   */
 
  static void
  FT_Outline_Get_CBox( const FT_Outline*  outline,
                       FT_BBox           *acbox )
  {
    Long  xMin, yMin, xMax, yMax;
 
 
    if ( outline && acbox )
    {
      if ( outline->n_points == 0 )
      {
        xMin = 0;
        yMin = 0;
        xMax = 0;
        yMax = 0;
      }
      else
      {
        FT_Vector*  vec   = outline->points;
        FT_Vector*  limit = vec + outline->n_points;
 
 
        xMin = xMax = vec->x;
        yMin = yMax = vec->y;
        vec++;
 
        for ( ; vec < limit; vec++ )
        {
          Long  x, y;
 
 
          x = vec->x;
          if ( x < xMin ) xMin = x;
          if ( x > xMax ) xMax = x;
 
          y = vec->y;
          if ( y < yMin ) yMin = y;
          if ( y > yMax ) yMax = y;
        }
      }
      acbox->xMin = xMin;
      acbox->xMax = xMax;
      acbox->yMin = yMin;
      acbox->yMax = yMax;
    }
  }
 
#endif /* STANDALONE_ */
 
 
  /**************************************************************************
   *
   * @Function:
   *   Render_Single_Pass
   *
   * @Description:
   *   Perform one sweep with sub-banding.
   *
   * @Input:
   *   flipped ::
   *     If set, flip the direction of the outline.
   *
   * @Return:
   *   Renderer error code.
   */
  static int
  Render_Single_Pass( RAS_ARGS Bool  flipped )
  {
    Short  i, j, k;
 
 
    while ( ras.band_top >= 0 )
    {
      ras.maxY = (Long)ras.band_stack[ras.band_top].y_max * ras.precision;
      ras.minY = (Long)ras.band_stack[ras.band_top].y_min * ras.precision;
 
      ras.top = ras.buff;
 
      ras.error = Raster_Err_None;
 
      if ( Convert_Glyph( RAS_VARS flipped ) )
      {
        if ( ras.error != Raster_Err_Overflow )
          return FAILURE;
 
        ras.error = Raster_Err_None;
 
        /* sub-banding */
 
#ifdef DEBUG_RASTER
        ClearBand( RAS_VARS TRUNC( ras.minY ), TRUNC( ras.maxY ) );
#endif
 
        i = ras.band_stack[ras.band_top].y_min;
        j = ras.band_stack[ras.band_top].y_max;
 
        k = (Short)( ( i + j ) / 2 );
 
        if ( ras.band_top >= 7 || k < i )
        {
          ras.band_top = 0;
          ras.error    = FT_THROW( Invalid );
 
          return ras.error;
        }
 
        ras.band_stack[ras.band_top + 1].y_min = k;
        ras.band_stack[ras.band_top + 1].y_max = j;
 
        ras.band_stack[ras.band_top].y_max = (Short)( k - 1 );
 
        ras.band_top++;
      }
      else
      {
        if ( ras.fProfile )
          if ( Draw_Sweep( RAS_VAR ) )
             return ras.error;
        ras.band_top--;
      }
    }
 
    return SUCCESS;
  }
 
 
  /**************************************************************************
   *
   * @Function:
   *   Render_Glyph
   *
   * @Description:
   *   Render a glyph in a bitmap.  Sub-banding if needed.
   *
   * @Return:
   *   FreeType error code.  0 means success.
   */
  static FT_Error
  Render_Glyph( RAS_ARG )
  {
    FT_Error  error;
 
 
    Set_High_Precision( RAS_VARS ras.outline.flags &
                                 FT_OUTLINE_HIGH_PRECISION );
 
    if ( ras.outline.flags & FT_OUTLINE_IGNORE_DROPOUTS )
      ras.dropOutControl = 2;
    else
    {
      if ( ras.outline.flags & FT_OUTLINE_SMART_DROPOUTS )
        ras.dropOutControl = 4;
      else
        ras.dropOutControl = 0;
 
      if ( !( ras.outline.flags & FT_OUTLINE_INCLUDE_STUBS ) )
        ras.dropOutControl += 1;
    }
 
    ras.second_pass = (Bool)( !( ras.outline.flags      &
                                 FT_OUTLINE_SINGLE_PASS ) );
 
    /* Vertical Sweep */
    FT_TRACE7(( "Vertical pass (ftraster)\n" ));
 
    ras.Proc_Sweep_Init = Vertical_Sweep_Init;
    ras.Proc_Sweep_Span = Vertical_Sweep_Span;
    ras.Proc_Sweep_Drop = Vertical_Sweep_Drop;
    ras.Proc_Sweep_Step = Vertical_Sweep_Step;
 
    ras.band_top            = 0;
    ras.band_stack[0].y_min = 0;
    ras.band_stack[0].y_max = (Short)( ras.target.rows - 1 );
 
    ras.bWidth  = (UShort)ras.target.width;
    ras.bOrigin = (Byte*)ras.target.buffer;
 
    if ( ras.target.pitch > 0 )
      ras.bOrigin += (Long)( ras.target.rows - 1 ) * ras.target.pitch;
 
    if ( ( error = Render_Single_Pass( RAS_VARS 0 ) ) != 0 )
      return error;
 
    /* Horizontal Sweep */
    if ( ras.second_pass && ras.dropOutControl != 2 )
    {
      FT_TRACE7(( "Horizontal pass (ftraster)\n" ));
 
      ras.Proc_Sweep_Init = Horizontal_Sweep_Init;
      ras.Proc_Sweep_Span = Horizontal_Sweep_Span;
      ras.Proc_Sweep_Drop = Horizontal_Sweep_Drop;
      ras.Proc_Sweep_Step = Horizontal_Sweep_Step;
 
      ras.band_top            = 0;
      ras.band_stack[0].y_min = 0;
      ras.band_stack[0].y_max = (Short)( ras.target.width - 1 );
 
      if ( ( error = Render_Single_Pass( RAS_VARS 1 ) ) != 0 )
        return error;
    }
 
    return Raster_Err_None;
  }
 
 
  static void
  ft_black_init( black_PRaster  raster )
  {
    FT_UNUSED( raster );
  }
 
 
  /**** RASTER OBJECT CREATION: In standalone mode, we simply use *****/
  /****                         a static object.                  *****/
 
 
#ifdef STANDALONE_
 
 
  static int
  ft_black_new( void*       memory,
                FT_Raster  *araster )
  {
     static black_TRaster  the_raster;
     FT_UNUSED( memory );
 
 
     *araster = (FT_Raster)&the_raster;
     FT_ZERO( &the_raster );
     ft_black_init( &the_raster );
 
     return 0;
  }
 
 
  static void
  ft_black_done( FT_Raster  raster )
  {
    /* nothing */
    FT_UNUSED( raster );
  }
 
 
#else /* !STANDALONE_ */
 
 
  static int
  ft_black_new( FT_Memory       memory,
                black_PRaster  *araster )
  {
    FT_Error       error;
    black_PRaster  raster = NULL;
 
 
    *araster = 0;
    if ( !FT_NEW( raster ) )
    {
      raster->memory = memory;
      ft_black_init( raster );
 
      *araster = raster;
    }
 
    return error;
  }
 
 
  static void
  ft_black_done( black_PRaster  raster )
  {
    FT_Memory  memory = (FT_Memory)raster->memory;
 
 
    FT_FREE( raster );
  }
 
 
#endif /* !STANDALONE_ */
 
 
  static void
  ft_black_reset( FT_Raster  raster,
                  PByte      pool_base,
                  ULong      pool_size )
  {
    FT_UNUSED( raster );
    FT_UNUSED( pool_base );
    FT_UNUSED( pool_size );
  }
 
 
  static int
  ft_black_set_mode( FT_Raster  raster,
                     ULong      mode,
                     void*      args )
  {
    FT_UNUSED( raster );
    FT_UNUSED( mode );
    FT_UNUSED( args );
 
    return 0;
  }
 
 
  static int
  ft_black_render( FT_Raster                raster,
                   const FT_Raster_Params*  params )
  {
    const FT_Outline*  outline    = (const FT_Outline*)params->source;
    const FT_Bitmap*   target_map = params->target;
 
#ifndef FT_STATIC_RASTER
    black_TWorker  worker[1];
#endif
 
    Long  buffer[FT_MAX_BLACK_POOL];
 
 
    if ( !raster )
      return FT_THROW( Not_Ini );
 
    if ( !outline )
      return FT_THROW( Invalid );
 
    /* return immediately if the outline is empty */
    if ( outline->n_points == 0 || outline->n_contours <= 0 )
      return Raster_Err_None;
 
    if ( !outline->contours || !outline->points )
      return FT_THROW( Invalid );
 
    if ( outline->n_points !=
           outline->contours[outline->n_contours - 1] + 1 )
      return FT_THROW( Invalid );
 
    /* this version of the raster does not support direct rendering, sorry */
    if ( params->flags & FT_RASTER_FLAG_DIRECT )
      return FT_THROW( Unsupported );
 
    if ( params->flags & FT_RASTER_FLAG_AA )
      return FT_THROW( Unsupported );
 
    if ( !target_map )
      return FT_THROW( Invalid );
 
    /* nothing to do */
    if ( !target_map->width || !target_map->rows )
      return Raster_Err_None;
 
    if ( !target_map->buffer )
      return FT_THROW( Invalid );
 
    ras.outline = *outline;
    ras.target  = *target_map;
 
    ras.buff     = buffer;
    ras.sizeBuff = (&buffer)[1]; /* Points to right after buffer. */
 
    return Render_Glyph( RAS_VAR );
  }
 
 
  FT_DEFINE_RASTER_FUNCS(
    ft_standard_raster,
 
    FT_GLYPH_FORMAT_OUTLINE,
 
    (FT_Raster_New_Func)     ft_black_new,       /* raster_new      */
    (FT_Raster_Reset_Func)   ft_black_reset,     /* raster_reset    */
    (FT_Raster_Set_Mode_Func)ft_black_set_mode,  /* raster_set_mode */
    (FT_Raster_Render_Func)  ft_black_render,    /* raster_render   */
    (FT_Raster_Done_Func)    ft_black_done       /* raster_done     */
  )
 
 
/* END */