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kc3-lang/freetype/src/smooth/ftgrays.c

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  • Author : Alexei Podtelezhnikov
    Date : 2011-03-17 20:24:57
    Hash : 8fb88414
    Message : A better fix for Savannah bug #32671. * src/smooth/ftgrays.c (gray_render_conic): Clean up code and replace WHILE loop with a more natural DO-WHILE construct.

  • src/smooth/ftgrays.c
  • /***************************************************************************/
    /*                                                                         */
    /*  ftgrays.c                                                              */
    /*                                                                         */
    /*    A new `perfect' anti-aliasing renderer (body).                       */
    /*                                                                         */
    /*  Copyright 2000-2003, 2005-2011 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 `ftgrays.h' and `ftimage.h' into the current            */
      /* compilation directory.  Typically, you could do something like        */
      /*                                                                       */
      /* - copy `src/smooth/ftgrays.c' (this file) to your current directory   */
      /*                                                                       */
      /* - copy `include/freetype/ftimage.h' and `src/smooth/ftgrays.h' to the */
      /*   same directory                                                      */
      /*                                                                       */
      /* - compile `ftgrays' with the _STANDALONE_ macro defined, as in        */
      /*                                                                       */
      /*     cc -c -D_STANDALONE_ ftgrays.c                                    */
      /*                                                                       */
      /* The renderer can be initialized with a call to                        */
      /* `ft_gray_raster.raster_new'; an anti-aliased bitmap can be generated  */
      /* with a call to `ft_gray_raster.raster_render'.                        */
      /*                                                                       */
      /* See the comments and documentation in the file `ftimage.h' for more   */
      /* details on how the raster works.                                      */
      /*                                                                       */
      /*************************************************************************/
    
      /*************************************************************************/
      /*                                                                       */
      /* This is a new anti-aliasing scan-converter for FreeType 2.  The       */
      /* algorithm used here is _very_ different from the one in the standard  */
      /* `ftraster' module.  Actually, `ftgrays' computes the _exact_          */
      /* coverage of the outline on each pixel cell.                           */
      /*                                                                       */
      /* It is based on ideas that I initially found in Raph Levien's          */
      /* excellent LibArt graphics library (see http://www.levien.com/libart   */
      /* for more information, though the web pages do not tell anything       */
      /* about the renderer; you'll have to dive into the source code to       */
      /* understand how it works).                                             */
      /*                                                                       */
      /* Note, however, that this is a _very_ different implementation         */
      /* compared to Raph's.  Coverage information is stored in a very         */
      /* different way, and I don't use sorted vector paths.  Also, it doesn't */
      /* use floating point values.                                            */
      /*                                                                       */
      /* This renderer has the following advantages:                           */
      /*                                                                       */
      /* - It doesn't need an intermediate bitmap.  Instead, one can supply a  */
      /*   callback function that will be called by the renderer to draw gray  */
      /*   spans on any target surface.  You can thus do direct composition on */
      /*   any kind of bitmap, provided that you give the renderer the right   */
      /*   callback.                                                           */
      /*                                                                       */
      /* - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on   */
      /*   each pixel cell.                                                    */
      /*                                                                       */
      /* - It performs a single pass on the outline (the `standard' FT2        */
      /*   renderer makes two passes).                                         */
      /*                                                                       */
      /* - It can easily be modified to render to _any_ number of gray levels  */
      /*   cheaply.                                                            */
      /*                                                                       */
      /* - For small (< 20) pixel sizes, it is faster than the standard        */
      /*   renderer.                                                           */
      /*                                                                       */
      /*************************************************************************/
    
    
      /*************************************************************************/
      /*                                                                       */
      /* 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  trace_smooth
    
    
    #ifdef _STANDALONE_
    
    
      /* define this to dump debugging information */
    /* #define FT_DEBUG_LEVEL_TRACE */
    
    
    #ifdef FT_DEBUG_LEVEL_TRACE
    #include <stdio.h>
    #include <stdarg.h>
    #endif
    
    #include <stddef.h>
    #include <string.h>
    #include <setjmp.h>
    #include <limits.h>
    #define FT_UINT_MAX  UINT_MAX
    #define FT_INT_MAX   INT_MAX
    
    #define ft_memset   memset
    
    #define ft_setjmp   setjmp
    #define ft_longjmp  longjmp
    #define ft_jmp_buf  jmp_buf
    
    typedef ptrdiff_t  FT_PtrDist;
    
    
    #define ErrRaster_Invalid_Mode      -2
    #define ErrRaster_Invalid_Outline   -1
    #define ErrRaster_Invalid_Argument  -3
    #define ErrRaster_Memory_Overflow   -4
    
    #define FT_BEGIN_HEADER
    #define FT_END_HEADER
    
    #include "ftimage.h"
    #include "ftgrays.h"
    
    
      /* 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)
    
    
      /* we only use level 5 & 7 tracing messages; cf. ftdebug.h */
    
    #ifdef FT_DEBUG_LEVEL_TRACE
    
      void
      FT_Message( const char*  fmt,
                  ... )
      {
        va_list  ap;
    
    
        va_start( ap, fmt );
        vfprintf( stderr, fmt, ap );
        va_end( ap );
      }
    
      /* we don't handle tracing levels in stand-alone mode; */
    #ifndef FT_TRACE5
    #define FT_TRACE5( varformat )  FT_Message varformat
    #endif
    #ifndef FT_TRACE7
    #define FT_TRACE7( varformat )  FT_Message varformat
    #endif
    #ifndef FT_ERROR
    #define FT_ERROR( varformat )   FT_Message varformat
    #endif
    
    #else /* !FT_DEBUG_LEVEL_TRACE */
    
    #define FT_TRACE5( x )  do { } while ( 0 )     /* nothing */
    #define FT_TRACE7( x )  do { } while ( 0 )     /* nothing */
    #define FT_ERROR( x )   do { } while ( 0 )     /* nothing */
    
    #endif /* !FT_DEBUG_LEVEL_TRACE */
    
    
    #define FT_DEFINE_OUTLINE_FUNCS( class_,               \
                                     move_to_, line_to_,   \
                                     conic_to_, cubic_to_, \
                                     shift_, delta_ )      \
              static const FT_Outline_Funcs class_ =       \
              {                                            \
                move_to_,                                  \
                line_to_,                                  \
                conic_to_,                                 \
                cubic_to_,                                 \
                shift_,                                    \
                delta_                                     \
             };
    
    #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 <ft2build.h>
    #include "ftgrays.h"
    #include FT_INTERNAL_OBJECTS_H
    #include FT_INTERNAL_DEBUG_H
    #include FT_OUTLINE_H
    
    #include "ftsmerrs.h"
    
    #include "ftspic.h"
    
    #define ErrRaster_Invalid_Mode      Smooth_Err_Cannot_Render_Glyph
    #define ErrRaster_Invalid_Outline   Smooth_Err_Invalid_Outline
    #define ErrRaster_Memory_Overflow   Smooth_Err_Out_Of_Memory
    #define ErrRaster_Invalid_Argument  Smooth_Err_Invalid_Argument
    
    #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
    
      /* as usual, for the speed hungry :-) */
    
    #ifndef FT_STATIC_RASTER
    
    #define RAS_ARG   PWorker  worker
    #define RAS_ARG_  PWorker  worker,
    
    #define RAS_VAR   worker
    #define RAS_VAR_  worker,
    
    #else /* FT_STATIC_RASTER */
    
    #define RAS_ARG   /* empty */
    #define RAS_ARG_  /* empty */
    #define RAS_VAR   /* empty */
    #define RAS_VAR_  /* empty */
    
    #endif /* FT_STATIC_RASTER */
    
    
      /* must be at least 6 bits! */
    #define PIXEL_BITS  8
    
    #define ONE_PIXEL       ( 1L << PIXEL_BITS )
    #define PIXEL_MASK      ( -1L << PIXEL_BITS )
    #define TRUNC( x )      ( (TCoord)( (x) >> PIXEL_BITS ) )
    #define SUBPIXELS( x )  ( (TPos)(x) << PIXEL_BITS )
    #define FLOOR( x )      ( (x) & -ONE_PIXEL )
    #define CEILING( x )    ( ( (x) + ONE_PIXEL - 1 ) & -ONE_PIXEL )
    #define ROUND( x )      ( ( (x) + ONE_PIXEL / 2 ) & -ONE_PIXEL )
    
    #if PIXEL_BITS >= 6
    #define UPSCALE( x )    ( (x) << ( PIXEL_BITS - 6 ) )
    #define DOWNSCALE( x )  ( (x) >> ( PIXEL_BITS - 6 ) )
    #else
    #define UPSCALE( x )    ( (x) >> ( 6 - PIXEL_BITS ) )
    #define DOWNSCALE( x )  ( (x) << ( 6 - PIXEL_BITS ) )
    #endif
    
    
      /*************************************************************************/
      /*                                                                       */
      /*   TYPE DEFINITIONS                                                    */
      /*                                                                       */
    
      /* don't change the following types to FT_Int or FT_Pos, since we might */
      /* need to define them to "float" or "double" when experimenting with   */
      /* new algorithms                                                       */
    
      typedef long  TCoord;   /* integer scanline/pixel coordinate */
      typedef long  TPos;     /* sub-pixel coordinate              */
    
      /* determine the type used to store cell areas.  This normally takes at */
      /* least PIXEL_BITS*2 + 1 bits.  On 16-bit systems, we need to use      */
      /* `long' instead of `int', otherwise bad things happen                 */
    
    #if PIXEL_BITS <= 7
    
      typedef int  TArea;
    
    #else /* PIXEL_BITS >= 8 */
    
      /* approximately determine the size of integers using an ANSI-C header */
    #if FT_UINT_MAX == 0xFFFFU
      typedef long  TArea;
    #else
      typedef int   TArea;
    #endif
    
    #endif /* PIXEL_BITS >= 8 */
    
    
      /* maximal number of gray spans in a call to the span callback */
    #define FT_MAX_GRAY_SPANS  32
    
    
      typedef struct TCell_*  PCell;
    
      typedef struct  TCell_
      {
        TPos   x;     /* same with TWorker.ex */
        TCoord cover; /* same with TWorker.cover */
        TArea  area;
        PCell  next;
    
      } TCell;
    
    
      typedef struct  TWorker_
      {
        TCoord  ex, ey;
        TPos    min_ex, max_ex;
        TPos    min_ey, max_ey;
        TPos    count_ex, count_ey;
    
        TArea   area;
        TCoord  cover;
        int     invalid;
    
        PCell   cells;
        FT_PtrDist  max_cells;
        FT_PtrDist  num_cells;
    
        TCoord  cx, cy;
        TPos    x,  y;
    
        TPos    last_ey;
    
        FT_Vector   bez_stack[32 * 3 + 1];
        int         lev_stack[32];
    
        FT_Outline  outline;
        FT_Bitmap   target;
        FT_BBox     clip_box;
    
        FT_Span     gray_spans[FT_MAX_GRAY_SPANS];
        int         num_gray_spans;
    
        FT_Raster_Span_Func  render_span;
        void*                render_span_data;
        int                  span_y;
    
        int  band_size;
        int  band_shoot;
    
        ft_jmp_buf  jump_buffer;
    
        void*       buffer;
        long        buffer_size;
    
        PCell*     ycells;
        TPos       ycount;
    
      } TWorker, *PWorker;
    
    
    #ifndef FT_STATIC_RASTER
    #define ras  (*worker)
    #else
      static TWorker  ras;
    #endif
    
    
      typedef struct TRaster_
      {
        void*    buffer;
        long     buffer_size;
        int      band_size;
        void*    memory;
        PWorker  worker;
    
      } TRaster, *PRaster;
    
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Initialize the cells table.                                           */
      /*                                                                       */
      static void
      gray_init_cells( RAS_ARG_ void*  buffer,
                       long            byte_size )
      {
        ras.buffer      = buffer;
        ras.buffer_size = byte_size;
    
        ras.ycells      = (PCell*) buffer;
        ras.cells       = NULL;
        ras.max_cells   = 0;
        ras.num_cells   = 0;
        ras.area        = 0;
        ras.cover       = 0;
        ras.invalid     = 1;
      }
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Compute the outline bounding box.                                     */
      /*                                                                       */
      static void
      gray_compute_cbox( RAS_ARG )
      {
        FT_Outline*  outline = &ras.outline;
        FT_Vector*   vec     = outline->points;
        FT_Vector*   limit   = vec + outline->n_points;
    
    
        if ( outline->n_points <= 0 )
        {
          ras.min_ex = ras.max_ex = 0;
          ras.min_ey = ras.max_ey = 0;
          return;
        }
    
        ras.min_ex = ras.max_ex = vec->x;
        ras.min_ey = ras.max_ey = vec->y;
    
        vec++;
    
        for ( ; vec < limit; vec++ )
        {
          TPos  x = vec->x;
          TPos  y = vec->y;
    
    
          if ( x < ras.min_ex ) ras.min_ex = x;
          if ( x > ras.max_ex ) ras.max_ex = x;
          if ( y < ras.min_ey ) ras.min_ey = y;
          if ( y > ras.max_ey ) ras.max_ey = y;
        }
    
        /* truncate the bounding box to integer pixels */
        ras.min_ex = ras.min_ex >> 6;
        ras.min_ey = ras.min_ey >> 6;
        ras.max_ex = ( ras.max_ex + 63 ) >> 6;
        ras.max_ey = ( ras.max_ey + 63 ) >> 6;
      }
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Record the current cell in the table.                                 */
      /*                                                                       */
      static PCell
      gray_find_cell( RAS_ARG )
      {
        PCell  *pcell, cell;
        TPos    x = ras.ex;
    
    
        if ( x > ras.count_ex )
          x = ras.count_ex;
    
        pcell = &ras.ycells[ras.ey];
        for (;;)
        {
          cell = *pcell;
          if ( cell == NULL || cell->x > x )
            break;
    
          if ( cell->x == x )
            goto Exit;
    
          pcell = &cell->next;
        }
    
        if ( ras.num_cells >= ras.max_cells )
          ft_longjmp( ras.jump_buffer, 1 );
    
        cell        = ras.cells + ras.num_cells++;
        cell->x     = x;
        cell->area  = 0;
        cell->cover = 0;
    
        cell->next  = *pcell;
        *pcell      = cell;
    
      Exit:
        return cell;
      }
    
    
      static void
      gray_record_cell( RAS_ARG )
      {
        if ( !ras.invalid && ( ras.area | ras.cover ) )
        {
          PCell  cell = gray_find_cell( RAS_VAR );
    
    
          cell->area  += ras.area;
          cell->cover += ras.cover;
        }
      }
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Set the current cell to a new position.                               */
      /*                                                                       */
      static void
      gray_set_cell( RAS_ARG_ TCoord  ex,
                              TCoord  ey )
      {
        /* Move the cell pointer to a new position.  We set the `invalid'      */
        /* flag to indicate that the cell isn't part of those we're interested */
        /* in during the render phase.  This means that:                       */
        /*                                                                     */
        /* . the new vertical position must be within min_ey..max_ey-1.        */
        /* . the new horizontal position must be strictly less than max_ex     */
        /*                                                                     */
        /* Note that if a cell is to the left of the clipping region, it is    */
        /* actually set to the (min_ex-1) horizontal position.                 */
    
        /* All cells that are on the left of the clipping region go to the */
        /* min_ex - 1 horizontal position.                                 */
        ey -= ras.min_ey;
    
        if ( ex > ras.max_ex )
          ex = ras.max_ex;
    
        ex -= ras.min_ex;
        if ( ex < 0 )
          ex = -1;
    
        /* are we moving to a different cell ? */
        if ( ex != ras.ex || ey != ras.ey )
        {
          /* record the current one if it is valid */
          if ( !ras.invalid )
            gray_record_cell( RAS_VAR );
    
          ras.area  = 0;
          ras.cover = 0;
        }
    
        ras.ex      = ex;
        ras.ey      = ey;
        ras.invalid = ( (unsigned)ey >= (unsigned)ras.count_ey ||
                                  ex >= ras.count_ex           );
      }
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Start a new contour at a given cell.                                  */
      /*                                                                       */
      static void
      gray_start_cell( RAS_ARG_ TCoord  ex,
                                TCoord  ey )
      {
        if ( ex > ras.max_ex )
          ex = (TCoord)( ras.max_ex );
    
        if ( ex < ras.min_ex )
          ex = (TCoord)( ras.min_ex - 1 );
    
        ras.area    = 0;
        ras.cover   = 0;
        ras.ex      = ex - ras.min_ex;
        ras.ey      = ey - ras.min_ey;
        ras.last_ey = SUBPIXELS( ey );
        ras.invalid = 0;
    
        gray_set_cell( RAS_VAR_ ex, ey );
      }
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Render a scanline as one or more cells.                               */
      /*                                                                       */
      static void
      gray_render_scanline( RAS_ARG_ TCoord  ey,
                                     TPos    x1,
                                     TCoord  y1,
                                     TPos    x2,
                                     TCoord  y2 )
      {
        TCoord  ex1, ex2, fx1, fx2, delta, mod, lift, rem;
        long    p, first, dx;
        int     incr;
    
    
        dx = x2 - x1;
    
        ex1 = TRUNC( x1 );
        ex2 = TRUNC( x2 );
        fx1 = (TCoord)( x1 - SUBPIXELS( ex1 ) );
        fx2 = (TCoord)( x2 - SUBPIXELS( ex2 ) );
    
        /* trivial case.  Happens often */
        if ( y1 == y2 )
        {
          gray_set_cell( RAS_VAR_ ex2, ey );
          return;
        }
    
        /* everything is located in a single cell.  That is easy! */
        /*                                                        */
        if ( ex1 == ex2 )
        {
          delta      = y2 - y1;
          ras.area  += (TArea)(( fx1 + fx2 ) * delta);
          ras.cover += delta;
          return;
        }
    
        /* ok, we'll have to render a run of adjacent cells on the same */
        /* scanline...                                                  */
        /*                                                              */
        p     = ( ONE_PIXEL - fx1 ) * ( y2 - y1 );
        first = ONE_PIXEL;
        incr  = 1;
    
        if ( dx < 0 )
        {
          p     = fx1 * ( y2 - y1 );
          first = 0;
          incr  = -1;
          dx    = -dx;
        }
    
        delta = (TCoord)( p / dx );
        mod   = (TCoord)( p % dx );
        if ( mod < 0 )
        {
          delta--;
          mod += (TCoord)dx;
        }
    
        ras.area  += (TArea)(( fx1 + first ) * delta);
        ras.cover += delta;
    
        ex1 += incr;
        gray_set_cell( RAS_VAR_ ex1, ey );
        y1  += delta;
    
        if ( ex1 != ex2 )
        {
          p    = ONE_PIXEL * ( y2 - y1 + delta );
          lift = (TCoord)( p / dx );
          rem  = (TCoord)( p % dx );
          if ( rem < 0 )
          {
            lift--;
            rem += (TCoord)dx;
          }
    
          mod -= (int)dx;
    
          while ( ex1 != ex2 )
          {
            delta = lift;
            mod  += rem;
            if ( mod >= 0 )
            {
              mod -= (TCoord)dx;
              delta++;
            }
    
            ras.area  += (TArea)(ONE_PIXEL * delta);
            ras.cover += delta;
            y1        += delta;
            ex1       += incr;
            gray_set_cell( RAS_VAR_ ex1, ey );
          }
        }
    
        delta      = y2 - y1;
        ras.area  += (TArea)(( fx2 + ONE_PIXEL - first ) * delta);
        ras.cover += delta;
      }
    
    
      /*************************************************************************/
      /*                                                                       */
      /* Render a given line as a series of scanlines.                         */
      /*                                                                       */
      static void
      gray_render_line( RAS_ARG_ TPos  to_x,
                                 TPos  to_y )
      {
        TCoord  ey1, ey2, fy1, fy2, mod;
        TPos    dx, dy, x, x2;
        long    p, first;
        int     delta, rem, lift, incr;
    
    
        ey1 = TRUNC( ras.last_ey );
        ey2 = TRUNC( to_y );     /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
        fy1 = (TCoord)( ras.y - ras.last_ey );
        fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
    
        dx = to_x - ras.x;
        dy = to_y - ras.y;
    
        /* XXX: we should do something about the trivial case where dx == 0, */
        /*      as it happens very often!                                    */
    
        /* perform vertical clipping */
        {
          TCoord  min, max;
    
    
          min = ey1;
          max = ey2;
          if ( ey1 > ey2 )
          {
            min = ey2;
            max = ey1;
          }
          if ( min >= ras.max_ey || max < ras.min_ey )
            goto End;
        }
    
        /* everything is on a single scanline */
        if ( ey1 == ey2 )
        {
          gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 );
          goto End;
        }
    
        /* vertical line - avoid calling gray_render_scanline */
        incr = 1;
    
        if ( dx == 0 )
        {
          TCoord  ex     = TRUNC( ras.x );
          TCoord  two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
          TArea   area;
    
    
          first = ONE_PIXEL;
          if ( dy < 0 )
          {
            first = 0;
            incr  = -1;
          }
    
          delta      = (int)( first - fy1 );
          ras.area  += (TArea)two_fx * delta;
          ras.cover += delta;
          ey1       += incr;
    
          gray_set_cell( RAS_VAR_ ex, ey1 );
    
          delta = (int)( first + first - ONE_PIXEL );
          area  = (TArea)two_fx * delta;
          while ( ey1 != ey2 )
          {
            ras.area  += area;
            ras.cover += delta;
            ey1       += incr;
    
            gray_set_cell( RAS_VAR_ ex, ey1 );
          }
    
          delta      = (int)( fy2 - ONE_PIXEL + first );
          ras.area  += (TArea)two_fx * delta;
          ras.cover += delta;
    
          goto End;
        }
    
        /* ok, we have to render several scanlines */
        p     = ( ONE_PIXEL - fy1 ) * dx;
        first = ONE_PIXEL;
        incr  = 1;
    
        if ( dy < 0 )
        {
          p     = fy1 * dx;
          first = 0;
          incr  = -1;
          dy    = -dy;
        }
    
        delta = (int)( p / dy );
        mod   = (int)( p % dy );
        if ( mod < 0 )
        {
          delta--;
          mod += (TCoord)dy;
        }
    
        x = ras.x + delta;
        gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, (TCoord)first );
    
        ey1 += incr;
        gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
    
        if ( ey1 != ey2 )
        {
          p     = ONE_PIXEL * dx;
          lift  = (int)( p / dy );
          rem   = (int)( p % dy );
          if ( rem < 0 )
          {
            lift--;
            rem += (int)dy;
          }
          mod -= (int)dy;
    
          while ( ey1 != ey2 )
          {
            delta = lift;
            mod  += rem;
            if ( mod >= 0 )
            {
              mod -= (int)dy;
              delta++;
            }
    
            x2 = x + delta;
            gray_render_scanline( RAS_VAR_ ey1, x,
                                           (TCoord)( ONE_PIXEL - first ), x2,
                                           (TCoord)first );
            x = x2;
    
            ey1 += incr;
            gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
          }
        }
    
        gray_render_scanline( RAS_VAR_ ey1, x,
                                       (TCoord)( ONE_PIXEL - first ), to_x,
                                       fy2 );
    
      End:
        ras.x       = to_x;
        ras.y       = to_y;
        ras.last_ey = SUBPIXELS( ey2 );
      }
    
    
      static void
      gray_split_conic( FT_Vector*  base )
      {
        TPos  a, b;
    
    
        base[4].x = base[2].x;
        b = base[1].x;
        a = base[3].x = ( base[2].x + b ) / 2;
        b = base[1].x = ( base[0].x + b ) / 2;
        base[2].x = ( a + b ) / 2;
    
        base[4].y = base[2].y;
        b = base[1].y;
        a = base[3].y = ( base[2].y + b ) / 2;
        b = base[1].y = ( base[0].y + b ) / 2;
        base[2].y = ( a + b ) / 2;
      }
    
    
      static void
      gray_render_conic( RAS_ARG_ const FT_Vector*  control,
                                  const FT_Vector*  to )
      {
        TPos        dx, dy;
        int         top, level;
        int*        levels;
        FT_Vector*  arc;
    
    
        arc      = ras.bez_stack;
        arc[0].x = UPSCALE( to->x );
        arc[0].y = UPSCALE( to->y );
        arc[1].x = UPSCALE( control->x );
        arc[1].y = UPSCALE( control->y );
        arc[2].x = ras.x;
        arc[2].y = ras.y;
    
        dx = FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x );
        dy = FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y );
        if ( dx < dy )
          dx = dy;
    
        level = 0;
        while ( dx > ONE_PIXEL / 6 )
        {
          dx >>= 2;
          level++;
        }
    
        levels    = ras.lev_stack;
        levels[0] = level;
        top       = 0;
    
        do
        {
          level = levels[top];
          if ( level > 1 )
          {
            /* check that the arc crosses the current band */
            TPos  min, max, y;
    
    
            min = max = arc[0].y;
    
            y = arc[1].y;
            if ( y < min ) min = y;
            if ( y > max ) max = y;
    
            y = arc[2].y;
            if ( y < min ) min = y;
            if ( y > max ) max = y;
    
            if ( TRUNC( min ) >= ras.max_ey || TRUNC( max ) < ras.min_ey )
              goto Draw;
    
            gray_split_conic( arc );
            arc += 2;
            top++;
            levels[top] = levels[top - 1] = level - 1;
            continue;
          }
    
        Draw:
          gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
          top--;
          arc -= 2;
    
        } while ( top >= 0 );
      }
    
    
      static void
      gray_split_cubic( FT_Vector*  base )
      {
        TPos  a, b, c, d;
    
    
        base[6].x = base[3].x;
        c = base[1].x;
        d = base[2].x;
        base[1].x = a = ( base[0].x + c ) / 2;
        base[5].x = b = ( base[3].x + d ) / 2;
        c = ( c + d ) / 2;
        base[2].x = a = ( a + c ) / 2;
        base[4].x = b = ( b + c ) / 2;
        base[3].x = ( a + b ) / 2;
    
        base[6].y = base[3].y;
        c = base[1].y;
        d = base[2].y;
        base[1].y = a = ( base[0].y + c ) / 2;
        base[5].y = b = ( base[3].y + d ) / 2;
        c = ( c + d ) / 2;
        base[2].y = a = ( a + c ) / 2;
        base[4].y = b = ( b + c ) / 2;
        base[3].y = ( a + b ) / 2;
      }
    
    
      static void
      gray_render_cubic( RAS_ARG_ const FT_Vector*  control1,
                                  const FT_Vector*  control2,
                                  const FT_Vector*  to )
      {
        FT_Vector*  arc;
    
    
        arc      = ras.bez_stack;
        arc[0].x = UPSCALE( to->x );
        arc[0].y = UPSCALE( to->y );
        arc[1].x = UPSCALE( control2->x );
        arc[1].y = UPSCALE( control2->y );
        arc[2].x = UPSCALE( control1->x );
        arc[2].y = UPSCALE( control1->y );
        arc[3].x = ras.x;
        arc[3].y = ras.y;
    
        for (;;)
        {
          /* Check that the arc crosses the current band. */
          TPos  min, max, y;
    
    
          min = max = arc[0].y;
    
          y = arc[1].y;
          if ( y < min )
            min = y;
          if ( y > max )
            max = y;
    
          y = arc[2].y;
          if ( y < min )
            min = y;
          if ( y > max )
            max = y;
    
          y = arc[3].y;
          if ( y < min )
            min = y;
          if ( y > max )
            max = y;
    
          if ( TRUNC( min ) >= ras.max_ey || TRUNC( max ) < ras.min_ey )
            goto Draw;
    
          /* Decide whether to split or draw. See `Rapid Termination          */
          /* Evaluation for Recursive Subdivision of Bezier Curves' by Thomas */
          /* F. Hain, at                                                      */
          /* http://www.cis.southalabama.edu/~hain/general/Publications/Bezier/Camera-ready%20CISST02%202.pdf */
    
          {
            TPos  dx, dy, dx_, dy_;
            TPos  dx1, dy1, dx2, dy2;
            TPos  L, s, s_limit;
    
    
            /* dx and dy are x and y components of the P0-P3 chord vector. */
            dx = arc[3].x - arc[0].x;
            dy = arc[3].y - arc[0].y;
    
            /* L is an (under)estimate of the Euclidean distance P0-P3.       */
            /*                                                                */
            /* If dx >= dy, then r = sqrt(dx^2 + dy^2) can be overestimated   */
            /* with least maximum error by                                    */
            /*                                                                */
            /*   r_upperbound = dx + (sqrt(2) - 1) * dy  ,                    */
            /*                                                                */
            /* where sqrt(2) - 1 can be (over)estimated by 107/256, giving an */
            /* error of no more than 8.4%.                                    */
            /*                                                                */
            /* Similarly, some elementary calculus shows that r can be        */
            /* underestimated with least maximum error by                     */
            /*                                                                */
            /*   r_lowerbound = sqrt(2 + sqrt(2)) / 2 * dx                    */
            /*                  + sqrt(2 - sqrt(2)) / 2 * dy  .               */
            /*                                                                */
            /* 236/256 and 97/256 are (under)estimates of the two algebraic   */
            /* numbers, giving an error of no more than 8.1%.                 */
    
            dx_ = FT_ABS( dx );
            dy_ = FT_ABS( dy );
    
            /* This is the same as                     */
            /*                                         */
            /*   L = ( 236 * FT_MAX( dx_, dy_ )        */
            /*       + 97 * FT_MIN( dx_, dy_ ) ) >> 8; */
            L = ( dx_ > dy_ ? 236 * dx_ +  97 * dy_
                            :  97 * dx_ + 236 * dy_ ) >> 8;
    
            /* Avoid possible arithmetic overflow below by splitting. */
            if ( L > 32767 )
              goto Split;
    
            /* Max deviation may be as much as (s/L) * 3/4 (if Hain's v = 1). */
            s_limit = L * (TPos)( ONE_PIXEL / 6 );
    
            /* s is L * the perpendicular distance from P1 to the line P0-P3. */
            dx1 = arc[1].x - arc[0].x;
            dy1 = arc[1].y - arc[0].y;
            s = FT_ABS( dy * dx1 - dx * dy1 );
    
            if ( s > s_limit )
              goto Split;
    
            /* s is L * the perpendicular distance from P2 to the line P0-P3. */
            dx2 = arc[2].x - arc[0].x;
            dy2 = arc[2].y - arc[0].y;
            s = FT_ABS( dy * dx2 - dx * dy2 );
    
            if ( s > s_limit )
              goto Split;
    
            /* If P1 or P2 is outside P0-P3, split the curve. */
            if ( dy * dy1 + dx * dx1 < 0                                     ||
                 dy * dy2 + dx * dx2 < 0                                     ||
                 dy * (arc[3].y - arc[1].y) + dx * (arc[3].x - arc[1].x) < 0 ||
                 dy * (arc[3].y - arc[2].y) + dx * (arc[3].x - arc[2].x) < 0 )
              goto Split;
    
            /* No reason to split. */
            goto Draw;
          }
    
        Split:
          gray_split_cubic( arc );
          arc += 3;
          continue;
    
        Draw:
          gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
    
          if ( arc == ras.bez_stack )
            return;
    
          arc -= 3;
        }
      }
    
    
      static int
      gray_move_to( const FT_Vector*  to,
                    PWorker           worker )
      {
        TPos  x, y;
    
    
        /* record current cell, if any */
        gray_record_cell( RAS_VAR );
    
        /* start to a new position */
        x = UPSCALE( to->x );
        y = UPSCALE( to->y );
    
        gray_start_cell( RAS_VAR_ TRUNC( x ), TRUNC( y ) );
    
        worker->x = x;
        worker->y = y;
        return 0;
      }
    
    
      static int
      gray_line_to( const FT_Vector*  to,
                    PWorker           worker )
      {
        gray_render_line( RAS_VAR_ UPSCALE( to->x ), UPSCALE( to->y ) );
        return 0;
      }
    
    
      static int
      gray_conic_to( const FT_Vector*  control,
                     const FT_Vector*  to,
                     PWorker           worker )
      {
        gray_render_conic( RAS_VAR_ control, to );
        return 0;
      }
    
    
      static int
      gray_cubic_to( const FT_Vector*  control1,
                     const FT_Vector*  control2,
                     const FT_Vector*  to,
                     PWorker           worker )
      {
        gray_render_cubic( RAS_VAR_ control1, control2, to );
        return 0;
      }
    
    
      static void
      gray_render_span( int             y,
                        int             count,
                        const FT_Span*  spans,
                        PWorker         worker )
      {
        unsigned char*  p;
        FT_Bitmap*      map = &worker->target;
    
    
        /* first of all, compute the scanline offset */
        p = (unsigned char*)map->buffer - y * map->pitch;
        if ( map->pitch >= 0 )
          p += (unsigned)( ( map->rows - 1 ) * map->pitch );
    
        for ( ; count > 0; count--, spans++ )
        {
          unsigned char  coverage = spans->coverage;
    
    
          if ( coverage )
          {
            /* For small-spans it is faster to do it by ourselves than
             * calling `memset'.  This is mainly due to the cost of the
             * function call.
             */
            if ( spans->len >= 8 )
              FT_MEM_SET( p + spans->x, (unsigned char)coverage, spans->len );
            else
            {
              unsigned char*  q = p + spans->x;
    
    
              switch ( spans->len )
              {
              case 7: *q++ = (unsigned char)coverage;
              case 6: *q++ = (unsigned char)coverage;
              case 5: *q++ = (unsigned char)coverage;
              case 4: *q++ = (unsigned char)coverage;
              case 3: *q++ = (unsigned char)coverage;
              case 2: *q++ = (unsigned char)coverage;
              case 1: *q   = (unsigned char)coverage;
              default:
                ;
              }
            }
          }
        }
      }
    
    
      static void
      gray_hline( RAS_ARG_ TCoord  x,
                           TCoord  y,
                           TPos    area,
                           TCoord  acount )
      {
        FT_Span*  span;
        int       count;
        int       coverage;
    
    
        /* compute the coverage line's coverage, depending on the    */
        /* outline fill rule                                         */
        /*                                                           */
        /* the coverage percentage is area/(PIXEL_BITS*PIXEL_BITS*2) */
        /*                                                           */
        coverage = (int)( area >> ( PIXEL_BITS * 2 + 1 - 8 ) );
                                                        /* use range 0..256 */
        if ( coverage < 0 )
          coverage = -coverage;
    
        if ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL )
        {
          coverage &= 511;
    
          if ( coverage > 256 )
            coverage = 512 - coverage;
          else if ( coverage == 256 )
            coverage = 255;
        }
        else
        {
          /* normal non-zero winding rule */
          if ( coverage >= 256 )
            coverage = 255;
        }
    
        y += (TCoord)ras.min_ey;
        x += (TCoord)ras.min_ex;
    
        /* FT_Span.x is a 16-bit short, so limit our coordinates appropriately */
        if ( x >= 32767 )
          x = 32767;
    
        /* FT_Span.y is an integer, so limit our coordinates appropriately */
        if ( y >= FT_INT_MAX )
          y = FT_INT_MAX;
    
        if ( coverage )
        {
          /* see whether we can add this span to the current list */
          count = ras.num_gray_spans;
          span  = ras.gray_spans + count - 1;
          if ( count > 0                          &&
               ras.span_y == y                    &&
               (int)span->x + span->len == (int)x &&
               span->coverage == coverage         )
          {
            span->len = (unsigned short)( span->len + acount );
            return;
          }
    
          if ( ras.span_y != y || count >= FT_MAX_GRAY_SPANS )
          {
            if ( ras.render_span && count > 0 )
              ras.render_span( ras.span_y, count, ras.gray_spans,
                               ras.render_span_data );
    
    #ifdef FT_DEBUG_LEVEL_TRACE
    
            if ( count > 0 )
            {
              int  n;
    
    
              FT_TRACE7(( "y = %3d ", ras.span_y ));
              span = ras.gray_spans;
              for ( n = 0; n < count; n++, span++ )
                FT_TRACE7(( "[%d..%d]:%02x ",
                            span->x, span->x + span->len - 1, span->coverage ));
              FT_TRACE7(( "\n" ));
            }
    
    #endif /* FT_DEBUG_LEVEL_TRACE */
    
            ras.num_gray_spans = 0;
            ras.span_y         = (int)y;
    
            count = 0;
            span  = ras.gray_spans;
          }
          else
            span++;
    
          /* add a gray span to the current list */
          span->x        = (short)x;
          span->len      = (unsigned short)acount;
          span->coverage = (unsigned char)coverage;
    
          ras.num_gray_spans++;
        }
      }
    
    
    #ifdef FT_DEBUG_LEVEL_TRACE
    
      /* to be called while in the debugger --                                */
      /* this function causes a compiler warning since it is unused otherwise */
      static void
      gray_dump_cells( RAS_ARG )
      {
        int  yindex;
    
    
        for ( yindex = 0; yindex < ras.ycount; yindex++ )
        {
          PCell  cell;
    
    
          printf( "%3d:", yindex );
    
          for ( cell = ras.ycells[yindex]; cell != NULL; cell = cell->next )
            printf( " (%3ld, c:%4ld, a:%6d)", cell->x, cell->cover, cell->area );
          printf( "\n" );
        }
      }
    
    #endif /* FT_DEBUG_LEVEL_TRACE */
    
    
      static void
      gray_sweep( RAS_ARG_ const FT_Bitmap*  target )
      {
        int  yindex;
    
        FT_UNUSED( target );
    
    
        if ( ras.num_cells == 0 )
          return;
    
        ras.num_gray_spans = 0;
    
        FT_TRACE7(( "gray_sweep: start\n" ));
    
        for ( yindex = 0; yindex < ras.ycount; yindex++ )
        {
          PCell   cell  = ras.ycells[yindex];
          TCoord  cover = 0;
          TCoord  x     = 0;
    
    
          for ( ; cell != NULL; cell = cell->next )
          {
            TPos  area;
    
    
            if ( cell->x > x && cover != 0 )
              gray_hline( RAS_VAR_ x, yindex, cover * ( ONE_PIXEL * 2 ),
                          cell->x - x );
    
            cover += cell->cover;
            area   = cover * ( ONE_PIXEL * 2 ) - cell->area;
    
            if ( area != 0 && cell->x >= 0 )
              gray_hline( RAS_VAR_ cell->x, yindex, area, 1 );
    
            x = cell->x + 1;
          }
    
          if ( cover != 0 )
            gray_hline( RAS_VAR_ x, yindex, cover * ( ONE_PIXEL * 2 ),
                        ras.count_ex - x );
        }
    
        if ( ras.render_span && ras.num_gray_spans > 0 )
          ras.render_span( ras.span_y, ras.num_gray_spans,
                           ras.gray_spans, ras.render_span_data );
    
        FT_TRACE7(( "gray_sweep: end\n" ));
      }
    
    
    #ifdef _STANDALONE_
    
      /*************************************************************************/
      /*                                                                       */
      /*  The following function should only compile in stand-alone mode,      */
      /*  i.e., when building this component without the rest of FreeType.     */
      /*                                                                       */
      /*************************************************************************/
    
      /*************************************************************************/
      /*                                                                       */
      /* <Function>                                                            */
      /*    FT_Outline_Decompose                                               */
      /*                                                                       */
      /* <Description>                                                         */
      /*    Walk over an outline's structure to decompose it into individual   */
      /*    segments and Bézier arcs.  This function is also able to emit      */
      /*    `move to' and `close to' operations to indicate the start and end  */
      /*    of new contours in the outline.                                    */
      /*                                                                       */
      /* <Input>                                                               */
      /*    outline        :: A pointer to the source target.                  */
      /*                                                                       */
      /*    func_interface :: A table of `emitters', i.e., function pointers   */
      /*                      called during decomposition to indicate path     */
      /*                      operations.                                      */
      /*                                                                       */
      /* <InOut>                                                               */
      /*    user           :: A typeless pointer which is passed to each       */
      /*                      emitter during the decomposition.  It can be     */
      /*                      used to store the state during the               */
      /*                      decomposition.                                   */
      /*                                                                       */
      /* <Return>                                                              */
      /*    Error code.  0 means success.                                      */
      /*                                                                       */
      static int
      FT_Outline_Decompose( const FT_Outline*        outline,
                            const FT_Outline_Funcs*  func_interface,
                            void*                    user )
      {
    #undef SCALED
    #define SCALED( x )  ( ( (x) << shift ) - delta )
    
        FT_Vector   v_last;
        FT_Vector   v_control;
        FT_Vector   v_start;
    
        FT_Vector*  point;
        FT_Vector*  limit;
        char*       tags;
    
        int         error;
    
        int   n;         /* index of contour in outline     */
        int   first;     /* index of first point in contour */
        char  tag;       /* current point's state           */
    
        int   shift;
        TPos  delta;
    
    
        if ( !outline || !func_interface )
          return ErrRaster_Invalid_Argument;
    
        shift = func_interface->shift;
        delta = func_interface->delta;
        first = 0;
    
        for ( n = 0; n < outline->n_contours; n++ )
        {
          int  last;  /* index of last point in contour */
    
    
          FT_TRACE5(( "FT_Outline_Decompose: Outline %d\n", n ));
    
          last  = outline->contours[n];
          if ( last < 0 )
            goto Invalid_Outline;
          limit = outline->points + last;
    
          v_start   = outline->points[first];
          v_start.x = SCALED( v_start.x );
          v_start.y = SCALED( v_start.y );
    
          v_last   = outline->points[last];
          v_last.x = SCALED( v_last.x );
          v_last.y = SCALED( v_last.y );
    
          v_control = v_start;
    
          point = outline->points + first;
          tags  = outline->tags   + first;
          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( 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--;
          }
    
          FT_TRACE5(( "  move to (%.2f, %.2f)\n",
                      v_start.x / 64.0, v_start.y / 64.0 ));
          error = func_interface->move_to( &v_start, user );
          if ( error )
            goto Exit;
    
          while ( point < limit )
          {
            point++;
            tags++;
    
            tag = FT_CURVE_TAG( tags[0] );
            switch ( tag )
            {
            case FT_CURVE_TAG_ON:  /* emit a single line_to */
              {
                FT_Vector  vec;
    
    
                vec.x = SCALED( point->x );
                vec.y = SCALED( point->y );
    
                FT_TRACE5(( "  line to (%.2f, %.2f)\n",
                            vec.x / 64.0, vec.y / 64.0 ));
                error = func_interface->line_to( &vec, user );
                if ( error )
                  goto Exit;
                continue;
              }
    
            case FT_CURVE_TAG_CONIC:  /* consume conic arcs */
              v_control.x = SCALED( point->x );
              v_control.y = SCALED( point->y );
    
            Do_Conic:
              if ( point < limit )
              {
                FT_Vector  vec;
                FT_Vector  v_middle;
    
    
                point++;
                tags++;
                tag = FT_CURVE_TAG( tags[0] );
    
                vec.x = SCALED( point->x );
                vec.y = SCALED( point->y );
    
                if ( tag == FT_CURVE_TAG_ON )
                {
                  FT_TRACE5(( "  conic to (%.2f, %.2f)"
                              " with control (%.2f, %.2f)\n",
                              vec.x / 64.0, vec.y / 64.0,
                              v_control.x / 64.0, v_control.y / 64.0 ));
                  error = func_interface->conic_to( &v_control, &vec, user );
                  if ( error )
                    goto Exit;
                  continue;
                }
    
                if ( tag != FT_CURVE_TAG_CONIC )
                  goto Invalid_Outline;
    
                v_middle.x = ( v_control.x + vec.x ) / 2;
                v_middle.y = ( v_control.y + vec.y ) / 2;
    
                FT_TRACE5(( "  conic to (%.2f, %.2f)"
                            " with control (%.2f, %.2f)\n",
                            v_middle.x / 64.0, v_middle.y / 64.0,
                            v_control.x / 64.0, v_control.y / 64.0 ));
                error = func_interface->conic_to( &v_control, &v_middle, user );
                if ( error )
                  goto Exit;
    
                v_control = vec;
                goto Do_Conic;
              }
    
              FT_TRACE5(( "  conic to (%.2f, %.2f)"
                          " with control (%.2f, %.2f)\n",
                          v_start.x / 64.0, v_start.y / 64.0,
                          v_control.x / 64.0, v_control.y / 64.0 ));
              error = func_interface->conic_to( &v_control, &v_start, user );
              goto Close;
    
            default:  /* FT_CURVE_TAG_CUBIC */
              {
                FT_Vector  vec1, vec2;
    
    
                if ( point + 1 > limit                             ||
                     FT_CURVE_TAG( tags[1] ) != FT_CURVE_TAG_CUBIC )
                  goto Invalid_Outline;
    
                point += 2;
                tags  += 2;
    
                vec1.x = SCALED( point[-2].x );
                vec1.y = SCALED( point[-2].y );
    
                vec2.x = SCALED( point[-1].x );
                vec2.y = SCALED( point[-1].y );
    
                if ( point <= limit )
                {
                  FT_Vector  vec;
    
    
                  vec.x = SCALED( point->x );
                  vec.y = SCALED( point->y );
    
                  FT_TRACE5(( "  cubic to (%.2f, %.2f)"
                              " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
                              vec.x / 64.0, vec.y / 64.0,
                              vec1.x / 64.0, vec1.y / 64.0,
                              vec2.x / 64.0, vec2.y / 64.0 ));
                  error = func_interface->cubic_to( &vec1, &vec2, &vec, user );
                  if ( error )
                    goto Exit;
                  continue;
                }
    
                FT_TRACE5(( "  cubic to (%.2f, %.2f)"
                            " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
                            v_start.x / 64.0, v_start.y / 64.0,
                            vec1.x / 64.0, vec1.y / 64.0,
                            vec2.x / 64.0, vec2.y / 64.0 ));
                error = func_interface->cubic_to( &vec1, &vec2, &v_start, user );
                goto Close;
              }
            }
          }
    
          /* close the contour with a line segment */
          FT_TRACE5(( "  line to (%.2f, %.2f)\n",
                      v_start.x / 64.0, v_start.y / 64.0 ));
          error = func_interface->line_to( &v_start, user );
    
       Close:
          if ( error )
            goto Exit;
    
          first = last + 1;
        }
    
        FT_TRACE5(( "FT_Outline_Decompose: Done\n", n ));
        return 0;
    
      Exit:
        FT_TRACE5(( "FT_Outline_Decompose: Error %d\n", error ));
        return error;
    
      Invalid_Outline:
        return ErrRaster_Invalid_Outline;
      }
    
    #endif /* _STANDALONE_ */
    
    
      typedef struct  TBand_
      {
        TPos  min, max;
    
      } TBand;
    
        FT_DEFINE_OUTLINE_FUNCS(func_interface,
          (FT_Outline_MoveTo_Func) gray_move_to,
          (FT_Outline_LineTo_Func) gray_line_to,
          (FT_Outline_ConicTo_Func)gray_conic_to,
          (FT_Outline_CubicTo_Func)gray_cubic_to,
          0,
          0
        )
    
      static int
      gray_convert_glyph_inner( RAS_ARG )
      {
    
        volatile int  error = 0;
    
    #ifdef FT_CONFIG_OPTION_PIC
          FT_Outline_Funcs func_interface;
          Init_Class_func_interface(&func_interface);
    #endif
    
        if ( ft_setjmp( ras.jump_buffer ) == 0 )
        {
          error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras );
          gray_record_cell( RAS_VAR );
        }
        else
          error = ErrRaster_Memory_Overflow;
    
        return error;
      }
    
    
      static int
      gray_convert_glyph( RAS_ARG )
      {
        TBand            bands[40];
        TBand* volatile  band;
        int volatile     n, num_bands;
        TPos volatile    min, max, max_y;
        FT_BBox*         clip;
    
    
        /* Set up state in the raster object */
        gray_compute_cbox( RAS_VAR );
    
        /* clip to target bitmap, exit if nothing to do */
        clip = &ras.clip_box;
    
        if ( ras.max_ex <= clip->xMin || ras.min_ex >= clip->xMax ||
             ras.max_ey <= clip->yMin || ras.min_ey >= clip->yMax )
          return 0;
    
        if ( ras.min_ex < clip->xMin ) ras.min_ex = clip->xMin;
        if ( ras.min_ey < clip->yMin ) ras.min_ey = clip->yMin;
    
        if ( ras.max_ex > clip->xMax ) ras.max_ex = clip->xMax;
        if ( ras.max_ey > clip->yMax ) ras.max_ey = clip->yMax;
    
        ras.count_ex = ras.max_ex - ras.min_ex;
        ras.count_ey = ras.max_ey - ras.min_ey;
    
        /* set up vertical bands */
        num_bands = (int)( ( ras.max_ey - ras.min_ey ) / ras.band_size );
        if ( num_bands == 0 )
          num_bands = 1;
        if ( num_bands >= 39 )
          num_bands = 39;
    
        ras.band_shoot = 0;
    
        min   = ras.min_ey;
        max_y = ras.max_ey;
    
        for ( n = 0; n < num_bands; n++, min = max )
        {
          max = min + ras.band_size;
          if ( n == num_bands - 1 || max > max_y )
            max = max_y;
    
          bands[0].min = min;
          bands[0].max = max;
          band         = bands;
    
          while ( band >= bands )
          {
            TPos  bottom, top, middle;
            int   error;
    
            {
              PCell  cells_max;
              int    yindex;
              long   cell_start, cell_end, cell_mod;
    
    
              ras.ycells = (PCell*)ras.buffer;
              ras.ycount = band->max - band->min;
    
              cell_start = sizeof ( PCell ) * ras.ycount;
              cell_mod   = cell_start % sizeof ( TCell );
              if ( cell_mod > 0 )
                cell_start += sizeof ( TCell ) - cell_mod;
    
              cell_end  = ras.buffer_size;
              cell_end -= cell_end % sizeof( TCell );
    
              cells_max = (PCell)( (char*)ras.buffer + cell_end );
              ras.cells = (PCell)( (char*)ras.buffer + cell_start );
              if ( ras.cells >= cells_max )
                goto ReduceBands;
    
              ras.max_cells = cells_max - ras.cells;
              if ( ras.max_cells < 2 )
                goto ReduceBands;
    
              for ( yindex = 0; yindex < ras.ycount; yindex++ )
                ras.ycells[yindex] = NULL;
            }
    
            ras.num_cells = 0;
            ras.invalid   = 1;
            ras.min_ey    = band->min;
            ras.max_ey    = band->max;
            ras.count_ey  = band->max - band->min;
    
            error = gray_convert_glyph_inner( RAS_VAR );
    
            if ( !error )
            {
              gray_sweep( RAS_VAR_ &ras.target );
              band--;
              continue;
            }
            else if ( error != ErrRaster_Memory_Overflow )
              return 1;
    
          ReduceBands:
            /* render pool overflow; we will reduce the render band by half */
            bottom = band->min;
            top    = band->max;
            middle = bottom + ( ( top - bottom ) >> 1 );
    
            /* This is too complex for a single scanline; there must */
            /* be some problems.                                     */
            if ( middle == bottom )
            {
    #ifdef FT_DEBUG_LEVEL_TRACE
              FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
    #endif
              return 1;
            }
    
            if ( bottom-top >= ras.band_size )
              ras.band_shoot++;
    
            band[1].min = bottom;
            band[1].max = middle;
            band[0].min = middle;
            band[0].max = top;
            band++;
          }
        }
    
        if ( ras.band_shoot > 8 && ras.band_size > 16 )
          ras.band_size = ras.band_size / 2;
    
        return 0;
      }
    
    
      static int
      gray_raster_render( PRaster                  raster,
                          const FT_Raster_Params*  params )
      {
        const FT_Outline*  outline    = (const FT_Outline*)params->source;
        const FT_Bitmap*   target_map = params->target;
        PWorker            worker;
    
    
        if ( !raster || !raster->buffer || !raster->buffer_size )
          return ErrRaster_Invalid_Argument;
    
        if ( !outline )
          return ErrRaster_Invalid_Outline;
    
        /* return immediately if the outline is empty */
        if ( outline->n_points == 0 || outline->n_contours <= 0 )
          return 0;
    
        if ( !outline->contours || !outline->points )
          return ErrRaster_Invalid_Outline;
    
        if ( outline->n_points !=
               outline->contours[outline->n_contours - 1] + 1 )
          return ErrRaster_Invalid_Outline;
    
        worker = raster->worker;
    
        /* if direct mode is not set, we must have a target bitmap */
        if ( !( params->flags & FT_RASTER_FLAG_DIRECT ) )
        {
          if ( !target_map )
            return ErrRaster_Invalid_Argument;
    
          /* nothing to do */
          if ( !target_map->width || !target_map->rows )
            return 0;
    
          if ( !target_map->buffer )
            return ErrRaster_Invalid_Argument;
        }
    
        /* this version does not support monochrome rendering */
        if ( !( params->flags & FT_RASTER_FLAG_AA ) )
          return ErrRaster_Invalid_Mode;
    
        /* compute clipping box */
        if ( !( params->flags & FT_RASTER_FLAG_DIRECT ) )
        {
          /* compute clip box from target pixmap */
          ras.clip_box.xMin = 0;
          ras.clip_box.yMin = 0;
          ras.clip_box.xMax = target_map->width;
          ras.clip_box.yMax = target_map->rows;
        }
        else if ( params->flags & FT_RASTER_FLAG_CLIP )
          ras.clip_box = params->clip_box;
        else
        {
          ras.clip_box.xMin = -32768L;
          ras.clip_box.yMin = -32768L;
          ras.clip_box.xMax =  32767L;
          ras.clip_box.yMax =  32767L;
        }
    
        gray_init_cells( RAS_VAR_ raster->buffer, raster->buffer_size );
    
        ras.outline        = *outline;
        ras.num_cells      = 0;
        ras.invalid        = 1;
        ras.band_size      = raster->band_size;
        ras.num_gray_spans = 0;
    
        if ( params->flags & FT_RASTER_FLAG_DIRECT )
        {
          ras.render_span      = (FT_Raster_Span_Func)params->gray_spans;
          ras.render_span_data = params->user;
        }
        else
        {
          ras.target           = *target_map;
          ras.render_span      = (FT_Raster_Span_Func)gray_render_span;
          ras.render_span_data = &ras;
        }
    
        return gray_convert_glyph( RAS_VAR );
      }
    
    
      /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/
      /****                         a static object.                   *****/
    
    #ifdef _STANDALONE_
    
      static int
      gray_raster_new( void*       memory,
                       FT_Raster*  araster )
      {
        static TRaster  the_raster;
    
        FT_UNUSED( memory );
    
    
        *araster = (FT_Raster)&the_raster;
        FT_MEM_ZERO( &the_raster, sizeof ( the_raster ) );
    
        return 0;
      }
    
    
      static void
      gray_raster_done( FT_Raster  raster )
      {
        /* nothing */
        FT_UNUSED( raster );
      }
    
    #else /* !_STANDALONE_ */
    
      static int
      gray_raster_new( FT_Memory   memory,
                       FT_Raster*  araster )
      {
        FT_Error  error;
        PRaster   raster = NULL;
    
    
        *araster = 0;
        if ( !FT_ALLOC( raster, sizeof ( TRaster ) ) )
        {
          raster->memory = memory;
          *araster = (FT_Raster)raster;
        }
    
        return error;
      }
    
    
      static void
      gray_raster_done( FT_Raster  raster )
      {
        FT_Memory  memory = (FT_Memory)((PRaster)raster)->memory;
    
    
        FT_FREE( raster );
      }
    
    #endif /* !_STANDALONE_ */
    
    
      static void
      gray_raster_reset( FT_Raster  raster,
                         char*      pool_base,
                         long       pool_size )
      {
        PRaster  rast = (PRaster)raster;
    
    
        if ( raster )
        {
          if ( pool_base && pool_size >= (long)sizeof ( TWorker ) + 2048 )
          {
            PWorker  worker = (PWorker)pool_base;
    
    
            rast->worker      = worker;
            rast->buffer      = pool_base +
                                  ( ( sizeof ( TWorker ) + sizeof ( TCell ) - 1 ) &
                                    ~( sizeof ( TCell ) - 1 ) );
            rast->buffer_size = (long)( ( pool_base + pool_size ) -
                                        (char*)rast->buffer ) &
                                          ~( sizeof ( TCell ) - 1 );
            rast->band_size   = (int)( rast->buffer_size /
                                         ( sizeof ( TCell ) * 8 ) );
          }
          else
          {
            rast->buffer      = NULL;
            rast->buffer_size = 0;
            rast->worker      = NULL;
          }
        }
      }
    
    
      FT_DEFINE_RASTER_FUNCS(ft_grays_raster,
        FT_GLYPH_FORMAT_OUTLINE,
    
        (FT_Raster_New_Func)     gray_raster_new,
        (FT_Raster_Reset_Func)   gray_raster_reset,
        (FT_Raster_Set_Mode_Func)0,
        (FT_Raster_Render_Func)  gray_raster_render,
        (FT_Raster_Done_Func)    gray_raster_done
      )
    
    
    /* END */
    
    
    /* Local Variables: */
    /* coding: utf-8    */
    /* End:             */