src/gui/painting/qgrayraster.c
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/gui/painting/qgrayraster.c	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,1946 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/***************************************************************************/
+/*                                                                         */
+/*  qgrayraster.c, derived from ftgrays.c                                  */
+/*                                                                         */
+/*    A new `perfect' anti-aliasing renderer (body).                       */
+/*                                                                         */
+/*  Copyright 2000-2001, 2002, 2003 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, ../../3rdparty/freetype/docs/FTL.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                        */
+  /* `qt_ft_gray_raster.raster_new'; an anti-aliased bitmap can be generated  */
+  /* with a call to `qt_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.                                                           */
+  /*                                                                       */
+  /*************************************************************************/
+
+/* experimental support for gamma correction within the rasterizer */
+#define xxxGRAYS_USE_GAMMA
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* The macro QT_FT_COMPONENT is used in trace mode.  It is an implicit      */
+  /* parameter of the QT_FT_TRACE() and QT_FT_ERROR() macros, used to print/log  */
+  /* messages during execution.                                            */
+  /*                                                                       */
+#undef  QT_FT_COMPONENT
+#define QT_FT_COMPONENT  trace_smooth
+
+
+#define ErrRaster_MemoryOverflow   -4
+
+#if defined(VXWORKS)
+#  include <vxWorksCommon.h>    /* needed for setjmp.h */
+#endif
+#include <string.h>             /* for qt_ft_memcpy() */
+#include <setjmp.h>
+#include <limits.h>
+
+#define QT_FT_UINT_MAX  UINT_MAX
+
+#define qt_ft_memset   memset
+
+#define qt_ft_setjmp   setjmp
+#define qt_ft_longjmp  longjmp
+#define qt_ft_jmp_buf  jmp_buf
+
+#define ErrRaster_Invalid_Mode      -2
+#define ErrRaster_Invalid_Outline   -1
+#define ErrRaster_Invalid_Argument  -3
+#define ErrRaster_Memory_Overflow   -4
+
+#define QT_FT_BEGIN_HEADER
+#define QT_FT_END_HEADER
+
+#include <private/qrasterdefs_p.h>
+#include <private/qgrayraster_p.h>
+
+#include <stdlib.h>
+#include <stdio.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 QT_FT_UNUSED( x )  (x) = (x)
+
+  /* Disable the tracing mechanism for simplicity -- developers can      */
+  /* activate it easily by redefining these two macros.                  */
+#ifndef QT_FT_ERROR
+#define QT_FT_ERROR( x )  do ; while ( 0 )     /* nothing */
+#endif
+
+#ifndef QT_FT_TRACE
+#define QT_FT_TRACE( x )  do ; while ( 0 )     /* nothing */
+#endif
+
+#ifndef QT_FT_MEM_SET
+#define QT_FT_MEM_SET( d, s, c )  qt_ft_memset( d, s, c )
+#endif
+
+#ifndef QT_FT_MEM_ZERO
+#define QT_FT_MEM_ZERO( dest, count )  QT_FT_MEM_SET( dest, 0, count )
+#endif
+
+  /* define this to dump debugging information */
+#define xxxDEBUG_GRAYS
+
+
+#define RAS_ARG   PWorker  worker
+#define RAS_ARG_  PWorker  worker,
+
+#define RAS_VAR   worker
+#define RAS_VAR_  worker,
+
+#define ras       (*worker)
+
+
+  /* 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 QT_FT_Int or QT_FT_Pos, since we might */
+  /* need to define them to "float" or "double" when experimenting with   */
+  /* new algorithms                                                       */
+
+  typedef int   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 QT_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 QT_FT_MAX_GRAY_SPANS  256
+
+
+  typedef struct TCell_*  PCell;
+
+  typedef struct  TCell_
+  {
+    int    x;
+    int    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;
+    int     cover;
+    int     invalid;
+
+    PCell   cells;
+    int     max_cells;
+    int     num_cells;
+
+    TCoord  cx, cy;
+    TPos    x,  y;
+
+    TPos    last_ey;
+
+    QT_FT_Vector   bez_stack[32 * 3 + 1];
+    int         lev_stack[32];
+
+    QT_FT_Outline  outline;
+    QT_FT_Bitmap   target;
+    QT_FT_BBox     clip_box;
+
+    QT_FT_Span     gray_spans[QT_FT_MAX_GRAY_SPANS];
+    int         num_gray_spans;
+
+    QT_FT_Raster_Span_Func  render_span;
+    void*                render_span_data;
+
+    int  band_size;
+    int  band_shoot;
+    int  conic_level;
+    int  cubic_level;
+
+    qt_ft_jmp_buf  jump_buffer;
+
+    void*       buffer;
+    long        buffer_size;
+
+    PCell*     ycells;
+    int        ycount;
+
+  } TWorker, *PWorker;
+
+
+  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 )
+  {
+    QT_FT_Outline*  outline = &ras.outline;
+    QT_FT_Vector*   vec     = outline->points;
+    QT_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;
+    int     x = ras.ex;
+
+
+    if ( x > ras.max_ex )
+      x = ras.max_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 )
+      qt_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;
+    long    p, first, dx;
+    int     incr, lift, mod, rem;
+
+
+    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;
+    TPos    dx, dy, x, x2;
+    long    p, first;
+    int     delta, rem, mod, 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 );
+      TPos    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, 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, 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( QT_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 QT_FT_Vector*  control,
+                              const QT_FT_Vector*  to )
+  {
+    TPos        dx, dy;
+    int         top, level;
+    int*        levels;
+    QT_FT_Vector*  arc;
+
+
+    dx = DOWNSCALE( ras.x ) + to->x - ( control->x << 1 );
+    if ( dx < 0 )
+      dx = -dx;
+    dy = DOWNSCALE( ras.y ) + to->y - ( control->y << 1 );
+    if ( dy < 0 )
+      dy = -dy;
+    if ( dx < dy )
+      dx = dy;
+
+    level = 1;
+    dx = dx / ras.conic_level;
+    while ( dx > 0 )
+    {
+      dx >>= 2;
+      level++;
+    }
+
+    /* a shortcut to speed things up */
+    if ( level <= 1 )
+    {
+      /* we compute the mid-point directly in order to avoid */
+      /* calling gray_split_conic()                          */
+      TPos  to_x, to_y, mid_x, mid_y;
+
+
+      to_x  = UPSCALE( to->x );
+      to_y  = UPSCALE( to->y );
+      mid_x = ( ras.x + to_x + 2 * UPSCALE( control->x ) ) / 4;
+      mid_y = ( ras.y + to_y + 2 * UPSCALE( control->y ) ) / 4;
+
+      gray_render_line( RAS_VAR_ mid_x, mid_y );
+      gray_render_line( RAS_VAR_ to_x, to_y );
+
+      return;
+    }
+
+    arc       = ras.bez_stack;
+    levels    = ras.lev_stack;
+    top       = 0;
+    levels[0] = level;
+
+    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;
+
+    while ( top >= 0 )
+    {
+      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:
+      {
+        TPos  to_x, to_y, mid_x, mid_y;
+
+
+        to_x  = arc[0].x;
+        to_y  = arc[0].y;
+        mid_x = ( ras.x + to_x + 2 * arc[1].x ) / 4;
+        mid_y = ( ras.y + to_y + 2 * arc[1].y ) / 4;
+
+        gray_render_line( RAS_VAR_ mid_x, mid_y );
+        gray_render_line( RAS_VAR_ to_x, to_y );
+
+        top--;
+        arc -= 2;
+      }
+    }
+
+    return;
+  }
+
+
+  static void
+  gray_split_cubic( QT_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 QT_FT_Vector*  control1,
+                              const QT_FT_Vector*  control2,
+                              const QT_FT_Vector*  to )
+  {
+    TPos        dx, dy, da, db;
+    int         top, level;
+    int*        levels;
+    QT_FT_Vector*  arc;
+
+
+    dx = DOWNSCALE( ras.x ) + to->x - ( control1->x << 1 );
+    if ( dx < 0 )
+      dx = -dx;
+    dy = DOWNSCALE( ras.y ) + to->y - ( control1->y << 1 );
+    if ( dy < 0 )
+      dy = -dy;
+    if ( dx < dy )
+      dx = dy;
+    da = dx;
+
+    dx = DOWNSCALE( ras.x ) + to->x - 3 * ( control1->x + control2->x );
+    if ( dx < 0 )
+      dx = -dx;
+    dy = DOWNSCALE( ras.y ) + to->y - 3 * ( control1->x + control2->y );
+    if ( dy < 0 )
+      dy = -dy;
+    if ( dx < dy )
+      dx = dy;
+    db = dx;
+
+    level = 1;
+    da    = da / ras.cubic_level;
+    db    = db / ras.conic_level;
+    while ( da > 0 || db > 0 )
+    {
+      da >>= 2;
+      db >>= 3;
+      level++;
+    }
+
+    if ( level <= 1 )
+    {
+      TPos   to_x, to_y, mid_x, mid_y;
+
+
+      to_x  = UPSCALE( to->x );
+      to_y  = UPSCALE( to->y );
+      mid_x = ( ras.x + to_x +
+                3 * UPSCALE( control1->x + control2->x ) ) / 8;
+      mid_y = ( ras.y + to_y +
+                3 * UPSCALE( control1->y + control2->y ) ) / 8;
+
+      gray_render_line( RAS_VAR_ mid_x, mid_y );
+      gray_render_line( RAS_VAR_ to_x, to_y );
+      return;
+    }
+
+    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;
+
+    levels    = ras.lev_stack;
+    top       = 0;
+    levels[0] = level;
+
+    while ( top >= 0 )
+    {
+      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;
+        y = arc[3].y;
+        if ( y < min ) min = y;
+        if ( y > max ) max = y;
+        if ( TRUNC( min ) >= ras.max_ey || TRUNC( max ) < 0 )
+          goto Draw;
+        gray_split_cubic( arc );
+        arc += 3;
+        top ++;
+        levels[top] = levels[top - 1] = level - 1;
+        continue;
+      }
+
+    Draw:
+      {
+        TPos  to_x, to_y, mid_x, mid_y;
+
+
+        to_x  = arc[0].x;
+        to_y  = arc[0].y;
+        mid_x = ( ras.x + to_x + 3 * ( arc[1].x + arc[2].x ) ) / 8;
+        mid_y = ( ras.y + to_y + 3 * ( arc[1].y + arc[2].y ) ) / 8;
+
+        gray_render_line( RAS_VAR_ mid_x, mid_y );
+        gray_render_line( RAS_VAR_ to_x, to_y );
+        top --;
+        arc -= 3;
+      }
+    }
+
+    return;
+  }
+
+
+
+  static int
+  gray_move_to( const QT_FT_Vector*  to,
+                PWorker           worker )
+  {
+    TPos  x, y;
+
+
+    /* record current cell, if any */
+    gray_record_cell( worker );
+
+    /* start to a new position */
+    x = UPSCALE( to->x );
+    y = UPSCALE( to->y );
+
+    gray_start_cell( worker, TRUNC( x ), TRUNC( y ) );
+
+    worker->x = x;
+    worker->y = y;
+    return 0;
+  }
+
+
+  static int
+  gray_line_to( const QT_FT_Vector*  to,
+                PWorker           worker )
+  {
+    gray_render_line( worker, UPSCALE( to->x ), UPSCALE( to->y ) );
+    return 0;
+  }
+
+
+  static int
+  gray_conic_to( const QT_FT_Vector*  control,
+                 const QT_FT_Vector*  to,
+                 PWorker           worker )
+  {
+    gray_render_conic( worker, control, to );
+    return 0;
+  }
+
+
+  static int
+  gray_cubic_to( const QT_FT_Vector*  control1,
+                 const QT_FT_Vector*  control2,
+                 const QT_FT_Vector*  to,
+                 PWorker           worker )
+  {
+    gray_render_cubic( worker, control1, control2, to );
+    return 0;
+  }
+
+
+  static void
+  gray_render_span( int             count,
+                    const QT_FT_Span*  spans,
+                    PWorker         worker )
+  {
+    unsigned char*  p;
+    QT_FT_Bitmap*      map = &worker->target;
+
+    for ( ; count > 0; count--, spans++ )
+    {
+      unsigned char  coverage = spans->coverage;
+
+      /* first of all, compute the scanline offset */
+      p = (unsigned char*)map->buffer - spans->y * map->pitch;
+      if ( map->pitch >= 0 )
+        p += ( map->rows - 1 ) * map->pitch;
+
+
+      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 )
+          QT_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,
+                       int     acount )
+  {
+    QT_FT_Span*  span;
+    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 & QT_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;
+
+    /* QT_FT_Span.x is a 16-bit short, so limit our coordinates appropriately */
+    if ( x >= 32768 )
+      x = 32767;
+
+    if ( coverage )
+    {
+      /* see whether we can add this span to the current list */
+      span  = ras.gray_spans + ras.num_gray_spans - 1;
+      if ( ras.num_gray_spans > 0             &&
+           span->y == y                       &&
+           (int)span->x + span->len == (int)x &&
+           span->coverage == coverage         )
+      {
+        span->len = (unsigned short)( span->len + acount );
+        return;
+      }
+
+      if ( ras.num_gray_spans >= QT_FT_MAX_GRAY_SPANS )
+      {
+        if ( ras.render_span )
+          ras.render_span( ras.num_gray_spans, ras.gray_spans,
+                           ras.render_span_data );
+        /* ras.render_span( span->y, ras.gray_spans, count ); */
+
+#ifdef DEBUG_GRAYS
+
+        if ( 1 )
+        {
+          int  n;
+
+
+          fprintf( stderr, "y=%3d ", y );
+          span = ras.gray_spans;
+          for ( n = 0; n < count; n++, span++ )
+            fprintf( stderr, "[%d..%d]:%02x ",
+                     span->x, span->x + span->len - 1, span->coverage );
+          fprintf( stderr, "\n" );
+        }
+
+#endif /* DEBUG_GRAYS */
+
+        ras.num_gray_spans = 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->y        = (short)y;
+      span->coverage = (unsigned char)coverage;
+
+      ras.num_gray_spans++;
+    }
+  }
+
+
+#ifdef DEBUG_GRAYS
+
+  /* to be called while in the debugger */
+  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( " (%3d, c:%4d, a:%6d)", cell->x, cell->cover, cell->area );
+      printf( "\n" );
+    }
+  }
+
+#endif /* DEBUG_GRAYS */
+
+
+  static void
+  gray_sweep( RAS_ARG_ const QT_FT_Bitmap*  target )
+  {
+    int  yindex;
+
+    QT_FT_UNUSED( target );
+
+
+    if ( ras.num_cells == 0 )
+      return;
+
+    for ( yindex = 0; yindex < ras.ycount; yindex++ )
+    {
+      PCell   cell  = ras.ycells[yindex];
+      TCoord  cover = 0;
+      TCoord  x     = 0;
+
+
+      for ( ; cell != NULL; cell = cell->next )
+      {
+        TArea  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 ( ras.count_ex > x && cover != 0 )
+        gray_hline( RAS_VAR_ x, yindex, cover * ( ONE_PIXEL * 2 ),
+                    ras.count_ex - x );
+    }
+  }
+
+  /*************************************************************************/
+  /*                                                                       */
+  /*  The following function should only compile in stand_alone mode,      */
+  /*  i.e., when building this component without the rest of FreeType.     */
+  /*                                                                       */
+  /*************************************************************************/
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    QT_FT_Outline_Decompose                                               */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Walks over an outline's structure to decompose it into individual  */
+  /*    segments and Bezier 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.                                      */
+  /*                                                                       */
+  /*    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  QT_FT_Outline_Decompose( const QT_FT_Outline*        outline,
+                             const QT_FT_Outline_Funcs*  func_interface,
+                             void*                    user )
+  {
+#undef SCALED
+#if 0
+#define SCALED( x )  ( ( (x) << shift ) - delta )
+#else
+#define SCALED( x )  (x)
+#endif
+
+    QT_FT_Vector   v_last;
+    QT_FT_Vector   v_control;
+    QT_FT_Vector   v_start;
+
+    QT_FT_Vector*  point;
+    QT_FT_Vector*  limit;
+    char*       tags;
+
+    int   n;         /* index of contour in outline     */
+    int   first;     /* index of first point in contour */
+    int   error;
+    char  tag;       /* current point's state           */
+
+#if 0
+    int   shift = func_interface->shift;
+    TPos  delta = func_interface->delta;
+#endif
+
+
+    first = 0;
+
+    for ( n = 0; n < outline->n_contours; n++ )
+    {
+      int  last;  /* index of last point in contour */
+
+
+      last  = outline->contours[n];
+      limit = outline->points + last;
+
+      v_start = outline->points[first];
+      v_last  = outline->points[last];
+
+      v_start.x = SCALED( v_start.x );
+      v_start.y = SCALED( v_start.y );
+
+      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   = QT_FT_CURVE_TAG( tags[0] );
+
+      /* A contour cannot start with a cubic control point! */
+      if ( tag == QT_FT_CURVE_TAG_CUBIC )
+        goto Invalid_Outline;
+
+      /* check first point to determine origin */
+      if ( tag == QT_FT_CURVE_TAG_CONIC )
+      {
+        /* first point is conic control.  Yes, this happens. */
+        if ( QT_FT_CURVE_TAG( outline->tags[last] ) == QT_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--;
+      }
+
+      error = func_interface->move_to( &v_start, user );
+      if ( error )
+        goto Exit;
+
+      while ( point < limit )
+      {
+        point++;
+        tags++;
+
+        tag = QT_FT_CURVE_TAG( tags[0] );
+        switch ( tag )
+        {
+        case QT_FT_CURVE_TAG_ON:  /* emit a single line_to */
+          {
+            QT_FT_Vector  vec;
+
+
+            vec.x = SCALED( point->x );
+            vec.y = SCALED( point->y );
+
+            error = func_interface->line_to( &vec, user );
+            if ( error )
+              goto Exit;
+            continue;
+          }
+
+        case QT_FT_CURVE_TAG_CONIC:  /* consume conic arcs */
+          {
+            v_control.x = SCALED( point->x );
+            v_control.y = SCALED( point->y );
+
+          Do_Conic:
+            if ( point < limit )
+            {
+              QT_FT_Vector  vec;
+              QT_FT_Vector  v_middle;
+
+
+              point++;
+              tags++;
+              tag = QT_FT_CURVE_TAG( tags[0] );
+
+              vec.x = SCALED( point->x );
+              vec.y = SCALED( point->y );
+
+              if ( tag == QT_FT_CURVE_TAG_ON )
+              {
+                error = func_interface->conic_to( &v_control, &vec,
+                                                  user );
+                if ( error )
+                  goto Exit;
+                continue;
+              }
+
+              if ( tag != QT_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;
+
+              error = func_interface->conic_to( &v_control, &v_middle,
+                                                user );
+              if ( error )
+                goto Exit;
+
+              v_control = vec;
+              goto Do_Conic;
+            }
+
+            error = func_interface->conic_to( &v_control, &v_start,
+                                              user );
+            goto Close;
+          }
+
+        default:  /* QT_FT_CURVE_TAG_CUBIC */
+          {
+            QT_FT_Vector  vec1, vec2;
+
+
+            if ( point + 1 > limit                             ||
+                 QT_FT_CURVE_TAG( tags[1] ) != QT_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 )
+            {
+              QT_FT_Vector  vec;
+
+
+              vec.x = SCALED( point->x );
+              vec.y = SCALED( point->y );
+
+              error = func_interface->cubic_to( &vec1, &vec2, &vec, user );
+              if ( error )
+                goto Exit;
+              continue;
+            }
+
+            error = func_interface->cubic_to( &vec1, &vec2, &v_start, user );
+            goto Close;
+          }
+        }
+      }
+
+      /* close the contour with a line segment */
+      error = func_interface->line_to( &v_start, user );
+
+   Close:
+      if ( error )
+        goto Exit;
+
+      first = last + 1;
+    }
+
+    return 0;
+
+  Exit:
+    return error;
+
+  Invalid_Outline:
+    return ErrRaster_Invalid_Outline;
+  }
+
+  typedef struct  TBand_
+  {
+    TPos  min, max;
+
+  } TBand;
+
+
+  static int
+  gray_convert_glyph_inner( RAS_ARG )
+  {
+    static
+    const QT_FT_Outline_Funcs  func_interface =
+    {
+      (QT_FT_Outline_MoveTo_Func) gray_move_to,
+      (QT_FT_Outline_LineTo_Func) gray_line_to,
+      (QT_FT_Outline_ConicTo_Func)gray_conic_to,
+      (QT_FT_Outline_CubicTo_Func)gray_cubic_to,
+      0,
+      0
+    };
+
+    volatile int  error = 0;
+
+    if ( qt_ft_setjmp( ras.jump_buffer ) == 0 )
+    {
+      error = QT_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;
+    QT_FT_BBox*         clip;
+
+    ras.num_gray_spans = 0;
+
+    /* 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;
+
+    /* simple heuristic used to speed-up the bezier decomposition -- see */
+    /* the code in gray_render_conic() and gray_render_cubic() for more  */
+    /* details                                                           */
+    ras.conic_level = 32;
+    ras.cubic_level = 16;
+
+    {
+      int level = 0;
+
+
+      if ( ras.count_ex > 24 || ras.count_ey > 24 )
+        level++;
+      if ( ras.count_ex > 120 || ras.count_ey > 120 )
+        level++;
+
+      ras.conic_level <<= level;
+      ras.cubic_level <<= level;
+    }
+
+    /* setup 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 = (int)(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 DEBUG_GRAYS
+          fprintf( stderr, "Rotten glyph!\n" );
+#endif
+          /* == Raster_Err_OutOfMemory in qblackraster.c */
+          return -6;
+        }
+
+        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.render_span && ras.num_gray_spans > 0 )
+        ras.render_span( ras.num_gray_spans,
+                         ras.gray_spans, ras.render_span_data );
+
+    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 QT_FT_Raster_Params*  params )
+  {
+    const QT_FT_Outline*  outline    = (const QT_FT_Outline*)params->source;
+    const QT_FT_Bitmap*   target_map = params->target;
+    PWorker            worker;
+
+
+    if ( !raster || !raster->buffer || !raster->buffer_size )
+      return ErrRaster_Invalid_Argument;
+
+    /* return immediately if the outline is empty */
+    if ( outline->n_points == 0 || outline->n_contours <= 0 )
+      return 0;
+
+    if ( !outline || !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 & QT_FT_RASTER_FLAG_DIRECT ) == 0 )
+    {
+      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 & QT_FT_RASTER_FLAG_AA ) )
+      return ErrRaster_Invalid_Mode;
+
+    /* compute clipping box */
+    if ( ( params->flags & QT_FT_RASTER_FLAG_DIRECT ) == 0 )
+    {
+      /* 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 & QT_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( worker, raster->buffer, raster->buffer_size );
+
+    ras.outline   = *outline;
+    ras.num_cells = 0;
+    ras.invalid   = 1;
+    ras.band_size = raster->band_size;
+
+    if ( target_map )
+      ras.target = *target_map;
+
+    ras.render_span      = (QT_FT_Raster_Span_Func)gray_render_span;
+    ras.render_span_data = &ras;
+
+    if ( params->flags & QT_FT_RASTER_FLAG_DIRECT )
+    {
+      ras.render_span      = (QT_FT_Raster_Span_Func)params->gray_spans;
+      ras.render_span_data = params->user;
+    }
+
+    return gray_convert_glyph( worker );
+  }
+
+
+  /**** RASTER OBJECT CREATION: In standalone mode, we simply use *****/
+  /****                         a static object.                  *****/
+
+  static int
+  gray_raster_new( void *  memory,
+                   QT_FT_Raster*  araster )
+  {
+    if (memory)
+      fprintf(stderr, "gray_raster_new(), memory ignored");
+    memory = malloc(sizeof(TRaster));
+    if (!memory) {
+        *araster = 0;
+        return ErrRaster_Memory_Overflow;
+    }
+    QT_FT_MEM_ZERO(memory, sizeof(TRaster));
+
+    *araster = (QT_FT_Raster) memory;
+    return 0;
+  }
+
+
+  static void
+  gray_raster_done( QT_FT_Raster  raster )
+  {
+    free(raster);
+  }
+
+
+  static void
+  gray_raster_reset( QT_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;
+      }
+    }
+  }
+
+  const QT_FT_Raster_Funcs  qt_ft_grays_raster =
+  {
+    QT_FT_GLYPH_FORMAT_OUTLINE,
+
+    (QT_FT_Raster_New_Func)     gray_raster_new,
+    (QT_FT_Raster_Reset_Func)   gray_raster_reset,
+    (QT_FT_Raster_Set_Mode_Func)0,
+    (QT_FT_Raster_Render_Func)  gray_raster_render,
+    (QT_FT_Raster_Done_Func)    gray_raster_done
+  };
+
+/* END */