misc/libfreetype/src/truetype/ttgxvar.c
changeset 5172 88f2e05288ba
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/truetype/ttgxvar.c	Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,1548 @@
+/***************************************************************************/
+/*                                                                         */
+/*  ttgxvar.c                                                              */
+/*                                                                         */
+/*    TrueType GX Font Variation loader                                    */
+/*                                                                         */
+/*  Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010 by                  */
+/*  David Turner, Robert Wilhelm, Werner Lemberg, and George Williams.     */
+/*                                                                         */
+/*  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.                                        */
+/*                                                                         */
+/***************************************************************************/
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* Apple documents the `fvar', `gvar', `cvar', and `avar' tables at      */
+  /*                                                                       */
+  /*   http://developer.apple.com/fonts/TTRefMan/RM06/Chap6[fgca]var.html  */
+  /*                                                                       */
+  /* The documentation for `fvar' is inconsistent.  At one point it says   */
+  /* that `countSizePairs' should be 3, at another point 2.  It should     */
+  /* be 2.                                                                 */
+  /*                                                                       */
+  /* The documentation for `gvar' is not intelligible; `cvar' refers you   */
+  /* to `gvar' and is thus also incomprehensible.                          */
+  /*                                                                       */
+  /* The documentation for `avar' appears correct, but Apple has no fonts  */
+  /* with an `avar' table, so it is hard to test.                          */
+  /*                                                                       */
+  /* Many thanks to John Jenkins (at Apple) in figuring this out.          */
+  /*                                                                       */
+  /*                                                                       */
+  /* Apple's `kern' table has some references to tuple indices, but as     */
+  /* there is no indication where these indices are defined, nor how to    */
+  /* interpolate the kerning values (different tuples have different       */
+  /* classes) this issue is ignored.                                       */
+  /*                                                                       */
+  /*************************************************************************/
+
+
+#include <ft2build.h>
+#include FT_INTERNAL_DEBUG_H
+#include FT_CONFIG_CONFIG_H
+#include FT_INTERNAL_STREAM_H
+#include FT_INTERNAL_SFNT_H
+#include FT_TRUETYPE_TAGS_H
+#include FT_MULTIPLE_MASTERS_H
+
+#include "ttpload.h"
+#include "ttgxvar.h"
+
+#include "tterrors.h"
+
+
+#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
+
+
+#define FT_Stream_FTell( stream )  \
+          ( (stream)->cursor - (stream)->base )
+#define FT_Stream_SeekSet( stream, off ) \
+              ( (stream)->cursor = (stream)->base+(off) )
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* 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_ttgxvar
+
+
+  /*************************************************************************/
+  /*************************************************************************/
+  /*****                                                               *****/
+  /*****                       Internal Routines                       *****/
+  /*****                                                               *****/
+  /*************************************************************************/
+  /*************************************************************************/
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* The macro ALL_POINTS is used in `ft_var_readpackedpoints'.  It        */
+  /* indicates that there is a delta for every point without needing to    */
+  /* enumerate all of them.                                                */
+  /*                                                                       */
+#define ALL_POINTS  (FT_UShort*)( -1 )
+
+
+#define GX_PT_POINTS_ARE_WORDS      0x80
+#define GX_PT_POINT_RUN_COUNT_MASK  0x7F
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    ft_var_readpackedpoints                                            */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Read a set of points to which the following deltas will apply.     */
+  /*    Points are packed with a run length encoding.                      */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    stream    :: The data stream.                                      */
+  /*                                                                       */
+  /* <Output>                                                              */
+  /*    point_cnt :: The number of points read.  A zero value means that   */
+  /*                 all points in the glyph will be affected, without     */
+  /*                 enumerating them individually.                        */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    An array of FT_UShort containing the affected points or the        */
+  /*    special value ALL_POINTS.                                          */
+  /*                                                                       */
+  static FT_UShort*
+  ft_var_readpackedpoints( FT_Stream  stream,
+                           FT_UInt   *point_cnt )
+  {
+    FT_UShort *points;
+    FT_Int     n;
+    FT_Int     runcnt;
+    FT_Int     i;
+    FT_Int     j;
+    FT_Int     first;
+    FT_Memory  memory = stream->memory;
+    FT_Error   error  = TT_Err_Ok;
+
+    FT_UNUSED( error );
+
+
+    *point_cnt = n = FT_GET_BYTE();
+    if ( n == 0 )
+      return ALL_POINTS;
+
+    if ( n & GX_PT_POINTS_ARE_WORDS )
+      n = FT_GET_BYTE() | ( ( n & GX_PT_POINT_RUN_COUNT_MASK ) << 8 );
+
+    if ( FT_NEW_ARRAY( points, n ) )
+      return NULL;
+
+    i = 0;
+    while ( i < n )
+    {
+      runcnt = FT_GET_BYTE();
+      if ( runcnt & GX_PT_POINTS_ARE_WORDS )
+      {
+        runcnt = runcnt & GX_PT_POINT_RUN_COUNT_MASK;
+        first  = points[i++] = FT_GET_USHORT();
+
+        if ( runcnt < 1 || i + runcnt >= n )
+          goto Exit;
+
+        /* first point not included in runcount */
+        for ( j = 0; j < runcnt; ++j )
+          points[i++] = (FT_UShort)( first += FT_GET_USHORT() );
+      }
+      else
+      {
+        first = points[i++] = FT_GET_BYTE();
+
+        if ( runcnt < 1 || i + runcnt >= n )
+          goto Exit;
+
+        for ( j = 0; j < runcnt; ++j )
+          points[i++] = (FT_UShort)( first += FT_GET_BYTE() );
+      }
+    }
+
+  Exit:
+    return points;
+  }
+
+
+  enum
+  {
+    GX_DT_DELTAS_ARE_ZERO      = 0x80,
+    GX_DT_DELTAS_ARE_WORDS     = 0x40,
+    GX_DT_DELTA_RUN_COUNT_MASK = 0x3F
+  };
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    ft_var_readpackeddeltas                                            */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Read a set of deltas.  These are packed slightly differently than  */
+  /*    points.  In particular there is no overall count.                  */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    stream    :: The data stream.                                      */
+  /*                                                                       */
+  /*    delta_cnt :: The number of to be read.                             */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    An array of FT_Short containing the deltas for the affected        */
+  /*    points.  (This only gets the deltas for one dimension.  It will    */
+  /*    generally be called twice, once for x, once for y.  When used in   */
+  /*    cvt table, it will only be called once.)                           */
+  /*                                                                       */
+  static FT_Short*
+  ft_var_readpackeddeltas( FT_Stream  stream,
+                           FT_Offset  delta_cnt )
+  {
+    FT_Short  *deltas = NULL;
+    FT_UInt    runcnt;
+    FT_Offset  i;
+    FT_UInt    j;
+    FT_Memory  memory = stream->memory;
+    FT_Error   error  = TT_Err_Ok;
+
+    FT_UNUSED( error );
+
+
+    if ( FT_NEW_ARRAY( deltas, delta_cnt ) )
+      return NULL;
+
+    i = 0;
+    while ( i < delta_cnt )
+    {
+      runcnt = FT_GET_BYTE();
+      if ( runcnt & GX_DT_DELTAS_ARE_ZERO )
+      {
+        /* runcnt zeroes get added */
+        for ( j = 0;
+              j <= ( runcnt & GX_DT_DELTA_RUN_COUNT_MASK ) && i < delta_cnt;
+              ++j )
+          deltas[i++] = 0;
+      }
+      else if ( runcnt & GX_DT_DELTAS_ARE_WORDS )
+      {
+        /* runcnt shorts from the stack */
+        for ( j = 0;
+              j <= ( runcnt & GX_DT_DELTA_RUN_COUNT_MASK ) && i < delta_cnt;
+              ++j )
+          deltas[i++] = FT_GET_SHORT();
+      }
+      else
+      {
+        /* runcnt signed bytes from the stack */
+        for ( j = 0;
+              j <= ( runcnt & GX_DT_DELTA_RUN_COUNT_MASK ) && i < delta_cnt;
+              ++j )
+          deltas[i++] = FT_GET_CHAR();
+      }
+
+      if ( j <= ( runcnt & GX_DT_DELTA_RUN_COUNT_MASK ) )
+      {
+        /* Bad format */
+        FT_FREE( deltas );
+        return NULL;
+      }
+    }
+
+    return deltas;
+  }
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    ft_var_load_avar                                                   */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Parse the `avar' table if present.  It need not be, so we return   */
+  /*    nothing.                                                           */
+  /*                                                                       */
+  /* <InOut>                                                               */
+  /*    face :: The font face.                                             */
+  /*                                                                       */
+  static void
+  ft_var_load_avar( TT_Face  face )
+  {
+    FT_Stream       stream = FT_FACE_STREAM(face);
+    FT_Memory       memory = stream->memory;
+    GX_Blend        blend  = face->blend;
+    GX_AVarSegment  segment;
+    FT_Error        error = TT_Err_Ok;
+    FT_ULong        version;
+    FT_Long         axisCount;
+    FT_Int          i, j;
+    FT_ULong        table_len;
+
+    FT_UNUSED( error );
+
+
+    blend->avar_checked = TRUE;
+    if ( (error = face->goto_table( face, TTAG_avar, stream, &table_len )) != 0 )
+      return;
+
+    if ( FT_FRAME_ENTER( table_len ) )
+      return;
+
+    version   = FT_GET_LONG();
+    axisCount = FT_GET_LONG();
+
+    if ( version != 0x00010000L                       ||
+         axisCount != (FT_Long)blend->mmvar->num_axis )
+      goto Exit;
+
+    if ( FT_NEW_ARRAY( blend->avar_segment, axisCount ) )
+      goto Exit;
+
+    segment = &blend->avar_segment[0];
+    for ( i = 0; i < axisCount; ++i, ++segment )
+    {
+      segment->pairCount = FT_GET_USHORT();
+      if ( FT_NEW_ARRAY( segment->correspondence, segment->pairCount ) )
+      {
+        /* Failure.  Free everything we have done so far.  We must do */
+        /* it right now since loading the `avar' table is optional.   */
+
+        for ( j = i - 1; j >= 0; --j )
+          FT_FREE( blend->avar_segment[j].correspondence );
+
+        FT_FREE( blend->avar_segment );
+        blend->avar_segment = NULL;
+        goto Exit;
+      }
+
+      for ( j = 0; j < segment->pairCount; ++j )
+      {
+        segment->correspondence[j].fromCoord =
+          FT_GET_SHORT() << 2;    /* convert to Fixed */
+        segment->correspondence[j].toCoord =
+          FT_GET_SHORT()<<2;    /* convert to Fixed */
+      }
+    }
+
+  Exit:
+    FT_FRAME_EXIT();
+  }
+
+
+  typedef struct  GX_GVar_Head_
+  {
+    FT_Long    version;
+    FT_UShort  axisCount;
+    FT_UShort  globalCoordCount;
+    FT_ULong   offsetToCoord;
+    FT_UShort  glyphCount;
+    FT_UShort  flags;
+    FT_ULong   offsetToData;
+
+  } GX_GVar_Head;
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    ft_var_load_gvar                                                   */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Parses the `gvar' table if present.  If `fvar' is there, `gvar'    */
+  /*    had better be there too.                                           */
+  /*                                                                       */
+  /* <InOut>                                                               */
+  /*    face :: The font face.                                             */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    FreeType error code.  0 means success.                             */
+  /*                                                                       */
+  static FT_Error
+  ft_var_load_gvar( TT_Face  face )
+  {
+    FT_Stream     stream = FT_FACE_STREAM(face);
+    FT_Memory     memory = stream->memory;
+    GX_Blend      blend  = face->blend;
+    FT_Error      error;
+    FT_UInt       i, j;
+    FT_ULong      table_len;
+    FT_ULong      gvar_start;
+    FT_ULong      offsetToData;
+    GX_GVar_Head  gvar_head;
+
+    static const FT_Frame_Field  gvar_fields[] =
+    {
+
+#undef  FT_STRUCTURE
+#define FT_STRUCTURE  GX_GVar_Head
+
+      FT_FRAME_START( 20 ),
+        FT_FRAME_LONG  ( version ),
+        FT_FRAME_USHORT( axisCount ),
+        FT_FRAME_USHORT( globalCoordCount ),
+        FT_FRAME_ULONG ( offsetToCoord ),
+        FT_FRAME_USHORT( glyphCount ),
+        FT_FRAME_USHORT( flags ),
+        FT_FRAME_ULONG ( offsetToData ),
+      FT_FRAME_END
+    };
+
+    if ( (error = face->goto_table( face, TTAG_gvar, stream, &table_len )) != 0 )
+      goto Exit;
+
+    gvar_start = FT_STREAM_POS( );
+    if ( FT_STREAM_READ_FIELDS( gvar_fields, &gvar_head ) )
+      goto Exit;
+
+    blend->tuplecount  = gvar_head.globalCoordCount;
+    blend->gv_glyphcnt = gvar_head.glyphCount;
+    offsetToData       = gvar_start + gvar_head.offsetToData;
+
+    if ( gvar_head.version   != (FT_Long)0x00010000L              ||
+         gvar_head.axisCount != (FT_UShort)blend->mmvar->num_axis )
+    {
+      error = TT_Err_Invalid_Table;
+      goto Exit;
+    }
+
+    if ( FT_NEW_ARRAY( blend->glyphoffsets, blend->gv_glyphcnt + 1 ) )
+      goto Exit;
+
+    if ( gvar_head.flags & 1 )
+    {
+      /* long offsets (one more offset than glyphs, to mark size of last) */
+      if ( FT_FRAME_ENTER( ( blend->gv_glyphcnt + 1 ) * 4L ) )
+        goto Exit;
+
+      for ( i = 0; i <= blend->gv_glyphcnt; ++i )
+        blend->glyphoffsets[i] = offsetToData + FT_GET_LONG();
+
+      FT_FRAME_EXIT();
+    }
+    else
+    {
+      /* short offsets (one more offset than glyphs, to mark size of last) */
+      if ( FT_FRAME_ENTER( ( blend->gv_glyphcnt + 1 ) * 2L ) )
+        goto Exit;
+
+      for ( i = 0; i <= blend->gv_glyphcnt; ++i )
+        blend->glyphoffsets[i] = offsetToData + FT_GET_USHORT() * 2;
+                                              /* XXX: Undocumented: `*2'! */
+
+      FT_FRAME_EXIT();
+    }
+
+    if ( blend->tuplecount != 0 )
+    {
+      if ( FT_NEW_ARRAY( blend->tuplecoords,
+                         gvar_head.axisCount * blend->tuplecount ) )
+        goto Exit;
+
+      if ( FT_STREAM_SEEK( gvar_start + gvar_head.offsetToCoord )       ||
+           FT_FRAME_ENTER( blend->tuplecount * gvar_head.axisCount * 2L )                   )
+        goto Exit;
+
+      for ( i = 0; i < blend->tuplecount; ++i )
+        for ( j = 0 ; j < (FT_UInt)gvar_head.axisCount; ++j )
+          blend->tuplecoords[i * gvar_head.axisCount + j] =
+            FT_GET_SHORT() << 2;                /* convert to FT_Fixed */
+
+      FT_FRAME_EXIT();
+    }
+
+  Exit:
+    return error;
+  }
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    ft_var_apply_tuple                                                 */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Figure out whether a given tuple (design) applies to the current   */
+  /*    blend, and if so, what is the scaling factor.                      */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    blend           :: The current blend of the font.                  */
+  /*                                                                       */
+  /*    tupleIndex      :: A flag saying whether this is an intermediate   */
+  /*                       tuple or not.                                   */
+  /*                                                                       */
+  /*    tuple_coords    :: The coordinates of the tuple in normalized axis */
+  /*                       units.                                          */
+  /*                                                                       */
+  /*    im_start_coords :: The initial coordinates where this tuple starts */
+  /*                       to apply (for intermediate coordinates).        */
+  /*                                                                       */
+  /*    im_end_coords   :: The final coordinates after which this tuple no */
+  /*                       longer applies (for intermediate coordinates).  */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    An FT_Fixed value containing the scaling factor.                   */
+  /*                                                                       */
+  static FT_Fixed
+  ft_var_apply_tuple( GX_Blend   blend,
+                      FT_UShort  tupleIndex,
+                      FT_Fixed*  tuple_coords,
+                      FT_Fixed*  im_start_coords,
+                      FT_Fixed*  im_end_coords )
+  {
+    FT_UInt   i;
+    FT_Fixed  apply;
+    FT_Fixed  temp;
+
+
+    apply = 0x10000L;
+    for ( i = 0; i < blend->num_axis; ++i )
+    {
+      if ( tuple_coords[i] == 0 )
+        /* It's not clear why (for intermediate tuples) we don't need     */
+        /* to check against start/end -- the documentation says we don't. */
+        /* Similarly, it's unclear why we don't need to scale along the   */
+        /* axis.                                                          */
+        continue;
+
+      else if ( blend->normalizedcoords[i] == 0                           ||
+                ( blend->normalizedcoords[i] < 0 && tuple_coords[i] > 0 ) ||
+                ( blend->normalizedcoords[i] > 0 && tuple_coords[i] < 0 ) )
+      {
+        apply = 0;
+        break;
+      }
+
+      else if ( !( tupleIndex & GX_TI_INTERMEDIATE_TUPLE ) )
+        /* not an intermediate tuple */
+        apply = FT_MulDiv( apply,
+                           blend->normalizedcoords[i] > 0
+                             ? blend->normalizedcoords[i]
+                             : -blend->normalizedcoords[i],
+                           0x10000L );
+
+      else if ( blend->normalizedcoords[i] <= im_start_coords[i] ||
+                blend->normalizedcoords[i] >= im_end_coords[i]   )
+      {
+        apply = 0;
+        break;
+      }
+
+      else if ( blend->normalizedcoords[i] < tuple_coords[i] )
+      {
+        temp = FT_MulDiv( blend->normalizedcoords[i] - im_start_coords[i],
+                          0x10000L,
+                          tuple_coords[i] - im_start_coords[i]);
+        apply = FT_MulDiv( apply, temp, 0x10000L );
+      }
+
+      else
+      {
+        temp = FT_MulDiv( im_end_coords[i] - blend->normalizedcoords[i],
+                          0x10000L,
+                          im_end_coords[i] - tuple_coords[i] );
+        apply = FT_MulDiv( apply, temp, 0x10000L );
+      }
+    }
+
+    return apply;
+  }
+
+
+  /*************************************************************************/
+  /*************************************************************************/
+  /*****                                                               *****/
+  /*****               MULTIPLE MASTERS SERVICE FUNCTIONS              *****/
+  /*****                                                               *****/
+  /*************************************************************************/
+  /*************************************************************************/
+
+
+  typedef struct  GX_FVar_Head_
+  {
+    FT_Long    version;
+    FT_UShort  offsetToData;
+    FT_UShort  countSizePairs;
+    FT_UShort  axisCount;
+    FT_UShort  axisSize;
+    FT_UShort  instanceCount;
+    FT_UShort  instanceSize;
+
+  } GX_FVar_Head;
+
+
+  typedef struct  fvar_axis_
+  {
+    FT_ULong   axisTag;
+    FT_ULong   minValue;
+    FT_ULong   defaultValue;
+    FT_ULong   maxValue;
+    FT_UShort  flags;
+    FT_UShort  nameID;
+
+  } GX_FVar_Axis;
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    TT_Get_MM_Var                                                      */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Check that the font's `fvar' table is valid, parse it, and return  */
+  /*    those data.                                                        */
+  /*                                                                       */
+  /* <InOut>                                                               */
+  /*    face   :: The font face.                                           */
+  /*              TT_Get_MM_Var initializes the blend structure.           */
+  /*                                                                       */
+  /* <Output>                                                              */
+  /*    master :: The `fvar' data (must be freed by caller).               */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    FreeType error code.  0 means success.                             */
+  /*                                                                       */
+  FT_LOCAL_DEF( FT_Error )
+  TT_Get_MM_Var( TT_Face      face,
+                 FT_MM_Var*  *master )
+  {
+    FT_Stream            stream = face->root.stream;
+    FT_Memory            memory = face->root.memory;
+    FT_ULong             table_len;
+    FT_Error             error  = TT_Err_Ok;
+    FT_ULong             fvar_start;
+    FT_Int               i, j;
+    FT_MM_Var*           mmvar;
+    FT_Fixed*            next_coords;
+    FT_String*           next_name;
+    FT_Var_Axis*         a;
+    FT_Var_Named_Style*  ns;
+    GX_FVar_Head         fvar_head;
+
+    static const FT_Frame_Field  fvar_fields[] =
+    {
+
+#undef  FT_STRUCTURE
+#define FT_STRUCTURE  GX_FVar_Head
+
+      FT_FRAME_START( 16 ),
+        FT_FRAME_LONG  ( version ),
+        FT_FRAME_USHORT( offsetToData ),
+        FT_FRAME_USHORT( countSizePairs ),
+        FT_FRAME_USHORT( axisCount ),
+        FT_FRAME_USHORT( axisSize ),
+        FT_FRAME_USHORT( instanceCount ),
+        FT_FRAME_USHORT( instanceSize ),
+      FT_FRAME_END
+    };
+
+    static const FT_Frame_Field  fvaraxis_fields[] =
+    {
+
+#undef  FT_STRUCTURE
+#define FT_STRUCTURE  GX_FVar_Axis
+
+      FT_FRAME_START( 20 ),
+        FT_FRAME_ULONG ( axisTag ),
+        FT_FRAME_ULONG ( minValue ),
+        FT_FRAME_ULONG ( defaultValue ),
+        FT_FRAME_ULONG ( maxValue ),
+        FT_FRAME_USHORT( flags ),
+        FT_FRAME_USHORT( nameID ),
+      FT_FRAME_END
+    };
+
+
+    if ( face->blend == NULL )
+    {
+      /* both `fvar' and `gvar' must be present */
+      if ( (error = face->goto_table( face, TTAG_gvar,
+                                      stream, &table_len )) != 0 )
+        goto Exit;
+
+      if ( (error = face->goto_table( face, TTAG_fvar,
+                                      stream, &table_len )) != 0 )
+        goto Exit;
+
+      fvar_start = FT_STREAM_POS( );
+
+      if ( FT_STREAM_READ_FIELDS( fvar_fields, &fvar_head ) )
+        goto Exit;
+
+      if ( fvar_head.version != (FT_Long)0x00010000L                      ||
+           fvar_head.countSizePairs != 2                                  ||
+           fvar_head.axisSize != 20                                       ||
+           /* axisCount limit implied by 16-bit instanceSize */
+           fvar_head.axisCount > 0x3FFE                                   ||
+           fvar_head.instanceSize != 4 + 4 * fvar_head.axisCount          ||
+           /* instanceCount limit implied by limited range of name IDs */
+           fvar_head.instanceCount > 0x7EFF                               ||
+           fvar_head.offsetToData + fvar_head.axisCount * 20U +
+             fvar_head.instanceCount * fvar_head.instanceSize > table_len )
+      {
+        error = TT_Err_Invalid_Table;
+        goto Exit;
+      }
+
+      if ( FT_NEW( face->blend ) )
+        goto Exit;
+
+      /* cannot overflow 32-bit arithmetic because of limits above */
+      face->blend->mmvar_len =
+        sizeof ( FT_MM_Var ) +
+        fvar_head.axisCount * sizeof ( FT_Var_Axis ) +
+        fvar_head.instanceCount * sizeof ( FT_Var_Named_Style ) +
+        fvar_head.instanceCount * fvar_head.axisCount * sizeof ( FT_Fixed ) +
+        5 * fvar_head.axisCount;
+
+      if ( FT_ALLOC( mmvar, face->blend->mmvar_len ) )
+        goto Exit;
+      face->blend->mmvar = mmvar;
+
+      mmvar->num_axis =
+        fvar_head.axisCount;
+      mmvar->num_designs =
+        (FT_UInt)-1;           /* meaningless in this context; each glyph */
+                               /* may have a different number of designs  */
+                               /* (or tuples, as called by Apple)         */
+      mmvar->num_namedstyles =
+        fvar_head.instanceCount;
+      mmvar->axis =
+        (FT_Var_Axis*)&(mmvar[1]);
+      mmvar->namedstyle =
+        (FT_Var_Named_Style*)&(mmvar->axis[fvar_head.axisCount]);
+
+      next_coords =
+        (FT_Fixed*)&(mmvar->namedstyle[fvar_head.instanceCount]);
+      for ( i = 0; i < fvar_head.instanceCount; ++i )
+      {
+        mmvar->namedstyle[i].coords  = next_coords;
+        next_coords                 += fvar_head.axisCount;
+      }
+
+      next_name = (FT_String*)next_coords;
+      for ( i = 0; i < fvar_head.axisCount; ++i )
+      {
+        mmvar->axis[i].name  = next_name;
+        next_name           += 5;
+      }
+
+      if ( FT_STREAM_SEEK( fvar_start + fvar_head.offsetToData ) )
+        goto Exit;
+
+      a = mmvar->axis;
+      for ( i = 0; i < fvar_head.axisCount; ++i )
+      {
+        GX_FVar_Axis  axis_rec;
+
+
+        if ( FT_STREAM_READ_FIELDS( fvaraxis_fields, &axis_rec ) )
+          goto Exit;
+        a->tag     = axis_rec.axisTag;
+        a->minimum = axis_rec.minValue;     /* A Fixed */
+        a->def     = axis_rec.defaultValue; /* A Fixed */
+        a->maximum = axis_rec.maxValue;     /* A Fixed */
+        a->strid   = axis_rec.nameID;
+
+        a->name[0] = (FT_String)(   a->tag >> 24 );
+        a->name[1] = (FT_String)( ( a->tag >> 16 ) & 0xFF );
+        a->name[2] = (FT_String)( ( a->tag >>  8 ) & 0xFF );
+        a->name[3] = (FT_String)( ( a->tag       ) & 0xFF );
+        a->name[4] = 0;
+
+        ++a;
+      }
+
+      ns = mmvar->namedstyle;
+      for ( i = 0; i < fvar_head.instanceCount; ++i, ++ns )
+      {
+        if ( FT_FRAME_ENTER( 4L + 4L * fvar_head.axisCount ) )
+          goto Exit;
+
+        ns->strid       =    FT_GET_USHORT();
+        (void) /* flags = */ FT_GET_USHORT();
+
+        for ( j = 0; j < fvar_head.axisCount; ++j )
+          ns->coords[j] = FT_GET_ULONG();     /* A Fixed */
+
+        FT_FRAME_EXIT();
+      }
+    }
+
+    if ( master != NULL )
+    {
+      FT_UInt  n;
+
+
+      if ( FT_ALLOC( mmvar, face->blend->mmvar_len ) )
+        goto Exit;
+      FT_MEM_COPY( mmvar, face->blend->mmvar, face->blend->mmvar_len );
+
+      mmvar->axis =
+        (FT_Var_Axis*)&(mmvar[1]);
+      mmvar->namedstyle =
+        (FT_Var_Named_Style*)&(mmvar->axis[mmvar->num_axis]);
+      next_coords =
+        (FT_Fixed*)&(mmvar->namedstyle[mmvar->num_namedstyles]);
+
+      for ( n = 0; n < mmvar->num_namedstyles; ++n )
+      {
+        mmvar->namedstyle[n].coords  = next_coords;
+        next_coords                 += mmvar->num_axis;
+      }
+
+      a = mmvar->axis;
+      next_name = (FT_String*)next_coords;
+      for ( n = 0; n < mmvar->num_axis; ++n )
+      {
+        a->name = next_name;
+
+        /* standard PostScript names for some standard apple tags */
+        if ( a->tag == TTAG_wght )
+          a->name = (char *)"Weight";
+        else if ( a->tag == TTAG_wdth )
+          a->name = (char *)"Width";
+        else if ( a->tag == TTAG_opsz )
+          a->name = (char *)"OpticalSize";
+        else if ( a->tag == TTAG_slnt )
+          a->name = (char *)"Slant";
+
+        next_name += 5;
+        ++a;
+      }
+
+      *master = mmvar;
+    }
+
+  Exit:
+    return error;
+  }
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    TT_Set_MM_Blend                                                    */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Set the blend (normalized) coordinates for this instance of the    */
+  /*    font.  Check that the `gvar' table is reasonable and does some     */
+  /*    initial preparation.                                               */
+  /*                                                                       */
+  /* <InOut>                                                               */
+  /*    face       :: The font.                                            */
+  /*                  Initialize the blend structure with `gvar' data.     */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    num_coords :: Must be the axis count of the font.                  */
+  /*                                                                       */
+  /*    coords     :: An array of num_coords, each between [-1,1].         */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    FreeType error code.  0 means success.                             */
+  /*                                                                       */
+  FT_LOCAL_DEF( FT_Error )
+  TT_Set_MM_Blend( TT_Face    face,
+                   FT_UInt    num_coords,
+                   FT_Fixed*  coords )
+  {
+    FT_Error    error = TT_Err_Ok;
+    GX_Blend    blend;
+    FT_MM_Var*  mmvar;
+    FT_UInt     i;
+    FT_Memory   memory = face->root.memory;
+
+    enum
+    {
+      mcvt_retain,
+      mcvt_modify,
+      mcvt_load
+
+    } manageCvt;
+
+
+    face->doblend = FALSE;
+
+    if ( face->blend == NULL )
+    {
+      if ( (error = TT_Get_MM_Var( face, NULL)) != 0 )
+        goto Exit;
+    }
+
+    blend = face->blend;
+    mmvar = blend->mmvar;
+
+    if ( num_coords != mmvar->num_axis )
+    {
+      error = TT_Err_Invalid_Argument;
+      goto Exit;
+    }
+
+    for ( i = 0; i < num_coords; ++i )
+      if ( coords[i] < -0x00010000L || coords[i] > 0x00010000L )
+      {
+        error = TT_Err_Invalid_Argument;
+        goto Exit;
+      }
+
+    if ( blend->glyphoffsets == NULL )
+      if ( (error = ft_var_load_gvar( face )) != 0 )
+        goto Exit;
+
+    if ( blend->normalizedcoords == NULL )
+    {
+      if ( FT_NEW_ARRAY( blend->normalizedcoords, num_coords ) )
+        goto Exit;
+
+      manageCvt = mcvt_modify;
+
+      /* If we have not set the blend coordinates before this, then the  */
+      /* cvt table will still be what we read from the `cvt ' table and  */
+      /* we don't need to reload it.  We may need to change it though... */
+    }
+    else
+    {
+      manageCvt = mcvt_retain;
+      for ( i = 0; i < num_coords; ++i )
+      {
+        if ( blend->normalizedcoords[i] != coords[i] )
+        {
+          manageCvt = mcvt_load;
+          break;
+        }
+      }
+
+      /* If we don't change the blend coords then we don't need to do  */
+      /* anything to the cvt table.  It will be correct.  Otherwise we */
+      /* no longer have the original cvt (it was modified when we set  */
+      /* the blend last time), so we must reload and then modify it.   */
+    }
+
+    blend->num_axis = num_coords;
+    FT_MEM_COPY( blend->normalizedcoords,
+                 coords,
+                 num_coords * sizeof ( FT_Fixed ) );
+
+    face->doblend = TRUE;
+
+    if ( face->cvt != NULL )
+    {
+      switch ( manageCvt )
+      {
+      case mcvt_load:
+        /* The cvt table has been loaded already; every time we change the */
+        /* blend we may need to reload and remodify the cvt table.         */
+        FT_FREE( face->cvt );
+        face->cvt = NULL;
+
+        tt_face_load_cvt( face, face->root.stream );
+        break;
+
+      case mcvt_modify:
+        /* The original cvt table is in memory.  All we need to do is */
+        /* apply the `cvar' table (if any).                           */
+        tt_face_vary_cvt( face, face->root.stream );
+        break;
+
+      case mcvt_retain:
+        /* The cvt table is correct for this set of coordinates. */
+        break;
+      }
+    }
+
+  Exit:
+    return error;
+  }
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    TT_Set_Var_Design                                                  */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Set the coordinates for the instance, measured in the user         */
+  /*    coordinate system.  Parse the `avar' table (if present) to convert */
+  /*    from user to normalized coordinates.                               */
+  /*                                                                       */
+  /* <InOut>                                                               */
+  /*    face       :: The font face.                                       */
+  /*                  Initialize the blend struct with `gvar' data.        */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    num_coords :: This must be the axis count of the font.             */
+  /*                                                                       */
+  /*    coords     :: A coordinate array with `num_coords' elements.       */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    FreeType error code.  0 means success.                             */
+  /*                                                                       */
+  FT_LOCAL_DEF( FT_Error )
+  TT_Set_Var_Design( TT_Face    face,
+                     FT_UInt    num_coords,
+                     FT_Fixed*  coords )
+  {
+    FT_Error        error      = TT_Err_Ok;
+    FT_Fixed*       normalized = NULL;
+    GX_Blend        blend;
+    FT_MM_Var*      mmvar;
+    FT_UInt         i, j;
+    FT_Var_Axis*    a;
+    GX_AVarSegment  av;
+    FT_Memory       memory = face->root.memory;
+
+
+    if ( face->blend == NULL )
+    {
+      if ( (error = TT_Get_MM_Var( face, NULL )) != 0 )
+        goto Exit;
+    }
+
+    blend = face->blend;
+    mmvar = blend->mmvar;
+
+    if ( num_coords != mmvar->num_axis )
+    {
+      error = TT_Err_Invalid_Argument;
+      goto Exit;
+    }
+
+    /* Axis normalization is a two stage process.  First we normalize */
+    /* based on the [min,def,max] values for the axis to be [-1,0,1]. */
+    /* Then, if there's an `avar' table, we renormalize this range.   */
+
+    if ( FT_NEW_ARRAY( normalized, mmvar->num_axis ) )
+      goto Exit;
+
+    a = mmvar->axis;
+    for ( i = 0; i < mmvar->num_axis; ++i, ++a )
+    {
+      if ( coords[i] > a->maximum || coords[i] < a->minimum )
+      {
+        error = TT_Err_Invalid_Argument;
+        goto Exit;
+      }
+
+      if ( coords[i] < a->def )
+      {
+        normalized[i] = -FT_MulDiv( coords[i] - a->def,
+                                    0x10000L,
+                                    a->minimum - a->def );
+      }
+      else if ( a->maximum == a->def )
+        normalized[i] = 0;
+      else
+      {
+        normalized[i] = FT_MulDiv( coords[i] - a->def,
+                                   0x10000L,
+                                   a->maximum - a->def );
+      }
+    }
+
+    if ( !blend->avar_checked )
+      ft_var_load_avar( face );
+
+    if ( blend->avar_segment != NULL )
+    {
+      av = blend->avar_segment;
+      for ( i = 0; i < mmvar->num_axis; ++i, ++av )
+      {
+        for ( j = 1; j < (FT_UInt)av->pairCount; ++j )
+          if ( normalized[i] < av->correspondence[j].fromCoord )
+          {
+            normalized[i] =
+              FT_MulDiv(
+                FT_MulDiv(
+                  normalized[i] - av->correspondence[j - 1].fromCoord,
+                  0x10000L,
+                  av->correspondence[j].fromCoord -
+                    av->correspondence[j - 1].fromCoord ),
+                av->correspondence[j].toCoord -
+                  av->correspondence[j - 1].toCoord,
+                0x10000L ) +
+              av->correspondence[j - 1].toCoord;
+            break;
+          }
+      }
+    }
+
+    error = TT_Set_MM_Blend( face, num_coords, normalized );
+
+  Exit:
+    FT_FREE( normalized );
+    return error;
+  }
+
+
+  /*************************************************************************/
+  /*************************************************************************/
+  /*****                                                               *****/
+  /*****                     GX VAR PARSING ROUTINES                   *****/
+  /*****                                                               *****/
+  /*************************************************************************/
+  /*************************************************************************/
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    tt_face_vary_cvt                                                   */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Modify the loaded cvt table according to the `cvar' table and the  */
+  /*    font's blend.                                                      */
+  /*                                                                       */
+  /* <InOut>                                                               */
+  /*    face   :: A handle to the target face object.                      */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    stream :: A handle to the input stream.                            */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    FreeType error code.  0 means success.                             */
+  /*                                                                       */
+  /*    Most errors are ignored.  It is perfectly valid not to have a      */
+  /*    `cvar' table even if there is a `gvar' and `fvar' table.           */
+  /*                                                                       */
+  FT_LOCAL_DEF( FT_Error )
+  tt_face_vary_cvt( TT_Face    face,
+                    FT_Stream  stream )
+  {
+    FT_Error    error;
+    FT_Memory   memory = stream->memory;
+    FT_ULong    table_start;
+    FT_ULong    table_len;
+    FT_UInt     tupleCount;
+    FT_ULong    offsetToData;
+    FT_ULong    here;
+    FT_UInt     i, j;
+    FT_Fixed*   tuple_coords    = NULL;
+    FT_Fixed*   im_start_coords = NULL;
+    FT_Fixed*   im_end_coords   = NULL;
+    GX_Blend    blend           = face->blend;
+    FT_UInt     point_count;
+    FT_UShort*  localpoints;
+    FT_Short*   deltas;
+
+
+    FT_TRACE2(( "CVAR " ));
+
+    if ( blend == NULL )
+    {
+      FT_TRACE2(( "tt_face_vary_cvt: no blend specified\n" ));
+
+      error = TT_Err_Ok;
+      goto Exit;
+    }
+
+    if ( face->cvt == NULL )
+    {
+      FT_TRACE2(( "tt_face_vary_cvt: no `cvt ' table\n" ));
+
+      error = TT_Err_Ok;
+      goto Exit;
+    }
+
+    error = face->goto_table( face, TTAG_cvar, stream, &table_len );
+    if ( error )
+    {
+      FT_TRACE2(( "is missing\n" ));
+
+      error = TT_Err_Ok;
+      goto Exit;
+    }
+
+    if ( FT_FRAME_ENTER( table_len ) )
+    {
+      error = TT_Err_Ok;
+      goto Exit;
+    }
+
+    table_start = FT_Stream_FTell( stream );
+    if ( FT_GET_LONG() != 0x00010000L )
+    {
+      FT_TRACE2(( "bad table version\n" ));
+
+      error = TT_Err_Ok;
+      goto FExit;
+    }
+
+    if ( FT_NEW_ARRAY( tuple_coords, blend->num_axis )    ||
+         FT_NEW_ARRAY( im_start_coords, blend->num_axis ) ||
+         FT_NEW_ARRAY( im_end_coords, blend->num_axis )   )
+      goto FExit;
+
+    tupleCount   = FT_GET_USHORT();
+    offsetToData = table_start + FT_GET_USHORT();
+
+    /* The documentation implies there are flags packed into the        */
+    /* tuplecount, but John Jenkins says that shared points don't apply */
+    /* to `cvar', and no other flags are defined.                       */
+
+    for ( i = 0; i < ( tupleCount & 0xFFF ); ++i )
+    {
+      FT_UInt   tupleDataSize;
+      FT_UInt   tupleIndex;
+      FT_Fixed  apply;
+
+
+      tupleDataSize = FT_GET_USHORT();
+      tupleIndex    = FT_GET_USHORT();
+
+      /* There is no provision here for a global tuple coordinate section, */
+      /* so John says.  There are no tuple indices, just embedded tuples.  */
+
+      if ( tupleIndex & GX_TI_EMBEDDED_TUPLE_COORD )
+      {
+        for ( j = 0; j < blend->num_axis; ++j )
+          tuple_coords[j] = FT_GET_SHORT() << 2; /* convert from        */
+                                                 /* short frac to fixed */
+      }
+      else
+      {
+        /* skip this tuple; it makes no sense */
+
+        if ( tupleIndex & GX_TI_INTERMEDIATE_TUPLE )
+          for ( j = 0; j < 2 * blend->num_axis; ++j )
+            (void)FT_GET_SHORT();
+
+        offsetToData += tupleDataSize;
+        continue;
+      }
+
+      if ( tupleIndex & GX_TI_INTERMEDIATE_TUPLE )
+      {
+        for ( j = 0; j < blend->num_axis; ++j )
+          im_start_coords[j] = FT_GET_SHORT() << 2;
+        for ( j = 0; j < blend->num_axis; ++j )
+          im_end_coords[j] = FT_GET_SHORT() << 2;
+      }
+
+      apply = ft_var_apply_tuple( blend,
+                                  (FT_UShort)tupleIndex,
+                                  tuple_coords,
+                                  im_start_coords,
+                                  im_end_coords );
+      if ( /* tuple isn't active for our blend */
+           apply == 0                                    ||
+           /* global points not allowed,           */
+           /* if they aren't local, makes no sense */
+           !( tupleIndex & GX_TI_PRIVATE_POINT_NUMBERS ) )
+      {
+        offsetToData += tupleDataSize;
+        continue;
+      }
+
+      here = FT_Stream_FTell( stream );
+
+      FT_Stream_SeekSet( stream, offsetToData );
+
+      localpoints = ft_var_readpackedpoints( stream, &point_count );
+      deltas      = ft_var_readpackeddeltas( stream,
+                                             point_count == 0 ? face->cvt_size
+                                                              : point_count );
+      if ( localpoints == NULL || deltas == NULL )
+        /* failure, ignore it */;
+
+      else if ( localpoints == ALL_POINTS )
+      {
+        /* this means that there are deltas for every entry in cvt */
+        for ( j = 0; j < face->cvt_size; ++j )
+          face->cvt[j] = (FT_Short)( face->cvt[j] +
+                                     FT_MulFix( deltas[j], apply ) );
+      }
+
+      else
+      {
+        for ( j = 0; j < point_count; ++j )
+        {
+          int  pindex = localpoints[j];
+
+          face->cvt[pindex] = (FT_Short)( face->cvt[pindex] +
+                                          FT_MulFix( deltas[j], apply ) );
+        }
+      }
+
+      if ( localpoints != ALL_POINTS )
+        FT_FREE( localpoints );
+      FT_FREE( deltas );
+
+      offsetToData += tupleDataSize;
+
+      FT_Stream_SeekSet( stream, here );
+    }
+
+  FExit:
+    FT_FRAME_EXIT();
+
+  Exit:
+    FT_FREE( tuple_coords );
+    FT_FREE( im_start_coords );
+    FT_FREE( im_end_coords );
+
+    return error;
+  }
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    TT_Vary_Get_Glyph_Deltas                                           */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Load the appropriate deltas for the current glyph.                 */
+  /*                                                                       */
+  /* <Input>                                                               */
+  /*    face        :: A handle to the target face object.                 */
+  /*                                                                       */
+  /*    glyph_index :: The index of the glyph being modified.              */
+  /*                                                                       */
+  /*    n_points    :: The number of the points in the glyph, including    */
+  /*                   phantom points.                                     */
+  /*                                                                       */
+  /* <Output>                                                              */
+  /*    deltas      :: The array of points to change.                      */
+  /*                                                                       */
+  /* <Return>                                                              */
+  /*    FreeType error code.  0 means success.                             */
+  /*                                                                       */
+  FT_LOCAL_DEF( FT_Error )
+  TT_Vary_Get_Glyph_Deltas( TT_Face      face,
+                            FT_UInt      glyph_index,
+                            FT_Vector*  *deltas,
+                            FT_UInt      n_points )
+  {
+    FT_Stream   stream = face->root.stream;
+    FT_Memory   memory = stream->memory;
+    GX_Blend    blend  = face->blend;
+    FT_Vector*  delta_xy;
+
+    FT_Error    error;
+    FT_ULong    glyph_start;
+    FT_UInt     tupleCount;
+    FT_ULong    offsetToData;
+    FT_ULong    here;
+    FT_UInt     i, j;
+    FT_Fixed*   tuple_coords    = NULL;
+    FT_Fixed*   im_start_coords = NULL;
+    FT_Fixed*   im_end_coords   = NULL;
+    FT_UInt     point_count, spoint_count = 0;
+    FT_UShort*  sharedpoints = NULL;
+    FT_UShort*  localpoints  = NULL;
+    FT_UShort*  points;
+    FT_Short    *deltas_x, *deltas_y;
+
+
+    if ( !face->doblend || blend == NULL )
+      return TT_Err_Invalid_Argument;
+
+    /* to be freed by the caller */
+    if ( FT_NEW_ARRAY( delta_xy, n_points ) )
+      goto Exit;
+    *deltas = delta_xy;
+
+    if ( glyph_index >= blend->gv_glyphcnt      ||
+         blend->glyphoffsets[glyph_index] ==
+           blend->glyphoffsets[glyph_index + 1] )
+      return TT_Err_Ok;               /* no variation data for this glyph */
+
+    if ( FT_STREAM_SEEK( blend->glyphoffsets[glyph_index] )   ||
+         FT_FRAME_ENTER( blend->glyphoffsets[glyph_index + 1] -
+                           blend->glyphoffsets[glyph_index] ) )
+      goto Fail1;
+
+    glyph_start = FT_Stream_FTell( stream );
+
+    /* each set of glyph variation data is formatted similarly to `cvar' */
+    /* (except we get shared points and global tuples)                   */
+
+    if ( FT_NEW_ARRAY( tuple_coords, blend->num_axis )    ||
+         FT_NEW_ARRAY( im_start_coords, blend->num_axis ) ||
+         FT_NEW_ARRAY( im_end_coords, blend->num_axis )   )
+      goto Fail2;
+
+    tupleCount   = FT_GET_USHORT();
+    offsetToData = glyph_start + FT_GET_USHORT();
+
+    if ( tupleCount & GX_TC_TUPLES_SHARE_POINT_NUMBERS )
+    {
+      here = FT_Stream_FTell( stream );
+
+      FT_Stream_SeekSet( stream, offsetToData );
+
+      sharedpoints = ft_var_readpackedpoints( stream, &spoint_count );
+      offsetToData = FT_Stream_FTell( stream );
+
+      FT_Stream_SeekSet( stream, here );
+    }
+
+    for ( i = 0; i < ( tupleCount & GX_TC_TUPLE_COUNT_MASK ); ++i )
+    {
+      FT_UInt   tupleDataSize;
+      FT_UInt   tupleIndex;
+      FT_Fixed  apply;
+
+
+      tupleDataSize = FT_GET_USHORT();
+      tupleIndex    = FT_GET_USHORT();
+
+      if ( tupleIndex & GX_TI_EMBEDDED_TUPLE_COORD )
+      {
+        for ( j = 0; j < blend->num_axis; ++j )
+          tuple_coords[j] = FT_GET_SHORT() << 2;  /* convert from        */
+                                                  /* short frac to fixed */
+      }
+      else if ( ( tupleIndex & GX_TI_TUPLE_INDEX_MASK ) >= blend->tuplecount )
+      {
+        error = TT_Err_Invalid_Table;
+        goto Fail3;
+      }
+      else
+      {
+        FT_MEM_COPY(
+          tuple_coords,
+          &blend->tuplecoords[(tupleIndex & 0xFFF) * blend->num_axis],
+          blend->num_axis * sizeof ( FT_Fixed ) );
+      }
+
+      if ( tupleIndex & GX_TI_INTERMEDIATE_TUPLE )
+      {
+        for ( j = 0; j < blend->num_axis; ++j )
+          im_start_coords[j] = FT_GET_SHORT() << 2;
+        for ( j = 0; j < blend->num_axis; ++j )
+          im_end_coords[j] = FT_GET_SHORT() << 2;
+      }
+
+      apply = ft_var_apply_tuple( blend,
+                                  (FT_UShort)tupleIndex,
+                                  tuple_coords,
+                                  im_start_coords,
+                                  im_end_coords );
+
+      if ( apply == 0 )              /* tuple isn't active for our blend */
+      {
+        offsetToData += tupleDataSize;
+        continue;
+      }
+
+      here = FT_Stream_FTell( stream );
+
+      if ( tupleIndex & GX_TI_PRIVATE_POINT_NUMBERS )
+      {
+        FT_Stream_SeekSet( stream, offsetToData );
+
+        localpoints = ft_var_readpackedpoints( stream, &point_count );
+        points      = localpoints;
+      }
+      else
+      {
+        points      = sharedpoints;
+        point_count = spoint_count;
+      }
+
+      deltas_x = ft_var_readpackeddeltas( stream,
+                                          point_count == 0 ? n_points
+                                                           : point_count );
+      deltas_y = ft_var_readpackeddeltas( stream,
+                                          point_count == 0 ? n_points
+                                                           : point_count );
+
+      if ( points == NULL || deltas_y == NULL || deltas_x == NULL )
+        ; /* failure, ignore it */
+
+      else if ( points == ALL_POINTS )
+      {
+        /* this means that there are deltas for every point in the glyph */
+        for ( j = 0; j < n_points; ++j )
+        {
+          delta_xy[j].x += FT_MulFix( deltas_x[j], apply );
+          delta_xy[j].y += FT_MulFix( deltas_y[j], apply );
+        }
+      }
+
+      else
+      {
+        for ( j = 0; j < point_count; ++j )
+        {
+          delta_xy[localpoints[j]].x += FT_MulFix( deltas_x[j], apply );
+          delta_xy[localpoints[j]].y += FT_MulFix( deltas_y[j], apply );
+        }
+      }
+
+      if ( localpoints != ALL_POINTS )
+        FT_FREE( localpoints );
+      FT_FREE( deltas_x );
+      FT_FREE( deltas_y );
+
+      offsetToData += tupleDataSize;
+
+      FT_Stream_SeekSet( stream, here );
+    }
+
+  Fail3:
+    FT_FREE( tuple_coords );
+    FT_FREE( im_start_coords );
+    FT_FREE( im_end_coords );
+
+  Fail2:
+    FT_FRAME_EXIT();
+
+  Fail1:
+    if ( error )
+    {
+      FT_FREE( delta_xy );
+      *deltas = NULL;
+    }
+
+  Exit:
+    return error;
+  }
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* <Function>                                                            */
+  /*    tt_done_blend                                                      */
+  /*                                                                       */
+  /* <Description>                                                         */
+  /*    Frees the blend internal data structure.                           */
+  /*                                                                       */
+  FT_LOCAL_DEF( void )
+  tt_done_blend( FT_Memory  memory,
+                 GX_Blend   blend )
+  {
+    if ( blend != NULL )
+    {
+      FT_UInt  i;
+
+
+      FT_FREE( blend->normalizedcoords );
+      FT_FREE( blend->mmvar );
+
+      if ( blend->avar_segment != NULL )
+      {
+        for ( i = 0; i < blend->num_axis; ++i )
+          FT_FREE( blend->avar_segment[i].correspondence );
+        FT_FREE( blend->avar_segment );
+      }
+
+      FT_FREE( blend->tuplecoords );
+      FT_FREE( blend->glyphoffsets );
+      FT_FREE( blend );
+    }
+  }
+
+#endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
+
+
+/* END */