harfbuzz-gpos.c

Pango is a library for layout and rendering of text, with an emphasis on internationalization. Pang

/*
 * Copyright (C) 1998-2004  David Turner and Werner Lemberg
 * Copyright (C) 2006  Behdad Esfahbod
 * Copyright (C) 2007  Red Hat, Inc.
 *
 * This is part of HarfBuzz, an OpenType Layout engine library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Red Hat Author(s): Behdad Esfahbod
 */

#include "harfbuzz-impl.h"
#include "harfbuzz-gpos-private.h"
#include "harfbuzz-open-private.h"
#include "harfbuzz-gdef-private.h"

struct  GPOS_Instance_
{
  HB_GPOSHeader*  gpos;
  HB_Font          font;
  HB_Bool          dvi;
  HB_UShort        load_flags;  /* how the glyph should be loaded */
  HB_Bool          r2l;

  HB_UShort        last;        /* the last valid glyph -- used
				   with cursive positioning     */
  HB_Fixed           anchor_x;    /* the coordinates of the anchor point */
  HB_Fixed           anchor_y;    /* of the last valid glyph             */
};

typedef struct GPOS_Instance_  GPOS_Instance;


static HB_Error  GPOS_Do_Glyph_Lookup( GPOS_Instance*    gpi,
				       HB_UShort         lookup_index,
				       HB_Buffer        buffer,
				       HB_UShort         context_length,
				       int               nesting_level );



/* the client application must replace this with something more
   meaningful if multiple master fonts are to be supported.     */

static HB_Error  default_mmfunc( HB_Font      font,
				 HB_UShort    metric_id,
				 HB_Fixed*      metric_value,
				 void*        data )
{
  HB_UNUSED(font);
  HB_UNUSED(metric_id);
  HB_UNUSED(metric_value);
  HB_UNUSED(data);
  return ERR(HB_Err_Not_Covered); /* ERR() call intended */
}



HB_Error  HB_Load_GPOS_Table( HB_Font          font,
			      HB_GPOSHeader** retptr,
			      HB_GDEFHeader*  gdef )
{
  HB_UInt         cur_offset, new_offset, base_offset;

  HB_GPOSHeader*  gpos;

  HB_Stream  stream = font->stream;
  HB_Error   error;


  if ( !retptr )
    return ERR(HB_Err_Invalid_Argument);

  if ( GOTO_Table( TTAG_GPOS ) )
    return error;

  base_offset = FILE_Pos();

  if ( ALLOC ( gpos, sizeof( *gpos ) ) )
    return error;

  gpos->gfunc = FT_Load_Glyph;
  gpos->mmfunc = default_mmfunc;

  /* skip version */

  if ( FILE_Seek( base_offset + 4L ) ||
       ACCESS_Frame( 2L ) )
    goto Fail4;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_ScriptList( &gpos->ScriptList,
				  stream ) ) != HB_Err_Ok )
    goto Fail4;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail3;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_FeatureList( &gpos->FeatureList,
				   stream ) ) != HB_Err_Ok )
    goto Fail3;
  (void)FILE_Seek( cur_offset );

  if ( ACCESS_Frame( 2L ) )
    goto Fail2;

  new_offset = GET_UShort() + base_offset;

  FORGET_Frame();

  cur_offset = FILE_Pos();
  if ( FILE_Seek( new_offset ) ||
       ( error = _HB_OPEN_Load_LookupList( &gpos->LookupList,
				  stream, HB_Type_GPOS ) ) != HB_Err_Ok )
    goto Fail2;

  gpos->gdef = gdef;      /* can be NULL */

  if ( ( error =  _HB_GDEF_LoadMarkAttachClassDef_From_LookupFlags( gdef, stream,
								     gpos->LookupList.Lookup,
								     gpos->LookupList.LookupCount ) ) )
	  goto Fail1;

  *retptr = gpos;

  return HB_Err_Ok;

Fail1:
  _HB_OPEN_Free_LookupList( &gpos->LookupList, HB_Type_GPOS );

Fail2:
  _HB_OPEN_Free_FeatureList( &gpos->FeatureList );

Fail3:
  _HB_OPEN_Free_ScriptList( &gpos->ScriptList );

Fail4:
  FREE( gpos );

  return error;
}


HB_Error  HB_Done_GPOS_Table( HB_GPOSHeader* gpos )
{
  _HB_OPEN_Free_LookupList( &gpos->LookupList, HB_Type_GPOS );
  _HB_OPEN_Free_FeatureList( &gpos->FeatureList );
  _HB_OPEN_Free_ScriptList( &gpos->ScriptList );

  FREE( gpos );

  return HB_Err_Ok;
}


/*****************************
 * SubTable related functions
 *****************************/

/* shared tables */

/* ValueRecord */

/* There is a subtle difference in the specs between a `table' and a
   `record' -- offsets for device tables in ValueRecords are taken from
   the parent table and not the parent record.                          */

static HB_Error  Load_ValueRecord( HB_ValueRecord*  vr,
				   HB_UShort         format,
				   HB_UInt          base_offset,
				   HB_Stream         stream )
{
  HB_Error  error;

  HB_UInt cur_offset, new_offset;


  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->XPlacement = GET_Short();

    FORGET_Frame();
  }
  else
    vr->XPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->YPlacement = GET_Short();

    FORGET_Frame();
  }
  else
    vr->YPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->XAdvance = GET_Short();

    FORGET_Frame();
  }
  else
    vr->XAdvance = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    vr->YAdvance = GET_Short();

    FORGET_Frame();
  }
  else
    vr->YAdvance = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      return error;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->XPlacementDevice,
				  stream ) ) != HB_Err_Ok )
	return error;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty1;
  }
  else
  {
  empty1:
    vr->XPlacementDevice.StartSize  = 0;
    vr->XPlacementDevice.EndSize    = 0;
    vr->XPlacementDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail3;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->YPlacementDevice,
				  stream ) ) != HB_Err_Ok )
	goto Fail3;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty2;
  }
  else
  {
  empty2:
    vr->YPlacementDevice.StartSize  = 0;
    vr->YPlacementDevice.EndSize    = 0;
    vr->YPlacementDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->XAdvanceDevice,
				  stream ) ) != HB_Err_Ok )
	goto Fail2;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty3;
  }
  else
  {
  empty3:
    vr->XAdvanceDevice.StartSize  = 0;
    vr->XAdvanceDevice.EndSize    = 0;
    vr->XAdvanceDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE_DEVICE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    new_offset = GET_UShort();

    FORGET_Frame();

    if ( new_offset )
    {
      new_offset += base_offset;

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
	   ( error = _HB_OPEN_Load_Device( &vr->YAdvanceDevice,
				  stream ) ) != HB_Err_Ok )
	goto Fail1;
      (void)FILE_Seek( cur_offset );
    }
    else
      goto empty4;
  }
  else
  {
  empty4:
    vr->YAdvanceDevice.StartSize  = 0;
    vr->YAdvanceDevice.EndSize    = 0;
    vr->YAdvanceDevice.DeltaValue = NULL;
  }

  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->XIdPlacement = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->XIdPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_PLACEMENT )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->YIdPlacement = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->YIdPlacement = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->XIdAdvance = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->XIdAdvance = 0;

  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_ADVANCE )
  {
    if ( ACCESS_Frame( 2L ) )
      goto Fail1;

    vr->YIdAdvance = GET_UShort();

    FORGET_Frame();
  }
  else
    vr->YIdAdvance = 0;

  return HB_Err_Ok;

Fail1:
  _HB_OPEN_Free_Device( &vr->YAdvanceDevice );

Fail2:
  _HB_OPEN_Free_Device( &vr->XAdvanceDevice );

Fail3:
  _HB_OPEN_Free_Device( &vr->YPlacementDevice );
  return error;
}


static void  Free_ValueRecord( HB_ValueRecord*  vr,
			       HB_UShort         format )
{
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE_DEVICE )
    _HB_OPEN_Free_Device( &vr->YAdvanceDevice );
  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE_DEVICE )
    _HB_OPEN_Free_Device( &vr->XAdvanceDevice );
  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT_DEVICE )
    _HB_OPEN_Free_Device( &vr->YPlacementDevice );
  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT_DEVICE )
    _HB_OPEN_Free_Device( &vr->XPlacementDevice );
}


static HB_Error  Get_ValueRecord( GPOS_Instance*    gpi,
				  HB_ValueRecord*  vr,
				  HB_UShort         format,
				  HB_Position      gd )
{
  HB_Fixed           value;
  HB_Short         pixel_value;
  HB_Error         error = HB_Err_Ok;
  HB_GPOSHeader*  gpos = gpi->gpos;

  HB_UShort  x_ppem, y_ppem;
  HB_16Dot16   x_scale, y_scale;


  if ( !format )
    return HB_Err_Ok;

  x_ppem  = gpi->font->size->metrics.x_ppem;
  y_ppem  = gpi->font->size->metrics.y_ppem;
  x_scale = gpi->font->size->metrics.x_scale;
  y_scale = gpi->font->size->metrics.y_scale;

  /* design units -> fractional pixel */

  if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT )
    gd->x_pos += x_scale * vr->XPlacement / 0x10000;
  if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT )
    gd->y_pos += y_scale * vr->YPlacement / 0x10000;
  if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE )
    gd->x_advance += x_scale * vr->XAdvance / 0x10000;
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE )
    gd->y_advance += y_scale * vr->YAdvance / 0x10000;

  if ( !gpi->dvi )
  {
    /* pixel -> fractional pixel */

    if ( format & HB_GPOS_FORMAT_HAVE_X_PLACEMENT_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->XPlacementDevice, x_ppem, &pixel_value );
      gd->x_pos += pixel_value << 6;
    }
    if ( format & HB_GPOS_FORMAT_HAVE_Y_PLACEMENT_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->YPlacementDevice, y_ppem, &pixel_value );
      gd->y_pos += pixel_value << 6;
    }
    if ( format & HB_GPOS_FORMAT_HAVE_X_ADVANCE_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->XAdvanceDevice, x_ppem, &pixel_value );
      gd->x_advance += pixel_value << 6;
    }
    if ( format & HB_GPOS_FORMAT_HAVE_Y_ADVANCE_DEVICE )
    {
      _HB_OPEN_Get_Device( &vr->YAdvanceDevice, y_ppem, &pixel_value );
      gd->y_advance += pixel_value << 6;
    }
  }

  /* values returned from mmfunc() are already in fractional pixels */

  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_PLACEMENT )
  {
    error = (gpos->mmfunc)( gpi->font, vr->XIdPlacement,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->x_pos += value;
  }
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_PLACEMENT )
  {
    error = (gpos->mmfunc)( gpi->font, vr->YIdPlacement,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->y_pos += value;
  }
  if ( format & HB_GPOS_FORMAT_HAVE_X_ID_ADVANCE )
  {
    error = (gpos->mmfunc)( gpi->font, vr->XIdAdvance,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->x_advance += value;
  }
  if ( format & HB_GPOS_FORMAT_HAVE_Y_ID_ADVANCE )
  {
    error = (gpos->mmfunc)( gpi->font, vr->YIdAdvance,
			    &value, gpos->data );
    if ( error )
      return error;
    gd->y_advance += value;
  }

  return error;
}


/* AnchorFormat1 */
/* AnchorFormat2 */
/* AnchorFormat3 */
/* AnchorFormat4 */

static HB_Error  Load_Anchor( HB_Anchor*  an,
			      HB_Stream    stream )
{
  HB_Error  error;

  HB_UInt cur_offset, new_offset, base_offset;


  base_offset = FILE_Pos();

  if ( ACCESS_Frame( 2L ) )
    return error;

  an->PosFormat = GET_UShort();

  FORGET_Frame();

  switch ( an->PosFormat )
  {
  case 1:
    if ( ACCESS_Frame( 4L ) )
      return error;

    an->af.af1.XCoordinate = GET_Short();
    an->af.af1.YCoordinate = GET_Short();

    FORGET_Frame();
    break;

  case 2:
    if ( ACCESS_Frame( 6L ) )
      return error;

    an->af.af2.XCoordinate = GET_Short();
    an->af.af2.YCoordinate = GET_Short();
    an->af.af2.AnchorPoint = GET_UShort();

    FORGET_Frame();
    break;

  case 3:
    if ( ACCESS_Frame( 6L ) )
      return error;

    an->af.af3.XCoordinate = GET_Short();
    an->af.af3.YCoordinate = GET_Short();