ftgloadr.c

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/***************************************************************************/
/*                                                                         */
/*  ftgloadr.c                                                             */
/*                                                                         */
/*    The FreeType glyph loader (body).                                    */
/*                                                                         */
/*  Copyright 2002-2018 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg                       */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/
 
 
#include <ft2build.h>
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_GLYPH_LOADER_H
#include FT_INTERNAL_MEMORY_H
#include FT_INTERNAL_OBJECTS_H
 
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_gloader
 
 
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  /*************************************************************************/
  /*                                                                       */
  /* The glyph loader is a simple object which is used to load a set of    */
  /* glyphs easily.  It is critical for the correct loading of composites. */
  /*                                                                       */
  /* Ideally, one can see it as a stack of abstract `glyph' objects.       */
  /*                                                                       */
  /*   loader.base     Is really the bottom of the stack.  It describes a  */
  /*                   single glyph image made of the juxtaposition of     */
  /*                   several glyphs (those `in the stack').              */
  /*                                                                       */
  /*   loader.current  Describes the top of the stack, on which a new      */
  /*                   glyph can be loaded.                                */
  /*                                                                       */
  /*   Rewind          Clears the stack.                                   */
  /*   Prepare         Set up `loader.current' for addition of a new glyph */
  /*                   image.                                              */
  /*   Add             Add the `current' glyph image to the `base' one,    */
  /*                   and prepare for another one.                        */
  /*                                                                       */
  /* The glyph loader is now a base object.  Each driver used to           */
  /* re-implement it in one way or the other, which wasted code and        */
  /* energy.                                                               */
  /*                                                                       */
  /*************************************************************************/
 
 
  /* create a new glyph loader */
  FT_BASE_DEF( FT_Error )
  FT_GlyphLoader_New( FT_Memory        memory,
                      FT_GlyphLoader  *aloader )
  {
    FT_GlyphLoader  loader = NULL;
    FT_Error        error;
 
 
    if ( !FT_NEW( loader ) )
    {
      loader->memory = memory;
      *aloader       = loader;
    }
    return error;
  }
 
 
  /* rewind the glyph loader - reset counters to 0 */
  FT_BASE_DEF( void )
  FT_GlyphLoader_Rewind( FT_GlyphLoader  loader )
  {
    FT_GlyphLoad  base    = &loader->base;
    FT_GlyphLoad  current = &loader->current;
 
 
    base->outline.n_points   = 0;
    base->outline.n_contours = 0;
    base->num_subglyphs      = 0;
 
    *current = *base;
  }
 
 
  /* reset the glyph loader, frees all allocated tables */
  /* and starts from zero                               */
  FT_BASE_DEF( void )
  FT_GlyphLoader_Reset( FT_GlyphLoader  loader )
  {
    FT_Memory memory = loader->memory;
 
 
    FT_FREE( loader->base.outline.points );
    FT_FREE( loader->base.outline.tags );
    FT_FREE( loader->base.outline.contours );
    FT_FREE( loader->base.extra_points );
    FT_FREE( loader->base.subglyphs );
 
    loader->base.extra_points2 = NULL;
 
    loader->max_points    = 0;
    loader->max_contours  = 0;
    loader->max_subglyphs = 0;
 
    FT_GlyphLoader_Rewind( loader );
  }
 
 
  /* delete a glyph loader */
  FT_BASE_DEF( void )
  FT_GlyphLoader_Done( FT_GlyphLoader  loader )
  {
    if ( loader )
    {
      FT_Memory memory = loader->memory;
 
 
      FT_GlyphLoader_Reset( loader );
      FT_FREE( loader );
    }
  }
 
 
  /* re-adjust the `current' outline fields */
  static void
  FT_GlyphLoader_Adjust_Points( FT_GlyphLoader  loader )
  {
    FT_Outline*  base    = &loader->base.outline;
    FT_Outline*  current = &loader->current.outline;
 
 
    current->points   = base->points   + base->n_points;
    current->tags     = base->tags     + base->n_points;
    current->contours = base->contours + base->n_contours;
 
    /* handle extra points table - if any */
    if ( loader->use_extra )
    {
      loader->current.extra_points  = loader->base.extra_points +
                                      base->n_points;
 
      loader->current.extra_points2 = loader->base.extra_points2 +
                                      base->n_points;
    }
  }
 
 
  FT_BASE_DEF( FT_Error )
  FT_GlyphLoader_CreateExtra( FT_GlyphLoader  loader )
  {
    FT_Error   error;
    FT_Memory  memory = loader->memory;
 
 
    if ( !FT_NEW_ARRAY( loader->base.extra_points, 2 * loader->max_points ) )
    {
      loader->use_extra          = 1;
      loader->base.extra_points2 = loader->base.extra_points +
                                   loader->max_points;
 
      FT_GlyphLoader_Adjust_Points( loader );
    }
    return error;
  }
 
 
  /* re-adjust the `current' subglyphs field */
  static void
  FT_GlyphLoader_Adjust_Subglyphs( FT_GlyphLoader  loader )
  {
    FT_GlyphLoad  base    = &loader->base;
    FT_GlyphLoad  current = &loader->current;
 
 
    current->subglyphs = base->subglyphs + base->num_subglyphs;
  }
 
 
  /* Ensure that we can add `n_points' and `n_contours' to our glyph.      */
  /* This function reallocates its outline tables if necessary.  Note that */
  /* it DOESN'T change the number of points within the loader!             */
  /*                                                                       */
  FT_BASE_DEF( FT_Error )
  FT_GlyphLoader_CheckPoints( FT_GlyphLoader  loader,
                              FT_UInt         n_points,
                              FT_UInt         n_contours )
  {
    FT_Memory    memory  = loader->memory;
    FT_Error     error   = FT_Err_Ok;
    FT_Outline*  base    = &loader->base.outline;
    FT_Outline*  current = &loader->current.outline;
    FT_Bool      adjust  = 0;
 
    FT_UInt      new_max, old_max;
 
 
    /* check points & tags */
    new_max = (FT_UInt)base->n_points + (FT_UInt)current->n_points +
              n_points;
    old_max = loader->max_points;
 
    if ( new_max > old_max )
    {
      new_max = FT_PAD_CEIL( new_max, 8 );
 
      if ( new_max > FT_OUTLINE_POINTS_MAX )
        return FT_THROW( Array_Too_Large );
 
      if ( FT_RENEW_ARRAY( base->points, old_max, new_max ) ||
           FT_RENEW_ARRAY( base->tags,   old_max, new_max ) )
        goto Exit;
 
      if ( loader->use_extra )
      {
        if ( FT_RENEW_ARRAY( loader->base.extra_points,
                             old_max * 2, new_max * 2 ) )
          goto Exit;
 
        FT_ARRAY_MOVE( loader->base.extra_points + new_max,
                       loader->base.extra_points + old_max,
                       old_max );
 
        loader->base.extra_points2 = loader->base.extra_points + new_max;
      }
 
      adjust = 1;
      loader->max_points = new_max;
    }
 
    /* check contours */
    old_max = loader->max_contours;
    new_max = (FT_UInt)base->n_contours + (FT_UInt)current->n_contours +
              n_contours;
    if ( new_max > old_max )
    {
      new_max = FT_PAD_CEIL( new_max, 4 );
 
      if ( new_max > FT_OUTLINE_CONTOURS_MAX )
        return FT_THROW( Array_Too_Large );
 
      if ( FT_RENEW_ARRAY( base->contours, old_max, new_max ) )
        goto Exit;
 
      adjust = 1;
      loader->max_contours = new_max;
    }
 
    if ( adjust )
      FT_GlyphLoader_Adjust_Points( loader );
 
  Exit:
    if ( error )
      FT_GlyphLoader_Reset( loader );
 
    return error;
  }
 
 
  /* Ensure that we can add `n_subglyphs' to our glyph. this function */
  /* reallocates its subglyphs table if necessary.  Note that it DOES */
  /* NOT change the number of subglyphs within the loader!            */
  /*                                                                  */
  FT_BASE_DEF( FT_Error )
  FT_GlyphLoader_CheckSubGlyphs( FT_GlyphLoader  loader,
                                 FT_UInt         n_subs )
  {
    FT_Memory     memory = loader->memory;
    FT_Error      error  = FT_Err_Ok;
    FT_UInt       new_max, old_max;
 
    FT_GlyphLoad  base    = &loader->base;
    FT_GlyphLoad  current = &loader->current;
 
 
    new_max = base->num_subglyphs + current->num_subglyphs + n_subs;
    old_max = loader->max_subglyphs;
    if ( new_max > old_max )
    {
      new_max = FT_PAD_CEIL( new_max, 2 );
      if ( FT_RENEW_ARRAY( base->subglyphs, old_max, new_max ) )
        goto Exit;
 
      loader->max_subglyphs = new_max;
 
      FT_GlyphLoader_Adjust_Subglyphs( loader );
    }
 
  Exit:
    return error;
  }
 
 
  /* prepare loader for the addition of a new glyph on top of the base one */
  FT_BASE_DEF( void )
  FT_GlyphLoader_Prepare( FT_GlyphLoader  loader )
  {
    FT_GlyphLoad  current = &loader->current;
 
 
    current->outline.n_points   = 0;
    current->outline.n_contours = 0;
    current->num_subglyphs      = 0;
 
    FT_GlyphLoader_Adjust_Points   ( loader );
    FT_GlyphLoader_Adjust_Subglyphs( loader );
  }
 
 
  /* add current glyph to the base image -- and prepare for another */
  FT_BASE_DEF( void )
  FT_GlyphLoader_Add( FT_GlyphLoader  loader )
  {
    FT_GlyphLoad  base;
    FT_GlyphLoad  current;
 
    FT_Int        n_curr_contours;
    FT_Int        n_base_points;
    FT_Int        n;
 
 
    if ( !loader )
      return;
 
    base    = &loader->base;
    current = &loader->current;
 
    n_curr_contours = current->outline.n_contours;
    n_base_points   = base->outline.n_points;
 
    base->outline.n_points =
      (short)( base->outline.n_points + current->outline.n_points );
    base->outline.n_contours =
      (short)( base->outline.n_contours + current->outline.n_contours );
 
    base->num_subglyphs += current->num_subglyphs;
 
    /* adjust contours count in newest outline */
    for ( n = 0; n < n_curr_contours; n++ )
      current->outline.contours[n] =
        (short)( current->outline.contours[n] + n_base_points );
 
    /* prepare for another new glyph image */
    FT_GlyphLoader_Prepare( loader );
  }
 
 
  FT_BASE_DEF( FT_Error )
  FT_GlyphLoader_CopyPoints( FT_GlyphLoader  target,
                             FT_GlyphLoader  source )
  {
    FT_Error  error;
    FT_UInt   num_points   = (FT_UInt)source->base.outline.n_points;
    FT_UInt   num_contours = (FT_UInt)source->base.outline.n_contours;
 
 
    error = FT_GlyphLoader_CheckPoints( target, num_points, num_contours );
    if ( !error )
    {
      FT_Outline*  out = &target->base.outline;
      FT_Outline*  in  = &source->base.outline;
 
 
      FT_ARRAY_COPY( out->points, in->points,
                     num_points );
      FT_ARRAY_COPY( out->tags, in->tags,
                     num_points );
      FT_ARRAY_COPY( out->contours, in->contours,
                     num_contours );
 
      /* do we need to copy the extra points? */
      if ( target->use_extra && source->use_extra )
      {
        FT_ARRAY_COPY( target->base.extra_points, source->base.extra_points,
                       num_points );
        FT_ARRAY_COPY( target->base.extra_points2, source->base.extra_points2,
                       num_points );
      }
 
      out->n_points   = (short)num_points;
      out->n_contours = (short)num_contours;
 
      FT_GlyphLoader_Adjust_Points( target );
    }
 
    return error;
  }
 
 
/* END */