[ft-devel] improved incremental interface for metrics

[Werner LEMBERG]

I've just changed the parsing routines of Type 1 charstrings to use
16.16 format internally, and I'm going to fix both Type 1 and Type 2
handling to use 16.16 format externally too:

  1. Add a new load flag so that outlines can be returned in 16.16
     font units.

  2. Round the coordinates *after* scaling, not before.

Handling item 1 is straightforward, however, item 2 needs a change in
the incremental interface for glyph metrics, I believe.  Currently
there is code like this (for example, in function
`T1_Parse_Glyph_And_Get_Char_String', file `t1gload.c'):

  /* Incremental fonts can optionally override the metrics. */
  if ( !error && inc && inc->funcs->get_glyph_metrics )
  {
    FT_Incremental_MetricsRec  metrics;


    metrics.bearing_x = FIXED_TO_INT( decoder->builder.left_bearing.x );
    metrics.bearing_y = FIXED_TO_INT( decoder->builder.left_bearing.y );
    metrics.advance   = FIXED_TO_INT( decoder->builder.advance.x );

    error = inc->funcs->get_glyph_metrics( inc->object,
                                           glyph_index, FALSE, &metrics );

    decoder->builder.left_bearing.x = INT_TO_FIXED( metrics.bearing_x );
    decoder->builder.left_bearing.y = INT_TO_FIXED( metrics.bearing_y );
    decoder->builder.advance.x      = INT_TO_FIXED( metrics.advance );
    decoder->builder.advance.y      = 0;
  }

The `FT_Incremental_MetricsRec' expects integer values.  My suggestion
is to introduce a new function `get_fractional_glyph_metrics'; if this
function is defined, use it, otherwise use `get_glyph_metrics'.
Objections?


    Werner