ftadvanc.c

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Author : Werner Lemberg
Date : 2017-04-22 13:27:21
Hash : 5aa6716a
Message : Add new `slight' auto-hinting mode. This mode uses fractional advance widths and doesn't scale glyphs horizontally, only applying vertical scaling and hinting. At the same time, the behaviour of the `light' auto-hinter gets restored for backwards compatibility: Both vertical and horizontal scaling is again based on rounded metrics values (this was changed in a commit from 2017-03-30 as a side effect). To be more precise, the behaviour is restored for TrueType fonts only; for other font formats like Type 1, this is a new feature of the `light' hinting mode. * include/freetype/freetype.h (FT_LOAD_TARGET_SLIGHT): New macro. (FT_RENDER_MODE_SLIGHT): New render mode. * include/freetype/internal/ftobjs.h (FT_Size_InternalRec): Add `autohint_mode' and `autohint_metrics' fields. * src/autofit/afcjk.c (af_cjk_hints_init), src/autofit/aflatin.c (af_latin_hints_init), src/autofit/aflatin2 (af_latin2_hints_init): Updated. * src/autofit/afloader.c (af_loader_embolden_glyph_in_slot): Use `autohint_metrics'. (af_loader_load_glyph): s/internal/slot_internal/. Initialize `autohint_metrics' and `autohint_mode' depending on current auto-hint mode. Use `autohint_metrics'. Updated. * src/base/ftadvanc.c (LOAD_ADVANCE_FAST_CHECK): Updated. * src/base/ftobjs.c (FT_Load_Glyph): Updated. (FT_New_Size): Allocate `internal' object. * src/pshinter/pshalgo.c (ps_hints_apply): Updated. * src/smooth/ftsmooth.c (ft_smooth_render): Updated.

src/base/ftadvanc.c

/***************************************************************************/
/*                                                                         */
/*  ftadvanc.c                                                             */
/*                                                                         */
/*    Quick computation of advance widths (body).                          */
/*                                                                         */
/*  Copyright 2008-2017 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_ADVANCES_H
#include FT_INTERNAL_OBJECTS_H


  static FT_Error
  _ft_face_scale_advances( FT_Face    face,
                           FT_Fixed*  advances,
                           FT_UInt    count,
                           FT_Int32   flags )
  {
    FT_Fixed  scale;
    FT_UInt   nn;


    if ( flags & FT_LOAD_NO_SCALE )
      return FT_Err_Ok;

    if ( !face->size )
      return FT_THROW( Invalid_Size_Handle );

    if ( flags & FT_LOAD_VERTICAL_LAYOUT )
      scale = face->size->metrics.y_scale;
    else
      scale = face->size->metrics.x_scale;

    /* this must be the same scaling as to get linear{Hori,Vert}Advance */
    /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c)        */

    for ( nn = 0; nn < count; nn++ )
      advances[nn] = FT_MulDiv( advances[nn], scale, 64 );

    return FT_Err_Ok;
  }


   /* at the moment, we can perform fast advance retrieval only in */
   /* the following cases:                                         */
   /*                                                              */
   /*  - unscaled load                                             */
   /*  - unhinted load                                             */
   /*  - light-hinted and slight-hinted load                       */
   /*  - if a variations font, it must have an `HVAR' or `VVAR'    */
   /*    table (thus the old MM or GX fonts don't qualify; this    */
   /*    gets checked by the driver-specific functions)            */

#define LOAD_ADVANCE_FAST_CHECK( face, flags )                           \
          ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING )         || \
            ( FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT  ||   \
              FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_SLIGHT ) )


  /* documentation is in ftadvanc.h */

  FT_EXPORT_DEF( FT_Error )
  FT_Get_Advance( FT_Face    face,
                  FT_UInt    gindex,
                  FT_Int32   flags,
                  FT_Fixed  *padvance )
  {
    FT_Face_GetAdvancesFunc  func;


    if ( !face )
      return FT_THROW( Invalid_Face_Handle );

    if ( !padvance )
      return FT_THROW( Invalid_Argument );

    if ( gindex >= (FT_UInt)face->num_glyphs )
      return FT_THROW( Invalid_Glyph_Index );

    func = face->driver->clazz->get_advances;
    if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) )
    {
      FT_Error  error;


      error = func( face, gindex, 1, flags, padvance );
      if ( !error )
        return _ft_face_scale_advances( face, padvance, 1, flags );

      if ( FT_ERR_NEQ( error, Unimplemented_Feature ) )
        return error;
    }

    return FT_Get_Advances( face, gindex, 1, flags, padvance );
  }


  /* documentation is in ftadvanc.h */

  FT_EXPORT_DEF( FT_Error )
  FT_Get_Advances( FT_Face    face,
                   FT_UInt    start,
                   FT_UInt    count,
                   FT_Int32   flags,
                   FT_Fixed  *padvances )
  {
    FT_Face_GetAdvancesFunc  func;
    FT_UInt                  num, end, nn;
    FT_Error                 error = FT_Err_Ok;


    if ( !face )
      return FT_THROW( Invalid_Face_Handle );

    if ( !padvances )
      return FT_THROW( Invalid_Argument );

    num = (FT_UInt)face->num_glyphs;
    end = start + count;
    if ( start >= num || end < start || end > num )
      return FT_THROW( Invalid_Glyph_Index );

    if ( count == 0 )
      return FT_Err_Ok;

    func = face->driver->clazz->get_advances;
    if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) )
    {
      error = func( face, start, count, flags, padvances );
      if ( !error )
        return _ft_face_scale_advances( face, padvances, count, flags );

      if ( FT_ERR_NEQ( error, Unimplemented_Feature ) )
        return error;
    }

    error = FT_Err_Ok;

    if ( flags & FT_ADVANCE_FLAG_FAST_ONLY )
      return FT_THROW( Unimplemented_Feature );

    flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY;
    for ( nn = 0; nn < count; nn++ )
    {
      error = FT_Load_Glyph( face, start + nn, flags );
      if ( error )
        break;

      /* scale from 26.6 to 16.16 */
      padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT )
                      ? face->glyph->advance.y * 1024
                      : face->glyph->advance.x * 1024;
    }

    return error;
  }


/* END */

kc3-lang/freetype/src/base/ftadvanc.c

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kc3-lang/freetype /src/base/ftadvanc.c