ftglyph.c

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/***************************************************************************/
/*                                                                         */
/*  ftglyph.c                                                              */
/*                                                                         */
/*    FreeType convenience functions to handle glyphs (body).              */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005 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.                                        */
/*                                                                         */
/***************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /*  This file contains the definition of several convenience functions   */
  /*  that can be used by client applications to easily retrieve glyph     */
  /*  bitmaps and outlines from a given face.                              */
  /*                                                                       */
  /*  These functions should be optional if you are writing a font server  */
  /*  or text layout engine on top of FreeType.  However, they are pretty  */
  /*  handy for many other simple uses of the library.                     */
  /*                                                                       */
  /*************************************************************************/


#include <ft2build.h>
#include FT_GLYPH_H
#include FT_OUTLINE_H
#include FT_BITMAP_H
#include FT_INTERNAL_OBJECTS_H


  /*************************************************************************/
  /*                                                                       */
  /* 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_glyph


  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   Convenience functions                                         ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/


  /* documentation is in ftglyph.h */

  FT_EXPORT_DEF( void )
  FT_Matrix_Multiply( const FT_Matrix*  a,
                      FT_Matrix        *b )
  {
    FT_Fixed  xx, xy, yx, yy;


    if ( !a || !b )
      return;

    xx = FT_MulFix( a->xx, b->xx ) + FT_MulFix( a->xy, b->yx );
    xy = FT_MulFix( a->xx, b->xy ) + FT_MulFix( a->xy, b->yy );
    yx = FT_MulFix( a->yx, b->xx ) + FT_MulFix( a->yy, b->yx );
    yy = FT_MulFix( a->yx, b->xy ) + FT_MulFix( a->yy, b->yy );

    b->xx = xx;  b->xy = xy;
    b->yx = yx;  b->yy = yy;
  }


  /* documentation is in ftglyph.h */

  FT_EXPORT_DEF( FT_Error )
  FT_Matrix_Invert( FT_Matrix*  matrix )
  {
    FT_Pos  delta, xx, yy;


    if ( !matrix )
      return FT_Err_Invalid_Argument;

    /* compute discriminant */
    delta = FT_MulFix( matrix->xx, matrix->yy ) -
            FT_MulFix( matrix->xy, matrix->yx );

    if ( !delta )
      return FT_Err_Invalid_Argument;  /* matrix can't be inverted */

    matrix->xy = - FT_DivFix( matrix->xy, delta );
    matrix->yx = - FT_DivFix( matrix->yx, delta );

    xx = matrix->xx;
    yy = matrix->yy;

    matrix->xx = FT_DivFix( yy, delta );
    matrix->yy = FT_DivFix( xx, delta );

    return FT_Err_Ok;
  }


  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   FT_BitmapGlyph support                                        ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/

  FT_CALLBACK_DEF( FT_Error )
  ft_bitmap_glyph_init( FT_Glyph      bitmap_glyph,
                        FT_GlyphSlot  slot )
  {
    FT_BitmapGlyph  glyph   = (FT_BitmapGlyph)bitmap_glyph;
    FT_Error        error   = FT_Err_Ok;
    FT_Library      library = FT_GLYPH( glyph )->library;


    if ( slot->format != FT_GLYPH_FORMAT_BITMAP )
    {
      error = FT_Err_Invalid_Glyph_Format;
      goto Exit;
    }

    glyph->left = slot->bitmap_left;
    glyph->top  = slot->bitmap_top;

    /* do lazy copying whenever possible */
    if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP )
    {
      glyph->bitmap = slot->bitmap;
      slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
    }
    else
    {
      FT_Bitmap_New( &glyph->bitmap );
      error = FT_Bitmap_Copy( library, &slot->bitmap, &glyph->bitmap );
    }

  Exit:
    return error;
  }


  FT_CALLBACK_DEF( FT_Error )
  ft_bitmap_glyph_copy( FT_Glyph  bitmap_source,
                        FT_Glyph  bitmap_target )
  {
    FT_Library      library = bitmap_source->library;
    FT_BitmapGlyph  source  = (FT_BitmapGlyph)bitmap_source;
    FT_BitmapGlyph  target  = (FT_BitmapGlyph)bitmap_target;


    target->left = source->left;
    target->top  = source->top;

    return FT_Bitmap_Copy( library, &source->bitmap, &target->bitmap );
  }


  FT_CALLBACK_DEF( void )
  ft_bitmap_glyph_done( FT_Glyph  bitmap_glyph )
  {
    FT_BitmapGlyph  glyph   = (FT_BitmapGlyph)bitmap_glyph;
    FT_Library      library = FT_GLYPH( glyph )->library;


    FT_Bitmap_Done( library, &glyph->bitmap );
  }


  FT_CALLBACK_DEF( void )
  ft_bitmap_glyph_bbox( FT_Glyph  bitmap_glyph,
                        FT_BBox*  cbox )
  {
    FT_BitmapGlyph  glyph = (FT_BitmapGlyph)bitmap_glyph;


    cbox->xMin = glyph->left << 6;
    cbox->xMax = cbox->xMin + ( glyph->bitmap.width << 6 );
    cbox->yMax = glyph->top << 6;
    cbox->yMin = cbox->yMax - ( glyph->bitmap.rows << 6 );
  }


  FT_CALLBACK_TABLE_DEF
  const FT_Glyph_Class  ft_bitmap_glyph_class =
  {
    sizeof ( FT_BitmapGlyphRec ),
    FT_GLYPH_FORMAT_BITMAP,

    ft_bitmap_glyph_init,
    ft_bitmap_glyph_done,
    ft_bitmap_glyph_copy,
    0,                          /* FT_Glyph_TransformFunc */
    ft_bitmap_glyph_bbox,
    0                           /* FT_Glyph_PrepareFunc   */
  };


  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   FT_OutlineGlyph support                                       ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/


  FT_CALLBACK_DEF( FT_Error )
  ft_outline_glyph_init( FT_Glyph      outline_glyph,
                         FT_GlyphSlot  slot )
  {
    FT_OutlineGlyph  glyph   = (FT_OutlineGlyph)outline_glyph;
    FT_Error         error   = FT_Err_Ok;
    FT_Library       library = FT_GLYPH( glyph )->library;
    FT_Outline*      source  = &slot->outline;
    FT_Outline*      target  = &glyph->outline;


    /* check format in glyph slot */
    if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
    {
      error = FT_Err_Invalid_Glyph_Format;
      goto Exit;
    }

    /* allocate new outline */
    error = FT_Outline_New( library, source->n_points, source->n_contours,
                            &glyph->outline );
    if ( error )
      goto Exit;

    FT_Outline_Copy( source, target );

  Exit:
    return error;
  }


  FT_CALLBACK_DEF( void )
  ft_outline_glyph_done( FT_Glyph  outline_glyph )
  {
    FT_OutlineGlyph  glyph = (FT_OutlineGlyph)outline_glyph;


    FT_Outline_Done( FT_GLYPH( glyph )->library, &glyph->outline );
  }


  FT_CALLBACK_DEF( FT_Error )
  ft_outline_glyph_copy( FT_Glyph  outline_source,
                         FT_Glyph  outline_target )
  {
    FT_OutlineGlyph  source  = (FT_OutlineGlyph)outline_source;
    FT_OutlineGlyph  target  = (FT_OutlineGlyph)outline_target;
    FT_Error         error;
    FT_Library       library = FT_GLYPH( source )->library;


    error = FT_Outline_New( library, source->outline.n_points,
                            source->outline.n_contours, &target->outline );
    if ( !error )
      FT_Outline_Copy( &source->outline, &target->outline );

    return error;
  }


  FT_CALLBACK_DEF( void )
  ft_outline_glyph_transform( FT_Glyph          outline_glyph,
                              const FT_Matrix*  matrix,
                              const FT_Vector*  delta )
  {
    FT_OutlineGlyph  glyph = (FT_OutlineGlyph)outline_glyph;


    if ( matrix )
      FT_Outline_Transform( &glyph->outline, matrix );

    if ( delta )
      FT_Outline_Translate( &glyph->outline, delta->x, delta->y );
  }


  FT_CALLBACK_DEF( void )
  ft_outline_glyph_bbox( FT_Glyph  outline_glyph,
                         FT_BBox*  bbox )
  {
    FT_OutlineGlyph  glyph = (FT_OutlineGlyph)outline_glyph;


    FT_Outline_Get_CBox( &glyph->outline, bbox );
  }


  FT_CALLBACK_DEF( FT_Error )
  ft_outline_glyph_prepare( FT_Glyph      outline_glyph,
                            FT_GlyphSlot  slot )
  {
    FT_OutlineGlyph  glyph = (FT_OutlineGlyph)outline_glyph;


    slot->format         = FT_GLYPH_FORMAT_OUTLINE;
    slot->outline        = glyph->outline;
    slot->outline.flags &= ~FT_OUTLINE_OWNER;

    return FT_Err_Ok;
  }


  FT_CALLBACK_TABLE_DEF
  const FT_Glyph_Class  ft_outline_glyph_class =
  {
    sizeof ( FT_OutlineGlyphRec ),
    FT_GLYPH_FORMAT_OUTLINE,

    ft_outline_glyph_init,
    ft_outline_glyph_done,
    ft_outline_glyph_copy,
    ft_outline_glyph_transform,
    ft_outline_glyph_bbox,
    ft_outline_glyph_prepare
  };


  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   FT_Glyph class and API                                        ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/