ftcsbits.c

一个Xpdf应用的例子

/***************************************************************************/
/*                                                                         */
/*  ftcsbits.c                                                             */
/*                                                                         */
/*    FreeType sbits manager (body).                                       */
/*                                                                         */
/*  Copyright 2000-2001 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_CACHE_H
#include FT_CACHE_SMALL_BITMAPS_H
#include FT_CACHE_INTERNAL_GLYPH_H
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_DEBUG_H
#include FT_ERRORS_H

#include "ftcerror.h"

#include <string.h>         /* memcmp() */


#define FTC_SBIT_ITEMS_PER_NODE  16


  typedef struct FTC_SBitNodeRec_*  FTC_SBitNode;

  typedef struct  FTC_SBitNodeRec_
  {
    FTC_GlyphNodeRec  gnode;
    FTC_SBitRec       sbits[FTC_SBIT_ITEMS_PER_NODE];

  } FTC_SBitNodeRec;


#define FTC_SBIT_NODE( x )  ( (FTC_SBitNode)( x ) )


  typedef struct  FTC_SBitQueryRec_
  {
    FTC_GlyphQueryRec  gquery;
    FTC_ImageDesc      desc;

  } FTC_SBitQueryRec, *FTC_SBitQuery;


#define FTC_SBIT_QUERY( x ) ( (FTC_SBitQuery)( x ) )


  typedef struct FTC_SBitFamilyRec_*  FTC_SBitFamily;

  /* sbit family structure */
  typedef struct  FTC_SBitFamilyRec_
  {
    FTC_GlyphFamilyRec  gfam;
    FTC_ImageDesc       desc;

  } FTC_SBitFamilyRec;
 
  
#define FTC_SBIT_FAMILY( x )         ( (FTC_SBitFamily)( x ) )
#define FTC_SBIT_FAMILY_MEMORY( x )  FTC_GLYPH_FAMILY_MEMORY( &( x )->cset )


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                     SBIT CACHE NODES                          *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/


  static FT_Error
  ftc_sbit_copy_bitmap( FTC_SBit    sbit,
                        FT_Bitmap*  bitmap,
                        FT_Memory   memory )
  {
    FT_Error  error;
    FT_Int    pitch = bitmap->pitch;
    FT_ULong  size;


    if ( pitch < 0 )
      pitch = -pitch;

    size = (FT_ULong)( pitch * bitmap->rows );

    if ( !ALLOC( sbit->buffer, size ) )
      MEM_Copy( sbit->buffer, bitmap->buffer, size );

    return error;
  }


  FT_CALLBACK_DEF( void )
  ftc_sbit_node_done( FTC_SBitNode  snode,
                      FTC_Cache     cache )
  {
    FTC_SBit   sbit  = snode->sbits;
    FT_UInt    count = FTC_GLYPH_NODE( snode )->item_count;
    FT_Memory  memory = cache->memory;


    for ( ; count > 0; sbit++, count-- )
      FREE( sbit->buffer );

    ftc_glyph_node_done( FTC_GLYPH_NODE( snode ), cache );
  }


  static FT_Error
  ftc_sbit_node_load( FTC_SBitNode    snode,
                      FTC_Manager     manager,
                      FTC_SBitFamily  sfam,
                      FT_UInt         gindex,
                      FT_ULong       *asize )
  {
    FT_Error       error;
    FTC_GlyphNode  gnode = FTC_GLYPH_NODE( snode );
    FT_Memory      memory;
    FT_Face        face;
    FT_Size        size;
    FTC_SBit       sbit;


    if ( gindex <  (FT_UInt)gnode->item_start                     ||
         gindex >= (FT_UInt)gnode->item_start + gnode->item_count )
    {
      FT_ERROR(( "ftc_sbit_node_load: invalid glyph index" ));
      return FTC_Err_Invalid_Argument;
    }

    memory = manager->library->memory;

    sbit = snode->sbits + ( gindex - gnode->item_start );

    error = FTC_Manager_Lookup_Size( manager, &sfam->desc.font,
                                     &face, &size );
    if ( !error )
    {
      FT_UInt  load_flags = FT_LOAD_DEFAULT;
      FT_UInt  type       = sfam->desc.type;


      /* determine load flags, depending on the font description's */
      /* image type                                                */

      if ( FTC_IMAGE_FORMAT( type ) == ftc_image_format_bitmap )
      {
        if ( type & ftc_image_flag_monochrome )
          load_flags |= FT_LOAD_MONOCHROME;

        /* disable embedded bitmaps loading if necessary */
        if ( type & ftc_image_flag_no_sbits )
          load_flags |= FT_LOAD_NO_BITMAP;
      }
      else
      {
        FT_ERROR((
          "ftc_sbit_node_load: cannot load scalable glyphs in an"
          " sbit cache, please check your arguments!\n" ));
        error = FTC_Err_Invalid_Argument;
        goto Exit;
      }

      /* always render glyphs to bitmaps */
      load_flags |= FT_LOAD_RENDER;

      if ( type & ftc_image_flag_unhinted )
        load_flags |= FT_LOAD_NO_HINTING;

      if ( type & ftc_image_flag_autohinted )
        load_flags |= FT_LOAD_FORCE_AUTOHINT;

      /* by default, indicates a `missing' glyph */
      sbit->buffer = 0;

      error = FT_Load_Glyph( face, gindex, load_flags );
      if ( !error )
      {
        FT_Int        temp;
        FT_GlyphSlot  slot   = face->glyph;
        FT_Bitmap*    bitmap = &slot->bitmap;
        FT_Int        xadvance, yadvance;


        /* check that our values fit into 8-bit containers!       */
        /* If this is not the case, our bitmap is too large       */
        /* and we will leave it as `missing' with sbit.buffer = 0 */

#define CHECK_CHAR( d )  ( temp = (FT_Char)d, temp == d )
#define CHECK_BYTE( d )  ( temp = (FT_Byte)d, temp == d )

        /* XXX: FIXME: add support for vertical layouts maybe */

        /* horizontal advance in pixels */
        xadvance = ( slot->metrics.horiAdvance + 32 ) >> 6;
        yadvance = ( slot->metrics.vertAdvance + 32 ) >> 6;

        if ( CHECK_BYTE( bitmap->rows  )     &&
             CHECK_BYTE( bitmap->width )     &&
             CHECK_CHAR( bitmap->pitch )     &&
             CHECK_CHAR( slot->bitmap_left ) &&
             CHECK_CHAR( slot->bitmap_top  ) &&
             CHECK_CHAR( xadvance )          &&
             CHECK_CHAR( yadvance )          )
        {
          sbit->width    = (FT_Byte)bitmap->width;
          sbit->height   = (FT_Byte)bitmap->rows;
          sbit->pitch    = (FT_Char)bitmap->pitch;
          sbit->left     = (FT_Char)slot->bitmap_left;
          sbit->top      = (FT_Char)slot->bitmap_top;
          sbit->xadvance = (FT_Char)xadvance;
          sbit->yadvance = (FT_Char)yadvance;
          sbit->format   = (FT_Byte)bitmap->pixel_mode;

          /* grab the bitmap when possible - this is a hack !! */
          if ( slot->flags & ft_glyph_own_bitmap )
          {
            slot->flags &= ~ft_glyph_own_bitmap;
            sbit->buffer = bitmap->buffer;
          }
          else
          {
            /* copy the bitmap into a new buffer -- ignore error */
            error = ftc_sbit_copy_bitmap( sbit, bitmap, memory );
          }

          /* now, compute size */
          if ( asize )
            *asize = ABS( sbit->pitch ) * sbit->height;

        }  /* glyph dimensions ok */

      } /* glyph loading successful */

      /* ignore the errors that might have occurred --   */
      /* we mark unloaded glyphs with `sbit.buffer == 0' */
      /* and 'width == 255', 'height == 0'               */
      /*                                                 */
      if ( error )
      {
        sbit->width = 255;
        error       = 0;
        /* sbit->buffer == NULL too! */
      }
    }

  Exit:
    return error;
  }


  FT_CALLBACK_DEF( FT_Error )
  ftc_sbit_node_init( FTC_SBitNode    snode,
                      FTC_GlyphQuery  gquery,
                      FTC_Cache       cache )
  {