kc3-lang/harfbuzz/util/helper-cairo-ft.hh

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• Hash : ab8b9b44
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  Date : 2022-12-29T18:33:12
  

  [view] Streamline cairo-ft face lifecycle management
  

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• util/helper-cairo-ft.hh

• /*
   * Copyright © 2022  Google, Inc.
   *
   *  This is part of HarfBuzz, a text shaping library.
   *
   * Permission is hereby granted, without written agreement and without
   * license or royalty fees, to use, copy, modify, and distribute this
   * software and its documentation for any purpose, provided that the
   * above copyright notice and the following two paragraphs appear in
   * all copies of this software.
   *
   * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
   * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
   * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
   * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
   * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
   * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
   * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
   *
   * Google Author(s): Behdad Esfahbod
   */
  
  #ifndef HELPER_CAIRO_FT_HH
  #define HELPER_CAIRO_FT_HH
  
  #include "font-options.hh"
  
  #include <cairo-ft.h>
  #include <hb-ft.h>
  #include FT_MULTIPLE_MASTERS_H
  
  static FT_Library ft_library;
  
  #ifdef HAVE_ATEXIT
  static inline
  void free_ft_library ()
  {
    FT_Done_FreeType (ft_library);
  }
  #endif
  
  static void
  _release_blob (void *arg)
  {
    FT_Face ft_face = (FT_Face) arg;
    hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);
  }
  
  static inline cairo_font_face_t *
  helper_cairo_create_ft_font_face (const font_options_t *font_opts)
  {
    cairo_font_face_t *cairo_face;
    /* We cannot use the FT_Face from hb_font_t, as doing so will confuse hb_font_t because
     * cairo will reset the face size.  As such, create new face...
     * TODO Perhaps add API to hb-ft to encapsulate this code. */
    FT_Face ft_face = nullptr;//hb_ft_font_get_face (font);
    if (!ft_face)
    {
      if (!ft_library)
      {
        FT_Init_FreeType (&ft_library);
  #ifdef HAVE_ATEXIT
        atexit (free_ft_library);
  #endif
      }
  
      unsigned int blob_length;
      const char *blob_data = hb_blob_get_data (font_opts->blob, &blob_length);
  
      if (FT_New_Memory_Face (ft_library,
  			    (const FT_Byte *) blob_data,
  			    blob_length,
  			    font_opts->face_index,
  			    &ft_face))
        fail (false, "FT_New_Memory_Face fail");
    }
    if (!ft_face)
    {
      /* This allows us to get some boxes at least... */
      cairo_face = cairo_toy_font_face_create ("@cairo:sans",
  					     CAIRO_FONT_SLANT_NORMAL,
  					     CAIRO_FONT_WEIGHT_NORMAL);
    }
    else
    {
      ft_face->generic.data = hb_blob_reference (font_opts->blob);
      ft_face->generic.finalizer = _release_blob;
  
  #if !defined(HB_NO_VAR) && defined(HAVE_FT_SET_VAR_BLEND_COORDINATES)
      unsigned int num_coords;
      const float *coords = hb_font_get_var_coords_design (font_opts->font, &num_coords);
      if (num_coords)
      {
        FT_Fixed *ft_coords = (FT_Fixed *) calloc (num_coords, sizeof (FT_Fixed));
        if (ft_coords)
        {
  	for (unsigned int i = 0; i < num_coords; i++)
  	  ft_coords[i] = coords[i] * 65536.f;
  	FT_Set_Var_Design_Coordinates (ft_face, num_coords, ft_coords);
  	free (ft_coords);
        }
      }
  #endif
  
      cairo_face = cairo_ft_font_face_create_for_ft_face (ft_face, font_opts->ft_load_flags);
    }
    return cairo_face;
  }
  
  static inline bool
  helper_cairo_ft_scaled_font_has_color (cairo_scaled_font_t *scaled_font)
  {
    bool ret = false;
  #ifdef FT_HAS_COLOR
    FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);
    if (ft_face)
    {
      if (FT_HAS_COLOR (ft_face))
        ret = true;
      cairo_ft_scaled_font_unlock_face (scaled_font);
    }
  #endif
    return ret;
  }
  
  #endif
  

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