lily/font-select.cc

   1 /*
   2   font-select.cc -- implement property -> font_metric routines.
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2003--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9
  10 #include "dimensions.hh"
  11 #include "all-font-metrics.hh"
  12 #include "output-def.hh"
  13 #include "font-interface.hh"
  14 #include "warn.hh"
  15 #include "pango-font.hh"
  16 #include "main.hh"
  17
  18 Font_metric *
  19 get_font_by_design_size (Output_def *layout, Real requested,
  20                          SCM font_vector)
  21 {
  22   int n = scm_c_vector_length (font_vector);
  23   Real size = 1e6;
  24   Real last_size = -1e6;
  25   int i = 0;
  26
  27   SCM pango_description_string = SCM_EOL;
  28   SCM last_pango_description_string = SCM_EOL;
  29   for (; i < n; i++)
  30     {
  31       SCM entry = scm_c_vector_ref (font_vector, i);
  32
  33       if (scm_promise_p (entry) == SCM_BOOL_T)
  34         {
  35           Font_metric *fm = unsmob_metrics (scm_force (entry));
  36           size = fm->design_size ();
  37         }
  38 #if HAVE_PANGO_FT2
  39       else if (scm_is_pair (entry)
  40                && scm_is_number (scm_car (entry))
  41                && scm_is_string (scm_cdr (entry)))
  42         {
  43           size = scm_to_double (scm_car (entry));
  44           pango_description_string
  45             = scm_cdr (entry);
  46         }
  47 #endif
  48
  49       if (size > requested)
  50         break;
  51       last_size = size;
  52       last_pango_description_string = pango_description_string;
  53     }
  54
  55   if (i == n)
  56     i = n - 1;
  57   else if (i > 0)
  58     {
  59       if ((requested / last_size) < (size / requested))
  60         {
  61           i--;
  62           size = last_size;
  63           pango_description_string = last_pango_description_string;
  64         }
  65     }
  66
  67   Font_metric *fm = 0;
  68   if (scm_is_string (pango_description_string))
  69     {
  70 #if HAVE_PANGO_FT2
  71       return find_pango_font (layout,
  72                               pango_description_string,
  73                               requested / size);
  74 #else
  75       error ("Trying to retrieve pango font without HAVE_PANGO_FT2.");
  76 #endif
  77     }
  78   else
  79     fm = unsmob_metrics (scm_force (scm_c_vector_ref (font_vector, i)));
  80
  81   return find_scaled_font (layout, fm, requested / size);
  82 }
  83
  84 Font_metric *
  85 get_font_by_mag_step (Output_def *layout, Real requested_step,
  86                       SCM font_vector, Real default_size)
  87 {
  88   return get_font_by_design_size (layout, default_size
  89                                   * pow (2.0, requested_step / 6.0),
  90                                   font_vector);
  91 }
  92
  93 SCM
  94 properties_to_font_size_family (SCM fonts, SCM alist_chain)
  95 {
  96   return scm_call_2 (ly_lily_module_constant ("lookup-font"), fonts,
  97                      alist_chain);
  98 }
  99
 100 Font_metric *
 101 select_encoded_font (Output_def *layout, SCM chain)
 102 {
 103   SCM name = ly_chain_assoc_get (ly_symbol2scm ("font-name"), chain, SCM_BOOL_F);
 104
 105   if (!scm_is_string (name))
 106     {
 107       SCM fonts = layout->lookup_variable (ly_symbol2scm ("fonts"));
 108       name = properties_to_font_size_family (fonts, chain);
 109     }
 110
 111 #if HAVE_PANGO_FT2
 112   if (scm_is_string (name))
 113     return select_pango_font (layout, chain);
 114   else
 115 #endif
 116     if (scm_instance_p (name))
 117       {
 118         SCM base_size = scm_slot_ref (name, ly_symbol2scm ("default-size"));
 119         SCM vec = scm_slot_ref (name, ly_symbol2scm ("size-vector"));
 120
 121         Real req = robust_scm2double (ly_chain_assoc_get (ly_symbol2scm ("font-size"), chain, SCM_BOOL_F),
 122                                       0.0);
 123
 124         return get_font_by_mag_step (layout, req, vec,
 125                                      scm_to_double (base_size));
 126       }
 127
 128   assert (0);
 129   return 0;
 130 }
 131
 132 Font_metric *
 133 select_font (Output_def *layout, SCM chain)
 134 {
 135   return select_encoded_font (layout, chain);
 136 }