source/texk/web2c/luatexdir/pdf/pdffont.w

   1 % pdffont.w
   2 %
   3 % Copyright 2009-2014 Taco Hoekwater <taco@@luatex.org>
   4 %
   5 % This file is part of LuaTeX.
   6 %
   7 % LuaTeX is free software; you can redistribute it and/or modify it under
   8 % the terms of the GNU General Public License as published by the Free
   9 % Software Foundation; either version 2 of the License, or (at your
  10 % option) any later version.
  11 %
  12 % LuaTeX is distributed in the hope that it will be useful, but WITHOUT
  13 % ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 % FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15 % License for more details.
  16 %
  17 % You should have received a copy of the GNU General Public License along
  18 % with LuaTeX; if not, see <http://www.gnu.org/licenses/>.
  19
  20 \def\pdfTeX{pdf\TeX}
  21
  22 @ @c
  23
  24 #include "ptexlib.h"
  25
  26 @ As \pdfTeX{} should also act as a back-end driver, it needs to support virtual
  27 fonts too. Information about virtual fonts can be found in the source of some
  28 \.{DVI}-related programs.
  29
  30 Whenever we want to write out a character in a font to PDF output, we
  31 should check whether the used character is a virtual or real character.
  32 The |has_packet()| C macro checks for this condition.
  33
  34 @ The following code typesets a character to PDF output
  35
  36 @c
  37 scaled_whd output_one_char(PDF pdf, halfword p)
  38 {
  39     internal_font_number f = font(p);
  40     int c = character(p);
  41     int ex_glyph = ex_glyph(p)/1000;
  42     scaled_whd ci = get_charinfo_whd(f, c); /* the real width, height and depth of the character */
  43     if (!(char_exists(f,c))) {
  44         char_warning(f,c);
  45         return ci;
  46     }
  47     ci.wd = ext_xn_over_d(ci.wd, 1000000 + ex_glyph(p), 1000000);
  48     switch (pdf->posstruct->dir) {
  49         case dir_TLT:
  50             break;
  51         case dir_TRT:
  52             pos_left(ci.wd);
  53             break;
  54         case dir_LTL:
  55             pos_down(ci.ht);
  56             pos_left(ci.wd);
  57             break;
  58         case dir_RTT:
  59             pos_down(ci.ht);
  60             pos_left(ci.wd / 2);
  61             break;
  62         default:
  63             formatted_warning("pdf backend","ignoring bad dir %i when outputting a character",pdf->posstruct->dir);
  64     }
  65     if (has_packet(f, c)) {
  66         do_vf_packet(pdf, f, c, ex_glyph);
  67     } else {
  68         /* |pdf_place_glyph(pdf, f, c, ex_glyph);| */
  69         backend_out[glyph_node] (pdf, f, c, ex_glyph);
  70     }
  71     return ci;
  72 }
  73
  74 @ Mark |f| as a used font; set |font_used(f)|, |font_size(f)| and |pdf_font_num(f)|
  75 @c
  76 static void pdf_use_font(internal_font_number f, int fontnum)
  77 {
  78     set_font_used(f, true);
  79     if ((fontnum > 0) || ((fontnum < 0) && (pdf_font_num(-fontnum) > 0))) {
  80         set_pdf_font_num(f, fontnum);
  81     } else {
  82         normal_error("pdf backend","bad font id");
  83     }
  84 }
  85
  86 @ To set PDF font we need to find out fonts with the same name, because \TeX\ can
  87 load the same font several times for various sizes. For such fonts we define only
  88 one font resource. The array |pdf_font_num| holds the object number of font
  89 resource. A negative value of an entry of |pdf_font_num| indicates that the
  90 corresponding font shares the font resource with the font
  91
  92 @c
  93 #define same(n,f,k) (n(f) != NULL && n(k) != NULL && strcmp(n(f), n(k)) == 0)
  94
  95 /*
  96     For some lua-loaded (for instance AFM) fonts, it is normal to have
  97     a zero cidregistry,  and such fonts do not have a fontmap entry yet
  98     at this point, so the test should use the other branch
  99 */
 100
 101 static boolean font_shareable(internal_font_number f, internal_font_number k)
 102 {
 103     if (font_cidregistry(f) == NULL && font_cidregistry(k) == NULL && font_encodingbytes(f) != 2 && font_encodingbytes(k) != 2) {
 104         if (font_map(k) != NULL && font_map(f) != NULL && (same(font_name, k, f))) {
 105             return 1;
 106         }
 107     } else if ((same(font_filename, k, f) && same(font_fullname, k, f))) {
 108         return 1;
 109     }
 110     return 0;
 111 }
 112
 113 @ create a font object
 114 @c
 115 void pdf_init_font(PDF pdf, internal_font_number f)
 116 {
 117     internal_font_number k;
 118     fm_entry *fm;
 119     int i, l;
 120     if (font_used(f)) {
 121         formatted_error("pdf backend","font %i gets initialized twice",(int) f);
 122     }
 123     /*
 124         check whether |f| can share the font object with some |k|: we have 2 cases
 125         here: 1) |f| and |k| have the same tfm name (so they have been loaded at
 126         different sizes, eg 'cmr10' and 'cmr10 at 11pt'); 2) |f| has been auto
 127         expanded from |k|
 128
 129         take over slant and extend from map entry, if not already set;
 130         this should also be the only place where getfontmap() may be called.
 131     */
 132     fm = getfontmap(font_name(f));
 133     if (font_map(f) == NULL && fm != NULL) {
 134         font_map(f) = fm;
 135         if (is_slantset(fm))
 136             font_slant(f) = fm->slant;
 137         if (is_extendset(fm))
 138             font_extend(f) = fm->extend;
 139     }
 140     i = pdf->head_tab[obj_type_font];
 141     while (i != 0) {
 142         k = obj_info(pdf, i);
 143         if (font_shareable(f, k)) {
 144             if (pdf_font_num(k) < 0)
 145                 pdf_use_font(f, pdf_font_num(k));
 146             else
 147                 pdf_use_font(f, -k);
 148             return;
 149         }
 150         i = obj_link(pdf, i);
 151     }
 152     /* create a new font object for |f| */
 153     l = pdf_create_obj(pdf, obj_type_font, f);
 154     pdf_use_font(f, l);
 155 }
 156
 157 @ set the actual font on PDF page; sets |ff| to the tfm number of the base font
 158 sharing the font object with |f|; |ff| is either |f| itself (then it is its own
 159 base font), or some font with the same tfm name at different size and/or
 160 expansion.
 161
 162 @c
 163 internal_font_number pdf_set_font(PDF pdf, internal_font_number f)
 164 {
 165     int ff; /* for use with |set_ff| */
 166     if (!font_used(f))
 167         pdf_init_font(pdf, f);
 168     ff = pdf_font_num(f) < 0 ? -pdf_font_num(f) : f; /* aka |set_ff(f)| */
 169     addto_page_resources(pdf, obj_type_font, pdf_font_num(ff));
 170     return ff;
 171 }
 172
 173 @ @c
 174 void pdf_include_chars(PDF pdf)
 175 {
 176     str_number s;
 177     unsigned char *k, *j; /* running index */
 178     internal_font_number f;
 179     scan_font_ident();
 180     f = cur_val;
 181     if (f == null_font)
 182         normal_error("pdf backend", "invalid font identifier for 'includechars'");
 183     pdf_check_vf(cur_val);
 184     if (!font_used(f))
 185         pdf_init_font(pdf, f);
 186     scan_toks(false, true);
 187     s = tokens_to_string(def_ref);
 188     delete_token_ref(def_ref);
 189     j = str_string(s) + str_length(s);
 190     for (k = str_string(s); k < j; k++) {
 191         pdf_mark_char(f, *k);
 192     }
 193     flush_str(s);
 194 }