[Dev-luatex] Re: Font patches

6 Jul 2023


      On Thu, 6 Jul 2023 at 08:04, Max Chernoff  wrote:
...
Hi Luigi,
I've attached a series of font-related patches.
Patch 1:
Even if you set "tounicode = 1" at the top level of a font, "tounicode =
<something>" for each character, and run "pdf.setgentounicode(1)",
LuaTeX will only write out a /ToUnicode entry if the document uses
"\pdfextension glyphtounicode" somewhere.
A minimal(-ish) example:
% \pdfextension glyphtounicode{fake!}{0000}
\newcount\fontid
   \directlua{
       local height = tex.sp("8bp")
       local width = tex.sp("36bp")
pdf.setgentounicode(1)
local inner = font.define {
           name = "fake-font-inner",
           parameters = {},
           properties = {},
           encodingbytes = 0,
           psname = "none",
           tounicode = 1,
           characters = {
               [1] = {
                   width = width,
                   height = height,
                   depth = 0,
                   tounicode = { 0x1f986 },
               }
           }
       }
tex.count.fontid = font.define {
           name = "fake-font-virtual",
           parameters = {},
           properties = {},
           characters = {
               [string.byte"x"] = {
                   width = width,
                   height = height,
                   depth = 0,
                   commands = {
                       { "slot", 1, 1 }
                   }
}
           },
           type = "virtual",
           fonts = {{ id = inner }},
       }
callback.register(
           "provide_charproc_data",
           function (mode, font_id, slot)
               if mode == 2 then
                   return pdf.immediateobj("stream", "36 0 d0 0 0 36 8 re
f"), 36
               elseif mode == 3 then
                   return 1 / 10
               end
           end
       )
   }
x{\setfontid\fontid x}x
\bye
You would expect that copying the black box would give you a duck, but
this only happens if the first line is uncommented. The first patch
should fix this.
Patch 2:
Defining a Type 3 font with a character index greater than 256 can cause
a segfault. Using an index >256 is impossible with a T3 font, but you
shouldn't be able to cause a segfault from Lua code.
Minimal example:
\directlua{
       local height = tex.sp("8bp")
       local width = tex.sp("36bp")
local id = font.define {
           name = "fake-font-inner",
           parameters = {},
           properties = {},
           encodingbytes = 0,
           psname = "none",
           tounicode = 1,
           characters = {
               [0x1f986] = {
                   width = width,
                   height = height,
                   depth = 0,
               }
           }
       }
callback.register(
           "provide_charproc_data",
           function (mode, font_id, slot)
               if mode == 2 then
                   return pdf.immediateobj("stream", "36 0 d0 0 0 36 8 re
f"), 36
               elseif mode == 3 then
                   return 1 / 10
               end
           end
       )
local glyph = node.new("glyph")
       glyph.font = id
       glyph.char = 0x1f986
tex.forcehmode()
       node.write(glyph)
   }
   \bye
The second patch catches this when the font is initialized, skips the
too-large character, and issues a warning.
Patch 3:
The third patch adds the "provide_charproc_data" callback to the manual.
Thanks,
-- Max
ok, I will check them during this weekend.

--
luigi

[Dev-luatex] Re: Font patches

luigi scarso