Re: Replace `-dgs-load-fonts' to `--bigpdfs' in lilypond-book (issue 300280043 by address@hidden)

[Masamichi Hosoda]

> About a month ago we discussed how to reduce the disk space necessary
> for builing the lilypond documentation.
> 
>> [...]  Since lilypond itself converts all fonts to PostScript
>> resources, why not writing those resources to a `fontresource'
>> directory instead of embedding?  We could add a checksum to the
>> resource name, just to be sure that, say, `foo.tff' and `foo.otf'
>> will be rejected.
>> 
>> Ideally, all intermediate PDFs also refer to this `fontresource'
>> directory, and only in the last step PDFs with subsetted, embedded
>> fonts are created.
> 
> Such an approach has now been discussed on the the pdftex mailing
> list, cf.
> 
>   http://tug.org/pipermail/pdftex/2016-July/009045.html
> 
> and the following e-mails in this thread.
> 
> I've just tested successfully the following method, except item 1,
> which I've executed manually.
> 
> 1. Instead of embedding font resources into the file, lilypond writes
>    them to a font resource directory and uses the `.loadfont' operator
>    in its PS output file.  For simplicity, the font resources should
>    have the PS font name as its file name (regardless of the font
>    format), e.g. `TeXGyraSchola-Regular'; we then don't need a font
>    map for ghostscript.
> 
> 2. Lilypond's PS files are converted to PDFs with the additional gs
>    option `-dEmbedAllFonts=false' (to be added to `postscript->PDF' in
>    file `backend-library.scm').
> 
> 3. Both xetex and pdftex accept the fontless PDFs without complaints;
>    they simply embed them into its output file without alterations,
>    AFAICS.
> 
> 4. After the output PDF is built, a call to
> 
>      ps2pdf -I<fontresourcedir> \
>             -dNOSAFER -P \
>             Fontless.pdf WithEmbeddedFonts.pdf
> 
>    creates the final document.
> 
> Comparing the `--bigpdfs' method with the fontless PDF approach as
> outlined above, the latter creates a final output file about 30%
> smaller (at least in my small test).

I've tried this way.
I use Ghostscript 9.20 and LilyPond 2.19.49.

`sample.tar.gz` is my test files.

`final-no-embed.png` is the generated file by this way.
Some glyphs are broken.

`final-embed-subset.png` is the generated file by conventional way.
It is no problem. No glyphs are broken.

You can get the results by the following command in `sample.tar.gz`.

$ ./makepdfs.sh

It seems that non-Latin glyphs in TrueType (TTF and TTC) fonts are broken.
In the case of Japanese TrueType fonts etc.,
most glyphs (also Latin glyphs) are broken.

Type 1 fonts and Open Type (OTF) fonts seem no problem.

Note:
Ghostscript does not find Japanese OTF fonts in -I<fontresourcedir>.
It find them in <fontresourcedir>/CIDFont/.

sample.tar.gz
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