Re: Gets vertical skylines from grob stencils (issue 5626052)

[Han-Wen Nienhuys]

On Fri, Feb 17, 2012 at 6:00 AM, address@hidden
<address@hidden> wrote:
>> This sounds wrong.  Where does this data come from ultimately?
>>
>
> The svg files.  I read them into lilypond and generate this informatin.

You mean the SVG fonts?  The SVG files are generated by FF in the same
step as the OTF files.  I suspect that whatever you need is easier to
generate in FF directly.

You could ask around on the fontforge mailing list.

>> Without knowing more, I suspect this data should be computed at font
>> generation time, and it should be embedded in the OTF file.
>
> It is created at font generation time (git grep font-cache.scm in 
> mf/GNUmakefile) but it is not part of the otf-table.

which branch has the latest version of this?

>  As I said, I'd like to do this, but I'm not comfortable enough with build to 
> know how its done.  Where and when are these files generated?  Are they 
> generated by metafont or python or

look at scripts/build/mf-to-table.py

Then there is

 scripts/build/gen-emmentaler-scripts.py

which generates a FontForge script file (.pe since it used to be
called PfaEdit) in mf/out/emmentaler-XX.pe.

The calls look like this,

 LoadTableFromFile("LILC", "feta11.otf-table");

> This doesn't seem impossible, but I'd want to make sure it's the right way to 
>go.  The advantage of font-cache.scm is that it defines box-hash in LilyPond 
>at runtime, and as hash-table-lookups are in constant time, this is lightning 
>fast compared to an alist, which is in linear time.

I'd store a separate hashtable of codepoint => list of boxes directly
in the OpenTypeFont struct.

> A separate issue should be opened in the tracker to use hash-tables instead 
> of alists for otf tables.

but it is using hashtables; check out

 Open_type_font::Open_type_font (FT_Face face)

the alist are converted to hash tables.

>I'm trying to think of this project in separable, manageable chunks.  I'd like 
>the first chunk to be the pushing of the skyline code you see on Rietveld so 
>that there is a direct effect straightaway in scores & so that we can get user 
>feedback before we make infrastructural changes (which may depend on what 
>people wind up asking for after the change).

I'd rather not introduce more fragility (cf the generated .scm files)
into the build process which is complicated enough as it is.  I think
users can wait for another week if need be.

-- 
Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen