Re: Progress update on adjustment database

> Thanks.  Do you have meanwhile found an explanation why o-tilde looks
so bad for Times New Roman at 16ppem?

All 4 letters in each row have a different approach:

õ: vertical stretch, no segment removal
ñ: no vertical stretch, segment removal
ã: vertical stretch and segment removal
all other tildes: no changes applied

Actually, I tried the o tilde character again with no adjustments and it
looked the same.  In this case, the vertical stretch wasn't enough to fix
the issue.

> Sounds good.  Unfortunately, I'm a bit short of time right now; I'll
think about your algorithm within the next few days.  However, please
proceed anyway!
I implemented the algorithm for all glyph variants!  The version I used is
different from what I wrote originally to fix some errors.  Here's the
current version:
results is now a global set of glyphs instead of an argument to the
function.  It initially starts empty
fs is a global set of features, also initially empty
all other definitions are the same

func all_glyphs(codepoint c)
{
    result = result ∪ lookup(c, fs)
    foreach (feature f ∈ (features - fs)) //for all features not already in
fs
    {
        new_glyphs = lookup(c, fs ∪ f) - result
        if (new_glyphs != ∅)
        {
            result = result ∪ new_glyphs
            fs = fs ∪ f
            all_glyphs(c)
            fs = fs - f
        }
    }
}
I've only tried it on a pretty simple case so far, so I'll need to assemble
a more complex test font or two.

On Mon, Sep 18, 2023, 4:03 AM Werner LEMBERG <[email protected]> wrote:

>
> > Is testing all these combinations really necessary?
>
> I don't know :-) I just wanted to point out that feature combinations
> have to be considered.
>
> > [...] My intuition says very few of these combinations actually
> > matter.
>
> Yes, I agree.
>
> > I wrote some pseudocode for a different approach that I believe
> > accomplishes the same thing, while being more efficient and hopefully
> > removing the need to constrain the set of features considered: [...]
>
> Sounds good.  Unfortunately, I'm a bit short of time right now; I'll
> think about your algorithm within the next few days.  However, please
> proceed anyway!
>
> > I attached some pictures of the tilde unflattening approaches.
>
> Thanks.  Do you have meanwhile found an explanation why o-tilde looks
> so bad for Times New Roman at 16ppem?
>
> > I chose sizes that showcase the differences between the approaches,
> > and also committed my current code if you would like to try it
> > yourself.
>
> Will try if I find some time.
>
>
>     Werner
>