[HarfBuzz] hb-shape to output applied features (optionally also an ultra-verbose XML log)?

[Adam Twardoch (List)]

On 12-08-29 01:20, Behdad Esfahbod wrote:
> I agree. But that's not the primary goal of HarfBuzz, and distracts us
> from the main goals. I'll see what I can do. 
I believe with such an ultra-verbose output, complex-script font
developers (even of proprietary ones) would be compelled to run the tool
using the "ot" and "uniscribe" backend, and report inconsistencies --
which would, after all, help HarfBuzz as well.

In a way, what I'm proposing is not at all contrary to the comprehensive
testing effort. And since Uniscribe is probably as much a matching
matching target as the Pango shapers are, this could be very useful.
You'd have a chance to tap at developers of high-end complex script
fonts such as, say, Tiro Typeworks. You give them a useful tool, they
give you useful feedback which helps improve your product.

Mostly, their primary deployment target is Uniscribe, so they won't
spend their time testing HarfBuzz *unless* you provide them with
something that doesn't exist yet. Such a tool doesn't, and HarfBuzz is
the perfect place to do such a job. As I mentioned earlier, I don't
insist exactly on the XML syntax I proposed. It does pretty much
exemplify in quite some detail what I think would be very useful,
though. Oh, BTW, the whole "processing" part could be optional. For some
scenarios, just the input and output, but with exact information, would
be of great use.

I believe that a very good way to test implementations of layout engines
is to collaborate with implementors of fonts (especially: complex fonts)
which run on such layout engines.

There won't be many users of the functionality I'm proposing, but the
ones who will use it will be of very high value for the development of
HarfBuzz, I believe. I don't develop fonts myself, so I don't actually
really have a stake in this. But I know from conversations with people
who do develop complex fonts that this functionality is of great
potential value for them. BTW, if some financing would be needed so you
could find a developer who would do this, please let me know and I think
I'll be able to gather something.

Best,
Adam

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May success attend your efforts,
-- Adam Twardoch
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