[HarfBuzz] Adding debug support to hb

Luis de Bethencourt luis at debethencourt.com
Thu Feb 13 21:22:21 CET 2014

How about to a similar model to GStreamer's debugging logs?

Compile time flags set the debugging completely on or off, so it can easily
be stripped in deployment builds. Then in the code there are different log
levels depending on severity: gst_debug_critical();, error, warning, info,
Later during execution you pass a runtime flag (e.g: x_DEBUG=*:3), and this
only prints to stderror the specified level or higher.
GStreamer does it in such a way where you request debug logging per plugin,
so you can get general information of all the pipeline but also low level
information of the component you are working on. I don't think harfbuzz
needs this level of granularity, but it would be nice.

Everytime I contribute to any other project I miss GStreamer debugging
system :)


On 13 February 2014 14:49, Behdad Esfahbod <behdad at behdad.org> wrote:

> On 14-02-10 09:11 PM, Martin Hosken wrote:
> > Dear Behdad,
> >
> > As we approach a v1.0 I would like to encourage us to add debug support
> for font developers.
> >
> > Looking at the rather nice hb_auto_trace, it would really help if the
> trace routine could be passed the buffer as well as the lookup being
> traced. That way a font debugger could show the glyph string state before
> and after a lookup runs, the position in the glyph string where the lookup
> is executed and which lookup executed.
> We need a concrete API proposal for this.  *How* it's implemented is
> irrelevant.  Last time Jonathan and I thought about it we couldn't come up
> with anything concrete.
> And it doesn't block a v1.0 anyway since it doesn't involve changing
> existing
> APIs.
> behdad
> > Yours,
> > Martin
> >
> > _______________________________________________
> > HarfBuzz mailing list
> > HarfBuzz at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/harfbuzz
> >
> --
> behdad
> http://behdad.org/
> _______________________________________________
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> HarfBuzz at lists.freedesktop.org
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