[HarfBuzz] Adding tracing

[Behdad Esfahbod]

On 05/13/2010 05:05 PM, Khaled Hosny wrote:
> On Thu, May 13, 2010 at 05:01:32PM -0400, Behdad Esfahbod wrote:
>> On 05/11/2010 02:09 PM, Martin Hosken wrote:
>>> Dear All,
>>>
>>> I've added tracing to harfbuzz-ng. This is to help font developers rather than programmers, figure out what is going on with their fonts. The cost is a simple if() for each lookup. If that is too high, we can probably make tracing optional.
>>
>>
>> Thanks Martin,
>>
>> I took a look. I'd rather do that as compile-time debugging like I do for
>> sanitize and apply currently.  Will get to it when fleshing hb_shape() out.
> 
> But I think it would be a very interesting feature for font developers,
> I use a similar feature in ConTeXt and it is quite handy in spotting
> flawed logic and other hard to find errors.

As I said, I'll consider it later on.  Not with a callback, but perhaps
controllable by envvars.

behdad