[CREATE] Resolution information in ORA

[Andrew Chadwick]

On 21 June 2013 11:11, Boudewijn Rempt <boud at valdyas.org> wrote:
> On Fri, 21 Jun 2013, Michael Natterer wrote:
>
>> On Fri, 2013-06-21 at 11:26 +0200, Boudewijn Rempt wrote:
>>>
>>> Hi,
>>>
>>> Jens Reuterberg (a Swedish illustrator) posted this bug for Krita:
>>> https://bugs.kde.org/show_bug.cgi?id=321106. He would like to roundtrip
>>> ppi information between krita, gimp and other apps that support ora.
>>>
>>> The spec doesn't define that at the moment. I see two possibilities:
>>>
>>> * use the resolution information in the embedded png files (I do that in
>>> Krita for now)
>>> * extend the stack spec with resolution information, for example like:
>>>
>>> <image w="300" h="177" xres="300" yres="300">
>>>
>>> I don't care particularly about the tags used, or whether we have
>>> resolution separate for x and y, or not.
>>>
>>> Option 2 has my preference...
>>
>>
>> I prefer option 2 too, and I would make it both-or-none, so either
>> specify both resolutions, or none, in which case ORA would have to
>> define a default, probably the omnipresent and useless 72 :)
>>
>
> Okay -- any preference for the actual attribute name?

Hi, sorry for the late reply. Boudewijn just reminded me of this on IRC.

Option 2 gets my vote too. I'd prefer "dpi" or "ppi" to make the unit
explicit, but *res is fine too.

Default value of 75dpi is fine, though apps can of course impose their own.

Do we really need separate X and Y resolutions? If some people *do*
need separate axis resolutions, what are apps which assume square
pixels to do? Average? Max? FWIW, I prefer a single resolution value,
but this is not my workflow so perhaps I'm ignorant of the
requirements here.

For conformance, I guess we should also state that resolutions
specified in stack.xml overrides any data/ source of resolution
information. Although the latter should agree.

-- 
Andrew Chadwick