Units can't be translated (units.xml not localizable)

[Patrick Storz]

Units in units.xml [1] currently can't be translated.

This was OK as long as all units were actually SI units (or at least commonly known and used units) and therefore used their internationally recognized unit symbol (all other strings in units.xml, e.g. description, aren't actually visible anywhere in Inscape anyway as far as I'm aware of).

However a recent change [2] introduced two new radial units: The "gradian" and the "turn".
- Both of them are not SI units!
- The "gradian" has a common unit symbol ("gon") which is not used, though. Instead the totally misleading "grad" is used (in German this is for example the exact translation for "degree")
- The "turn" does not have a common unit symbol at all (therefore without translation this unit is totally unusable)!

Therefore this bug needs basically two decisions:
1. Do we offer a possibility to translate units.xml? Then such ambiguities can be resolved by proper translation.
2. Do we simply drop the two units? They are very uncommon anyway and (at least the "turn") can't be reasonably used without translation. Then we could probably do without translation.

[1] http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/view/head:/share/ui/units.xml
[2] http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/13648

[su_v (suv-lp)]

The new units were originally added in r13614:
https://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/13614#share/ui/units.xml

as partial merge of GSoC Project 2014: Better support for SVG paints
http://www.google-melange.com/gsoc/proposal/public/google/gsoc2014/penginsbacon/5629499534213120

[jazzynico (jazzynico)]

> Both of them are not SI units!

Well, inch and foot aren't in the SI, but are in the same file. (see http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf, page 129 -37 in the PDF document- chapter 4.2 "Other non-SI units not recommended for use").

> The "gradian" has a common unit symbol ("gon") which is not used, though.

Confirmed. Note that the "gon" is mentioned page 124 (32 in the PDF) because of its use in navigation.
But SVG 1.1 uses "grad"... (see http://www.w3.org/TR/SVG/types.html#BasicDataTypes, and http://www.w3.org/TR/SVG/types.html#InterfaceSVGAngle -no change in SVG 2 apparently). I'd favor "gon".

> The "turn" does not have a common unit symbol at all

It's a bit more difficult. The turn is not mentioned at all in the SI documents, and it seems that its symbol varies...
In France, the official symbol is "tr" (tour), and I read "rev" (revolution) in English papers.
Note that turn is also defined in src/svg/svg-angle.h (see https://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/13614#src/svg/svg-angle.h).

That said, I'm not sure how the unit.xml file is used in Inkscape. If it's for UI purpose only, I guess we could define and use a primary key for each entry and allow all the other elements to be translated.

[Patrick Storz (ede123)]

Let's continue at https://gitlab.com/inkscape/inkscape/issues/83