Rather than trying to implement full i18n plural support, we just remove
this failed attempt from the past. The fact is that to get proper
support, we'd basically need to reimplement a Gettext-like plural
definition syntax within our API, then ask people to write down this
plural definition for their language, then to write every plural form…
all this for custom units which only them will ever see!
Moreover code investigation shows that the singular form was simply
never used, and the plural form was always used (whatever the actual
unit value displayed).
As for the "identifier", this was a text which was never shown anywhere
(except in the unit editor) and for all built-in units, as well as
default unitrc units, it was equivalent to the English plural value.
So we now just have a unique name which is the "long label" to be used
everywhere in the GUI, and abbreviation will be basically the "short
label". That's it. No useless (or worse, not actually usable because it
was not generic internationalization) values anymore!
This fixes all our GObject Introspection issues with GimpUnit which was
both an enum and an int-derived type of user-defined units *completing*
the enum values. GIR clearly didn't like this!
Now GimpUnit is a proper class and units are unique objects, allowing to
compare them with an identity test (i.e. `unit == gimp_unit_pixel ()`
tells us if unit is the pixel unit or not), which makes it easy to use,
just like with int, yet adding also methods, making for nicer
introspected API.
As an aside, this also fixes#10738, by having all the built-in units
retrievable even if libgimpbase had not been properly initialized with
gimp_base_init().
I haven't checked in details how GIR works to introspect, but it looks
like it loads the library to inspect and runs functions, hence
triggering some CRITICALS because virtual methods (supposed to be
initialized with gimp_base_init() run by libgimp) are not set. This new
code won't trigger any critical because the vtable method are now not
necessary, at least for all built-in units.
Note that GimpUnit is still in libgimpbase. It could have been moved to
libgimp in order to avoid any virtual method table (since we need to
keep core and libgimp side's units in sync, PDB is required), but too
many libgimpwidgets widgets were already using GimpUnit. And technically
most of GimpUnit logic doesn't require PDB (only the creation/sync
part). This is one of the reasons why user-created GimpUnit list is
handled and stored differently from other types of objects.
Globally this simplifies the code a lot too and we don't need separate
implementations of various utils for core and libgimp, which means less
prone to errors.
It was a bad idea to bind width/height with pixel density. These are separate
things. You may want to set specific pixel dimensions while keeping a given
resolution.
Moreover I am now properly storing aspect ratio in the widget, otherwise with
integer computation, we are just losing too much precision and the ratio is in
fact changing constantly as you change dimensions.
The code comes from plug-ins/common/file-pdf-load.c and apparently it used to be
in libgimpwidgets (very long ago). I'm copying it to its own file and massively
improve the code (depending on property binding which makes the behavior much
more robust).
Still I left it as private because I don't want to say the API is finale without
having tested it a bit more. But eventually we should make it public for
plug-ins to use it directly too. When this happens, it should get back to
libgimpwidgets.
Jehan