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.
… native dimensions/ratio display by default.
Also adding gimp_vector_load_procedure_extract_dimensions() public
function allowing plug-ins to query the native size or ratio of a vector
file.
Instead of filling default GUI for a specific type of plug-in procedure in
fill_list(), we add 2 methods:
* fill_start() is ensured to run once (and only once) before any fill_list()
code runs.
* fill_end() is ensured to run once (and only once) after all fill_list() ran.
This takes care of 2 kind of GUI bugs which we could have:
1. First if no explicit fill were run (i.e. neither gimp_procedure_dialog_fill()
nor gimp_procedure_dialog_fill_list() were ever run), then the default
interface would not be added to the dialog. Yet this case could happen when
we don't want anything else but the default GUI (this will be the case in the
upcoming file-wmf-load GUI).
2. Second if at the opposite, you fill several times fill functions (I hadn't
thought of this, but noticed some already started to do this in our ported
plug-ins), we obviously don't want the default GUI to be added several times
either.
As expected, it is made to reuse shared code for every GimpVectorLoadProcedure.
In particular, they all need to choose dimensions to load at, so we are sharing
a same GimpResolutionEntry widget logic everywhere now.
I am in fact still very unsure about the code logic for this widget by the way
for these reasons:
* It still puts too much emphasis on the "resolution" (pixel density) part,
which makes people believe it's important, while they should in fact choose
the pixel dimensions most of the time and not care about the pixel density.
* Right now we can't break ratio (which in fact was already impossible in most
vector format plug-ins we had). Do we want to add a chain and allow this?
* If we consider the pixel density as the one we want to set the document with
(which may not be the same thing as the one from when we load the document),
we also want to break link between width/height dimensions and pixel density.
Right now we can't (updating one field updates the others too).
* There is always this issue of precision with pixel density vs. pixel
dimensions because we don't necessarily find the same values when computing
from one side to another because of lack of precision and this confuses
people.
* Finally there is the question of multi-page documents (e.g. PDF) where the
chosen dimensions are the document dimensions whereas each page may have a
different size which has to be recomputed independently and this got me
off-by-one errors. I think I'll need to review a bit the logic, but I'll do
once I've ported all the vector format load plug-ins first to see the most
common usages.
Jehan