This allows for easier code reading and changing.

Current logics of dealing with duplicate accelerators was just to delete
one randomly. This works ok in most case since we can't be in the head
of people and can't know which one they want to keep (yet we can't keep
both because that makes it very complicated to reset the shortcut
appropriately by hand/GUI, without a tedious work of researching which
other action uses the same shortcut. See commit 2a232398).

There is still some cases where we can be a bit more clever than random
deletion: when one of the accelerator is mapped to a non-existing
action. In this case, let's delete this accelerator in priority. Not
only the chances of this being the expected result are higher; but even
worse, there is anyway no GUI way to delete the accelerator for the
non-existing action! Thus you could try and reset your existing action's
shortcut as many times as you want in the GUI, it would always end up
deleted at next startup!

Note that if the non-existing action's shortcut has no duplicate, it
won't be deleted. This ensure that you could uninstall a plugin, then
reinstall it later and still have your custom shortcuts saved in the
meantime. A shortcut of a non-existing action will *only* be cleaned out
if it is redundant with the shortcut of an existing action.

Use gimp:buffer-source-validate, introduced in the previous commit,
for the source node of GimpDrawables.  This avoids threading issues
with layer groups, or any other drawables that may use a validating
buffer, by making sure the buffer is validated before any
succeeding operations, and hence the associated graph is processed
on the same thread as the parent composition.

Restore multithreaded processing in GimpOperationLayerMode.

gimp:buffer-source-validate is a drop-in replacement for
gegl:buffer-source, however, if the attached buffer has a
validating tile-handler, it makes sure the required region is
validated during process().  This avoids a situation in which
validation happens in different worker threads at the same time
during the processing of a succeeding operation; since validation
is protected by the buffer's tile-storage mutex, this can result in
either a deadlock (currently), or an effective fallback to single-
threaded processing.

Commit 4b521435 uses recursive
regex patterns in gimp-mkenums, which requires perl >= 5.10.0.

Do not use the bytes-per-pixel size of the input drawable.
Use the bpp of the output format instead.

When switching a group layer from pass-through mode to a non-pass-
through mode, flush the projection synchrnously, to make sure that
the projection's buffer gets properly invalidated at that point,
and can be subsequently used as a source for the rest of the
composition.

Add a boolean 'pass_through' member to GimpGroupLayerPrivate, which
indicates if the group is a pass-through group, and use it instead
of checking the group's mode, so that we can detect that the group
used to be a pass-through group when the mode changes, and to
simplify the rest of the code.

The source node of pass-through groups doesn't use the projection's
buffer, hence there's no need to invalidate it synchronously, which
is faster.

... since we don't actually render anything, only invalidate.

Set the priority of group-layer projections according to the group
layer's depth, so that top-level groups have a priority of 1
(compared to a priority of 0 for the image projection), and nested
groups have a priority one greater than their parent (in other
words, shallower groups have higher priority than deeper groups,
all of which have lower priority than the image.)

This makes pass-through groups much faster, in particular.

... which control the priority of the projection's idle source.

The projection's priority is specified relatively to
GIMP_PRIORITY_PROJECTION_IDLE (i.e., a priority of 1 results in an
idle source with priority GIMP_PRIORITY_PROJECTION_IDLE + 1, etc.)

Add GimpViewable::ancestry-changed signal, which is emitted when
the viewable's ancestry changes, i.e., when its parent, or the
parent of one of its ancestors, changes.

Add gimp_viewable_get_depth() function, which returns the
viewable's depth in the hierarchy, i.e., its ancestor count.

Thanks to Massimo for the solution!

...is a regression in common cases

Commit the free select tool on double click inside the polygon.

Done by implementing GimpCanvasItem::hit() in GimpCanvasPolygon, using
ugly code.

g_type_from_name ("PixbufStyle") might return 0. So we also need to
protect this case.

Massimo is worried that it could unload the module (maybe in some
specific cases?), which could indeed happen when the g_type_class_ref()
just before was the first call to the class (hence it's the only ref).
So let's just unref() in the exit() function instead.

There's no real reason not to do it (has no visible effect if the
model has no abbreviations to begin with), and it means less
special casing.

... and a small cleanup.

This person implemented the enhanced smudge tool and another bug fix.
We only have this username to credit the contributor.

Not sure if g_type_class_ref() can actually return NULL here, but let's
add a check, just in case.
Also unref() after since we ref-ed it ourselves.
Finally reorganize a bit to keep the private functions together and
named appropriately, clean some tabs and add a comment to remind of
further check/cleanup once we port to GTK+3.

Massimo Valentini authored Nov 30, 2017 and Jehan committed Dec 01, 2017

Comment by Jehan after review:
"Quick and dirty hack" but a working one. Since the bug will likely
disappear with the GTK+3 port (to be verified) which uses another theme
system, let's just do it this way.

Add abbreviated versions for long layer mode names.  In particular,
replace the "(legacy)" suffixes with "(l)" in the abbreviated
versions.

Move the abbreviated descriptions to the "abbrev" parameter, and
use full strings for the descriptions.

... to match the old gradient editor menu labels.

Use gimp_int_combo_box_set_layout() to set the mode-group combo box
layout to ICON_ONLY, instead of manually constructing an icon-only
cell-layout.

The value descriptions of GimpGradientColor,
GimpGradientSegmentColor, and GimpGradientSegmentType enums appear
in the on-canvas gradient editor UI, as combo-box items in the tool
GUI overlay.  Since we want to keep the overlay as small as
possible, we previously used abbreviations for these descriptions
(e.g., "FG (t)", instead of "Foreground (transparent)").

Replace the abbreviated descriptions with unabbreviated ones, and
move the abbreviations to the "abbrev" parameter.  This way we get
the abbreviated version in the combo-box, and the full version in
the combo-box's menu.

... using enum models with abbreviated labels

The "layout" proerty controls the combo-box layout (but not its
menu layout), and can be one of:

  - ICON_ONLY:  Only show icons.

  - ABBREVIATED:  Show icons and abbreviated labels (or full
    labels, when there is no abbreviation).

  - FULL:  Show icons and full labels.  Default.

Avoid reconstructing the combo's cell-layout when the menu is
shown/hidden, by maintaining the combo's cell-layout and the menu's
cell-layout separately (probably a terrible hack, but one we already
use :P).

Use gimp_enum_value_get_abbrev() to fill the ABBREV column of
GimpEnumStore.

... which holds an abbreviated label, or NULL to use the normal
label.