After much thought, tests and discussions with Aryeom, we decided adding
back an active item concept additionally to the selected items ones is a
bad idea as it makes only usage unecessarily complex.
We will just have selected layers. Some kind of operations will work
when more than one item (layers, channels, vectors) are selected while
others will require exacty one item.
In particular, let's replace instances of gimp_image_(s|g)et_active_*()
by corresponding gimp_image_(s|g)et_selected_*(). Also replace single
item in various undo classes by GList of items.
Also "active-*-changed" GimpImage signals are no more, fully replaced by
"selected-*s-changed".
This is still work-in-progress.
Add an optional "format" parameter to gimp_drawable_merge_filter(),
which specifies the format to use for the output, possibly changing
the drawable's format.
In GimpDrawableFilter, add a gimp_drawable_filter_set_add_alpha()
function, which allows the filter to add an alpha channel to the
drawable when committed (by passing an appropriate format to
gimp_drawable_merge_filter()).
When attaching a floating selection to a layer, don't clip the
floating selection to the layer's boundary, and instead resize the
layer to include the entire floating selection when it's anchored.
As per the last commit, this can be prevented by locking the
layer's position.
Add a new "clip" parameter to gimp_drawable_merge_filter(). When
set to FALSE, the function resizes the drawable to the bounding box
of the filter's output, instead of clipping the output to the
drawable's boundary.
In gimp_drawable_merge_filter(), add an "update" parameter, which
specifies whether to update the affected region of the drawable
after applying the filter. Avoid updating the drawable when
commiting a GimpDrawableFilter (and manually update the drawable if
filter application was cancelled), and when anchoring a floating
selection, since in both cases the relevant region of the drawable
has already been updated.
Replace the GIMP_BOUNDARY_HALF_WAY macro by two others : one for perceptual and
one for linear gamma.
Use the GIMP_BOUNDARY_HALF_WAY_LINEAR to compute channels and floating selection
boundaries.
Jehan