Override GimpItem::resize(), instead of GimpLayer::resize(), when
resizing a group layer, so that GimpLayer doesn't try to resize the
mask. Instead, the let the usual mask resizing logic in
GimpGroupLayer handle that.
Also, make sure that the mask is properly restored upon undo when
group resizing is suspended outside of any mask-suspension block,
which can happen when resizing the group.
Add layer-mask support for group layers. Group-layer masks work
similarly to ordinary-layer masks, with the following
considerations:
The group's mask size is the same as group's size (i.e., the
bounding box of its children) at all times. When the group's size
changes, the mask is cropped to the new size -- areas of the mask
that fall outside of the new bounds are discarded and their data is
lost (sans undo), and newly added areas are filled with black (and
hence are transparent by default).
The new gimp_group_layer_{suspend,resume}_mask() functions can be
used to modify this behavior. Between the outermost pair of
suspend/resume calls, the old mask data is remembered, and is used
to fill the newly added areas while cropping the mask when the
group is resized. We override GimpItem::{start,end}_move() for
GimpLayer, to call these functions (suspend() in start_move(), and
resume() in end_move()) for each of the layer's ancestors.
As a result, while moving a layer, or a set of layers, atomically,
such as while dragging with the move tool, or moving linked layers,
the ancestors' mask data is not lost, and is only discarded at the
end of the operation.
This commit also takes care of properly handling undo for group-
layer mask crops, properly invalidating the image when the group
layer's mask is shown, and enabling the mask actions for group
layers (obviously :).
making its external API "complete". Remove the redundant
"new_base_type" and "new_precision" from the internal (vfunc) API (the
Babl format has the same information).
* app/core/gimpdrawable.[ch]: add "gboolean push_undo" to
GimpDrawable::convert_type().
* app/core/gimpdrawable-convert.[ch]: same here for the gray and rgb
conversion functions.
* app/core/gimpchannel.c
* app/core/gimplayer.c: pass FALSE when called from GimpItem::convert()
because it can be called on unattached items only.
* app/core/gimpimage-convert.c: pass TRUE.
* app/core/core-enums.[ch]
* app/core/gimpgrouplayerundo.[ch]
* app/core/gimpimage-undo-push.[ch]: add GIMP_UNDO_GROUP_LAYER_CONVERT
which simply calls gimp_drawable_convert_type() with the old type
when undone/redone.
* app/core/gimpgrouplayer.c: push a group layer convert undo so this
can be properly undone/redone.
* app/core/gimpgrouplayer.[ch]: add gimp_group_layer_suspend_resize()
and gimp_group_layer_resume_resize() and call them around functions
where all a group's children are transformed (translated, resized
etc). This way we go from the worst case of reallocating the
group's projection tiles once for each child down to exactly one
reallocation.
* app/core/Makefile.am
* app/core/core-enums.[ch]
* app/core/core-types.h
* app/core/gimpimage-undo-push.[ch]
* app/core/gimpgrouplayerundo.[ch]: add new undo class
GimpGroupLayerUndo which implements undos for suspend/resume of
group layers and calls them in reverse order when undoing.
