transparency.viewOpacityMask {on?, id?} shows only the opacity mask on the
canvas as greyscale coverage (luminance, clip and invert applied; the rest of
the art hidden) and enters mask editing; called again it shows the artwork and
keeps editing. The Transparency panel's mask thumbnail runs it on Alt-click and
is outlined in the accent colour while the mask is viewed. The state is
DocState.mask_view (shown while that mask is edited: DocState::shown_mask) and
reaches the renderer as RenderOptions.mask_view.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Clicking a Layers panel target circle runs `layer.target {id}`: a layer gets its art
selected and becomes the target (`Selection.target`) of the appearance, effect,
transparency and opacity-mask commands, which then edit the layer itself; the
Appearance panel lists it. Dragging a circle onto another runs
`appearance.transfer {source, target, copy?}` (Alt copies), dropping it on the trash
clears it. Filled dots also mark groups and layers with fills of their own, masked
objects get a dashed underline, and while an opacity mask is edited the panel lists
only an `<Opacity Mask>` entry and the tab says so.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Knockout Group is now Knockout {Neutral, Off, On} (old files' true loads as
On, false as Neutral). In a knockout group each child erases what the
children below it drew where it paints, then adds itself, so it composites
against the group's backdrop; neutral plain groups pass their children
through to the enclosing knockout group. transparency.set / object.setProps
take knockout "on"|"off"|"neutral"|bool; transparency.info reports the
state. PDF and SVG write knockout groups as nested soft masks with the same
look (PDF warns); the Transparency panel has a tri-state checkbox.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
While a mask is edited, the Transparency panel and its commands act on the
masked object (Release leaves editing first). Mask commands and
transparency.set take ids and work without a selection; Make Opacity Mask
with one object adds an empty mask and enters editing. Opacity is 0..100 in
every command. transparency.info reports the panel's values with null for
mixed ones, shown blank. Saves and exports never include the editing layer
(Document::without_edit_modes; mask_edit is not serialized).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
