Module transitions_ui

Transitions panel. Catalogue: one CARD per TransitionKind (same size and frame as an effect card), previewing the transition half-way over the stock picture the effect thumbnails are rendered from — the app hands it over with set_stock, and without it a card falls back to a neutral named tile. A card selects the kind, right-clicking it applies the transition straight away (start / end of the selection, or every cut on its track), and a press-and-move drags DragPayload::Transition. Next to the grid the default duration DragValue (0.1..5 s), a colour button for FadeToColor and a direction selector for Push/Wipe. “Add at start” / “Add at end” apply it to EVERY selected clip through add_transitions, which is also what the menu, the hotkeys and MCP call — it records the choice in TransitionsState, so Ctrl+T (Action::AddLastTransition) repeats whatever was applied last, whichever path applied it. A clip with no neighbour on that side gets an EDGE transition (blend from/to nothing) instead of a cut transition, so lone clips can fade in/out too. Below: the transitions touching the first selected clip (Project::transitions_of): kind combo, position combo (Start / End / Last / Next — re-anchors the transition relative to the clip), duration, colour/direction/ease editors, remove. Returns true when the project changed (call undo once per gesture first).

Structs

TransitionsState

Enums

Pos 🔒

Where a transition sits relative to the selected clip — the panel’s position selector.

Constants

PREVIEW_P 🔒

Half-way through the transition: enough to show the wipe/push/fade on a still card.

STOCK 🔒

The catalogue’s stock picture, uploaded by the app from the same source as the effect thumbnails. The handle lives here so the texture outlives the app’s own thumbnail list.

Functions

add_transitions 🔒

Add a transition at the cut left of every id (or at its right edge with at_end), with the colour and direction from st, and record the choice in st. A clip with no neighbour on that side gets an edge transition instead (blend from/to nothing). THE funnel: panel, menu, hotkeys and MCP all come through here (or call remember), which is what keeps Ctrl+T on the last transition actually used. Returns how many were added — a transition always belongs to the clip on the RIGHT of the cut, and Project::add_transition replaces the one already on that cut, so overlapping selections are fine.

dir_vec 🔒

Where the incoming clip travels from, mirroring compose::dir_vec (0 left, 1 right, 2 up, 3 down).

direction_row 🔒

drop_at_end 🔒

A transition card dropped on a clip at timeline time t: which of the clip’s two cuts it means. The half you drop on picks it, so the gesture reads the same as “Add at start” / “Add at end”. Shared so the timeline’s drop highlight and the app’s drop handler cannot drift apart.

has_left 🔒

A clip abuts the left edge of id, i.e. there is a cut to put a transition on.

move_transition 🔒

Re-anchor a transition at a new position relative to sel, keeping its settings. Returns true when it moved (the target position must exist).

paint_preview 🔒

Draw the transition over the stock picture: A is the picture, B the same picture tinted, so the two sides of the cut read apart without decoding a second image.

right_neighbor 🔒

The clip starting exactly where id ends, on the same track.

set_stock

The app hands over the picture the effect catalogue renders from; the cards preview over it.

show

transition_card 🔒

One catalogue card: the preview tile with the name underneath, selected/hover border. Clicking it selects the kind, right-clicking opens its quick actions; a deliberate press-and-move drags DragPayload::Transition (ui::drag_source).

wipe_rect 🔒

The part of the tile the incoming clip has reached at p (same regions as compose’s wipe).