Shape tweens

A shape tween morphs the drawing on one keyframe into the drawing on the next: outline, fill colour, stroke colour and stroke width all change gradually. Use a motion tween to move one object; use a shape tween to turn one drawing into another.

A star morphing into a ring over seven frames

Seven frames of one tween, rendered by the export rasterizer: the outline, both colours and the stroke width blend, and the ring's hole opens from the centre.

Creating one

Draw on a keyframe.
Create a later keyframe on the same layer (F6 or F7) and draw the shape it should become.
Select any frame between the two and click the shape tween button in the timeline toolbar (a square turning into a circle, next to the motion tween button), choose Create shape tween from the timeline context menu, or press Ctrl+Alt+S. The shortcut can be changed in Settings > Keyboard shortcuts.

The span turns green in the timeline. Motion tweens keep their usual colour. Both pairs of colours (fill and arrow, for motion and for shape tweens) can be set separately under Settings > custom colours > timeline.

Both keyframes need drawn vector shapes: brush strokes, pencil lines, shapes and bucket fills. Symbols, bitmaps and text on the same keyframe are left alone and simply held for the span; break them apart first if they should morph.

A shape-tweened drawing is still a drawing. The brush, eraser, bucket and path selection keep working on both keyframes; only a motion tween turns artwork into an object.

To remove the tween, right-click a frame inside it and choose Remove shape tween; the menu shows this in place of the two Create entries whenever the selection touches a tween. To change the pacing, select a frame inside it and use the tween section in Properties, which can also remove it. Shape tweens accept the same easing presets and custom curves as motion tweens.

How shapes are matched

There are no shape hints. The match is worked out from the drawings:

Shapes pair up by position and size, closest and most similar first.
If the next keyframe has more shapes, the nearest shape splits; if it has fewer, the spare shapes merge into their nearest neighbour.
Inside a shape, each outline or stroke pairs with the nearest one of similar size, so a drawing made of many strokes keeps every stroke in place. A hole pairs with a hole and an open line with an open line. An outline with no partner grows or shrinks where it is.
Every corner and curve of both drawings is kept: the in-between has a point wherever either drawing has one, so the frame before the next keyframe looks like that keyframe, not like a simplified copy.
Drawing direction and the point where an outline starts do not matter.
A fill or stroke that exists on only one side fades in or out.
If the next keyframe is blank, the shapes shrink and fade away.

When a morph takes an unexpected route, add a keyframe in the middle and correct the drawing there.

Keyframes inside a tween

Pressing F6 on a frame inside a shape tween creates a keyframe holding the in-between drawing exactly as it was shown. Both halves stay shape tweens: the first keyframe morphs into the new one, and the new one goes on morphing into the original destination. Each half keeps the tween's easing.

Editing artwork on an in-between frame does the same thing first.

Pressing F7 inside a shape tween ends the tween at the new blank keyframe. Whatever you draw there next takes over and morphs on into the original destination, so you can redraw the middle of a morph from scratch. If the project is closed before anything is drawn on that blank keyframe, create the second tween by hand.

Strokes added later to a keyframe that already starts a shape tween join that tween automatically.

Dragging either keyframe of a tween along its layer retimes the tween; this applies to motion tweens too. A keyframe with a tween on each side keeps both. The tween is only cut when the move makes it impossible: the end keyframe is dragged to or before the start, another keyframe ends up between the two, or the keyframe is dragged to a different layer.

Removing the keyframe a tween points to removes the tween.

Where it plays

Shape tweens play in the editor stage, outline mode, Animation Preview, Fast Preview, q0player and every q0enc export (q0s, MP4, q0v, PNG sequence, GIF, still images).

FLA and XFL import

Animate frames with tweenType="shape" import as shape tweens, including classic ease values and custom ease curves. Animate shape hints are not read. Motion tweens import as before. The legacy binary FLA reader does not import tweens of either kind.

File compatibility

A project that contains a shape tween is saved as q1s v39 and exported as q0s v38. Editors and players older than this version cannot open those files. Projects without shape tweens keep their previous file version and still open in older builds.

Limits

Gradient fills and mask-eraser appearance are not morphed; in-between frames use the flat fill colour.
Placement effects other than tint and opacity (blur, glow, shadow, blend modes) are not applied to in-between frames in the editor stage and q0player. Exports apply them.
On an in-between frame, clicking and hovering still follow the first keyframe's outline, not the morphed one.
In the editor, a layer that masks or is masked while it morphs is drawn by the slower raster path for those frames.
Rig bindings do not apply to in-between shapes.