Canvas element types

Every Canvas element is a flat record with an ID, type, position (x, y), size (w, h), angle, fractional z-order index, deletion and collaboration metadata, and a type-specific props object. Group, frame, and mind-map membership uses IDs rather than nested records, so elements can move and sync independently.

New writes use named style tokens, while colour strings, numeric stroke widths, and numeric font sizes remain accepted for older elements.

Canonical contract values:

• rectangle
• ellipse
• diamond
• triangle
• text
• note
• line
• arrow
• freehand
• image
• frame
• group
• mindmap
• edgeless-text
• plait

Elements

Rectangle rectangle

A rectangular box with optional corner radius and text. Its style includes fill, stroke, stroke width, dash, opacity, clean or scribbled rendering, sloppiness, fill style, edge style, and font, weight, style, size, colour, and alignment. It may be locked or belong to a frame, group, or mind map.

Ellipse ellipse

An oval using the same paint, hand-drawn look, text, and membership settings as a Rectangle, except it has no corner-radius setting. Its default box is square, but its width and height may differ.

Diamond diamond

A decision-style diamond rendered with the Rectangle prop contract: fill, stroke, dash, opacity, look, optional text, radius-compatible legacy data, and membership. The type controls geometry; the stored props do not contain four corner points.

Triangle triangle

A triangular shape with the same shared box, text, look, and membership settings as Rectangle. Rotation comes from the element record’s angle rather than a triangle-specific property.

Text text

A lightweight editable text element. It stores text, a block style (paragraph, heading 1–6, code, quote, bulleted, numbered, or to-do), colour, font size and family, alignment, opacity, and membership. It omits font weight and italic settings; use Edgeless text when those are needed.

Note note

A card that can be a sticky note, page card, embed, or file card. Besides text and typography it may store title, URL, file identity, linked workspace item, link-preview metadata, embed view, and a snapshot of page blocks. A linked database may use databaseId plus the card’s own embedded view kind and manifest; older static database previews still decode as a fallback.

Line line

A connector without arrowheads. Its points are stored relative to the element box; it also stores stroke, width, dash, opacity, and straight, curved, or orthogonal routing. Optional start and end bindings name another element and a normalised anchor, so the line reroutes when that shape moves.

Arrow arrow

A Line with optional start and end arrowhead kinds and a text label. It has the same point geometry, routing modes, bindings, paint, opacity, locking, and container membership. A missing binding leaves that endpoint free-floating.

Freehand freehand

A drawn stroke made from box-relative point samples. Points may carry pointer pressure; the renderer turns them into an outline. Props contain stroke, width, opacity, and membership, but no fill, dash, routing mode, or arrowhead.

Image image

An asset image selected by canonical fileId, with a resolved src, alt text, optional template or sticker asset kind, and object fit of cover, contain, or fill. Natural pixel dimensions support aspect-aware resizing. The URL may be absent until asset resolution completes.

Frame frame

A titled spatial container. It stores name, fill, opacity, whether children are clipped, and optional zero-based presentation order. Children persist the frame’s ID in their own props. Frames own members by spatial containment and move or clip them; the current contract does not support nesting frames.

Group group

A zero-cost grouping container with optional name and locked state. Members point back by group ID, so selecting or transforming the group fans out to them. Unlike a Frame, a Group has no visible fill, header, clipping, or containment-based membership.

Mind map mindmap

The root of a live mind map. It stores root node ID, member node IDs, style preset one through four, layout balance, left, or right, and locked state. Member nodes and connectors point back with mindmapId; the root does not embed their full records.

Edgeless text edgeless-text

A richer floating text block. It stores the same block-style vocabulary as Text plus font weight and font style, colour, size, family, alignment, opacity, locking, and container membership. It is editable as text but remains a Canvas element, not a Page block.

Plait plait

A native document node owned by the Plait whiteboard engine. Snoze stores a required JSON-safe data payload with the engine node’s top-level ID omitted; the Canvas element ID remains canonical for events and sync. Snoze validates the outer element geometry and identity, but the internal grammar belongs to Plait and is intentionally not described by individual Snoze props.

Behaviour by element role

Line and Arrow are connector types. Line, Arrow, and Freehand are point-based. Frame, Group, and Mind map are container types, with the different ownership rules described above. Text, Note, and Edgeless text expose direct text editing. The shared style panel uses per-type rules, so it does not offer fill on a connector or arrowheads on a rectangle.

Canvas changes are synchronised as insert, update, and delete operations. Durable changes enter undo history; ephemeral drag updates are squashed before they are stored and sent. This does not change the element vocabulary, but it explains why a live drag is not hundreds of permanent history entries.