JSON Canvas

JSON Canvas Skill

File Structure

A canvas file (.canvas) contains two top-level arrays following the JSON Canvas Spec 1.0:

{
  "nodes": [],
  "edges": []
}

Common Workflows

1. Create a New Canvas

1. Create a .canvas file with the base structure {"nodes": [], "edges": []}
2. Generate unique 16-character hex IDs for each node (e.g., "6f0ad84f44ce9c17")
3. Add nodes with required fields: id, type, x, y, width, height
4. Add edges referencing valid node IDs via fromNode and toNode
5. Validate: Verify all fromNode/toNode values exist in the nodes array

2. Add a Node to an Existing Canvas

1. Read and parse the existing .canvas file
2. Generate a unique ID that does not collide with existing IDs
3. Choose position (x, y) that avoids overlapping existing nodes (50-100px spacing)
4. Append the new node object to the nodes array
5. Validate: Confirm all IDs are unique and all edge references resolve

3. Connect Two Nodes

1. Identify the source and target node IDs
2. Generate a unique edge ID
3. Set fromNode and toNode to the source and target IDs
4. Optionally set fromSide/toSide (top, right, bottom, left) and label
5. Validate: Confirm both IDs reference existing nodes

Nodes

Nodes are objects placed on the canvas. Array order determines z-index (first = bottom layer).

Generic Node Attributes

Text Node

{
  "id": "6f0ad84f44ce9c17",
  "type": "text",
  "x": 0, "y": 0, "width": 400, "height": 200,
  "text": "# Hello World\n\nThis is **Markdown** content."
}

Newline pitfall: Use \n in JSON strings. Do not use literal \\n.

File Node

{
  "id": "a1b2c3d4e5f67890",
  "type": "file",
  "x": 500, "y": 0, "width": 400, "height": 300,
  "file": "Attachments/diagram.png"
}

Link Node

{
  "id": "c3d4e5f678901234",
  "type": "link",
  "x": 1000, "y": 0, "width": 400, "height": 200,
  "url": "https://obsidian.md"
}

Group Node

{
  "id": "d4e5f6789012345a",
  "type": "group",
  "x": -50, "y": -50, "width": 1000, "height": 600,
  "label": "Project Overview",
  "color": "4"
}

Edges

{
  "id": "0123456789abcdef",
  "fromNode": "6f0ad84f44ce9c17",
  "fromSide": "right",
  "toNode": "a1b2c3d4e5f67890",
  "toSide": "left",
  "label": "leads to"
}

Colors

Layout Guidelines

• Coordinates can be negative (canvas extends infinitely)
• x increases right, y increases down; position is the top-left corner
• Space nodes 50-100px apart; leave 20-50px padding inside groups
• Align to grid (multiples of 10 or 20) for cleaner layouts

Validation Checklist

After creating or editing a canvas file:

1. All id values are unique across both nodes and edges
2. Every fromNode and toNode references an existing node ID
3. Required fields are present for each node type
4. type is one of: text, file, link, group
5. Side values are one of: top, right, bottom, left
6. End values are one of: none, arrow
7. JSON is valid and parseable

References

• JSON Canvas Spec 1.0
• JSON Canvas GitHub