Canvas

canvas: AI-Orchestrated Visual Production

Claude acts as Creative Director for Obsidian Canvas. Describe what you want and get a fully populated, professionally laid-out .canvas file.

Context Detection

Before any operation, determine the canvas directory:

1. If wiki/canvases/ exists in the current directory or a parent: use it (claude-obsidian vault mode).
   • Media goes to _attachments/images/canvas/
2. Otherwise: use .canvases/ in the current working directory (standalone mode).
   • Media goes to .canvases/assets/
3. Create the directory if it doesn't exist.

Default canvas: [canvas_dir]/main.canvas

Command Routing

Status / List (Inline Operations)

/canvas (no args)

1. Detect canvas directory (vault or standalone).
2. Find default canvas (main.canvas).
3. If exists: read JSON, count nodes by type, list zone labels. Report: "Canvas has N nodes: X images, Y text, Z files. Zones: [list]"
4. If not exists: report "No canvas found. Run /canvas create [name] to start."

/canvas list

1. Glob [canvas_dir]/*.canvas.
2. For each: read JSON, count nodes by type.
3. Report table:

main.canvas              14 nodes (8 images, 3 text, 2 file, 1 group)
design-ideas.canvas      42 nodes (30 images, 4 text, 8 groups)

Key References

Read these references before performing canvas operations:

• references/canvas-spec.md — JSON Canvas 1.0 format, coordinate system, node types, edges, colors, sizing
• references/performance-guide.md — Node limits, GIF lag, SVG gotchas, 20px grid snapping

Additional references:

• references/layout-algorithms.md — 6 layout algorithms (canvas-layout)

• references/template-catalog.md — 12 archetypes (canvas-template)

• references/presentation-spec.md — Advanced Canvas slides (canvas-present)

• references/mermaid-patterns.md — Mermaid in text nodes (canvas-populate, canvas-generate)

• references/media-guide.md — Image/GIF/SVG integration (canvas-generate, canvas-populate)

Auto-Positioning Algorithm

Used by canvas-populate to place new nodes. Read references/canvas-spec.md for the full coordinate system.

def next_position(canvas_nodes, target_zone_label, new_w, new_h):
    # Find zone group node
    zone = next((n for n in canvas_nodes
                 if n.get('type') == 'group'
                 and n.get('label') == target_zone_label), None)

    if zone is None:
        # No zone: place below all content
        max_y = max((n['y'] + n.get('height', 0) for n in canvas_nodes), default=-140)
        return snap_grid(-400, max_y + 60)

    zx, zy = zone['x'], zone['y']
    zw, zh = zone['width'], zone['height']

    # Nodes inside this zone (exclude groups)
    inside = [n for n in canvas_nodes
              if n.get('type') != 'group'
              and zx <= n['x'] < zx + zw
              and zy <= n['y'] < zy + zh]

    if not inside:
        return snap_grid(zx + 20, zy + 20)

    # Find the bottom-most row: nodes whose bottom edge is closest to the zone bottom
    max_bottom = max(n['y'] + n.get('height', 0) for n in inside)
    # Nodes on the last row: those whose top y is within one row-height of the bottom
    last_row = [n for n in inside if n['y'] + n.get('height', 0) >= max_bottom - 20]
    if not last_row:
        last_row = inside  # fallback

    rightmost_x = max(n['x'] + n.get('width', 0) for n in last_row)
    next_x = rightmost_x + 40

    if next_x + new_w > zx + zw:
        # Overflow: new row below the current last row
        return snap_grid(zx + 20, max_bottom + 20)

    # Same row: align to top of the LAST row (not all nodes)
    current_row_y = min(n['y'] for n in last_row)
    return snap_grid(next_x, current_row_y)

def snap_grid(x, y, grid=20):
    return (round(x / grid) * grid, round(y / grid) * grid)

ID Generation

Read the canvas JSON first. Collect all existing IDs. Never reuse one.

Pattern: [type]-[content-slug]-[full-unix-timestamp]

Use the full 10-digit Unix timestamp to avoid collisions in batch operations.

Examples: img-cover-1744032823, text-note-1744032845, zone-branding-1744032901

If a collision is detected (ID already exists), append -2, -3, etc.

Canvas JSON Structure

The minimal valid canvas:

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

Z-index rule: First node in the array renders at the bottom (background). Last node renders on top (foreground). Groups MUST come before their contained nodes so content renders in front of zone backgrounds.

Grid snapping: All x, y, width, height values should be multiples of 20.

Node limit: Warn the user if a canvas exceeds 100 nodes. Error if it exceeds 200.

Quality Standards (MANDATORY)

Every canvas produced by any sub-skill MUST pass these checks before reporting success. These are not optional — they are the definition of "done."

Content Quality

• NO placeholder text in any node. Replace ALL of these:
  • "Describe this step" → write a real step description relevant to the title
  • "YYYY-MM-DD" → use today's date or a realistic date
  • "Value: 0, Target: 100" → use realistic example values
  • "Content goes here" → write actual content matching the slide topic
  • "Define this entity" → write a real definition
  • "What happened" → write a real event description
• Every text node must contain real, useful content that a user can immediately understand
• Template instantiation is STEP 1 — writing real content into the nodes is STEP 2 (never skip it)

Layout Quality

• Minimum 80px horizontal gap between adjacent content nodes
• Minimum 60px vertical gap between adjacent content nodes
• Mind-map canvases must have radial layout (run canvas layout radial after instantiation)
• Knowledge-graph canvases must have force layout (run canvas layout force after instantiation)
• Flowchart canvases should have dagre layout applied (run canvas layout dagre for proper hierarchy)
• No overlapping nodes — run canvas_validate.py to confirm

Structural Quality

• Groups (zones) appear BEFORE content nodes in the array (z-index)
• All coordinates are multiples of 20 (grid snapping)
• Node count under 120 (warn at 100, error at 200)
• All file paths are vault-relative (no absolute paths)
• Edge IDs are unique, node IDs are unique

Before Reporting Success

1. Run python3 scripts/canvas_validate.py <path> — must return valid: true with 0 errors
2. Visually scan the generated JSON — are there any "Describe this" or "YYYY-MM-DD" strings remaining?
3. If the canvas has groups, verify content nodes are inside their designated zones (center-point check)
4. If the archetype needs a specific layout (mind-map→radial, kg→force), verify it was applied

Integration with Other Skills

banana (AI image generation):

• /canvas add banana [prompt] delegates to the banana skill, then adds the result as a file node.
• /canvas from banana reads .recent-images.txt or finds images modified in the last 10 minutes.
• If banana is not installed, report gracefully: "Install the banana skill for AI image generation."

svg (diagram/chart/icon generation):

• /canvas add svg [description] delegates to the svg skill, then adds the SVG as a file node.
• SVGs render as <img> in Obsidian — no interactivity. Must include viewBox for proper scaling.

claude-gif-* (GIF generation/editing):

• /canvas add gif [description] delegates to the gif skill, then adds as a file node.
• Performance warning: limit to 3 GIFs per canvas, cap dimensions at 480px width.

Mermaid (native in text nodes):

• Mermaid code blocks render natively in Obsidian text nodes. No external skill needed.
• Wrap in triple-backtick mermaid code fence inside a text node.