json-canvas

name	json-canvas
description	Create and edit JSON Canvas files (.canvas) with nodes, edges, groups, and connections. Use when working with .canvas files, creating visual canvases, mind maps, flowcharts, or when the user mentions Canvas files in Obsidian.

JSON Canvas Skill

This skill enables Claude Code to create and edit valid JSON Canvas files (.canvas) used in Obsidian and other applications.

Overview

JSON Canvas is an open file format for infinite canvas data. Canvas files use the .canvas extension and contain valid JSON following the JSON Canvas Spec 1.0.

File Structure

A canvas file contains two top-level arrays:

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

• nodes (optional): Array of node objects
• edges (optional): Array of edge objects connecting nodes

Nodes

Nodes are objects placed on the canvas. There are four node types:

• text - Text content with Markdown
• file - Reference to files/attachments
• link - External URL
• group - Visual container for other nodes

Z-Index Ordering

Nodes are ordered by z-index in the array:

• First node = bottom layer (displayed below others)
• Last node = top layer (displayed above others)

Generic Node Attributes

All nodes share these attributes:

Attribute	Required	Type	Description
id	Yes	string	Unique identifier for the node
type	Yes	string	Node type: text, file, link, or group
x	Yes	integer	X position in pixels
y	Yes	integer	Y position in pixels
width	Yes	integer	Width in pixels
height	Yes	integer	Height in pixels
color	No	canvasColor	Node color (see Color section)

Text Nodes

Text nodes contain Markdown content.

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

Attribute	Required	Type	Description
text	Yes	string	Plain text with Markdown syntax

File Nodes

File nodes reference files or attachments (images, videos, PDFs, notes, etc.).

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

{
  "id": "b2c3d4e5f6789012",
  "type": "file",
  "x": 500,
  "y": 400,
  "width": 400,
  "height": 300,
  "file": "Notes/Project Overview.md",
  "subpath": "#Implementation"
}

Attribute	Required	Type	Description
file	Yes	string	Path to file within the system
subpath	No	string	Link to heading or block (starts with #)

Link Nodes

Link nodes display external URLs.

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

Attribute	Required	Type	Description
url	Yes	string	External URL

Group Nodes

Group nodes are visual containers for organizing other nodes.

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

{
  "id": "e5f67890123456ab",
  "type": "group",
  "x": 0,
  "y": 700,
  "width": 800,
  "height": 500,
  "label": "Resources",
  "background": "Attachments/background.png",
  "backgroundStyle": "cover"
}

Attribute	Required	Type	Description
label	No	string	Text label for the group
background	No	string	Path to background image
backgroundStyle	No	string	Background rendering style

Background Styles

Value	Description
cover	Fills entire width and height of node
ratio	Maintains aspect ratio of background image
repeat	Repeats image as pattern in both directions

Edges

Edges are lines connecting nodes.

{
  "id": "f67890123456789a",
  "fromNode": "6f0ad84f44ce9c17",
  "toNode": "a1b2c3d4e5f67890"
}

{
  "id": "0123456789abcdef",
  "fromNode": "6f0ad84f44ce9c17",
  "fromSide": "right",
  "fromEnd": "none",
  "toNode": "b2c3d4e5f6789012",
  "toSide": "left",
  "toEnd": "arrow",
  "color": "1",
  "label": "leads to"
}

Attribute	Required	Type	Default	Description
id	Yes	string	-	Unique identifier for the edge
fromNode	Yes	string	-	Node ID where connection starts
fromSide	No	string	-	Side where edge starts
fromEnd	No	string	none	Shape at edge start
toNode	Yes	string	-	Node ID where connection ends
toSide	No	string	-	Side where edge ends
toEnd	No	string	arrow	Shape at edge end
color	No	canvasColor	-	Line color
label	No	string	-	Text label for the edge

Side Values

Value	Description
top	Top edge of node
right	Right edge of node
bottom	Bottom edge of node
left	Left edge of node

End Shapes

Value	Description
none	No endpoint shape
arrow	Arrow endpoint

Colors

The canvasColor type can be specified in two ways:

Hex Colors

{
  "color": "#FF0000"
}

Preset Colors

{
  "color": "1"
}

Preset	Color
"1"	Red
"2"	Orange
"3"	Yellow
"4"	Green
"5"	Cyan
"6"	Purple

Note: Specific color values for presets are intentionally undefined, allowing applications to use their own brand colors.

Complete Examples

Simple Canvas with Text and Connections

{
  "nodes": [
    {
      "id": "8a9b0c1d2e3f4a5b",
      "type": "text",
      "x": 0,
      "y": 0,
      "width": 300,
      "height": 150,
      "text": "# Main Idea\n\nThis is the central concept."
    },
    {
      "id": "1a2b3c4d5e6f7a8b",
      "type": "text",
      "x": 400,
      "y": -100,
      "width": 250,
      "height": 100,
       
    
    
       
       
       
       
       
       
       
    
  
   
    
       
       
       
       
       
    
    
       
       
       
       
       
    
  

Project Board with Groups

{
  "nodes": [
    {
      "id": "5e6f7a8b9c0d1e2f",
      "type": "group",
      "x": 0,
      "y": 0,
      "width": 300,
      "height": 500,
      "label": "To Do",
      "color": "1"
    },
    {
      "id": "6f7a8b9c0d1e2f3a",
      "type": "group",
      "x": 350,
      "y": 0,
      "width": 300,
       
       
       
    
    
       
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
  
   

Research Canvas with Files and Links

{
  "nodes": [
    {
      "id": "1e2f3a4b5c6d7e8f",
      "type": "text",
      "x": 300,
      "y": 200,
      "width": 400,
      "height": 200,
      "text": "# Research Topic\n\n## Key Questions\n\n- How does X affect Y?\n- What are the implications?",
      "color": "5"
    },
    {
      "id": "2f3a4b5c6d7e8f9a",
      "type": "file",
      "x": 0,
      "y": 0,
      "width": 250
       
       
    
    
       
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
  
   
    
       
       
       
       
       
       
    
    
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
    
  

Flowchart

{
  "nodes": [
    {
      "id": "a0b1c2d3e4f5a6b7",
      "type": "text",
      "x": 200,
      "y": 0,
      "width": 150,
      "height": 60,
      "text": "**Start**",
      "color": "4"
    },
    {
      "id": "b1c2d3e4f5a6b7c8",
      "type": "text",
      "x": 200,
      "y": 100,
      "width": 150,
       
       
    
    
       
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
       
    
  
   
    
       
       
       
       
       
    
    
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
       
       
    
    
       
       
       
       
       
    
  

ID Generation

Node and edge IDs must be unique strings. Obsidian generates 16-character hexadecimal IDs:

"id": "6f0ad84f44ce9c17"
"id": "a3b2c1d0e9f8g7h6"
"id": "1234567890abcdef"

This format is a 16-character lowercase hex string (64-bit random value).

Layout Guidelines

Positioning

• Coordinates can be negative (canvas extends infinitely)
• x increases to the right
• y increases downward
• Position refers to top-left corner of node

Recommended Sizes

Node Type	Suggested Width	Suggested Height
Small text	200-300	80-150
Medium text	300-450	150-300
Large text	400-600	300-500
File preview	300-500	200-400
Link preview	250-400	100-200
Group	Varies	Varies

Spacing

• Leave 20-50px padding inside groups
• Space nodes 50-100px apart for readability
• Align nodes to grid (multiples of 10 or 20) for cleaner layouts

Validation Rules

1. All id values must be unique across nodes and edges
2. fromNode and toNode must reference existing node IDs
3. Required fields must be present for each node type
4. type must be one of: text, file, link, group
5. backgroundStyle must be one of: cover, ratio, repeat
6. fromSide, toSide must be one of: top, right, bottom, left
7. fromEnd, toEnd must be one of: none, arrow
8. Color presets must be "1" through "6" or valid hex color

Canvas 可视化规范（Miro 风格）

布局原则

1. 顶部参与者区（横向排列）

• 使用 Emoji 图标增强识别度
• 按角色分组着色：
  • 🟢 绿色 (4): 用户侧（管理员、前端、用户钱包）
  • 🔵 蓝色 (5): 合约/系统侧
  • 🟡 黄色 (3): 外部服务
  • 🟣 紫色 (6): VRF/Oracle/异步服务

2. 左侧阶段标签（垂直排列）

• 使用大型半透明容器（group 节点）作为背景分组
• 每个阶段使用不同颜色标识

3. 中央流程区（垂直流向）

• 动作卡片：白色背景，左上角蓝底白字数字编号 [1]-[N]
• 条件分支容器：
  • 🔴 红色 (1)：路径 A
  • 🟠 橙色 (2)：路径 B
• 平滑连线：带标签的箭头连接

4. 右侧说明栏（Note Cards）

• 📌 技术说明
• 💰 对比表格
• 🎲 算法详解
• 🎨 图例与符号说明

节点结构示例

动作卡片节点：

{
  "id": "unique-id",
  "type": "text",
  "text": "**[N]** 步骤标题\n\n详细说明",
  "x": 0,
  "y": 0,
  "width": 280,
  "height": 120,
  "color": "1"
}

阶段分组节点：

{
  "id": "phase-1",
  "type": "group",
  "label": "🔷 阶段一: 初始化",
  "x": -50,
  "y": 0,
  "width": 800,
  "height": 300,
  "color": "5"
}

连线结构示例

带标签的流程连线：

{
  "id": "edge-id",
  "fromNode": "node-id-1",
  "fromSide": "right",
  "toNode": "node-id-2",
  "toSide": "left",
  "toEnd": "arrow",
  "label": "连线标签"
}

条件分支连线（带颜色）：

{
  "id": "branch-yes",
  "fromNode": "decision",
  "fromSide": "right",
  "toNode": "path-a",
  "toSide": "left",
  "label": "Yes",
  "color": "4"
}

Emoji 图标规范

图标	用途
⏱️	时间相关说明
🔷	蓝色阶段标记
🔶	橙色阶段标记
✅	成功/完成
🔁	循环操作
📌	技术说明
💰	金额/对比
🎲	随机/算法
🎨	图例/说明

推荐配色方案

主题	颜色代码	适用场景
红色	"1" / #E74C3C	错误路径、强调
橙色	"2" / #F39C12	警告、次要路径
黄色	"3" / #F1C40F	外部服务
绿色	"4" / #27AE60	成功、用户侧
青色	"5" / #3498DB	系统侧、主流程
紫色	"6" / #9B59B6	异步服务

设计最佳实践

1. 高对比度：使用鲜明颜色确保清晰可见
2. 色彩层次：
   • 主要交互流程使用深色
   • 阶段标签使用中等饱和度
   • 注释说明使用浅色背景
3. 可读性优先：深色文字配浅色背景，浅色文字配深色背景
4. 视觉引导：使用鲜明颜色引导用户视线沿着流程走

References

• JSON Canvas Spec 1.0
• JSON Canvas GitHub