ComfyUI_Viewer

ComfyUI Content Viewer

A powerful, extensible ComfyUI custom node with a modular Views Extension System that renders content in a secure embedded iframe viewer. Views are dynamically loaded and can be added, removed, or modified without touching core code.

Table of Contents

• Screenshots
• Features
• Third-Party Views
• Built-in Views
• Installation
• Usage
• Creating Extensions
• Troubleshooting
• Third-Party Licenses
• License

Screenshots

<details> <summary><strong>Screenshots</strong></summary>

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Features

Views Extension System

• Modular architecture - Each content type is handled by its own view extension
• Dynamic loading - Views are auto-discovered from web/views/view_manifest.js
• Priority-based detection - Higher priority views are checked first for content matching
• Extensible - Add custom views without modifying core viewer code
• Theme integration - All views receive ComfyUI theme tokens for consistent styling

Multi-View Support

• Automatic detection - When multiple views can handle the same content, a view selector appears
• View switching - Toggle between different visualizations of the same data (e.g., tensor as Canvas vs Object inspector)
• Priority-based default - The highest priority matching view is shown by default
• Common use case - IMAGE tensors are detected by both Canvas (for compositing) and Object (for metrics/inspection) views

Controls

• Edit - Modify content directly in the node (supports both single and list content)
• Clear - Reset all content
• Fullscreen - Expand viewer to full screen (press Escape to exit)
• Download - Save content with auto-detected file extension
  • Single content → Downloads with appropriate extension (.html, .svg, .md, .py, etc.)
  • List content → Downloads as .zip containing individually named files

String List Support

• Multiple items - Displays list inputs as individual indexed containers
• Per-item checkboxes - Filter which items to include in output
• Per-item copy buttons - Copy individual list items to clipboard
• Per-item editing - Edit each list item in its own textarea

Data Flow

• Flexible input - Accepts any type via content input (STRING, lists, objects, IMAGE tensors)
• Content priority - User edits > Backend execution > Connected content
• Workflow persistence - Manual edits saved with the workflow

Security

• Sandboxed iframe - Content runs in isolated sandbox without access to parent page
• No same-origin - Iframe cannot access ComfyUI's JavaScript context or localStorage

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Third-Party Views

| View Name | View Description | View Link | |-----------|------------------|-----------| | Image Search | Search input/output/temp directories for images by input image | Image Search | | OpenReel Video | Edit videos generated within ComfyUI (e.g., from Wan, LTX,, etc.) | OpenReel Video |

Built-in Views

The Content Viewer includes 12 built-in views, listed by detection priority:

| View | Priority | Detection | Description | |------|----------|-----------|-------------| | SVG | 110 | <svg tag with xmlns | Renders SVG graphics centered in viewport | | HTML | 100 | <!DOCTYPE, <html, common HTML tags | Full HTML rendering with scripts | | Canvas (alpha wip) | 95 | JSON with type: "canvas_composer" | Beta implementation of a infinite canvas image compositor with layers | | JSON | 90 | Valid JSON starting with { or [ | Collapsible tree view with syntax highlighting | | Terminal | 80 | ANSI escape codes (\x1b[, \033[) | Colored terminal output parser | | Markdown | 70 | Headers, lists, links, code blocks | Full MD with Mermaid diagrams & KaTeX math | | Python | 60 | import, def, class, self. | Prism.js syntax highlighting | | JavaScript | 55 | function, const, let, arrow functions | Prism.js syntax highlighting | | CSV | 50 | Comma-separated values across lines | Styled table rendering | | CSS | 45 | Selectors with {}, properties | Prism.js syntax highlighting | | YAML | 40 | Key-value pairs, --- markers | Syntax highlighted display | | Text | 0 | Default fallback | Monospace plain text |

View Details

<details> <summary><strong>Canvas View</strong> - Infinite canvas image compositor</summary>

The Canvas view provides a full-featured image compositing workspace:

• Layer management - Add, reorder, hide/show, delete layers
• Transform tools - Move, scale, rotate layers with handles
• Brush tools - Paint, erase, clone stamp with adjustable size/hardness/opacity
• Layer effects - Opacity, blend modes (16 modes), stroke, shadow
• Layer masks - Non-destructive masking with brush tools
• Export - Download PNG or send composite to node output as IMAGE tensor
• Navigator - Mini-map for large canvas navigation
• Keyboard shortcuts - V (select), H (pan), B (brush), Delete, Ctrl+Z/Y

The Canvas view outputs IMAGE and MASK tensors that can be connected to other ComfyUI nodes.

</details> <details> <summary><strong>Markdown View</strong> - Rich text with diagrams and math</summary>

Supports full Markdown syntax plus:

• Mermaid diagrams - Flowcharts, sequence diagrams, etc. in ```mermaid blocks
• KaTeX math - LaTeX formulas via $$...$$ (block) or $...$ (inline)
• Tables - Styled with zebra striping
• Code blocks - Syntax highlighted with Prism.js
• Task lists - Checkbox items - [x] and - [ ]

</details> <details> <summary><strong>JSON View</strong> - Interactive tree viewer</summary>

• Collapsible nodes - Click to expand/collapse objects and arrays
• Syntax highlighting - Keys, strings, numbers, booleans, null
• Copy on click - Click any value to copy it
• Nested formatting - Proper indentation for deep structures

</details> <details> <summary><strong>Terminal View</strong> - ANSI escape code parser</summary>

Renders terminal output with full ANSI support:

• 16 colors - Standard terminal colors
• 256 colors - Extended color palette
• 24-bit colors - True color RGB
• Styles - Bold, italic, underline, strikethrough
• Reset codes - Proper handling of reset sequences

</details>

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Installation

Option A (git clone)

cd ComfyUI/custom_nodes
git clone https://github.com/WASasquatch/ComfyUI_Viewer.git

Option B (ComfyUI Manager)

• Open Manager and search for ComfyUI_Viewer

Option C (zip)

• Download and extract to ComfyUI/custom_nodes/ComfyUI_Viewer

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Usage

Basic Usage

1. Add the Content Viewer node (found in WAS/View category)
2. Connect any STRING output to the content input
3. Content type is auto-detected and rendered with the appropriate view

As a Notes/Documentation Node

1. Add the Content Viewer node
2. Click Edit in the controls bar
3. Enter your HTML, Markdown, or text content
4. Click Save to render

Using the Canvas Compositor

1. Connect IMAGE outputs to the Canvas Composer node
2. Images appear in the source panel - drag them onto the canvas
3. Use transform handles to position and scale
4. Use brush tools to paint or mask
5. Click Send to Output to pass the composite downstream

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Creating Extensions

The Content Viewer supports custom view extensions for adding new content types, interactive UIs, and visualizations.

📖 See the Extension Development Guide for complete documentation on:

• Creating extension packages for distribution
• Adding frontend views (JavaScript)
• Adding backend parsers (Python)
• Parser + View integration
• Troubleshooting

Quick install for users:

1. Download an extension .zip file
2. Place it in ComfyUI_Viewer/extensions/
3. Restart ComfyUI

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Troubleshooting

Content not updating

• Ensure the connected node is executing (queue the workflow)
• Try disconnecting and reconnecting the input

View not detecting content

• Check the browser console (F12) for [WAS Viewer] messages
• Verify your view's detect() returns a score > 0 for your content
• Check priority - higher priority views are tested first

Canvas images not loading

• Ensure images are in ComfyUI's input directory.
  • Search for a folder that looks like was_viewer_032bb95c where the last part is a unique hash for that nodes canvas content.
• Check for CORS errors in browser console

Custom view not appearing

• Verify the file is listed in view_manifest.js
• Check for JavaScript errors in browser console
• Ensure export default YourViewClass is present

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Third-Party Licenses

This project includes the following third-party libraries:

| Library | License | Description | Location | |---------|---------|-------------|----------| | Prism.js | MIT | Syntax highlighting for code blocks | web/views/code_scripts/ | | KaTeX | MIT | LaTeX math rendering | web/views/markdown_scripts/ | | Mermaid | MIT | Diagram and flowchart rendering | web/views/markdown_scripts/ | | KaTeX Fonts | SIL OFL 1.1 | Math fonts for KaTeX | fonts/ |

Full license texts are included with each library in their respective directories.

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License

MIT License - See LICENSE for details