ComfyUI Smart Resolution Calculator

Flexible resolution and latent generation for ComfyUI with compact custom widgets. Specify any combination of dimensions and aspect ratio - the node calculates missing values automatically.

Overview

Smart Resolution Calculator brings intuitive dimension control to ComfyUI workflows. Instead of manually calculating widths from heights or dimensions from megapixels, simply enable the values you know and let the node compute the rest. Compact rgthree-style widgets keep your workflow clean while providing powerful calculation modes.

Example workflow showing the Smart Resolution Calculator with image input (AR Only mode), HEIGHT enabled at 1200, SCALE at 1.10x, calculating width from 1:1 aspect ratio, and outputting 1320×1320 to ClownsharkKSampler.

Features

• Image dimension extraction - Connect images to auto-extract aspect ratio or exact dimensions (detailed guide)
• Interactive tooltips - Hover over widget labels for quick help, extended explanations, and links to documentation
• One-click resolution setup - Toggle dimensions you want, node calculates the rest
• 5 calculation modes - Width+Height, Width+AR, Height+AR, Megapixels+AR, or defaults
• Scale multiplier - Scale dimensions up/down (0-10x) with custom widget and real-time preview
• Compact custom widgets - rgthree-style controls with inline toggles
• Values preserved when toggled off - Change your mind without losing settings
• Direct latent output - No separate Empty Latent Image node needed
• 23 preset aspect ratios - From 1:1 to 32:9, plus custom ratio support
• Visual preview - See exact dimensions and aspect ratio before generation
• Divisibility control - Ensures compatibility with SD/Flux models (8/16/32/64)
• Workflow persistence - Widget states save/load with workflows

Prerequisites

• ComfyUI installation
• Python 3.10+ (or ComfyUI's embedded Python)
• No additional dependencies (uses ComfyUI's PyTorch, PIL, numpy)

Installation

ComfyUI Registry (Recommended)

The easiest way to install is through the ComfyUI Registry:

1. Open ComfyUI Manager in your ComfyUI interface
2. Search for "Smart Resolution Calculator" or "djdarcy"
3. Click Install and restart ComfyUI

The node will appear under: Smart Resolution → Smart Resolution Calculator

Alternatively, use the command line:

comfy node install comfyui-smart-resolution-calc

Git Clone

cd ComfyUI/custom_nodes
git clone https://github.com/djdarcy/ComfyUI-Smart-Resolution-Calc.git

Then restart ComfyUI or use Manager → Refresh Node Definitions.

Manual Installation

1. Download the latest release and extract to ComfyUI/custom_nodes/ComfyUI-Smart-Resolution-Calc/
2. Restart ComfyUI
3. Find the node in: Smart Resolution → Smart Resolution Calculator

Usage

Basic Workflow

1. Add Smart Resolution Calculator to your workflow
2. Select an aspect ratio (default: 3:4 Golden Ratio)
3. Enable the dimensions you know/want by clicking toggle switches
4. The node automatically calculates missing values
5. Check the info output to verify the calculation mode
6. Connect latent output to your KSampler

Calculation Modes

Mode 1: Height + Aspect Ratio (Typical Designer Workflow)

Perfect when you know the exact height you want:

• Enable: HEIGHT toggle
• Set: height to 1920
• Select: aspect ratio 4:3
• Result: Width automatically calculated as 1536
• Info: Mode: Height + Aspect Ratio | Calculated Width: 1536 | MP: 2.95 | Div: 16

Mode 2: Width + Aspect Ratio

When you know the width but not the height:

• Enable: WIDTH toggle
• Set: width to 1920
• Select: aspect ratio 16:9
• Result: Height automatically calculated as 1080
• Info: Mode: Width + Aspect Ratio | Calculated Height: 1080 | MP: 2.07 | Div: 16

Mode 3: Megapixels + Aspect Ratio

Original Flux Resolution Calc behavior:

• Enable: MEGAPIXEL toggle
• Set: megapixels to 1.0
• Select: aspect ratio 16:9
• Result: Both width and height calculated
• Info: Mode: Megapixels + Aspect Ratio | Calculated W: 1216 × H: 688 | Div: 16

Mode 4: Both Dimensions

Override aspect ratio with exact dimensions:

• Enable: Both WIDTH and HEIGHT toggles
• Set: width 1920, height 1080
• Result: Megapixels calculated, actual ratio may differ
• Info: Mode: Width + Height | Calculated MP: 2.07 | Div: 16

Mode 5: Default

No toggles active uses 1.0 MP with selected aspect ratio:

• Result: Default dimensions for selected ratio
• Info: Mode: Default (1.0 MP) | W: 1216 × H: 688 | Div: 16

Image Input

Connect an IMAGE output to automatically extract dimensions or aspect ratio. See the Image Input Guide for detailed documentation.

Quick Start:

• Connect image → Extraction modes automatically available
• AR Only (default): Extracts aspect ratio, uses with megapixel setting
• Exact Dims: Uses exact image dimensions with scale applied
• Copy Button: Extract once, then manually adjust

Aspect Ratio Presets

• Portrait (11 ratios): 2:3, 3:4 (default), 3:5, 4:5, 5:7, 5:8, 7:9, 9:16, 9:19, 9:21, 9:32
• Square (1 ratio): 1:1
• Landscape (11 ratios): 3:2, 4:3, 5:3, 5:4, 7:5, 8:5, 9:7, 16:9, 19:9, 21:9, 32:9

Custom Ratios: Enable "custom_ratio" and enter any ratio (e.g., "5:3")

Outputs

• megapixels (FLOAT) - Calculated or user-specified MP value
• width (INT) - Final width after divisibility rounding
• height (INT) - Final height after divisibility rounding
• resolution (STRING) - Formatted string (e.g., "1920 x 1080")
• preview (IMAGE) - Visual preview with dimensions and aspect ratio
• latent (LATENT) - Ready-to-use latent tensor for sampling
• info (STRING) - Calculation mode and computed values

How It Works

1. User enables dimension toggles (megapixels, width, or height)
2. Node checks which dimensions are active (priority order)
3. Calculates missing values using aspect ratio
4. Rounds to divisibility requirement (8/16/32/64)
5. Generates latent tensor [batch_size, 4, height//8, width//8]
6. Outputs dimensions, preview image, and latent

Priority Order (first match wins):

1. Width + Height → calculate megapixels
2. Width + Aspect Ratio → calculate height
3. Height + Aspect Ratio → calculate width
4. Megapixels + Aspect Ratio → calculate both
5. None active → default to 1.0 MP + aspect ratio

Troubleshooting

Common Issues

Widget toggles don't affect calculation

• Enable debug mode to verify data flow
• Ensure ComfyUI restarted after installation
• Check browser console for JavaScript errors

Workflow doesn't save widget states

• Verify browser console shows configure called logs
• Re-save workflow after toggling widgets
• Clear browser cache if issues persist

Latent tensor errors

• Update ComfyUI to latest version
• Check ComfyUI console for error details
• Verify PyTorch installation

Debug Mode

Enable detailed logging for troubleshooting:

Python Logging (ComfyUI console):

# Windows
set COMFY_DEBUG_SMART_RES_CALC=true

# Linux/Mac
export COMFY_DEBUG_SMART_RES_CALC=true

JavaScript Logging (Browser console F12):

// Standard debug logging
localStorage.setItem('DEBUG_SMART_RES_CALC', 'true');

// Verbose logging (includes coordinates, hit areas, detailed state)
localStorage.setItem('VERBOSE_SMART_RES_CALC', 'true');

Debug logs show widget data flow, calculation steps, and final results. Verbose mode adds detailed coordinate logging for tooltip positioning and widget layout debugging.

Disable:

set COMFY_DEBUG_SMART_RES_CALC=false
localStorage.removeItem('DEBUG_SMART_RES_CALC');
localStorage.removeItem('VERBOSE_SMART_RES_CALC');

Documentation

• CHANGELOG.md - Version history and release notes
• Image Input Guide - Detailed documentation for image dimension extraction feature
• CONTRIBUTING.md - Development setup and contribution guidelines

Contributing

Contributions welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Test changes in ComfyUI (see CONTRIBUTING.md for debug setup)
4. Submit a pull request

See CONTRIBUTING.md for detailed guidelines including VSCode debugging setup.

Like the project?

Development Setup

git clone https://github.com/djdarcy/ComfyUI-Smart-Resolution-Calc.git
cd ComfyUI-Smart-Resolution-Calc
# Copy to ComfyUI custom_nodes and restart ComfyUI

For VSCode debugging with ComfyUI, see the "VSCode Debugging" section in CONTRIBUTING.md.

Technical Details

Divisibility Rounding

Ensures dimensions work with model latent space:

• 8: Minimum (latent space 8x downsampled)
• 16: Safer for most models
• 32: Recommended
• 64: Maximum compatibility (default)

Rounding applied separately to width and height.

Latent Format

Compatible with Stable Diffusion and Flux:

• Format: [batch_size, 4, height // 8, width // 8]
• 4-channel latent space
• Auto-placed on appropriate device (CPU/GPU)

Architecture

Custom JavaScript widgets with compact 24px height design:

• Widgets declared in INPUT_TYPES["hidden"] for data flow
• serialize_widgets = true enables workflow persistence
• Data structure: {on: boolean, value: number}

NOTE: ComfyUI requires both INPUT_TYPES["hidden"] declarations AND serialize_widgets = true for proper widget data flow. One alone is insufficient.

Acknowledgments

• controlaltai-nodes - Flux Resolution Calc inspiration
• rgthree-comfy - Power Lora Loader compact widget design
• ComfyUI - The amazing UI framework
• ComfyUI community - Testing and feedback

Development

For contributors: This project uses Git-RepoKit hooks for automatic version tracking. Run ./scripts/install-hooks.sh to set up versioning hooks.

License

Smart Resolution Calculator, Copyright (C) 2025 Dustin Darcy

This project is licensed under the MIT License - see the LICENSE file for details.