SheetForge

About

SheetForge is a powerful tool for game developers and web designers that automatically detects sprites from a sheet, packs them efficiently, and exports to multiple formats.

The tool uses transparency detection to identify individual sprites, filters out tiny artifacts, and arranges sprites in rows to create an optimized sprite sheet.

How to Use

Upload a sprite sheet by dragging and dropping or using the file picker
Adjust settings like alpha threshold, minimum sprite size, and padding
Click "Process" to detect and pack sprites
View the results in the preview area and sprite list
Export to your preferred format using the download buttons

Settings

Alpha ≥: Minimum alpha value (0-255) to consider a pixel part of a sprite
Min size: Minimum width and height for a sprite (filters out small artifacts)
Padding: Space between sprites in the packed output
Max width: Maximum width of the output sprite sheet
Output name: Filename for the generated sprite sheet
Background: Choose between transparent background (default) or a custom color for the sprite sheet

Export Formats

SheetForge supports multiple export formats to fit your development needs:

PNG

Standard image format of the packed sprite sheet for general use

Phaser

Atlas format (PNG + JSON) compatible with Phaser game engine

ZIP

Archive containing individual sprite images

Unity

Sprite metadata format for Unity game engine

HTML5 Canvas

JavaScript code for drawing sprites on canvas

CSS Sprites

CSS classes with background positions

Godot

Atlas format for Godot game engine

XML

TexturePacker-compatible XML format

UI Features

Dark/Light Mode: Toggle between themes using the button in the top-right corner
Fullscreen View: Expand the mappings and spritesheet to a fullscreen view for better visibility with zoom controls
Sprite Highlighting: Click on a sprite in the list to highlight it in the preview, or hover directly over sprites in the preview to see their names
Filtering: Search for specific sprites by name
JSON View: Switch between list and raw JSON views
Notifications: Toast notifications for operation feedback
About Modal: Learn about the creator and why SheetForge is free via the about button in the header
Donation Modal: Support the project's development through PayPal donations via the donate button in the header
Keyboard Shortcuts: Use keyboard shortcuts for faster access to common functions (see Keyboard Shortcuts section below)

Keyboard Shortcuts

SheetForge supports the following keyboard shortcuts to help you work more efficiently:

Shortcut	Action
Ctrl+V / ⌘+V	Paste image from clipboard
Ctrl+O / ⌘+O	Open file dialog
Ctrl+P / ⌘+P	Process the current spritesheet
Ctrl+S / ⌘+S	Save/Download the current PNG
Ctrl+E / ⌘+E	Toggle fullscreen view
Ctrl+F / ⌘+F	Focus on filter input
Ctrl+H / ⌘+H	Toggle help modal
Ctrl+A / ⌘+A	Toggle about modal
Ctrl+D / ⌘+D	Toggle dark/light mode
Ctrl+Z / ⌘+Z	Reset zoom in fullscreen view
Esc	Close any open modal

Project Management

SheetForge includes project management features to help you save and restore your work:

Save Settings

Save your current configuration settings to your browser's local storage for quick access later

Load Settings

Restore previously saved configuration settings from your browser's local storage

Export Project

Export your current project (including settings and atlas data) to a JSON file that can be shared or backed up

Import Project

Import a previously exported project from a JSON file to restore your settings and sprite mappings

How Import Project Works:

Click "Import Project" and select a previously exported project file (.json)
The settings and sprite atlas data will be loaded
Upload the original image that was used when the project was exported
Click "Process" to apply the imported sprite mappings to the image

Important: The project file contains the sprite positions and settings, but not the actual image data. You must upload the same original image that was used when creating the exported project file.

Technical Details

The sprite detection algorithm uses a flood fill approach to identify connected non-transparent pixels. The packing algorithm arranges sprites in rows to minimize wasted space while maintaining a maximum width constraint.

All processing happens in your browser - no files are uploaded to any server.

Sprite Sheet Configuration

Project Management

Individual Sprites Export

Export Options

Phaser

Unity

HTML5 Canvas

CSS Sprites

Godot

XML

Mappings

SheetForge Help

About

How to Use

Settings

Export Formats

PNG

Phaser

ZIP

Unity

HTML5 Canvas

CSS Sprites

Godot

XML

UI Features

Keyboard Shortcuts

Project Management

Save Settings

Load Settings

Export Project

Import Project

Technical Details

About SheetForge

Created By a Kid, For Kids

Why SheetForge is Free

The Problem with Sprite Slicers

Supporting the Project

Support SheetForge

How Your Support Helps

Future Improvements

SheetForge Fullscreen View

Sprite Sheet Configuration

Project Management

Individual Sprites Export

Export Options

Phaser

Unity

HTML5 Canvas

CSS Sprites

Godot

XML

Mappings