A Flutter application for reading and visualizing Concepts app (.concept) files.

Try it live

Concepts is an infinite canvas drawing app for iPad, iPhone, and other platforms. It's used by designers, architects, and illustrators for sketching, wireframing, and visual thinking. Files are saved in a proprietary .concept format.

• Open .concept files: Load and parse Concepts app documents
• Interactive canvas: Pan and zoom with touch gestures
• Double-tap to fit: Automatically fit content to screen
• Document info: View document statistics

• Flutter SDK 3.0.0 or later
• Dart SDK 3.0.0 or later

1. Clone the repository:

git clone <repository-url>
cd concepts_reader

2. Install dependencies:

flutter pub get

3. Run the app:

flutter run

1. Launch the app
2. Tap "Open File" to select a .concept file
3. Use pinch gestures to zoom in/out (on web/desktop, use Ctrl/Cmd + scroll wheel)
4. Drag to pan around the canvas
5. Double-tap to fit content to screen

Concepts files (.concept) are ZIP archives containing:

• Strokes.plist - Binary plist with stroke data
• Resources.plist - Image resource mappings
• Drawing.plist - Document-level transform matrix
• ImportedImages/ - Embedded image files
• Thumb.jpg - Optional thumbnail

Inspired by ConceptsAppiOSFileViewer by Max Liebscher.

MIT License

This is an unofficial viewer and is not affiliated with Concepts (TopHatch, Inc.).