Crop and Lock

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Overview

The Crop and Lock module in PowerToys allows users to crop a current application into a smaller window or create a thumbnail. This utility enhances productivity by enabling users to focus on specific parts of an application window.

Features

Thumbnail Mode

Creates a window showing the selected area of the original window. Changes in the original window are reflected in the thumbnail.

Reparent Mode

Creates a window that replaces the original window, showing only the selected area. The application is controlled through the cropped window.

Screenshot Mode

Creates a window showing a freezed snapshot of the original window.

Code Structure

Project Layout

The Crop and Lock module is part of the PowerToys solution. All the logic-related settings are in the main.cpp. The main implementations are in ThumbnailCropAndLockWindow and ReparentCropAndLockWindow. ChildWindow and OverlayWindow distinguish the two different modes of windows implementations.

Key Files

• ThumbnailCropAndLockWindow.cpp: Defines the UI for the thumbnail mode.
• OverlayWindow.cpp: Thumbnail module type's window concrete implementation.
• ReparentCropAndLockWindow.cpp: Defines the UI for the reparent mode.
• ChildWindow.cpp: Reparent module type's window concrete implementation.
• ScreenshotCropAndLockWindow.cpp: Defines the UI for the screenshot mode.

Known Issues

• Cropping maximized or full-screen windows in "Reparent" mode might not work properly.
• Some UWP apps may not respond well to being cropped in "Reparent" mode.
• Applications with sub-windows or tabs can have compatibility issues in "Reparent" mode.

Debug

1. build the entire project
2. launch the built Powertoys
3. select CropAndLock as the startup project in VS
4. In the debug button, choose "Attach to process".
5. Attach to CropAndLock.