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Peek is a quick file previewer that lets you view file contents instantly without launching full applications. Press the activation shortcut while selecting files in File Explorer to get an immediate preview.

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Activation

1

Select Files

In File Explorer, select one or more files you want to preview.
2

Activate Peek

Press Ctrl + Space to open the Peek preview window.
3

Close Preview

Press Esc or Ctrl + Space again to close.
Peek works exclusively within File Explorer. The activation shortcut has no effect in other applications.

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Supported File Types

Peek uses a previewer architecture to support different file formats. Each previewer implements the IPreviewer interface from /src/modules/peek/Peek.FilePreviewer/Previewers/Interfaces/IPreviewer.cs.

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Image Files

Preview images with support for:
  • Common formats: PNG, JPG, GIF, BMP, TIFF, ICO
  • Advanced formats: WebP, SVG
  • RAW camera formats (through Windows codecs)
  • Animated GIFs
Features:
  • Zoom and pan support
  • Display image dimensions and file size
  • EXIF metadata display (for supported formats)

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Video Files

Preview video files using Windows Media Foundation:
  • MP4, AVI, MKV, MOV, WMV
  • MPEG, FLV, WebM
  • Display duration, resolution, codec information
  • Basic playback controls

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Audio Files

Preview audio files with:
  • MP3, WAV, FLAC, AAC, OGG, WMA
  • Display duration, bitrate, sample rate
  • Waveform visualization
  • Playback controls
Implementation: /src/modules/peek/Peek.FilePreviewer/Controls/AudioControl.xaml.cs

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Archive Files

Browse archive contents without extraction:
  • ZIP, RAR, 7Z, TAR, GZ
  • Display folder structure
  • Show file count and sizes
  • Preview individual files within archives
Implementation: /src/modules/peek/Peek.FilePreviewer/Controls/ArchiveControl.xaml.cs

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Code & Text Files

Syntax-highlighted preview for:
  • Programming languages: C#, C++, JavaScript, Python, Java, Go, Rust, etc.
  • Markup: HTML, XML, JSON, YAML, TOML
  • Scripts: PowerShell, Bash, Batch
  • Configuration files
  • Plain text

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PDF Files

Preview PDF documents with:
  • Page navigation
  • Zoom controls
  • Multi-page support
  • Text selection

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Office Documents

Preview Microsoft Office files:
  • Word (.docx, .doc)
  • Excel (.xlsx, .xls)
  • PowerPoint (.pptx, .ppt)
Uses Windows Shell preview handlers.

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Web Files

Preview web content:
  • HTML files with rendering
  • CSS files with syntax highlighting
  • JavaScript files
Implementation: /src/modules/peek/Peek.FilePreviewer/Controls/BrowserControl.xaml.cs

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Special Folders & Drives

Preview drives and special folders with:
  • Disk space information
  • Drive type and file system
  • Folder metadata
Implementation: /src/modules/peek/Peek.FilePreviewer/Controls/DriveControl.xaml.cs

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Features

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Multi-File Preview

Select one file and press Ctrl + Space to preview it in a centered window.

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Preview States

Peek implements state management through the PreviewState enum: 
public enum PreviewState
{
    Uninitialized,  // Preview not yet started
    Loading,        // Loading file content
    Loaded,         // Successfully loaded
    Error,          // Failed to preview
}
From /src/modules/peek/Peek.FilePreviewer/Previewers/Interfaces/IPreviewer.cs:24-30

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Window Features

Custom title bar with:
  • File name display
  • File path
  • Close button
  • Drag to move window
Implementation: /src/modules/peek/Peek.UI/Views/TitleBar.xaml
When a file type isn’t supported, Peek displays:
  • File icon
  • File name and path
  • File size
  • Modification date
  • Option to open in default application
Implementation: /src/modules/peek/Peek.UI/Views/UnsupportedFile.xaml

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File Actions

1

Copy File Path

Right-click or use context menu to copy the file path to clipboard.
2

Open in Default App

Click “Open” button to launch the file in its default application.
3

Open File Location

Quickly navigate to the file’s containing folder.

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Configuration

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Activation Shortcut

Customize the activation shortcut in PowerToys Settings:
  1. Open PowerToys Settings
  2. Navigate to Peek
  3. Change “Activation shortcut” (default: Ctrl + Space)
Avoid conflicts with other applications. Common alternatives: Ctrl + Shift + Space, Alt + P

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Preview Settings

Configure default preview window dimensions and position.
Enable or disable specific previewers:
  • Disable resource-intensive previewers (video, large images)
  • Control which file types trigger preview
  • Max file size for preview
  • Loading timeout
  • Memory limits for large files

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Use Cases

Quick Inspection

Verify file contents without opening apps - perfect for checking downloads, screenshots, or documents.

Archive Browsing

Browse ZIP/archive contents without extraction. Navigate folder structures and preview files inside.

Code Review

Quickly scan source code files with syntax highlighting. Review changes across multiple files.

Media Management

Preview images, videos, and audio files instantly while organizing media libraries.

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Keyboard Shortcuts

ShortcutAction
Ctrl + SpaceOpen/Close Peek (default)
EscClose preview window
← →Navigate between multiple selected files
Ctrl + CCopy file path
Ctrl + OOpen in default application
Ctrl + WClose window

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Advanced Features

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Shell Preview Handler Integration

Peek integrates with Windows Shell Preview Handlers for file types without native previewers: 
Implementation: /src/modules/peek/Peek.FilePreviewer/Controls/ShellPreviewHandlerControl.xaml.cs
This enables preview support for:
  • Third-party file formats with installed preview handlers
  • Custom file types
  • Fallback for unsupported formats

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WinUI 3 Architecture

Peek is built on WinUI 3 (Windows App SDK) for modern UI: 
<PropertyGroup>
  <UseWinUI>true</UseWinUI>
  <WindowsAppSDKSelfContained>true</WindowsAppSDKSelfContained>
  <OutputType>WinExe</OutputType>
</PropertyGroup>
From /src/modules/peek/Peek.UI/Peek.UI.csproj:15, 22

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Preview Size Calculation

Each previewer implements GetPreviewSizeAsync() to calculate optimal window dimensions: 
Task<PreviewSize> GetPreviewSizeAsync(CancellationToken cancellationToken);
This ensures previews are sized appropriately for content type and screen resolution.

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Performance Considerations

For optimal performance with large files:
  1. Set maximum file size limits in settings
  2. Disable video preview for very large video files
  3. Use timeout settings to prevent hanging on slow drives
  4. Peek processes previews asynchronously to avoid blocking File Explorer

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Troubleshooting

  • Ensure Peek is enabled in PowerToys Settings
  • Verify file type is supported
  • Check activation shortcut isn’t conflicting with other apps
  • Restart File Explorer if Peek stops responding
  • Large files may take time to load
  • Check if file is on network drive or slow storage
  • Reduce maximum file size in settings
  • File type may not have a built-in previewer
  • Install Windows codec packs for additional format support
  • Some proprietary formats require native applications

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Source Code

Location: /src/modules/peek/
  • Main UI: Peek.UI/
  • File previewers: Peek.FilePreviewer/
  • Common utilities: Peek.Common/
  • Project file: Peek.UI/Peek.UI.csproj

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