PiP Monitor

PiP Monitor is a Windows desktop app for watching multiple running application windows from one picture-in-picture dashboard. It uses the Windows Desktop Window Manager (DWM) compositor, so live previews are rendered by Windows instead of being copied through a CPU-based screen-capture pipeline.

Current version: v0.0.7

Highlights

• Discover and filter visible top-level windows by process name, title, or PID.
• Select multiple windows and monitor them together in a resizable grid.
• Use the dedicated Monitor page for a larger dashboard view.
• Pause, resume, pop out, or remove individual previews.
• Open borderless, always-on-top pop-outs that preserve the source aspect ratio.
• Right-click a pop-out to toggle full-screen mode on the monitor that currently contains most of the PiP, including monitors with different sizes or aspect ratios.
• Select a region inside one source window and open it as a separate cropped PiP without changing the existing full-window preview or pop-out.
• Adjust the global refresh target from 1 to 120 FPS and the tile width from 220 to 720 pixels. The default refresh target is 60 FPS.
• Pause or resume all previews and keep the main dashboard always on top.
• Automatically rescale the dashboard, fonts, spacing, and custom controls when it moves between monitors using different Windows scaling percentages.
• Switch the interface between Traditional Chinese (zh-TW) and English.
• Run without third-party runtime packages; the app uses tkinter, ctypes, and the native Win32/DWM APIs.

Requirements

• Windows with Desktop Window Manager composition available
• Python 3.10 or newer when running from source
• A Python installation that includes tkinter (included with the standard Windows installer from python.org)

PiP Monitor currently supports Windows only.

Run from source

Clone or download the project, then run:

python .\pip_monitor.py

You can also double-click run_pip_monitor.bat. It first looks for the standard per-user Python 3.10 installation and otherwise falls back to python on PATH.

There are no third-party runtime dependencies. The following command is optional and only confirms that requirements.txt is satisfied:

python -m pip install -r .\requirements.txt

Basic controls

1. On Process Discovery, select one or more windows. Use the search field to filter the list, then choose Add selected. Double-clicking a row also adds it. The window list refreshes automatically every two seconds; the Refresh button remains available for an immediate update.
2. Use Pause, Pop, or X on a preview tile to control that window. Region PiP is an additional action that opens a live crop from inside the selected source window; the original Pop action still opens the complete window.
3. Open Monitor from the sidebar for the full dashboard view.
4. Use the bottom control bar to change FPS, tile width, dashboard always-on-top behavior, or the global paused state.

Pop-out controls:

• Drag anywhere inside the picture with the left mouse button to move it.
• Drag an edge or corner with the left mouse button to resize it while preserving the source aspect ratio.
• Press the middle mouse button or press Esc to close the pop-out.
• Right-click to expand the PiP to the full bounds of its current monitor; right-click again to restore its exact previous position and size. Both the press and release are consumed so the click does not pass through to the application or desktop behind the PiP.
• Full-screen mode preserves the complete source or crop without stretching. Black bars are centered when the monitor has a different aspect ratio. Moving and resizing are temporarily disabled until the PiP is restored.

Region PiP controls:

• Choose Region PiP on a preview tile, then drag over the desired part of the source window.
• Press Esc or right-click during selection to cancel without opening a PiP.
• Close an existing cropped PiP before choosing a different region from the same preview tile.
• Crops are stored proportionally, so the selected area follows later source window resizing.

Rendering backend

The only runtime backend is the Windows DWM GPU compositor. Dashboard tiles and pop-outs use DwmRegisterThumbnail and DwmUpdateThumbnailProperties. CPU work is limited to UI controls, window enumeration, and thumbnail geometry updates; Windows handles frame composition and scaling.

The app does not copy frames through PhotoImage, PrintWindow, GDI bitmaps, Pillow, OpenCV, or windows-capture.

Known limitations

Some apps block or bypass normal Windows composition. Minimized, DRM-protected, exclusive-fullscreen, UWP, Chromium, video, and hardware-accelerated windows can show a black or stale preview depending on the source application. This is a Windows or source-app limitation rather than a screen-region capture issue.

Closing a source window also ends its live preview. Process Discovery updates the list of available windows automatically.

Tests

Run the unit tests from the project root:

python -m unittest discover -s .\tests -v

The current test suite covers middle-click close safety, consumed right-click events, full-screen toggle and restore geometry, aspect-ratio fitting on different monitor shapes, mixed-DPI native monitor bounds, normalized region-crop geometry, automatic Process Discovery refresh scheduling, and GUI rescaling at 100%, 125%, 150%, 175%, and 200%.

Build a portable executable

Install PyInstaller, then create a single-file Windows executable:

python -m pip install pyinstaller
python -m PyInstaller --noconfirm --noconsole --onefile --name "PiP-Monitor-v0.0.7" --icon .\assets\app_icon.ico --add-data ".\assets;assets" --manifest .\packaging\windows_app.manifest --version-file .\packaging\windows_version_info.txt --distpath .\release\exe --workpath .\build\pyinstaller\v0.0.7 .\pip_monitor.py
Compress-Archive -LiteralPath .\release\exe\PiP-Monitor-v0.0.7.exe -DestinationPath .\release\PiP-Monitor-v0.0.7-portable-win64.zip -CompressionLevel Optimal

App icons are stored under assets/. The main window uses assets/app_icon.ico for the title bar, taskbar, and Alt-Tab surfaces.

Before producing a release build, keep the version values in the command above and packaging/windows_version_info.txt synchronized.