✍️ SketchCam

Write in the air with your finger — watch it appear on your screen in real time.

No special hardware. No downloads. Just your webcam and your hands.

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⬇️ Clone & Run (VS Code)

Fastest way to get it running — copy-paste into the VS Code terminal.

1. Open VS Code, then open the terminal with Ctrl+` (backtick key).
2. Paste the block for your system and press Enter:

Windows (PowerShell)

git clone https://github.com/Himesh-rupchandani/SketchCam.git
cd SketchCam
pip install -r requirements.txt
python sketchcam.py

macOS / Linux

git clone https://github.com/Himesh-rupchandani/SketchCam.git
cd SketchCam
pip install -r requirements.txt
python3 sketchcam.py

That's it — the webcam window opens and you can start writing in the air.

New to git? Install it from git-scm.com, or on Windows download Git for Windows. VS Code's terminal can then run git automatically.

python not recognized? Try py sketchcam.py instead, or reinstall Python from python.org and tick "Add Python to PATH".

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🚀 What is SketchCam?

SketchCam turns your built-in webcam into an air-writing canvas. It uses AI hand tracking (MediaPipe) to follow both of your hands, then paints your finger strokes onto a transparent layer floating over the live camera feed — so it feels like writing on a whiteboard, in real time.

camera frame  →  AI finds your hands  →  finger pose = pen  →  paint  →  show

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✨ Features

• ✍️ Air drawing — your right index fingertip is the pen
• 🖐️ Two-hand gestures — right hand draws, left hand controls
• 🧽 Eraser — gesture, toolbar button, or E key
• 🎨 Color picker — 8 colors in the toolbar
• 🖌️ Brush size — gesture, -/+ buttons, or [/] keys
• ↩️ Undo last stroke
• 🗑️ Clear the whole canvas
• 💾 Save your drawing as a PNG (into the sketches/ folder)
• ✨ Neon hand-skeleton theme — left hand glows cyan, right hand glows magenta

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📦 Quick Start

You need Python 3.8 – 3.12.

Windows

Open PowerShell or Command Prompt in the project folder and run:

pip install -r requirements.txt
python sketchcam.py

Or just double-click run.bat — it installs everything and starts the app for you.

Don't type the #!/usr/bin/env python3 line from the top of the file — that's a Linux/macOS hint, not a Windows command. On Windows just use python sketchcam.py (or py sketchcam.py).

macOS / Linux

pip install -r requirements.txt
python3 sketchcam.py

The first launch downloads nothing extra — the pinned MediaPipe version ships its hand-tracking model inside the package, so it works fully offline. Make sure your webcam isn't in use by another app.

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🖐️ Gestures

Stand so both hands are visible to the camera.

Right hand = the pen

Gesture	Action
☝️ Index finger only	Draw
✌️ Index + middle finger	Erase (left hand neutral)
✋ Open hand	Lift the pen (move, don't draw)

Left hand = the modifier

Gesture	Action
✋ Left palm open + right hand ✌️ (peace)	Increase brush size (hold)
✊ Left fist + right hand ✌️ (peace)	Decrease brush size (hold)
✊ Both fists, hold ~3 seconds	Clear the whole canvas

While your left hand is open (or closed in a fist), the right hand's ☝️ still draws normally — only ✌️ is repurposed into resizing the brush: left open ✋ + ✌️ grows it, left fist ✊ + ✌️ shrinks it.

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🖱️ Toolbar & Keyboard

Toolbar (click with your mouse)

Color swatches · Eraser · brush -/+ · Undo · Clear · Save

Keyboard shortcuts

Key	Action
q / Esc	Quit
u	Undo last stroke
c	Clear canvas
s	Save drawing
e	Toggle eraser
[ / ]	Brush smaller / larger
h	Show / hide help overlay

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⌨️ Command-line options

python sketchcam.py --camera 1                  # use a different webcam (0, 1, 2, ...)
python sketchcam.py --width 640 --height 480    # lower resolution = faster
python sketchcam.py --swap-hands                # if it confuses your left and right hands

If the clear / size gestures don't respond as expected, your camera may be reporting hands mirrored — run with --swap-hands to flip them.

The toolbar is laid out for a 1280 px-wide window. At very low resolutions (e.g. 640 px) the rightmost buttons may be cropped — keep the default resolution, or use the keyboard shortcuts instead.

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💻 Running in VS Code

1. Open the folder — File → Open Folder… and pick the SketchCam folder.
2. Install the Python extension — Extensions panel (Ctrl+Shift+X), search Python (by Microsoft), install it.
3. Create a virtual environment (optional but recommended) — in the VS Code terminal (Ctrl+`` ):

   python -m venv .venv

   Then select it as the interpreter: Ctrl+Shift+P → Python: Select Interpreter → choose .venv.
4. Install dependencies — in the terminal:

   pip install -r requirements.txt

5. Run it:
   • Press F5 (uses the included .vscode/launch.json), or
   • Click the ▶ Run button in the top-right corner of sketchcam.py, or
   • In the terminal: python sketchcam.py

The drawing window is a separate OpenCV window, not part of VS Code — move the terminal aside and keep the camera window focused to use the keyboard shortcuts (q to quit).

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🧠 How it works (in 30 seconds)

1. Every frame, the webcam image is sent to MediaPipe, which finds 21 key points on each hand (fingertips, knuckles, wrist).
2. The code compares each fingertip with its knuckle to decide which fingers are raised — that pattern becomes your gesture (draw / erase / lift / fist).
3. Your right index fingertip is the pen. Its position is lightly smoothed, then a line is drawn from the last point to the current one.
4. Strokes are painted onto a transparent canvas overlaid on the video — a "mask" tracks which pixels you've drawn on, so the video shows through everywhere else.
5. Erase = remove pixels from the mask. Undo = replay all strokes except the last. Save = write the canvas pixels to a PNG.

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💡 Tips for best tracking

• Use good, even lighting; avoid a bright window behind you.
• Keep your hand about 0.5–1.5 m from the camera.
• Spread your fingers so the tracker can tell them apart.
• Move smoothly — jitter is already smoothed, but slow steady strokes look best.

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🛠️ Troubleshooting

• AttributeError: module 'mediapipe' has no attribute 'solutions' — you have mediapipe 1.x installed, which removed the solutions API this app uses. Fix it with:

  pip uninstall -y mediapipe numpy
  pip install "mediapipe==0.10.21" "numpy>=1.24,<2"
  

  Then make sure your requirements.txt pins mediapipe==0.10.21 and numpy>=1.24.0,<2 (never mediapipe>=0.10.0, which lets pip install 1.x).
• ImportError: libGL.so.1: cannot open shared object file (Linux/Codespace) — OpenCV needs a system OpenGL library. On Ubuntu/Debian run: sudo apt-get update && sudo apt-get install -y libgl1 libglib2.0-0
• "Could not open camera" — try another index: python sketchcam.py --camera 1
• Hand not detected — brighten the room, keep fingers spread, slow down.
• Erase feels too big/small — the eraser is 3× your brush size; adjust the brush.

⚠️ Codespaces / headless servers: SketchCam needs a webcam and a screen, which a Codespace doesn't have. For the real experience, run it on your laptop or desktop (Windows / macOS / Linux) with pip install -r requirements.txt then python sketchcam.py.

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📁 Project structure

SketchCam/
├── sketchcam.py          # the whole app (run this)
├── requirements.txt      # Python dependencies
├── run.bat               # Windows one-click launcher
├── .vscode/launch.json   # VS Code F5 run configuration
├── README.md             # this file
└── sketches/             # your saved drawings (PNG) appear here

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Made with 🖐️ + 💻 — enjoy writing in the air!