Gamma Watermark Remover

A local web tool to strip the "Made with Gamma" branding from files exported from gamma.app free accounts — including PDF, PowerPoint (.pptx), Apple Keynote (.key), and PNG slide ZIP exports.

It runs a FastAPI backend that parses the document structure to identify and remove specific watermark elements based on coordinates and object properties.

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Features

• PDF: Scans pages using PyMuPDF (fitz) for images linked to the gamma.app domain located in the bottom-right corner.
• PPTX: Uses python-pptx to parse the presentation. Since Gamma embeds the watermark in the Slide Layouts (masters) rather than individual slides, the script targets the master layouts to remove the branding globally.
• Keynote (.key): macOS only. Uses AppleScript to drive the Keynote app — converts .key → .pptx, cleans watermarks, then converts back to .key. Requires Keynote to be installed. Tip: Keeping the Keynote app open in the background before starting the conversion is highly recommended; it speeds up the conversion process significantly and prevents potential macOS permission prompt blocks or startup timeout issues.
• PNG ZIP / Folder: Processes ZIP archives (or extracted folders) of Gamma's PNG slide exports. Uses per-row background colour sampling to seamlessly paint over the bottom-right watermark badge on every slide image.
• Batch-ready: Upload multiple files at once from the web UI.
• Dark / Light mode: Toggle between themes; preference is saved locally.
• Session history: Track your processed files within a browser session.

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Quick Start

Requires Python 3.9+.

1. Clone the repo:

   git clone https://github.com/DedInc/gamma-ai-watermark-remover.git
   cd gamma-ai-watermark-remover

2. Create a virtual environment and install dependencies:

   python3 -m venv .venv
   source .venv/bin/activate
   pip install -r requirements.txt

3. Run the server:

   python app.py

4. Open http://localhost:8999 in your browser.

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Technical Notes

The detection logic is heuristic-based:

• PPTX / Keynote: Checks prs.slide_layouts. If a shape contains a hyperlink to gamma.app and is positioned beyond the 70% mark of the slide width/height, it gets deleted.
• PDF: Iterates through page objects. If a clickable image points to the Gamma domain, the object is removed from the drawing stream.
• PNG exports: The watermark occupies the bottom-right ~22% × 10% of each slide image. The remover samples the background colour row-by-row to the left of the watermark region and fills it in, producing a seamless patch.
• Google Slides exports: Gamma exports Google Slides-compatible files as .pptx. Upload the downloaded .pptx directly — it is already supported.

Note: If Gamma changes their export coordinates or DOM structure, the coordinate offsets in the processor modules will need to be updated.

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Dependencies

Package	Purpose
fastapi / uvicorn	Web server
pymupdf (fitz)	PDF processing
python-pptx	PowerPoint manipulation
Pillow	PNG image processing
python-multipart	File uploads
jinja2	HTML templating

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Project Structure

├── app.py                      # FastAPI application entry point
├── processors/
│   ├── pdf/
│   │   ├── detector.py         # PDF watermark detection
│   │   └── remover.py          # PDF watermark removal
│   ├── pptx/
│   │   ├── detector.py         # PPTX watermark detection
│   │   └── remover.py          # PPTX watermark removal
│   ├── png/
│   │   └── remover.py          # PNG slide watermark removal (PIL)
│   └── keynote/
│       └── converter.py        # Keynote ↔ PPTX via AppleScript (macOS)
├── utils/
│   ├── file_helpers.py         # File type validation & MIME types
│   └── processors.py           # High-level processor orchestration
├── templates/
│   └── index.html              # Web UI (single-page)
├── uploads/                    # Temporary upload storage
├── outputs/                    # Processed file output
└── test/                       # Analysis & test scripts

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Troubleshooting

Issue	Solution
Port already in use	Change the port in app.py (line uvicorn.run(...))
Large file processing is slow	This is expected for presentations with heavy graphics. The UI will show elapsed time.
"No watermark found" on a Gamma file	Gamma may have changed their watermark format. Open an issue with a sample file.
Import errors	Make sure you ran pip install -r requirements.txt inside your activated virtual environment.
Keynote (.key) not processing	Apple Keynote must be installed on your Mac. Make sure the Keynote app is already open/running in the background for a seamless and much faster conversion.
PNG ZIP — "No PNG files found"	Ensure the ZIP contains PNG files directly or inside a folder. Nested ZIPs are not supported.

🔧 Fixing a Broken Virtual Environment

If your .venv becomes corrupted or you see unexpected import errors after updating Python, recreate it from scratch:

# 1. Remove the broken venv
rm -rf .venv

# 2. Create a fresh virtual environment
python3 -m venv .venv

# 3. Activate it
source .venv/bin/activate   # macOS / Linux
# .venv\Scripts\activate    # Windows

# 4. Re-install all dependencies
pip install -r requirements.txt

# 5. Start the server
python app.py

Tip: If python3 -m venv fails because the venv module is missing (common on some minimal Linux installs), run sudo apt install python3-venv first, then retry.

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Disclaimer

This tool is for educational purposes only. I am not affiliated with Gamma. Please consider upgrading to their paid tier if you use the software for professional work.