PowerPoint Watermark Script

A Python script to automatically add watermarks to all slides in PowerPoint presentations. Supports both standard positioning and ribbon-style watermarks that span across slides.

Website: Add Watermark to PowerPoint

✨ Features

• Multiple positioning options: Standard corners, center, or full ribbon styles
• Smart ribbon sizing: Automatically adjusts ribbon height based on watermark aspect ratio
• Opacity control: Set transparency from 0% to 100%
• Aspect ratio preservation: No image stretching or distortion
• Layering control: Place watermarks on top or underneath slide content
• Batch processing: Applies watermark to all slides at once

🚀 Quick Start

Installation

1. Clone or download this repository
2. Install dependencies:

   pip install -r requirements.txt

Basic Usage

from main import add_watermark_to_pptx

# Simple watermark in bottom-right corner
add_watermark_to_pptx(
    pptx_path="your_presentation.pptx",
    watermark_path="your_logo.png"
)

📋 Requirements

• Python 3.7+
• python-pptx>=1.0.2
• Pillow>=10.0.0

🎯 Position Options

Standard Positions

• center - Center of slide
• bottom-right - Bottom right corner with margin
• bottom-left - Bottom left corner with margin
• top-right - Top right corner with margin
• top-left - Top left corner with margin

Ribbon Positions

• diagonal-ribbon - Diagonal ribbon across entire slide
• horizontal-ribbon - Horizontal ribbon across slide width
• vertical-ribbon - Vertical ribbon across slide height

🛠️ Parameters

Parameter	Type	Default	Description
pptx_path	str	Required	Path to input PowerPoint file
watermark_path	str	Required	Path to watermark image
output_path	str	None	Output file path (auto-generated if None)
opacity	float	0.5	Watermark opacity (0.0 to 1.0)
position	str	"center"	Watermark position (see options above)
size_percentage	float	0.3	Size relative to slide width (ignored for ribbons)
on_top	bool	True	Whether watermark appears above content

📚 Examples

Example 1: Standard Logo in Corner

add_watermark_to_pptx(
    pptx_path="presentation.pptx",
    watermark_path="company_logo.png",
    opacity=0.7,
    position="bottom-right",
    size_percentage=0.15
)

Example 2: Diagonal "CONFIDENTIAL" Ribbon

add_watermark_to_pptx(
    pptx_path="sensitive_doc.pptx",
    watermark_path="confidential.png",
    output_path="confidential_presentation.pptx",
    opacity=0.3,
    position="diagonal-ribbon"
)

Example 3: Subtle Background Watermark

add_watermark_to_pptx(
    pptx_path="presentation.pptx",
    watermark_path="background_logo.png",
    opacity=0.1,
    position="center",
    size_percentage=0.5,
    on_top=False  # Behind content
)

Example 4: Horizontal Brand Banner

add_watermark_to_pptx(
    pptx_path="brand_presentation.pptx",
    watermark_path="brand_banner.png",
    opacity=0.4,
    position="horizontal-ribbon"
)

🎨 Smart Ribbon Sizing

The script automatically adjusts ribbon height based on your watermark's aspect ratio:

• Wide images (width/height > 2.5): 20% of slide height
• Normal/tall images: 35% of slide height

This ensures wide text watermarks don't create overly tall ribbons, while square logos get appropriate prominence.

🔄 Aspect Ratio Preservation

Unlike simple image insertion, this script:

• ✅ Maintains original image proportions
• ✅ Scales appropriately for different positions
• ✅ Prevents stretching or distortion
• ✅ Automatically calculates optimal dimensions

💡 Tips

1. For text watermarks: Use wide PNG images with transparent backgrounds
2. For logo watermarks: Square or vertical orientations work best for ribbons
3. Opacity suggestions:
   • Logos: 0.7-1.0
   • Background watermarks: 0.1-0.3
   • Text overlays: 0.3-0.6
4. File formats: PNG with transparency recommended for best results

🐛 Troubleshooting

Import errors: Make sure you're in the virtual environment:

source venv/bin/activate  # On macOS/Linux
# or
venv\Scripts\activate     # On Windows

Watermark too big/small: Adjust size_percentage for standard positions or check your image's aspect ratio for ribbons.

Watermark not visible: Check opacity setting and ensure on_top=True if you want it above content.

📄 License

This project is open source. Feel free to modify and distribute as needed.

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Need help? Check the examples above or examine the script's docstrings for detailed parameter information.