WatermarkToPdf

WatermarkToPdf is a Ruby gem that allows you to easily add text-based watermarks to PDF files. It leverages MiniMagick for manipulating images and ImageMagick for processing PDF pages into images, applying the watermark, and converting them back into a PDF.

To install the gem and add it to your application's Gemfile, execute:

$ bundle add watermark_to_pdf

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install watermark_to_pdf

Ensure you have ImageMagick installed on your system. Use the following commands based on your OS:

For macOS:

$ brew install imagemagick

For Linux:

$ sudo apt-get install imagemagick

You will also need the following Ruby gem to manipulate PDFs:

$ gem install mini_magick

To add a watermark to a PDF file, use the WatermarkToPdf module as follows:

require 'watermark_to_pdf'

file = File.open('path_to_your_pdf_file.pdf')

options = {
  texts: [
    {
      text: "Confidential",
      position: [0, 0],   # Offset from the center (x, y)
      size: 150,          # Font size
      color: "rgba(255, 0, 0, 0.3)", # Red with transparency
      font: "Helvetica-Bold",
      weight: 700         # Font weight
    }
  ]
}

# Add the watermark to the PDF
watermarked_pdf = WatermarkToPdf.add_watermark(file, options)

# Save the watermarked PDF to a desired location
FileUtils.mv(watermarked_pdf, 'path_to_save_watermarked_pdf.pdf')

The options hash allows you to customize the watermark by providing an array of texts with the following options:

• text: The text to display as a watermark.
• position: An array [x, y] that defines the position offset from the center of the page.
• size: The font size of the watermark text.
• color: The color of the watermark text in rgba format (e.g., rgba(128, 128, 128, 0.5) for a semi-transparent gray).
• font: The font family for the watermark text (default is Helvetica-Oblique).
• weight: The font weight (e.g., 700 for bold).

You can specify multiple texts with different positions and styles.

Bug reports and pull requests are welcome on GitHub at https://github.com/[Junaid0118]/watermark_to_pdf. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.