ThumbGen

Welcome to ThumbGen, a powerful Ruby gem designed to generate images with customized text overlays.
Perfect for automating thumbnail creation, blog banners, and promotional images.

🖼️ Example

Input Image	Output Image

💎 Installation

Add to your Gemfile:

bundle add thumb_gen

Or install manually:

gem install thumb_gen

✨ Usage

You can generate an image by providing background, output path, and an array of text overlays:

require 'thumb_gen'

output_path = 'sample_output.jpg'
background_url = 'sample_input.jpg'

texts = [
  {
    text: 'ThumbGen is a Ruby gem that simplifies the creation of article thumbnails',
    wrapped_width: 800,
    font: 'PublicSans-Bold',
    font_size: 80,
    color: '#047857',
    outline_color: '#f8fafc',
    outline_width: 1,
    gravity: 'northwest',
    position_x: 40,
    position_y: 120
  },
  {
    text: '5 min read',
    wrapped_width: 800,
    font: 'Roboto-Italic',
    font_size: 48,
    color: '#09090b',
    gravity: 'southwest',
    position_x: 400,
    position_y: 40
  },
  {
    text: 'My Blog',
    wrapped_width: 1280,
    font: 'Roboto-BoldItalic',
    font_size: 64,
    color: '#86198f',
    gravity: 'northeast',
    position_x: 200,
    position_y: 30
  }
]

options = {
  width: 1280,
  height: 720,
  format: 'jpg'
}

ThumbGen.generate(output_path, background_url, texts, options)

Font files like Roboto-BoldItalic.ttf are bundled in the gem’s fonts/ folder.
Use only the filename without extension as the font: value.

PublicSans-Regular
PublicSans-Bold
PublicSans-BoldItalic
PublicSans-Thin
PublicSans-ThinItalic
Roboto-Regular
Roboto-Bold
Roboto-BoldItalic
Roboto-Italic
Roboto-Thin
Roboto-ThinItalic
For Japanese:
- NotoSansJP-Regular
- NotoSansJP-Bold
- NotoSansJP-Thin
For Korean:
- NotoSansKR-Regular
- NotoSansKR-Bold
- NotoSansKR-Thin
For Simplified Chinese
- NotoSansSC-Regular
- NotoSansSC-Bold
- NotoSansSC-Thin

🛠 Development

After cloning the repo, install dependencies:

bin/setup

Run tests:

rake spec

Try it in IRB:

bin/console

To install the gem locally:

bundle exec rake install

To release a new version:

Update the version in lib/thumb_gen/version.rb
Run:

bundle exec rake release

🤝 Contributing

Bug reports and pull requests are welcome at:
https://github.com/YutoYasunaga/thumb_gen

📄 License

Released under the MIT License

thumb_gen