Stability

Provides easy access to the Stable Image REST API provided by stability.ai. This library is maintained by Obie Fernandez and the team at Olympia, the world's premier Ruby on Rails-based AI platform, offering AI-powered teams for solopreneurs and small businesses. You can support this project by being a customer of Olympia, or buying Obie's book Patterns of Application Development Using AI

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add stability

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

$ gem install stability

Usage

First, configure the Stability client with your API key. You can set the API key directly or use environment variables.

require 'stability'

Stability.configure do |config|
  config.api_key = ENV['STABILITY_API_KEY'] # or set directly: config.api_key = 'your_api_key'
end

Text-to-Image Generation

To generate an image from a text prompt, use the generate_core method. This method allows you to specify various options such as aspect ratio, negative prompts, seed, style presets, and output format.

client = Stability::Client.new

prompt = "A beautiful sunset over the city"
options = {
  aspect_ratio: "16:9",
  negative_prompt: "No people",
  seed: 12345,
  style_preset: "photographic",
  output_format: "png"
}

response = client.generate_core(prompt, options: options, json: true)

if response["finish_reason"] == "SUCCESS"
  image_data = Base64.decode64(response["image"])
  File.open("/tmp/generated_image.png", "wb") { |file| file.write(image_data) }
  puts "Image generated successfully!"
else
  puts "Failed to generate image: #{response['error']['message']}"
end

Image-to-Image Generation

To generate an image from an existing image and a text prompt, use the generate_sd3 method with the image-to-image mode. This method requires additional parameters such as the input image and the strength of the transformation.

client = Stability::Client.new

prompt = "A futuristic cityscape at night"
image_path = "path/to/your/input_image.png"
image_file = File.open(image_path, "rb")
strength = 0.75

options = {
  mode: "image-to-image",
  image: image_file,
  strength: strength,
  negative_prompt: "No people",
  model: "sd3",
  seed: 12345,
  output_format: "png"
}

response = client.generate_sd3(prompt, options: options, json: true)

if response["finish_reason"] == "SUCCESS"
  image_data = Base64.decode64(response["image"])
  File.open("/tmp/generated_image.png", "wb") { |file| file.write(image_data) }
  puts "Image generated successfully!"
else
  puts "Failed to generate image: #{response['error']['message']}"
end

Note that a full guide to image generation models and their parameters is available here.

Handling Errors

Both methods raise a ServerError if the response is empty or contains an error message. Ensure you handle these exceptions appropriately in your application.

begin
  response = client.generate_core(prompt, options: options, json: true)
  # Process response
rescue Stability::ServerError => e
  puts "An error occurred: #{e.message}"
end

Rate Limiting

The Stability API is rate-limited to 150 requests every 10 seconds. If you exceed this limit, you will receive a 429 response and be timed out for 60 seconds. Ensure your application handles rate limiting appropriately.

begin
  response = client.generate_core(prompt, options: options, json: true)
  # Process response
rescue Stability::RateLimitError => e
  puts "Rate limit exceeded: #{e.message}"
  sleep(60) # Wait for the timeout period before retrying
  retry
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

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

License

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

Code of Conduct

Everyone interacting in our codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.