Getting Started with Prawn for PDF Creation

Installing and Configuring Prawn for Ruby on Rails

To begin using Prawn, add it to your Gemfile and run bundle install. Once installed, Prawn can be used across Rails controllers or service objects:

# In your Gemfile
gem 'prawn'

# Run this to install
$ bundle install

With Prawn configured, you can call it within a controller or service object to create PDFs on demand.

Understanding Basic Prawn Syntax and PDF Structure

Prawn’s syntax is intuitive, using commands like text, image, and table to build PDF documents. A basic PDF layout in Prawn might look like this:

Prawn::Document.generate("example.pdf") do |pdf|
  pdf.text "Welcome to Prawn PDF Generation"
  pdf.image "/path/to/image.jpg", width: 100, height: 100
end

This code creates a simple PDF with text and an image, providing a foundation for more complex layouts.

Essential Prawn Methods for Text, Images, and Tables

To build out your documents, Prawn offers powerful methods for handling text, images, and tables:

Prawn::Document.generate("example.pdf") do |pdf|
  pdf.text "Invoice Report", size: 24, style: :bold
  pdf.text "Customer: John Doe", size: 14
  
  pdf.image "/path/to/logo.jpg", position: :center, width: 100, height: 50
  
  data = [["Item", "Quantity", "Price"], ["Widget", 2, "$20"], ["Gadget", 1, "$15"]]
  pdf.table(data, header: true)
end

This sample adds an invoice header, an image, and a table with headers, showcasing Prawn’s capacity for structured data layouts.

Styling and Formatting: Fonts, Colors, and Layouts

With Prawn, you control fonts, colors, and positioning, allowing fine-tuned customization. Here’s how to style text and elements:

Prawn::Document.generate("styled_example.pdf") do |pdf|
  pdf.font "Helvetica"
  pdf.fill_color "0096D6"
  pdf.text "Styled Invoice", size: 20, align: :center
  pdf.stroke_color "FF0000"
  pdf.stroke_horizontal_rule
end

This styling provides branding consistency, enhancing the document’s professional appearance.

Generating PDFs from HTML in Ruby on Rails

Creating a Complete Invoice HTML/CSS File as an Example

Start with a simple HTML file for an invoice template. This example will then be used to generate PDF files dynamically.

<!-- invoice.html.erb -->
<div class="invoice">
  <h1>Invoice Report</h1>
  <p>Customer: John Doe</p>
  <table>
    <thead><tr><th>Item</th><th>Quantity</th><th>Price</th></tr></thead>
    <tbody>
      <tr><td>Widget</td><td>2</td><td>$20</td></tr>
      <tr><td>Gadget</td><td>1</td><td>$15</td></tr>
    </tbody>
  </table>
</div>

Include CSS to style the HTML, ensuring it resembles the final PDF’s layout and appearance.

Creating the Invoice Example Using Prawn Methods

Using the HTML structure, recreate the invoice in Prawn to maintain layout consistency:

Prawn::Document.generate("invoice.pdf") do |pdf|
  pdf.text "Invoice Report", size: 20, style: :bold
  pdf.text "Customer: John Doe", size: 14
  
  items = [["Item", "Quantity", "Price"], ["Widget", 2, "$20"], ["Gadget", 1, "$15"]]
  pdf.table(items, header: true)
end

Integrating HTML Templates for Dynamic PDF Content

Dynamic content, such as variable customer information or item lists, can be integrated by passing data from the Rails controller:

# invoices_controller.rb
def show
  customer = Customer.find(params[:id])
  Prawn::Document.generate("invoice_#{customer.id}.pdf") do |pdf|
    pdf.text "Invoice for #{customer.name}"
  end
end

This integration allows flexible content generation directly from Rails models.

Using Prawn with Rails Views: Rendering HTML to PDF

Rendering an HTML view as a PDF in Rails involves generating HTML content, converting it, and applying Prawn’s PDF methods to structure it:

# invoices_controller.rb
def download_invoice
  respond_to do |format|
    format.html
    format.pdf do
      render pdf: "invoice",
             template: "invoices/show.html.erb",
             layout: 'pdf'
    end
  end
end

Adding Page Numbers, Headers, and Footers

Adding elements like page numbers enhances readability. With Prawn, footers and headers are easy to implement:

Prawn::Document.generate("invoice.pdf") do |pdf|
  pdf.number_pages "<page> of <total>", at: [pdf.bounds.right - 50, 0]
end

Creating Interactive Elements: Links and Buttons

Prawn supports clickable links for a more interactive PDF experience. Here’s how to add a link:

pdf.text "Visit our website", link: "https://example.com"

Alternative: Convert HTML to PDF Using pdf noodle

Managing HTML-to-PDF conversion at scale can quickly become a nightmare!

Especially in serverless environments where cold starts, memory limits, and headless browser quirks love to break at the worst possible time (we even wrote a full article about it). Add constant template iterations, version control headaches, and the need to support non-technical contributors, and suddenly your “simple PDF library” turns into an ongoing engineering project.

pdf noodle eliminates all of that.

Instead of maintaining brittle infrastructure or wrestling with outdated pdf libraries, pdf noodle gives you a battle-tested PDF generation API that just works!

Fast, scalable, and designed for both developers and non-developers. You send raw HTML or use our AI-powered template builder, and pdf noodle handles the rendering, scaling, optimization, and delivery so your team doesn’t have to.

Here's an example of a simple API request to generate your pixel-perfect PDF with just a few lines of code:

require 'net/http'
require 'json'
require 'uri'

class PdfApiService
  def self.generate_pdf(html_content)
    uri = URI("https://api.pdfnoodle.com/v1/html-to-pdf/sync")
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    request = Net::HTTP::Post.new(uri.path, {
      'Content-Type' => 'application/json',
      'Authorization' => "Bearer your-api-key"
    })
    request.body = {
      html: html_content
    }.to_json
    response = http.request(request)
    response.body if response.is_a?(Net::HTTPSuccess)
  end
end

pdf noodle also includes a powerful AI Agent that can generate PDF templates instantly, along with a modern editor for refining the design, also using AI, to match your brand. You don't need developing or design experience to quickly update layouts, adjust styling, and manage template versions.

Here’s a quick demo showing how it works:

You can create your account and design your first template without any upfront payment.

Conclusion

For complete control over PDF layout, Prawn is an excellent tool in Ruby on Rails, particularly when fine-tuning and complex designs are needed.

When simpler HTML-to-PDF conversion suffices, consider alternatives like WickedPDF or PDFkit.

If you don't want to waste time maintaining pdfs layouts and their infrastructure or if you don't want to keep track of best practices to generate PDFs at scale, third-party PDF APIs like pdf noodle will save you hours of work and deliver a high quality pdf layout.