# ChromicPDF
[](https://hex.pm/packages/chromic_pdf)
[](https://hexdocs.pm/chromic_pdf/ChromicPDF.html)
[](https://www.apache.org/licenses/LICENSE-2.0)
[](https://circleci.com/gh/bitcrowd/chromic_pdf)
ChromicPDF is a small wrapper around Chrome's `printToPDF` API that allows to print a URL to PDF.
## Features
* **Node-free**: In contrast to [many other](https://hex.pm/packages?search=pdf&sort=recent_downloads) packages, it does not use [puppeteer](https://github.com/puppeteer/puppeteer), and hence does not require Node.js. It communicates directly with Chrome's [DevTools API](https://chromedevtools.github.io/devtools-protocol/) over pipes, offering the same performance as puppeteer, if not better.
* **Header/Footer**: Using the DevTools API allows to apply the full set of options of the [`printToPDF`](https://chromedevtools.github.io/devtools-protocol/tot/Page#method-printToPDF) function. Most notably, it supports header and footer HTML templates.
* **PDF/A**: It can convert printed files to PDF/A using Ghostscript, inspired by the `pdf2archive` script originally created by [@matteosecli](https://github.com/matteosecli/pdf2archive) and later enhanced by [@JaimeChavarriaga](https://github.com/JaimeChavarriaga/pdf2archive/tree/feature/support_pdf2b). Created PDF/A-2b and PDF/A-3b files pass the [verapdf](https://verapdf.org/) compliance checks.
## Requirements
* Chromium or Chrome
* Ghostscript (for PDF/A support)
## Installation
ChromicPDF is a supervision tree (rather than an application). You will need to inject it into the supervision tree of your application. First, add ChromicPDF to your runtime dependencies:
```elixir
def deps do
[
{:chromic_pdf, "~> 0.3.1"}
]
end
```
Next, start ChromicPDF as part of your application:
```elixir
# lib/my_app/application.ex
def MyApp.Application do
def start(_type, _args) do
children = [
# other apps...
ChromicPDF
]
Supervisor.start_link(children, strategy: :one_for_one, name: MyApp.Supervisor)
end
end
```
## Usage
### Main API
```elixir
ChromicPDF.print_to_pdfa(
# URL to of local file to print
{:url, "file:///example.html"},
# Parameters to the PDF renderer, specifically for Chromium's printToPDF function,
# see https://chromedevtools.github.io/devtools-protocol/tot/Page#method-printToPDF
print_to_pdf: %{
# Margins are in given inches
marginTop: 0.393701,
marginLeft: 0.787402,
marginRight: 0.787402,
marginBottom: 1.1811,
# Print header and footer (on each page).
# This will print the default templates if none are given.
displayHeaderFooter: true,
# Even on empty string.
# To disable header or footer, pass an empty element.
headerTemplate: "<span></span>",
# Example footer template.
# They are completely unstyled by default and have a font-size of zero,
# so don't despair if they don't show up at first.
# There's a lot of documentation online about how to style them properly,
# this is just a basic example. The <span> classes shown below are
# interpolated by Chrome, see the printToPDF documentation.
footerTemplate: """
<style>
p {
color: #333;
font-size: 10pt;
text-align: right;
margin: 0 0.787402in;
width: 100%;
z-index: 1000;
}
</style>
<p>
Page <span class="pageNumber"></span> of <span class="totalPages"></span>
</p>
"""
},
# Parameters for the PDF/A converter
info: %{
title: "Example",
author: "Jane Doe",
creator: "ChromicPDF"
},
pdfa_version: "3",
# Output path.
output: "test.pdf"
)
```
### Sample boilerplate for a template
This more sophisticated example shows how to use `Phoenix.View` to move HTML markup into template
files.
```elixir
defmodule MyApp.InvoiceView do
use Phoenix.View,
root: "lib/my_app/path/to/pdf_templates",
namespace: MyApp
def print_to_pdf(assigns) do
[content: content(assigns)]
|> ChromicPDF.Template.source_and_options()
|> ChromicPDF.print_to_pdf()
end
@style File.read!("../path/to/assets/css/invoice.css")
defp content(assigns) do
[
@style,
Phoenix.HTML.safe_to_string(render("content.html", assigns))
]
end
end
```
## Development
For running the full suite of integration tests, please install and have in your `$PATH`:
* [`verapdf`](https://verapdf.org/)
* For `pdfinfo` and `pdftotext`, you need `poppler-utils` (most Linux distributions) or [Xpdf](https://www.xpdfreader.com/) (OSX)
* For the odd ZUGFeRD test in [`pdfa_generation_test.exs`](test/integration/pdfa_generation_test.exs), you need to download [ZUV](https://github.com/ZUGFeRD/ZUV) and set the `$ZUV_JAR` environment variable.
