PdfElixide

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Elixir CI Hex.pm Hex.pm License: MIT

Elixir bindings for pdf_oxide, a high-performance PDF library written in Rust. Built on top of Rustler.

⚠️ Status: This project is under active development and the public API is subject to change without notice until a 1.0 release. Expect breaking changes between minor versions.

Features

  • Open PDF documents from a file path or an in-memory binary
  • Query the PDF specification version
  • Get the page count
  • Extract text from a specific page
  • Extract AcroForm fields (name, kind, value)
  • Fill AcroForm fields and save the result to a file or in-memory binary

Requirements

  • Elixir ~> 1.15
  • Erlang/OTP compatible with the above
  • A working Rust toolchain (stable) for compiling the NIF

Installation

Add pdf_elixide to your dependencies in mix.exs:

def deps do
  [
    {:pdf_elixide, "~> 0.3.1"}
  ]
end

Then fetch and compile:

mix deps.get
mix compile

The Rust NIF is compiled automatically by Rustler on first build.

Usage

Opening a document

Document inspection lives on PdfElixide.Document (open, version, page count, text extraction).

# Open from a file path
{:ok, doc} = PdfElixide.Document.open("path/to/file.pdf")

# Or from an in-memory binary
{:ok, bytes} = File.read("path/to/file.pdf")
{:ok, doc}   = PdfElixide.Document.from_binary(bytes)

Inspecting a document

alias PdfElixide.Document

# Version is read directly from the struct — returned as a {major, minor} tuple.
{1, 4} = Document.version(doc)

# Page count is fetched from the underlying PDF and may fail.
{:ok, 3} = Document.page_count(doc)

# Extract text from a single page (zero-based index).
{:ok, text} = Document.extract_text(doc, 0)

# Source path is the file the document was opened from, or `nil` when it was loaded from a binary.
"path/to/file.pdf" = Document.source_path(doc)

Each fallible function ships with a bang variant that returns the value directly and raises on error:

doc   = PdfElixide.Document.open!("path/to/file.pdf")
pages = PdfElixide.Document.page_count!(doc)
text  = PdfElixide.Document.extract_text!(doc, 0)

Extracting form fields

PdfElixide.Form.fields/1 returns the AcroForm fields of the document as a list of %PdfElixide.Form.Field{} structs:

{:ok, fields} = PdfElixide.Form.fields(doc)

Enum.each(fields, fn %PdfElixide.Form.Field{name: name, kind: kind, value: value} ->
  IO.inspect({name, kind, value})
end)

Each field carries:

  • :name — the field's PDF name (String.t())

  • :kind — one of :button | :text | :choice | :signature | :unknown

  • :value — one of {:text, String.t()} | {:boolean, boolean()} | {:name, String.t()} | {:array, [String.t()]} | nil

A bang variant, PdfElixide.Form.fields!/1, returns the list directly and raises on error.

Filling form fields

To modify a PDF, open it as a PdfElixide.Editor instead of a PdfElixide.Document, set values with PdfElixide.Form.set_value/3, then persist the result with PdfElixide.Editor.save/3 (file) or PdfElixide.Editor.to_binary/2 (in-memory).

alias PdfElixide.Editor
alias PdfElixide.Form

{:ok, editor} = Editor.open("path/to/form.pdf")

# Values use the same tagged-tuple shape returned by Form.fields/1.
:ok = Form.set_value(editor, "full_name", {:text, "Jane Doe"})
:ok = Form.set_value(editor, "subscribe", {:boolean, true})

# Write the filled PDF to disk.
:ok = Editor.save(editor, "path/to/filled.pdf")

# Or get the bytes back for streaming / storage.
{:ok, bytes} = Editor.to_binary(editor)

Both save/3 and to_binary/2 accept a keyword list of options (:incremental, :compress, :linearize, :garbage_collect). For form filling against an existing PDF, an incremental save preserves the original AcroForm structure and only appends the field-value updates:

:ok = Editor.save(editor, "path/to/filled.pdf", incremental: true)

Bang variants Editor.open!/1, Editor.save!/3, Editor.to_binary!/2, and Form.set_value!/3 raise on error.

Documentation

Full API documentation is published on HexDocs.

License

Released under the MIT License.