PDFium

Native bindings for pdfium project

Installing

• for Mix projects, add the following under deps in mix.exs:

    {:pdfium, "~> 0.1"}

• for single-file Elixir scripts, add the following:

    Mix.install([pdfium: "~> 0.1"])

Usage

1. open a PDF file descriptor:

   {:ok, document} = PDFium.load_document("file.pdf")
   # => {:ok, #Reference<0.2181297728.2193227786.166499>}

2. get the number of pages in the file:

   {:ok, pages} = PDFium.get_page_count(document)
   # => {:ok, 1}

3. render a page to file:

   {:ok, ref} = PDFium.load_document("/Users/eugene/Downloads/7ade6db09604a8b41104763c6f16a987.pdf")
   {:ok, binary, w, h} = PDFium.get_page_bitmap(ref, 0, 300) # 300 for DPI
   {:ok, image} = Vix.Vips.Image.new_from_binary(binary, w, h, 4, :VIPS_FORMAT_UCHAR)
   {:ok, _image} = Image.write(image, "/tmp/sample.png")

Releasing

1. bump version in VERSION file. Run:

   echo -n (awk 'BEGIN{FS=OFS="."} {$NF+=1}1' VERSION) > VERSION

2. commit and push the change:

   git add VERSION
   git commit --message "Bump library version"
   git push origin main

3. create a PR from main to stable. Run:

   gh pr create --base stable --fill

4. wait until the PR checks are green, then merge the PR

Running CI steps locally

1. Prepare:

   mkdir output

2. Build:

   dagger call \
     precompile --src-dir . --platform-name linux/arm64 --abi musl \
     export --path output/ --allowParentDirPath

3. Test:

   dagger call test \
     --precompiled output/pdfium-nif-2.17-aarch64-linux-musl-0.1.23.tar.gz \
     --abi musl --platform-name linux/arm64

Releasing manually

1. open PR with a new libpdfium tag:

    env GITHUB_TOKEN=(gh auth token) dagger call prepare-release-pull-request \
      --base stable \
      --libpdfium-tag chromium/7506 \
      --actor 41898282+github-actions[bot] \
      --github-token GITHUB_TOKEN

2. wait until the PR is green, then merge it and release a package on hex:

    HEX_API_KEY=483a... GITHUB_TOKEN=(gh auth token) dagger call create-release \
      --pr 99 \
      --actor gmile \
      --github-token GITHUB_TOKEN \
      --hex-api-key HEX_API_KEY

Updating OTP version (for macOS)

wget https://github.com/erlef/otp_builds/releases/download/OTP-28.1/OTP-28.1-macos-amd64.tar.gz /tmp
wget https://github.com/erlef/otp_builds/releases/download/OTP-28.1/OTP-28.1-macos-arm64.tar.gz /tmp

shasum -a 256 /tmp/OTP-28.1-macos-amd64.tar.gz
shasum -a 256 /tmp/OTP-28.1-macos-arm64.tar.gz

# Then edit custom/build.json by inserting the hashes

Known issues

• Installing the library was tested and will work in macOS and inside Docker images built by Bob. Installing currently doesn't work under Elixir installed via package managers, such as via apk add elixir for example.

License

See [LICENSE].