czyzby / wesnoth-png-optimizer

A GitHub Action that verifies Wesnoth PNG images

Wesnoth Image Optimizer

A GitHub Action for Wesnoth add-ons. Verifies PNG images using the woptipng tool from a partially cloned Wesnoth repository.

Usage

Create a .github/workflows folder in your GitHub repository. Add a workflow that triggers this action. For more info, see the following examples of GitHub workflows.

The optimization threshold for the woptipng tool can be configured with the threshold parameter. By default, a threshold of 10 is used, which means that the uploaded PNG files can be within 10% of the size of the compressed images. If any of the images are larger than that, the action will fail, and the files will be listed by the woptipng tool.

The Wesnoth version that the PNG images are checked against can be specified with the wesnoth-version parameter. It can match any Wesnoth branch or tag.

The folder or file that should be validated can be specified with the path parameter. By default, all images in the project will be verified.

Examples

A workflow that verifies PNG images on every push to the repository, as well as every pull request:

name: check

on: [push, pull_request]

jobs:
  check:
    runs-on: ubuntu-latest

    steps:
    - name: Repository checkout
      uses: actions/checkout@v4
    - name: Verify images
      uses: czyzby/wesnoth-png-optimizer@v1

A workflow that verifies WML files in the images/units/ folder against Wesnoth 1.16 woptipng with a custom threshold on every push or pull request to a specific branch:

name: check

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  check:
    runs-on: ubuntu-latest

    steps:
    - name: Repository checkout
      uses: actions/checkout@v4
    - name: Verify images
      uses: czyzby/wesnoth-png-optimizer@v1
      with:
        path: images/units/
        threshold: 5
        wesnoth-version: 1.16

By leveraging the continue-on-error flag and write permissions, GitHub Action can also be set up to optimize and commit the images rather than verify them. This is an example of an action that runs on every push to the main branch and optimizes all images from the repository:

name: optimize

on:
  push:
    branches: [ main ]

permissions:
  contents: write

jobs:
  optimize:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout repository
      uses: actions/checkout@v4
    - name: Optimize images
      uses: czyzby/wesnoth-png-optimizer@v1
      continue-on-error: true
      with:
        threshold: 0
    - name: Commit images
      run: |
        git config --global user.name "github-actions"
        git config --global user.email "[e-mail]"
        git commit -am "🤖 Optimize $GITHUB_REPOSITORY@$GITHUB_SHA"
        git push

The following example similarly optimizes the images instead of just verifying them, but instead of pushing commits directly to the branch, it sets up a PR after each successful optimization. This might be preferable to the previous approach if you'd like to accept the changes manually, or if the main branch is protected. Note that it requires setting up a private access token and adding it in the repository Settings tab under Secrets and variables > Actions as PRIVATE_ACCESS_TOKEN.

name: optimize

on:
  push:
    branches: [ main ]
  workflow_dispatch:

permissions:
  contents: write

jobs:
  optimize:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout repository
      uses: actions/checkout@v4
    - name: Optimize images
      uses: czyzby/wesnoth-png-optimizer@v1
      continue-on-error: true
      with:
        threshold: 0
    - name: Commit changes
      continue-on-error: true
      run: |
        git config user.name "GitHub Action"
        git config user.email "[e-mail]"
        git config --add --bool push.autoSetupRemote true
        git checkout -b "optimize/$GITHUB_SHA"
        git commit -am "🤖 Optimize $GITHUB_REPOSITORY@$GITHUB_SHA" && git push

    - name: Create pull request
      run: gh pr create -B main -H "optimize/$GITHUB_SHA" --title "Optimize images from @${GITHUB_SHA::7}" --body "Images from $GITHUB_REPOSITORY@$GITHUB_SHA optimized with `woptipng`."
      continue-on-error: true
      env:
        GITHUB_TOKEN: ${{ secrets.PRIVATE_ACCESS_TOKEN }}

Notes

Use @v1 for the latest stable release. Use @latest for the latest version directly from the default development branch.

See also

• czyzby/wesnoth-wml-linter: a GitHub Action that verifies WML files with wmllint and wmlindent.
• czyzby/wesnoth-wml-scope: a GitHub Action that verifies project resources with wmlscope.