How to have an application Icon with Elixir desktop?

Indeed strange, no as far as I can tell you’re not doing anything wrong. This application icon is loaded IMHO by erlang native based on the environment variable WX_APP_ICON which is being set in the ./run bash script using export WX_APP_ICON="priv/icon.png"

Do you have any mismatches there? Is the priv/icon.png not present anymore?

This are the contents of run:

#!/bin/bash
export WX_APP_ICON="priv/icon.png"
export WX_APP_TITLE="Todo"
exec iex -S mix

And this is the directory structure with all the files:

.
├── assets
│   ├── css
│   │   ├── app.scss
│   │   └── todo.scss
│   ├── js
│   │   └── app.js
│   ├── node_modules
│   │   └── nprogress
│   │       ├── bower.json
│   │       ├── component.json
│   │       ├── History.md
│   │       ├── License.md
│   │       ├── Notes.md
│   │       ├── nprogress.css
│   │       ├── nprogress.js
│   │       ├── package.json
│   │       ├── Readme.md
│   │       └── test
│   │           ├── component.html
│   │           └── test.js
│   ├── package.json
│   └── package-lock.json
├── config
│   ├── config.exs
│   ├── dev.exs
│   ├── prod.exs
│   └── test.exs
├── lib
│   ├── todo_app
│   │   ├── menu_bar.ex
│   │   ├── menu.ex
│   │   ├── menu.html.heex
│   │   ├── repo.ex
│   │   └── todo.ex
│   ├── todo_app.ex
│   ├── todo_web
│   │   ├── channels
│   │   │   └── user_socket.ex
│   │   ├── controllers
│   │   │   └── error.ex
│   │   ├── endpoint.ex
│   │   ├── gettext.ex
│   │   ├── live
│   │   │   ├── todo_live.ex
│   │   │   └── todo_live.html.leex
│   │   ├── router.ex
│   │   ├── sup.ex
│   │   ├── templates
│   │   │   └── layout
│   │   │       ├── app.html.eex
│   │   │       ├── live.html.leex
│   │   │       └── root.html.leex
│   │   └── views
│   │       ├── error_helpers.ex
│   │       ├── error_view.ex
│   │       └── layout_view.ex
│   └── todo_web.ex
├── mix.exs
├── mix.lock
├── nodeploy
│   ├── android_todo.png
│   ├── icon.png
│   ├── ios_todo.png
│   ├── linux_todo.png
│   ├── logo2.svg
│   ├── logo.svg
│   ├── macos_todo.png
│   └── windows_todo.png
├── priv
│   ├── gettext
│   │   ├── de
│   │   │   └── LC_MESSAGES
│   │   │       └── default.po
│   │   └── default.pot
│   ├── icon.png
│   ├── icon32x32-done.png
│   ├── icon32x32.png
│   └── static
│       ├── assets
│       │   ├── app-4a3041c06bffeb8037c41842519865bf.css
│       │   ├── app-4a3041c06bffeb8037c41842519865bf.css.gz
│       │   ├── app.css
│       │   ├── app.css.gz
│       │   ├── app-ff0646ba3b536d27d22b58ff63cb77af.js
│       │   ├── app-ff0646ba3b536d27d22b58ff63cb77af.js.gz
│       │   ├── app.js
│       │   └── app.js.gz
│       ├── cache_manifest.json
│       ├── favicon-16a9a02d013524d236c09776f9c9302b.ico
│       ├── favicon.ico
│       ├── images
│       │   ├── icon-a1aeeeb2169d741501861d0b319d2755.svg
│       │   ├── icon-a1aeeeb2169d741501861d0b319d2755.svg.gz
│       │   ├── icon.svg
│       │   └── icon.svg.gz
│       ├── robots-067185ba27a5d9139b10a759679045bf.txt
│       ├── robots-067185ba27a5d9139b10a759679045bf.txt.gz
│       ├── robots.txt
│       └── robots.txt.gz
├── README.md
├── run
├── run.bat
└── test
    ├── support
    │   ├── channel_case.ex
    │   └── conn_case.ex
    └── test_helper.exs

It looks to me like everything is in place.

I’m currently looking into elixir-desktop as well. Is the environment variable the only way to have the icon be set? It doesn’t seem to be working for me with the settings on Desktop.Window on mac os.

Yes unfortunately the env variable is currently the only way Erlangs wx app overriding the icon. That said in MacOS things are a bit different, there to get your own icon in the Dock you have to create a MacOS app structure that contains your icon:

todo.app/Contents
todo.app/Contents/MacOS
todo.app/Contents/MacOS/run
todo.app/Contents/Resources
todo.app/Contents/Resources/icon.icns
todo.app/Contents/Info.plist
todo.app/Contents/PkgInfo

with Info.plist that names the icon file.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>CFBundleDevelopmentRegion</key>
    <string>English</string>
    <key>CFBundleExecutable</key>
    <string>run</string>
    <key>CFBundleGetInfoString</key>
    <string>TodoApp version 3.3.0</string>
    <key>CFBundleIconFile</key>
    <string>icon.icns</string>
    <key>CFBundleIdentifier</key>
    <string>org.yourdomain.todoapp</string>
    <key>CFBundleInfoDictionaryVersion</key>
    <string>6.0</string>
    <key>CFBundleLongVersionString</key>
    <string>3.3.0, (c) 2023 You</string>
    <key>CFBundleName</key>
    <string>TodoApp</string>
    <key>CFBundlePackageType</key>
    <string>APPL</string>
    <key>CFBundleShortVersionString</key>
    <string>3.3</string>
    <key>CFBundleVersion</key>
    <string>3.3.0</string>
    <key>NSHumanReadableCopyright</key>
    <string>Copyright 2023 You</string>
    <key>ATSApplicationFontsPath</key>
    <string>Fonts</string>
    <key>NSPrincipalClass</key>
    <string>wxNSApplication</string>
</dict>
</plist>

For testing the icon around Erlang you can use the existing :wx.demo() and just create (or take an existing) app structure and copy erl into the app.

cp `which erl` todo.app/Contents/MacOS/run
vi todo.app/Contents/MacOS/run

Update exec "$BINDIR/erlexec" ${1+"$@"} to exec "$BINDIR/erlexec" ${1+"$@"} -eval 'wx:demo().' -noshell in todo.app/Contents/MacOS/run

Then running that app using open todo.app will show the icon.icns icon in the dock.

Should this be documented? Why is Desktop.Window documenting a config for the icon i if it would never be applied?

More documentation is absolutely the right thing. Especially around these icons it took myself quite a while to grasp whats’ going on. But essentially there are three different icons (or two dependent on the platform).

From the top of the head this is it:

Screenshot from 2024-01-04 18-32-31690×391 62.3 KB

I’ll update the documentation.