feat: port icons guide (#2979)

Author: FabianLars

src/content/docs/develop/icons.mdx

@@ -0,0 +1,119 @@
+---
+title: App Icons
+sidebar:
+  order: 1
+---
+
+{/* TODO: More platform specific explanations like macOS requiring padding in the icon (waiting for https://github.com/tauri-apps/tauri/pull/11037) */}
+
+import CommandTabs from '@components/CommandTabs.astro';
+
+Tauri ships with a default iconset based on its logo. This is NOT what you want when you ship your application. To remedy this common situation, Tauri provides the `icon` command that will take an input file (`"./app-icon.png"` by default) and create all the icons needed for the various platforms.
+
+:::note[Note on filetypes]
+
+- `icon.icns` = macOS
+- `icon.ico` = Windows
+- `*.png` = Linux
+- `Square*Logo.png` & `StoreLogo.png` = Currently unused but intended for AppX/MS Store targets.
+
+Some icon types may be used on platforms other than those listed above (especially `png`). Therefore we recommend including all icons even if you intend to only build for a subset of platforms.
+
+:::
+
+## Command Usage
+
+<CommandTabs
+  npm="npm run tauri icon"
+  yarn="yarn tauri icon"
+  pnpm="pnpm tauri icon"
+  cargo="cargo tauri icon"
+  deno="deno task tauri icon"
+/>
+
+```console
+> pnpm tauri icon --help
+
+Generate various icons for all major platforms
+
+Usage: pnpm run tauri icon [OPTIONS] [INPUT]
+
+Arguments:
+  [INPUT]  Path to the source icon (squared PNG or SVG file with transparency) [default: ./app-icon.png]
+
+Options:
+  -o, --output <OUTPUT>        Output directory. Default: 'icons' directory next to the tauri.conf.json file
+  -v, --verbose...             Enables verbose logging
+  -p, --png <PNG>              Custom PNG icon sizes to generate. When set, the default icons are not generated
+      --ios-color <IOS_COLOR>  The background color of the iOS icon - string as defined in the W3C's CSS Color Module Level 4 <https://www.w3.org/TR/css-color-4/> [default: #fff]
+  -h, --help                   Print help
+  -V, --version                Print version
+```
+
+The **desktop** icons will be placed in your `src-tauri/icons` folder by default, where they will be included in your built app automatically. If you want to source your icons from a different location, you can edit this part of the `tauri.conf.json` file:
+
+```json
+{
+  "bundle": {
+    "icon": [
+      "icons/32x32.png",
+      "icons/128x128.png",
+      "icons/[email protected]",
+      "icons/icon.icns",
+      "icons/icon.ico"
+    ]
+  }
+}
+```
+
+The **mobile** icons will be placed into the Xcode and Android Studio projects directly!
+
+## Creating icons manually
+
+If you prefer to build these icons yourself, for example if you want to have a simpler design for small sizes or because you don't want to depend on the CLI's internal image resizing, you must make sure your icons meet some requirements:
+
+- `icon.icns`: The required layer sizes and names for the [`icns`] file are described [in the Tauri repo]
+- `icon.ico`: The [`ico`] file must include layers for 16, 24, 32, 48, 64 and 256 pixels. For an optimal display of the ICO image _in development_, the 32px layer should be the first layer.
+- `png`: The requirements for the png icons are: width == height, RGBA (RGB + Transparency), and 32bit per pixel (8bit per channel). Commonly expected sizes on desktop are 32, 128, 256, and 512 pixels. We recommend to at least match the output of `tauri icon`: `32x32.png`, `128x128.png`, `[email protected]`, and `icon.png`.
+
+### Android
+
+On Android you will need png icons with the same requirements but in different sizes. They will also need to be placed directly in the Android Studio project:
+
+- `src-tauri/gen/android/app/src/main/res/`
+  - `mipmap-hdpi/`
+    - `ic_launcher.png` & `ic_launcher_round.png`: 49x49px
+    - `ic_launcher_foreground.png`: 162x162px
+  - `mipmap-mdpi/`
+    - `ic_launcher.png` & `ic_launcher_round.png`: 48x48px
+    - `ic_launcher_foreground.png`: 108x108px
+  - `mipmap-xhdpi/`
+    - `ic_launcher.png` & `ic_launcher_round.png`: 96x96px
+    - `ic_launcher_foreground.png`: 216x216px
+  - `mipmap-xxhdpi/`
+    - `ic_launcher.png` & `ic_launcher_round.png`: 144x144px
+    - `ic_launcher_foreground.png`: 324x324px
+  - `mipmap-xxxhdpi/`
+    - `ic_launcher.png` & `ic_launcher_round.png`: 192x192px
+    - `ic_launcher_foreground.png`: 432x432px
+
+If `tauri icon` cannot be used, we recommend checking out Android Studio's [Image Asset Studio] instead.
+
+### iOS
+
+On iOS you will need png icons with the same requirements but **without transparency** and in different sizes. They will also need to be placed directly in the Xcode project into `src-tauri/gen/apple/Assets.xcassets/AppIcon.appiconset/`. The following icons are expected:
+
+- 20px in 1x, 2x, 3x, with an extra icon
+- 29px in 1x, 2x, 3x, with an extra icon
+- 40px in 1x, 2x, 3x, with an extra icon
+- 60px in 2x, 3x
+- 76px in 1x, 2x
+- 83.5px in 2x
+- 512px in 2x saved as `[email protected]`
+
+The file names are in the format of `AppIcon-{size}x{size}@{scaling}{extra}.png`. For the 20px icons this means you need icons in sizes 20x20, 40x40 and 60x60 named as `[email protected]`, `[email protected]`, `[email protected]` and `2x` saved additionally as `[email protected]` ("extra icon").
+
+[in the tauri repo]: https://github.com/tauri-apps/tauri/blob/1.x/tooling/cli/src/helpers/icns.json
+[`icns`]: https://en.wikipedia.org/wiki/Apple_Icon_Image_format
+[`ico`]: https://en.wikipedia.org/wiki/ICO_(file_format)
+[image asset studio]: https://developer.android.com/studio/write/create-app-icons