skills/generate-icon/references/platform-requirements.md

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Platform Icon Requirements

Detailed specifications for each platform's icon requirements.

Apple App Store (iOS/iPadOS)

Key Requirements:

  • NO transparency - must have solid background
  • NO rounded corners - iOS applies mask automatically
  • 1024x1024px for App Store
  • sRGB color space

Required Sizes:

Size Usage
1024x1024 App Store
180x180 iPhone @3x
167x167 iPad Pro @2x
152x152 iPad @2x
120x120 iPhone @2x, iPhone Spotlight @3x
87x87 iPhone Settings @3x
80x80 iPad Spotlight @2x
76x76 iPad
60x60 iPhone Notification @3x
58x58 iPhone/iPad Settings @2x
40x40 iPhone Spotlight @2x, iPad Notification @2x
29x29 iPhone/iPad Settings
20x20 iPhone/iPad Notification

Asset Catalog Structure:

AppIcon.appiconset/
├── Contents.json
├── AppIcon-1024.png
├── AppIcon-60@3x.png
├── AppIcon-60@2x.png
└── ...

Google Play Store (Android)

Key Requirements:

  • 512x512px for Play Store listing
  • Transparency allowed
  • 32-bit PNG (ARGB)

Adaptive Icons (Android 8.0+):

  • Foreground layer: 108dp (432px @xxxhdpi)
  • Safe zone: 72dp centered (66% of total)
  • Background layer: separate solid or gradient
  • System applies various masks (circle, squircle, etc.)

Required Sizes (mipmap folders):

Density Size Folder
xxxhdpi 192x192 mipmap-xxxhdpi
xxhdpi 144x144 mipmap-xxhdpi
xhdpi 96x96 mipmap-xhdpi
hdpi 72x72 mipmap-hdpi
mdpi 48x48 mipmap-mdpi

Adaptive Foreground Sizes:

Density Size
xxxhdpi 432x432
xxhdpi 324x324
xhdpi 216x216
hdpi 162x162
mdpi 108x108

Favicon (Web)

Key Requirements:

  • favicon.ico for legacy browser support
  • PNG fallbacks for modern browsers
  • apple-touch-icon.png for iOS Safari

Recommended Files:

File Size Usage
favicon.ico 16, 32, 48 Legacy browsers, Windows
favicon-32x32.png 32x32 Standard browsers
favicon-16x16.png 16x16 Browser tabs
apple-touch-icon.png 180x180 iOS Safari
safari-pinned-tab.svg Vector Safari pinned tabs
favicon-256x256.png 256x256 High-DPI, thumbnails

HTML Integration:

<link rel="icon" type="image/x-icon" href="/favicon.ico">
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">
<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">

PWA (Progressive Web App)

Key Requirements:

  • Multiple sizes for manifest.json
  • Maskable icons for Android adaptive display
  • Transparency allowed

Manifest Sizes:

Size Purpose
512x512 Install prompt, splash screen
384x384 Splash screen
256x256 Various contexts
192x192 Home screen (Android)
144x144 Taskbar
128x128 Chrome Web Store
96x96 Older Android
72x72 Legacy
48x48 Legacy

Maskable Icons:

  • Safe zone: 80% of icon area (centered)
  • Used for adaptive home screen icons
  • Same sizes as standard icons

manifest.json Example:

{
  "icons": [
    { "src": "/icon-192x192.png", "sizes": "192x192", "type": "image/png" },
    { "src": "/icon-512x512.png", "sizes": "512x512", "type": "image/png" },
    { "src": "/maskable-192x192.png", "sizes": "192x192", "type": "image/png", "purpose": "maskable" },
    { "src": "/maskable-512x512.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable" }
  ]
}

macOS (.icns)

Key Requirements:

  • ICNS format (Apple proprietary bundle)
  • Created via iconutil -c icns
  • Requires .iconset directory with specific filenames

Required Sizes:

Filename Size Usage
icon_512x512@2x.png 1024x1024 Retina
icon_512x512.png 512x512 Standard
icon_256x256@2x.png 512x512 Retina
icon_256x256.png 256x256 Standard
icon_128x128@2x.png 256x256 Retina
icon_128x128.png 128x128 Standard
icon_32x32@2x.png 64x64 Retina
icon_32x32.png 32x32 Standard
icon_16x16@2x.png 32x32 Retina
icon_16x16.png 16x16 Standard

Creation Process:

# Create iconset directory
mkdir MyApp.iconset

# Add all required PNGs with exact filenames
# Then convert to ICNS
iconutil -c icns MyApp.iconset -o MyApp.icns

Windows (.ico)

Key Requirements:

  • ICO format (multi-resolution container)
  • Created via ImageMagick or similar
  • Includes multiple sizes in one file

Required Sizes:

Size Usage
256x256 High-DPI, Windows 10+
128x128 Large icons view
64x64 Medium icons
48x48 Explorer, Start menu
32x32 Desktop, taskbar
24x24 Toolbar
16x16 Title bar, small icons

Creation with ImageMagick:

convert icon-256.png icon-128.png icon-64.png icon-48.png icon-32.png icon-24.png icon-16.png app.ico

Note: PNG compression is supported in ICO files for sizes ≥256px.