rshankras/app-icon-generator

App Icon Generator

Generate production-quality app icons programmatically using a CoreGraphics Swift script. Produces all required sizes and installs into the Xcode asset catalog.

When This Skill Activates

Use this skill when the user:

• Asks to "generate an app icon" or "create an icon"
• Wants a "placeholder icon" or "app icon design"
• Mentions "icon for my app" or "need an app icon"
• Asks to "update the app icon"

Pre-Generation Checks

1. Project Context Detection

Glob: **/Assets.xcassets/AppIcon.appiconset/Contents.json

• Identify platform: macOS, iOS, or universal
• Check for existing icon files (warn before overwriting)
• Read Contents.json to understand required sizes

2. App Context Detection

Gather app information to customize the icon:

Read: .planning/APP.md          (if exists — app definition)
Read: .planning/CODEBASE.md     (if exists — app description)
Grep: "CFBundleName" or app name in project files

If no planning files exist, ask the user.

Configuration Questions

Ask via AskUserQuestion:

Question 1: App Category

"What category best describes your app?"

• Productivity — Clean geometric shapes, blues/teals
• Creative/Media — Vibrant colors, camera/brush/music motifs
• Developer Tools — Dark backgrounds, terminal/code symbols
• Utilities — Functional shapes, neutral/system colors

Question 2: Visual Style

"What visual style do you prefer?"

• Bold Symbol — Single prominent shape/icon centered (like the record button)
• Contained Scene — A scene inside a shape (like a monitor with elements)
• Abstract Mark — Geometric/abstract design (like viewfinder brackets)
• Gradient Glyph — SF Symbol-style glyph on gradient background

Question 3: Color Palette

"What color palette fits your app?"

• Deep Blue/Indigo — Professional, trustworthy (navy #0f0c29 to indigo #302b63)
• Teal/Cyan — Fresh, modern (dark teal #0a1628 to blue #1a4a6b)
• Purple/Violet — Creative, premium (midnight #1a0533 to violet #4a1a8a)
• Warm/Orange — Energetic, friendly (dark red #2d1117 to orange #c0392b)

Question 4: Accent Color

"What accent color for the focal element?"

• Red — Attention, recording, alerts (#ff453a to #d63031)
• Blue — Trust, communication (#007aff to #0056b3)
• Green — Success, nature, health (#34c759 to #248a3d)
• Gold/Yellow — Premium, energy (#ffd60a to #c7a600)

Apple HIG Icon Guidelines

Read apple-hig-icons.md before generating. Key rules:

1. No text in the icon — must be universally recognizable
2. Single focal point — one clear element the eye is drawn to
3. Simple shapes — must be legible at 16x16 (macOS menu bar)
4. Fill the canvas — macOS/iOS apply the rounded rect mask automatically
5. Front-facing perspective — no 3D tilts or dramatic angles
6. Use gradients sparingly — subtle depth, not rainbow
7. Ensure contrast — the focal element must stand out from background
8. Platform-appropriate:
   • macOS: Can be more detailed (icons display larger)
   • iOS: Keep simpler (smaller grid, more rounded)

Generation Process

Step 1: Determine Icon Design

Based on the user's answers (or app context), select:

• Background: Gradient direction, colors, optional radial glow
• Primary Element: The main shape/symbol
• Secondary Elements: Optional ring, glow, accent shapes
• Style Modifiers: Shine, shadow, stroke weight

Step 2: Generate Swift Script

Create a self-contained Swift script at scripts/generate-icon.swift that:

• Uses import AppKit and CoreGraphics (no dependencies)
• Generates 3 variants at 1024x1024
• Saves to icon-variants/ directory
• Uses the design parameters from Step 1

Script structure:

#!/usr/bin/env swift
import AppKit
import CoreGraphics

let size: CGFloat = 1024
// ... helper functions (gradients, glows, shapes)
// ... variant generation functions
// ... save and output

Design building blocks (combine these based on category/style):

| Building Block | Function | Use For | |---------------|----------|---------| | drawGradientBackground | Linear gradient fill | All icons | | drawRadialGlow | Soft colored glow behind focal element | Adding depth | | drawCircle | Filled/stroked circle | Record buttons, dots, orbs | | drawRoundedRect | Rounded rectangle | Screens, cards, containers | | drawRing | Circle outline | Borders, focus rings | | drawBrackets | Corner bracket marks | Viewfinders, capture | | drawMonitor | Screen + stand shape | Screen/display apps | | drawShield | Shield outline | Security/privacy apps | | drawGear | Gear/cog shape | Settings/utility apps | | drawWaveform | Audio waveform bars | Audio/music apps | | drawDocument | Page with fold corner | Document/writing apps | | drawShine | Elliptical specular highlight | Adding polish | | drawShadow | Drop shadow beneath element | Adding depth |

Step 3: Run Script and Present Variants

swift scripts/generate-icon.swift

Show all 3 variants to the user using the Read tool (Claude can view images). Ask the user to pick one, or request adjustments.

Step 4: Resize and Install

Once the user picks a variant:

1. Resize using sips (built into macOS):

For macOS (10 sizes):

sips -z 16 16     master.png --out icon_16x16.png
sips -z 32 32     master.png --out [email protected]
sips -z 32 32     master.png --out icon_32x32.png
sips -z 64 64     master.png --out [email protected]
sips -z 128 128   master.png --out icon_128x128.png
sips -z 256 256   master.png --out [email protected]
sips -z 256 256   master.png --out icon_256x256.png
sips -z 512 512   master.png --out [email protected]
sips -z 512 512   master.png --out icon_512x512.png
sips -z 1024 1024 master.png --out [email protected]

For iOS (single 1024x1024):

cp master.png icon_1024x1024.png

2. Write Contents.json for the asset catalog

For macOS:

{
  "images": [
    { "filename": "icon_16x16.png", "idiom": "mac", "scale": "1x", "size": "16x16" },
    { "filename": "[email protected]", "idiom": "mac", "scale": "2x", "size": "16x16" },
    { "filename": "icon_32x32.png", "idiom": "mac", "scale": "1x", "size": "32x32" },
    { "filename": "[email protected]", "idiom": "mac", "scale": "2x", "size": "32x32" },
    { "filename": "icon_128x128.png", "idiom": "mac", "scale": "1x", "size": "128x128" },
    { "filename": "[email protected]", "idiom": "mac", "scale": "2x", "size": "128x128" },
    { "filename": "icon_256x256.png", "idiom": "mac", "scale": "1x", "size": "256x256" },
    { "filename": "[email protected]", "idiom": "mac", "scale": "2x", "size": "256x256" },
    { "filename": "icon_512x512.png", "idiom": "mac", "scale": "1x", "size": "512x512" },
    { "filename": "[email protected]", "idiom": "mac", "scale": "2x", "size": "512x512" }
  ],
  "info": { "author": "xcode", "version": 1 }
}

For iOS (single size, system generates others):

{
  "images": [
    { "filename": "icon_1024x1024.png", "idiom": "universal", "platform": "ios", "size": "1024x1024" }
  ],
  "info": { "author": "xcode", "version": 1 }
}

3. Copy files into the asset catalog directory
4. Build to verify: xcodebuild build -scheme <scheme> -destination 'platform=<platform>' -quiet

Step 5: Cleanup

• Keep scripts/generate-icon.swift for future regeneration
• Remove icon-variants/ directory (or add to .gitignore)

Category-Specific Design Recipes

Productivity Apps

• Background: Deep blue (#0f1b3d) to teal (#1a4a6b)
• Element: Checkmark, list, or document shape in white
• Accent: Green checkmark or blue highlight
• Style: Clean, minimal, professional

Creative/Media Apps

• Background: Dark purple (#1a0533) to magenta (#6b1a5c)
• Element: Camera lens, brush stroke, play button, or waveform
• Accent: Red record dot, orange/yellow creative spark
• Style: Vibrant, expressive

Developer Tools

• Background: Near-black (#0d1117) to dark gray (#1a1a2e)
• Element: Terminal bracket >_, code braces {}, or gear
• Accent: Green (#34c759) or cyan (#00d4ff) terminal glow
• Style: Monospace feel, technical

Communication Apps

• Background: Blue (#0a2463) to lighter blue (#1e5aa8)
• Element: Speech bubble, person silhouette, or connection lines
• Accent: White or light blue
• Style: Friendly, approachable

Utility Apps

• Background: Dark gray (#1a1a2e) to medium gray (#2d2d44)
• Element: Gear, wrench, shield, or lightning bolt
• Accent: System blue (#007aff) or orange (#ff9500)
• Style: Functional, trustworthy

Finance Apps

• Background: Dark green (#0a2e1a) to emerald (#1a6b3a)
• Element: Chart line, coin, or dollar symbol
• Accent: Gold (#ffd60a) or green (#34c759)
• Style: Secure, premium

Health/Fitness Apps

• Background: Dark red (#2d1117) to pink (#6b1a3a)
• Element: Heart, activity ring, or pulse line
• Accent: Red (#ff3b30) or green (#34c759)
• Style: Energetic, motivating

Education Apps

• Background: Deep blue (#0f0c29) to royal blue (#302b63)
• Element: Book, graduation cap, or lightbulb
• Accent: Yellow (#ffd60a) or white
• Style: Inspiring, trustworthy

Output Summary

After completion, report:

Icon installed successfully!

Master: scripts/generate-icon.swift (re-run to regenerate)
Sizes:  [list of sizes generated]
Location: [path to AppIcon.appiconset]

Build and run to see the icon in:
- Menu bar (macOS)
- Home screen (iOS)
- Finder / Spotlight
- About view

Iteration

If the user wants changes:

1. Modify the Swift script parameters (colors, shapes, sizes)
2. Re-run: swift scripts/generate-icon.swift
3. Show the updated variants
4. Resize and reinstall once approved

Common adjustment requests:

• "Make the record dot bigger/smaller" → adjust radius parameter
• "Different background color" → change gradient hex values
• "Add more depth" → add radial glow or shine
• "Too busy, simplify" → remove secondary elements
• "Doesn't look good at small size" → increase stroke widths, simplify shapes