Flutter App Icon Generator

Generate or update the app icon for a Flutter project correctly across Android (adaptive) and iOS (full-bleed).

Arguments

$ARGUMENTS — Optional description of the desired icon design. If empty, redesign the existing icon or use a sensible default for the project.

Rules — read before touching any file

Why these rules exist

• Android API 26+ uses adaptive icons: the OS composites a foreground layer (PNG with transparent bg) over a background layer (solid color or image) and then clips both with a shape mask (squircle, circle, etc.). If you bake rounded corners into the source image, Android clips it again → "icon inside icon."
• iOS applies its own squircle mask to a full-bleed square. Pre-baked rounded corners leave visible corner padding inside the squircle → same inset problem.

Correct approach

Android safe zone: the center 72/108 = 66.7% of the canvas is always visible regardless of mask shape. Keep all meaningful content (outer_r, etc.) within that region. For a 1024 px canvas: safe = 683 px, so outer_r ≤ 340.

Steps

1. Check prerequisites

python3 -c "from PIL import Image; print('ok')" 2>/dev/null || pip3 install Pillow

Check pubspec.yaml for flutter_launcher_icons in dev_dependencies. If absent, add it:

dev_dependencies:
  flutter_launcher_icons: ^0.14.1

2. Create icon assets directory

mkdir -p assets/icon

3. Generate icon PNGs with Python/Pillow

Write and run a Python script that produces two files:

assets/icon/app_icon_ios.png — 1024×1024, full-bleed square

from PIL import Image, ImageDraw
size = 1024
img = Image.new('RGBA', (size, size), BACKGROUND_COLOR)  # solid fill, no rounded_rectangle
draw = ImageDraw.Draw(img)
# ... draw design centered on canvas ...
img.save('assets/icon/app_icon_ios.png')

• Use Image.new('RGBA', (size, size), bg_color) for the background — not draw.rounded_rectangle.
• Design fills edge-to-edge; iOS clips to squircle automatically.

assets/icon/app_icon_foreground.png — 1024×1024, transparent background

fg = Image.new('RGBA', (size, size), (0, 0, 0, 0))  # fully transparent
draw = ImageDraw.Draw(fg)
# ... draw design centered, scaled so outer_r ≤ 340 for 1024px canvas ...
# When cutting out a center hole in a donut, fill with (0,0,0,0) not the bg color
fg.save('assets/icon/app_icon_foreground.png')

• Background must be transparent — (0, 0, 0, 0).
• Any "hole" in the design (donut center, gaps) must also be (0, 0, 0, 0).
• Scale all radii/sizes proportionally so content stays inside the 683 px safe zone.

4. Update pubspec.yaml

Set the flutter_launcher_icons section to:

flutter_launcher_icons:
  android: true
  ios: true
  image_path_android: "assets/icon/app_icon_ios.png"   # legacy Android (API < 26)
  image_path_ios: "assets/icon/app_icon_ios.png"
  adaptive_icon_background: "#RRGGBB"                  # match the bg color used in app_icon_ios.png
  adaptive_icon_foreground: "assets/icon/app_icon_foreground.png"
  min_sdk_android: 21
  remove_alpha_ios: true

• image_path_android (legacy) and image_path_ios must both be present — the tool errors if either is missing when using the split-path form.
• adaptive_icon_background is a hex color string matching the background of app_icon_ios.png.
• Do not use the single image_path key when you also set adaptive icon keys.

5. Run the generator

flutter pub get && dart run flutter_launcher_icons

Expected output includes:

• • Creating adaptive icons Android
• • Creating mipmap xml file Android
• ✓ Successfully generated launcher icons

Verify that android/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml was created — this is the adaptive icon XML. If it's missing, the Android "icon inside icon" bug is not fixed.

6. Verify

After running, confirm:

• android/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml exists and references @color/ic_launcher_background + @drawable/ic_launcher_foreground
• android/app/src/main/res/values/colors.xml contains the ic_launcher_background color
• ios/Runner/Assets.xcassets/AppIcon.appiconset/ contains updated PNGs

Common mistakes to avoid

• ❌ Drawing the background with draw.rounded_rectangle(...) — causes double-rounding on both platforms
• ❌ Filling the donut center hole with the background color in the foreground PNG — should be (0,0,0,0)
• ❌ Omitting image_path_android when using image_path_ios — tool will error
• ❌ Making outer_r > 340 on a 1024px foreground — content gets clipped by aggressive masks (circle)
• ❌ Using a single image_path for both platforms — loses adaptive icon support on Android

Source: albertopeam/macro-tracker — distributed by TomeVault.