Flet platform assets

Turns one source image into every app icon and splash screen a platform expects — iOS and macOS asset catalogs, Android mipmaps and adaptive layers, a multi-size Windows .ico, the Linux hicolor tree, and web favicons, maskable icons and splash images.

Used by flet build, and importable on its own. Pillow is the only dependency; nothing here imports flet or flet-cli.

Rendering is separate from writing

render_*() is pure: it takes images and returns images, never touching the filesystem and never printing. That makes it usable behind a UI that previews icons before anything is built.

from flet_platform_assets import IconOptions, load_source, render_icons, write

source, _ = load_source("assets/icon.png")
result = render_icons(source, IconOptions())

for asset in result.assets:          # preview
    print(asset.relative_path, asset.image.size, asset.image.mode)
for warning in result.warnings:      # diagnostics are data, not log output
    print(warning)

write(result, "build/flutter")       # the only step that touches disk

What it will not do

It never re-frames your artwork. The padding inside your icon is a design decision, so only transforms the platform actually requires are applied — flattening where alpha is rejected, the macOS icon grid, multi-size .ico, opaque maskable icons.

The one exception is the Android 12 splash icon, whose canvas is a platform frame with a guaranteed-cropped outer third; there the artwork is fitted to the visible circle rather than silently clipped.