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.

Try Flet online in Flet Studio

Start your next Flet app in the browser, then use this package locally to prepare its icons and splash screens. Write your own Python code or get help from the AI agent.

Used by flet build, and importable on its own. Pillow handles raster images and resvg_py renders SVG; neither requires a separately installed conversion tool. 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.svg")
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

SVG sources are rendered in memory to fit within 2048 × 2048 pixels, keeping their aspect ratio and transparency. A square viewBox, such as 0 0 24 24, works at every output size; no intermediate PNG is written to your assets. Use self-contained SVGs with vector paths and embedded images. Convert text to paths to keep the result independent of fonts installed on the build host.

load_source(path, svg_size=1024) uses a smaller SVG render canvas. flet build uses this for splashes, matching the on-screen size of a 1024px PNG source.

DEFAULT_ICON is the path to the bundled Flet logo SVG. flet build renders icons and the splash from it, with derived=True, for an app that supplies no icon, so a preview made from it matches what the build produces.

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.