contoured_shadow

Soft, shape-following shadows for Flutter — painted from the child's own silhouette rather than a rectangle.

Wrap a cutout image, icon, or any widget with transparency. Opaque pixels cast the shadow; transparent pixels do not. Ideal for product cutouts, badges, and irregular shapes where BoxShadow looks wrong.

Demo

Features

Shadow contour matches the child's alpha / shape
Configurable blur, offset, color, and opacity
Implemented as a lightweight RenderProxyBox (no third-party deps)
Alias ContouredShadowWidget for drop-in familiarity

Install

dependencies:
  contoured_shadow: ^0.1.0

import 'package:contoured_shadow/contoured_shadow.dart';

Usage

ContouredShadow(
  blurSigma: 8,
  offset: const Offset(0, 6),
  opacity: 0.3,
  child: Image.asset(
    'assets/product_cutout.png',
    width: 180,
  ),
)

The child's opacity and shape define the shadow contour. Fully transparent regions cast no shadow; anti-aliased edges produce a soft matching outline.

Customization

Parameter	Default	Description
`child`	required	Widget whose silhouette becomes the shadow
`blurSigma`	`5`	Gaussian blur radius of the shadow
`offset`	`Offset(0, 4)`	Shadow displacement relative to the child
`shadowColor`	black	Base shadow color (before opacity)
`opacity`	`0.25`	Shadow opacity (0–1)

Example

See the example/ app for icons and shaped surfaces with contoured shadows.

License

MIT