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.

Features #

• Shadow contour matches the child's alpha / shape
• Configurable blur (isotropic or per-axis), offset, color, opacity, and blend mode
• Toggle shadows with enabled without removing the widget
• Implemented as a lightweight RenderProxyBox (no third-party deps)
• Alias ContouredShadowWidget for drop-in familiarity

Install #

dependencies:
  contoured_shadow: ^0.2.0

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.

Asymmetric blur #

blurSigma remains the primary radius for both axes. Set blurSigmaX and/or blurSigmaY to override an axis; any missing axis falls back to blurSigma.

ContouredShadow(
  blurSigma: 6,
  blurSigmaX: 14, // wide horizontal soft edge
  blurSigmaY: 4,  // tighter vertical blur
  offset: const Offset(0, 8),
  child: Icon(Icons.star, size: 64),
)

Disable without removing the wrap #

ContouredShadow(
  enabled: showShadow,
  child: myWidget,
)

Customization #

Example #

See the example/ app for icons and shaped surfaces with contoured shadows, including an enabled toggle and asymmetric blur demo.

License #

MIT