holo_shiny

holo_shiny is a Flutter package that renders shader-driven holographic shine.

It exposes two widget layers:

• Shiny: apply shine to any widget (no clipping and no rotation)
• ShinyCard: card-oriented convenience widget with shape clipping and tilt rotation

Features

• GLSL shader-driven holographic effects
• Optional motion input via sensors or custom tilt stream
• Generic wrapper API for any widget via Shiny(child: ...)
• Card API with background, foreground, shape, and drag tilt via ShinyCard
• Built-in sparkle presets including none (default), 8-point star, 5-point star, rectangle, diamond, hexagon, random polygon, and confetti
• Custom sparkle shapes via parameterized SparkleShapeSpec factories
• Global shader opacity control via opacity
• Cross-platform Flutter support (mobile, web, desktop)

Installation

Add the package:

dependencies:
  holo_shiny: ^0.1.0

Then run:

flutter pub get

Quick Start

import 'package:flutter/material.dart';
import 'package:holo_shiny/holo_shiny.dart';

class Demo extends StatelessWidget {
  const Demo({super.key});

  @override
  Widget build(BuildContext context) {
    return const Shiny(
      child: ColoredBox(
        color: Color(0xFF202A3A),
        child: SizedBox(width: 280, height: 80),
      ),
    );
  }
}

Card Usage

ShinyCard(
  controller: controller,
  background: Container(color: const Color(0xFF1B2D4B)),
  foreground: const Center(child: Text('HOLO')),
  sparkleShape: SparkleShapeSpec.none,
  opacity: 1.0,
)

Motion with Controller

final ShinyController controller = ShinyController(useSensor: true);

Shiny(
  controller: controller,
  child: Container(color: const Color(0xFF1B2D4B)),
)

Sparkle Shapes

Use built-in sparkle presets:

ShinyCard(
  sparkleShape: SparkleShapeSpec.none,
)

ShinyCard(
  sparkleShape: SparkleShapeSpec.hexagon,
)

Or create your own parameterized shapes:

ShinyCard(
  sparkleShape: SparkleShapeSpec.customStar(
    points: 7,
    innerRatio: 0.36,
  ),
)

Shiny(
  sparkleShape: SparkleShapeSpec.customPolygon(
    sides: 8,
    aspectRatio: 1.2,
    rotation: 0.2,
  ),
  child: const SizedBox(width: 240, height: 120),
)

You can also provide a custom stream:

final StreamController<Offset> input = StreamController<Offset>.broadcast();
final ShinyController controller = ShinyController(tiltStream: input.stream);

API Summary

• Shiny: generic effect wrapper
• ShinyCard: shape + rotation + composition convenience widget
• SparkleShapeSpec: built-in and custom sparkle silhouette configuration
• ShinyController: optional source selection for tilt
• SensorTiltController: low-level sensor fusion stream utility

Important defaults:

• sparkleShape defaults to SparkleShapeSpec.none (no sparkles)
• opacity defaults to 1.0

Platform Notes

• Shader uses Flutter runtime effects and avoids derivative functions (dFdx, dFdy, fwidth) for web compatibility.
• If a sensor is unavailable, motion input simply emits no events.

Example

See the package example app in example/ for:

• Basic usage
• Any-widget shiny wrapper usage
• Sensor-driven motion
• External stream override
• Custom card shape/background/foreground composition
• Built-in sparkle shape toggles in the demo UI
• User-defined sparkle shape presets using SparkleShapeSpec

Publishing Notes

Replace placeholder package metadata URLs in pubspec.yaml before publishing.