102 lines
2.6 KiB
Dart
102 lines
2.6 KiB
Dart
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import 'package:flutter/material.dart';
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class FlowShader extends StatefulWidget {
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const FlowShader({
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Key? key,
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required this.child,
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this.duration = const Duration(seconds: 2),
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this.direction = Axis.horizontal,
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this.flowColors = const <Color>[Colors.white, Colors.black],
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}) : assert(flowColors.length == 2),
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super(key: key);
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final Widget child;
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final Axis direction;
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final Duration duration;
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final List<Color> flowColors;
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@override
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FlowShaderState createState() => FlowShaderState();
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}
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class FlowShaderState extends State<FlowShader>
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with SingleTickerProviderStateMixin {
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late AnimationController controller;
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late Animation animation1;
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late Animation animation2;
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late Animation animation3;
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@override
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void dispose() {
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controller.dispose();
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super.dispose();
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}
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@override
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void initState() {
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super.initState();
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controller = AnimationController(
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vsync: this,
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duration: widget.duration,
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);
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final TweenSequenceItem seqbw = TweenSequenceItem(
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tween: ColorTween(
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begin: widget.flowColors.last,
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end: widget.flowColors.first,
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),
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weight: 1,
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);
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final TweenSequenceItem seqwb = TweenSequenceItem(
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tween: ColorTween(
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begin: widget.flowColors.first,
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end: widget.flowColors.last,
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),
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weight: 1,
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);
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animation1 = TweenSequence([seqbw, seqwb]).animate(
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CurvedAnimation(
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parent: controller,
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curve: const Interval(0.0, 0.45, curve: Curves.linear),
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),
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);
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animation2 = TweenSequence([seqbw, seqwb]).animate(
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CurvedAnimation(
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parent: controller,
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curve: const Interval(0.15, 0.75, curve: Curves.linear),
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),
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);
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animation3 = TweenSequence([seqbw, seqwb]).animate(
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CurvedAnimation(
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parent: controller,
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curve: const Interval(0.45, 1, curve: Curves.linear),
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),
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);
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controller.repeat();
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controller.addListener(() {
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setState(() {});
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});
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}
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@override
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Widget build(BuildContext context) {
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return ShaderMask(
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shaderCallback: (rect) {
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return LinearGradient(
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colors: [
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animation3.value,
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animation2.value,
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animation1.value,
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],
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begin: widget.direction == Axis.horizontal
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? Alignment.centerLeft
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: Alignment.topCenter,
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end: widget.direction == Axis.horizontal
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? Alignment.centerRight
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: Alignment.bottomCenter,
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).createShader(rect);
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},
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child: widget.child,
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);
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}
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}
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