67 lines
2.0 KiB
Dart
67 lines
2.0 KiB
Dart
import "package:flutter/material.dart";
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import "package:flutter/rendering.dart";
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void main() {
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runApp(const MainApp());
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}
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class MainApp extends StatelessWidget {
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const MainApp({super.key});
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@override
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Widget build(BuildContext context) {
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return LayoutBuilder(
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builder: (context, constraints) => CustomPaint(
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size: constraints.biggest,
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painter: Sky(),
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),
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);
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}
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}
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class Sky extends CustomPainter {
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@override
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void paint(Canvas canvas, Size size) {
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final Rect rect = Offset.zero & size;
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const RadialGradient gradient = RadialGradient(
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center: Alignment(0.7, -0.6),
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radius: 0.2,
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colors: <Color>[Color(0xFFFFFF00), Color(0xFF0099FF)],
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stops: <double>[0.4, 1.0],
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);
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canvas.drawRect(rect, Paint()..shader = gradient.createShader(rect));
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}
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@override
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SemanticsBuilderCallback get semanticsBuilder {
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return (Size size) {
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// Annotate a rectangle containing the picture of the sun
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// with the label "Sun". When text to speech feature is enabled on the
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// device, a user will be able to locate the sun on this picture by
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// touch.
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Rect rect = Offset.zero & size;
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final double width = size.shortestSide * 0.4;
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rect = const Alignment(0.8, -0.9).inscribe(Size(width, width), rect);
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return <CustomPainterSemantics>[
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CustomPainterSemantics(
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rect: rect,
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properties: const SemanticsProperties(
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label: "Sun",
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textDirection: TextDirection.ltr,
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),
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),
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];
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};
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}
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// Since this Sky painter has no fields, it always paints
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// the same thing and semantics information is the same.
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// Therefore we return false here. If we had fields (set
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// from the constructor) then we would return true if any
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// of them differed from the same fields on the oldDelegate.
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@override
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bool shouldRepaint(Sky oldDelegate) => false;
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@override
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bool shouldRebuildSemantics(Sky oldDelegate) => false;
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}
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