84 lines
1.8 KiB
Dart
84 lines
1.8 KiB
Dart
import 'dart:async';
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import 'dart:ui' as ui;
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import 'package:flutter/cupertino.dart';
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import 'package:flutter/material.dart';
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import 'package:flutter/services.dart';
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import '../components/coordinate.dart';
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/// create by 张风捷特烈 on 2020-03-19
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/// contact me by email 1981462002@qq.com
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/// 说明: 纸
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class Paper extends StatefulWidget {
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const Paper({super.key});
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@override
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_PaperState createState() => _PaperState();
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}
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class _PaperState extends State<Paper> {
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ui.Image? _image;
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@override
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void initState() {
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super.initState();
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_loadImage();
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}
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void _loadImage() async {
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_image =
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await loadImageFromAssets('assets/images/wy_300x200.jpg');
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setState(() {});
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}
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@override
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Widget build(BuildContext context) {
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return Container(
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color: Colors.white, child: CustomPaint(painter: PaperPainter(_image)));
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}
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//读取 assets 中的图片
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Future<ui.Image>? loadImageFromAssets(String path) async {
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ByteData data = await rootBundle.load(path);
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return decodeImageFromList(data.buffer.asUint8List());
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}
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}
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class PaperPainter extends CustomPainter {
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late Paint _paint;
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final double strokeWidth = 0.5;
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final Color color = Colors.blue;
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final ui.Image? image;
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final Coordinate coordinate = Coordinate();
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PaperPainter(this.image) {
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_paint = Paint()
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..style = PaintingStyle.fill
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..strokeWidth = strokeWidth
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..color = color;
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}
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@override
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void paint(Canvas canvas, Size size) {
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coordinate.paint(canvas, size);
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canvas.translate(size.width / 2, size.height / 2);
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_drawImage(canvas);
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}
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@override
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bool shouldRepaint(PaperPainter oldDelegate) =>
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image != oldDelegate.image;
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void _drawImage(Canvas canvas) {
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if (image != null) {
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canvas.drawImage(
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image!, Offset(-image!.width / 2, -image!.height / 2), _paint);
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}
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}
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}
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