forked from lxm_flutter/FlutterUnit
92 lines
2.3 KiB
Dart
92 lines
2.3 KiB
Dart
import 'dart:async';
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import 'package:flutter/material.dart';
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import 'dart:ui' as ui;
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import 'package:flutter/services.dart';
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/// create by 张风捷特烈 on 2020/10/10
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/// contact me by email 1981462002@qq.com
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/// 说明:
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class DrawPicture extends StatefulWidget {
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@override
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_DrawPictureState createState() => _DrawPictureState();
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}
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class _DrawPictureState extends State<DrawPicture> {
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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 = await loadImageFromAssets('assets/images/sabar.webp');
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if (mounted) setState(() {});
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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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List<int> bytes =
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data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
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return decodeImageFromList(bytes);
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}
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@override
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Widget build(BuildContext context) {
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double size = MediaQuery.of(context).size.shortestSide;
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return CustomPaint(size: Size(size, size), painter: PaperPainter(_image));
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}
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}
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class PaperPainter extends CustomPainter {
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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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PaperPainter(this.image)
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: _paint = Paint()
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..filterQuality = FilterQuality.high
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..color = Colors.black.withAlpha(180);
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@override
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void paint(Canvas canvas, Size size) {
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canvas.clipRect(Offset.zero & size);
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_drawImage(canvas, size);
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_drawLine(size, canvas);
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}
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void _drawLine(Size size, Canvas canvas) {
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_paint..color = const Color(0xFFF0F0F0);
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double step = 10.0;
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for (int i = 1; i <= size.height / step; i++) {
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canvas.drawLine(Offset(step * i, 0), Offset(0, step * i), _paint);
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canvas.drawLine(
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Offset(step * i, size.height), Offset(size.width, step * i), _paint);
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}
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}
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void _drawImage(Canvas canvas, Size size) {
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if (image != null) {
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canvas.drawImageRect(
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image,
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Rect.fromCenter(
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center: Offset(image.width / 2, image.height / 2),
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width: image.width * 1.0,
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height: image.width * 1.0),
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Rect.fromLTRB(0, 0, size.width, size.height),
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_paint);
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}
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}
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@override
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bool shouldRepaint(PaperPainter oldDelegate) => oldDelegate.image != image;
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}
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