124 lines
3.1 KiB
Dart
124 lines
3.1 KiB
Dart
import 'dart:async';
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import 'dart:ui' as ui;
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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_pro.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? _srcImage;
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ui.Image? _dstImage;
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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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_srcImage = await loadImageFromAssets('assets/images/src.png');
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_dstImage = await loadImageFromAssets('assets/images/dst.png');
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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,
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child: CustomPaint(painter: PaperPainter(_srcImage, _dstImage)));
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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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final ui.Image? srcImage;
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final ui.Image? dstImage;
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PaperPainter(this.srcImage, this.dstImage);
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static const double step = 20; // 方格变长
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final Coordinate coordinate = Coordinate(step: step);
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@override
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void paint(Canvas canvas, Size size) {
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if (dstImage == null || srcImage == null) return;
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Paint srcPaint = Paint();
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Paint dstPaint = Paint();
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int index = 4;
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BlendMode srcModel = BlendMode.dstOver;
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BlendMode dstModel = BlendMode.srcOver;
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srcPaint
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..blendMode = srcModel;
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dstPaint
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..blendMode = dstModel;
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_simpleDrawText(canvas, BlendMode.values[index].toString().split(".")[1],
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fontSize: 16,
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offset: Offset(50, 50));
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canvas.translate(size.width / 2, size.height / 2);
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canvas.drawImageRect(
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dstImage!,
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Rect.fromPoints(
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Offset.zero, Offset(dstImage!.width * 1.0, dstImage!.height * 1.0)),
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Rect.fromCenter(
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center: Offset.zero, width: 400, height: 400),
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dstPaint);
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canvas.drawImageRect(
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srcImage!,
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Rect.fromPoints(
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Offset.zero, Offset(srcImage!.width * 1.0, srcImage!.height * 1.0)),
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Rect.fromCenter(
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center: Offset.zero, width: 400, height: 400),
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srcPaint);
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}
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@override
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bool shouldRepaint(CustomPainter oldDelegate) => true;
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void _simpleDrawText(Canvas canvas, String str,
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{double fontSize = 11,Offset offset = Offset.zero, Color color = Colors.black}) {
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var builder = ui.ParagraphBuilder(ui.ParagraphStyle(
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textAlign: TextAlign.left,
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fontSize: fontSize,
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textDirection: TextDirection.ltr,
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maxLines: 1,
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))
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..pushStyle(
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ui.TextStyle(color: color, textBaseline: ui.TextBaseline.alphabetic),
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)
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..addText(str);
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canvas.drawParagraph(
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builder.build()
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..layout(ui.ParagraphConstraints(width: fontSize * str.length)),
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offset);
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}
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}
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