124 lines
2.9 KiB
Dart
124 lines
2.9 KiB
Dart
import 'dart:async';
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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 'dart:ui' as ui;
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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? _img;
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bool get hasImage => _img != null;
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@override
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void initState() {
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_loadImage();
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super.initState();
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}
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void _loadImage() async {
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_img = await loadImageFromAssets('assets/images/wy_200x300.jpg');
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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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return decodeImageFromList(data.buffer.asUint8List());
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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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child: hasImage ? CustomPaint(
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painter: PaperPainter(_img) ,
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): Container(),
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);
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}
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}
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class PaperPainter extends CustomPainter {
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ui.Image? img;
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PaperPainter(this.img);
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@override
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void paint(Canvas canvas, Size size) {
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if(img!=null) {
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drawColorFilter(canvas);
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}
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}
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double get imgW => img!.width.toDouble();
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double get imgH => img!.height.toDouble();
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void drawColorFilter(Canvas canvas) {
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var paint =Paint();
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const ColorFilter identity = ColorFilter.matrix(<double>[
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1, 0, 0, 0, 0,
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0, 1, 0, 0, 0,
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0, 0, 1, 0, 0,
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0, 0, 0, 1, 0,
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]);
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_drawImage(canvas, paint..colorFilter=identity,move: false);
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const ColorFilter sepia = ColorFilter.matrix(<double>[
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0.393, 0.769, 0.189, 0, 0,
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0.349, 0.686, 0.168, 0, 0,
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0.272, 0.534, 0.131, 0 , 0,
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0, 0, 0, 1, 0,
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]);
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_drawImage(canvas, paint..colorFilter=sepia);
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const ColorFilter invert = ColorFilter.matrix(<double>[
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-1, 0, 0, 0, 255,
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0, -1, 0, 0, 255,
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0, 0, -1, 0, 255,
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0, 0, 0, 1, 0,
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]);
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_drawImage(canvas, paint..colorFilter=invert);
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const ColorFilter greyscale = ColorFilter.matrix(<double>[
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0.2126, 0.7152, 0.0722, 0, 0,
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0.2126, 0.7152, 0.0722, 0, 0,
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0.2126, 0.7152, 0.0722, 0, 0,
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0, 0, 0, 1, 0,
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]);
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_drawImage(canvas, paint..colorFilter=greyscale);
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const n = 90.0;
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const ColorFilter light = ColorFilter.matrix(<double>[
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1,0,0,0,n,
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0,1,0,0,n,
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0,0,1,0,n,
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0,0,0,1,0
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]);
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_drawImage(canvas, paint..colorFilter=light);
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}
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void _drawImage(Canvas canvas, Paint paint,{bool move=true}) {
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if(move){
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canvas.translate(120, 0);
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}else{
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canvas.translate(20, 20);
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}
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canvas.drawImageRect(img!,
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Rect.fromLTRB(0, 0, imgW, imgH),
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Rect.fromLTRB(0, 0, imgW/2, imgH/2),
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paint);
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}
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@override
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bool shouldRepaint(CustomPainter oldDelegate) => true;
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}
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