154 lines
3.6 KiB
Dart
154 lines
3.6 KiB
Dart
import 'dart:async';
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import 'dart:math';
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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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State<Paper> createState() => _PaperState();
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}
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class _PaperState extends State<Paper> {
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double _rotate = 0;
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@override
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Widget build(BuildContext context) {
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return Center(
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child: Row(
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mainAxisSize: MainAxisSize.min,
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children: [
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Transform.rotate(
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angle: _rotate,
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child:
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Container(
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color: Colors.blue,
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alignment: Alignment.center,
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width: 100,
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height: 100,
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),
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),
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HandleWidget(
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onMove: _onMove,
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),
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],
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),
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);
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}
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void _onMove(double rotate, double distance) {
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setState(() {
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_rotate= rotate;
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});
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}
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}
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class HandleWidget extends StatefulWidget {
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final double size;
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final double handleRadius;
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final void Function(double rotate, double distance) onMove;
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HandleWidget(
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{Key? key,
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this.size = 160,
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this.handleRadius = 20.0,
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required this.onMove})
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: super(key: key);
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@override
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_HandleWidgetState createState() => _HandleWidgetState();
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}
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class _HandleWidgetState extends State<HandleWidget> {
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ValueNotifier<Offset> _offset = ValueNotifier(Offset.zero);
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@override
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Widget build(BuildContext context) {
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return RepaintBoundary(
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child: GestureDetector(
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onPanEnd: reset,
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onPanUpdate: parser,
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child: CustomPaint(
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size: Size(widget.size, widget.size),
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painter: _HandlePainter(
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color: Colors.green,
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handleR: widget.handleRadius,
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offset: _offset))),
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);
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}
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reset(DragEndDetails details) {
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_offset.value = Offset.zero;
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widget.onMove(0, 0);
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}
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parser(DragUpdateDetails details) {
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final offset = details.localPosition;
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double dx = 0.0;
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double dy = 0.0;
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dx = offset.dx - widget.size / 2;
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dy = offset.dy - widget.size / 2;
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var rad = atan2(dx, dy);
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if (dx < 0) {
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rad += 2 * pi;
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}
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var bgR = widget.size / 2 - widget.handleRadius;
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var thta = rad - pi / 2; //旋转坐标系90度
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var d = sqrt(dx * dx + dy * dy);
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if (d > bgR) {
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dx = bgR * cos(thta);
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dy = -bgR * sin(thta);
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}
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widget.onMove(thta, d);
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_offset.value = Offset(dx, dy);
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}
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}
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class _HandlePainter extends CustomPainter {
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var _paint = Paint();
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final ValueNotifier<Offset> offset;
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final Color color;
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var handleR;
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_HandlePainter({this.handleR,required this.offset, this.color = Colors.blue})
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: super(repaint: offset);
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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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final bgR = size.width / 2 - handleR;
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canvas.translate(size.width / 2, size.height / 2);
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_paint.style = PaintingStyle.fill;
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_paint.color = color.withAlpha(100);
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canvas.drawCircle(Offset(0, 0), bgR, _paint);
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_paint.color = color.withAlpha(150);
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canvas.drawCircle(
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Offset(offset.value.dx, offset.value.dy), handleR, _paint);
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_paint.color = color;
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_paint.style = PaintingStyle.stroke;
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canvas.drawLine(Offset.zero, offset.value, _paint);
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}
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@override
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bool shouldRepaint(_HandlePainter oldDelegate) =>
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oldDelegate.offset != offset ||
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oldDelegate.color != color ||
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oldDelegate.handleR != handleR;
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}
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