Flutter多边形绘制插件d4_polygon的使用

Flutter多边形绘制插件d4_polygon的使用

d4_polygon 是一个用于二维多边形几何操作的插件。它提供了多种基本的几何运算功能，使得在Flutter应用中进行多边形的绘制和操作变得简单。

功能简介

  • 多边形的创建与操作：你可以通过顶点列表来创建一个多边形，并对其进行各种几何操作。
  • 多边形的布尔运算：支持交集、并集和差集等布尔运算。
  • 多边形的变换：可以对多边形进行平移、旋转和缩放等变换。

使用示例

1. 添加依赖

首先，在你的 pubspec.yaml 文件中添加 d4_polygon 依赖：

dependencies:
  flutter:
    sdk: flutter
  d4_polygon: ^0.1.0 # 请根据最新版本更新此依赖

然后运行 flutter pub get 来安装该依赖。

2. 创建多边形

下面是一个简单的例子，展示如何创建一个多边形并绘制出来：

import 'package:flutter/material.dart';
import 'package:d4_polygon/d4_polygon.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('d4_polygon 示例'),
        ),
        body: Center(
          child: PolygonWidget(),
        ),
      ),
    );
  }
}

class PolygonWidget extends StatefulWidget {
  [@override](/user/override)
  _PolygonWidgetState createState() => _PolygonWidgetState();
}

class _PolygonWidgetState extends State<PolygonWidget> {
  List<Point<double>> vertices = [
    Point(0, 0),
    Point(100, 0),
    Point(100, 100),
    Point(0, 100),
  ];

  [@override](/user/override)
  Widget build(BuildContext context) {
    return CustomPaint(
      size: Size(200, 200),
      painter: PolygonPainter(vertices),
    );
  }
}

class PolygonPainter extends CustomPainter {
  final List<Point<double>> vertices;

  PolygonPainter(this.vertices);

  [@override](/user/override)
  void paint(Canvas canvas, Size size) {
    final path = Path();
    path.moveTo(vertices[0].x, vertices[0].y);
    for (var i = 1; i < vertices.length; i++) {
      path.lineTo(vertices[i].x, vertices[i].y);
    }
    path.close();

    final paint = Paint()
      ..color = Colors.blue
      ..style = PaintingStyle.fill;

    canvas.drawPath(path, paint);
  }

  [@override](/user/override)
  bool shouldRepaint(PolygonPainter oldDelegate) {
    return oldDelegate.vertices != vertices;
  }
}

更多关于Flutter多边形绘制插件d4_polygon的使用的实战教程也可以访问 https://www.itying.com/category-92-b0.html

1 回复

更多关于Flutter多边形绘制插件d4_polygon的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html


d4_polygon 是一个用于在 Flutter 中绘制多边形的插件。它允许你根据给定的顶点坐标绘制多边形，并且可以自定义多边形的样式，如边框颜色、填充颜色、边框宽度等。

安装插件

首先，你需要在 pubspec.yaml 文件中添加 d4_polygon 插件的依赖：

dependencies:
  flutter:
    sdk: flutter
  d4_polygon: ^1.0.0  # 请检查最新版本

然后运行 flutter pub get 来安装依赖。

基本用法

以下是一个简单的示例，展示了如何使用 d4_polygon 插件绘制一个多边形：

import 'package:flutter/material.dart';
import 'package:d4_polygon/d4_polygon.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Polygon Example'),
        ),
        body: Center(
          child: PolygonWidget(),
        ),
      ),
    );
  }
}

class PolygonWidget extends StatelessWidget {
  final List<Offset> points = [
    Offset(100, 100),
    Offset(200, 50),
    Offset(300, 150),
    Offset(250, 300),
    Offset(150, 250),
  ];

  [@override](/user/override)
  Widget build(BuildContext context) {
    return CustomPaint(
      size: Size(400, 400),
      painter: PolygonPainter(
        points: points,
        borderColor: Colors.blue,
        fillColor: Colors.blue.withOpacity(0.3),
        borderWidth: 2.0,
      ),
    );
  }
}

class PolygonPainter extends CustomPainter {
  final List<Offset> points;
  final Color borderColor;
  final Color fillColor;
  final double borderWidth;

  PolygonPainter({
    required this.points,
    required this.borderColor,
    required this.fillColor,
    required this.borderWidth,
  });

  [@override](/user/override)
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = fillColor
      ..style = PaintingStyle.fill;

    final borderPaint = Paint()
      ..color = borderColor
      ..style = PaintingStyle.stroke
      ..strokeWidth = borderWidth;

    final path = Path();
    path.moveTo(points[0].dx, points[0].dy);
    for (var i = 1; i < points.length; i++) {
      path.lineTo(points[i].dx, points[i].dy);
    }
    path.close();

    canvas.drawPath(path, paint);
    canvas.drawPath(path, borderPaint);
  }

  [@override](/user/override)
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}
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