关于flutter:Flutter深入浅出组件篇ClipOvalClipPath

ClipOval 介绍

ClipOval是裁剪子组件为椭圆的组件，默认状况下，将轴对齐的椭圆内切到其布局尺寸中，并避免其子项在该椭圆外绘制，但能够应用自定义剪刀自定义剪辑椭圆的大小和地位。

示例代码

本文中很多成果都没有截图，可下载源代码运行我的项目 源代码地址，或者通过视频教程查看 视频教程地址

什么状况下应用 ClipOval？

当咱们须要对子组件进行椭圆裁剪时咱们就用ClipOval，罕用于圆角头像等。

ClipOval 的属性和阐明

ClipOval 应用

ClipOval 根本应用

咱们这里展现一张图片，用 ClipOval 进行包裹裁剪为椭圆，当超出的不飞粉将会被裁剪。

import 'package:flutter/material.dart';

class ClipOvalExample extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("ClipRectExample"),
      ),
      backgroundColor: Colors.red.shade100,
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            ClipOval(
              /// 自定义裁剪门路
              // clipper: ClipperPath(),
              child: Image.network("https://img1.baidu.com/it/u=2324541312,3167046558&fm=253&fmt=auto&app=120&f=JPEG?w=601&h=400"),
            ),
          ],
        ),
      ),
    );
  }
}

成果展现

ClipOval 自定义裁剪应用

第一步：定义自定义裁剪类

import 'package:flutter/material.dart';

class ClipperOvalPath extends CustomClipper<Rect>{
  @override
  Rect getClip(Size size) {return Rect.fromLTRB(50, 50, size.width - 20, size.height - 20);
  }

  @override
  bool shouldReclip(CustomClipper<Rect> oldClipper) {return false;}
}

第二步：应用自定义裁剪

import 'package:flutter/material.dart';
import 'package:flutter_code/ClipOvalExample/ClipperOvalPath.dart';

class ClipOvalExample extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("ClipRectExample"),
      ),
      backgroundColor: Colors.red.shade100,
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            ClipOval(
              /// 自定义裁剪门路
              clipper: ClipperOvalPath(),
              child: Image.network("https://img1.baidu.com/it/u=2324541312,3167046558&fm=253&fmt=auto&app=120&f=JPEG?w=601&h=400"),
            ),
          ],
        ),
      ),
    );
  }
}

成果展现

ClipPath 介绍

ClipPath是能够应用门路裁剪，每当要绘制子组件时，对委托调用回调。回调返回一个门路，并且子组件阻止在门路外绘画。

什么状况下应用 ClipPath?

须要只做一些非凡的形态是，比方五角星，那咱们就须要用ClipPath。

ClipPath 的属性和阐明

ClipPath 的根本应用

第一步：自定义裁剪类（五角星）

import 'dart:math';

import 'package:flutter/material.dart';

class ClipStarPath extends CustomClipper<Path> {ClipStarPath({this.scale = 2.5});

  final double scale;

  double perDegree = 36;

  /// 角度转弧度公式
  double degree2Radian(double degree) {return (pi * degree / 180);
  }

  @override
  Path getClip(Size size) {var R = min(size.width / 2, size.height / 2);
    var r = R / scale;
    var x = size.width / 2;
    var y = size.height / 2;

    var path = Path();
    path.moveTo(x, y - R);
    path.lineTo(x - sin(degree2Radian(perDegree)) * r,
        y - cos(degree2Radian(perDegree)) * r);
    path.lineTo(x - sin(degree2Radian(perDegree * 2)) * R,
        y - cos(degree2Radian(perDegree * 2)) * R);
    path.lineTo(x - sin(degree2Radian(perDegree * 3)) * r,
        y - cos(degree2Radian(perDegree * 3)) * r);
    path.lineTo(x - sin(degree2Radian(perDegree * 4)) * R,
        y - cos(degree2Radian(perDegree * 4)) * R);
    path.lineTo(x - sin(degree2Radian(perDegree * 5)) * r,
        y - cos(degree2Radian(perDegree * 5)) * r);
    path.lineTo(x - sin(degree2Radian(perDegree * 6)) * R,
        y - cos(degree2Radian(perDegree * 6)) * R);
    path.lineTo(x - sin(degree2Radian(perDegree * 7)) * r,
        y - cos(degree2Radian(perDegree * 7)) * r);
    path.lineTo(x - sin(degree2Radian(perDegree * 8)) * R,
        y - cos(degree2Radian(perDegree * 8)) * R);
    path.lineTo(x - sin(degree2Radian(perDegree * 9)) * r,
        y - cos(degree2Radian(perDegree * 9)) * r);
    path.lineTo(x - sin(degree2Radian(perDegree * 10)) * R,
        y - cos(degree2Radian(perDegree * 10)) * R);
    return path;
  }

  @override
  bool shouldReclip(ClipStarPath oldClipper) {return oldClipper.scale != this.scale;}
}

第二步：应用自定义裁剪

import 'package:flutter/material.dart';
import 'package:flutter_code/ClipOvalExample/ClipStarPath.dart';

class ClipOvalExample extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("ClipRectExample"),
      ),
      backgroundColor: Colors.red.shade100,
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            ClipPath(clipper: ClipStarPath(),
              child: Container(
                width: 200,
                height: 200,
                color: Colors.blue,
              ),
            )
          ],
        ),
      ),
    );
  }
}

成果展现

总结

ClipOval 次要是对子组件进行裁剪椭圆等成果，而当咱们须要对一些子组件定义一些简单的图形时，咱们就须要用到ClipPath。