GDI+绘制五星红旗

2023-01-29 08:06:17

五星红旗是由红色背景，加5个黄色五角星组成。绘制一个五星红旗的思路，就是先定义一个五角星的自定义控件，然后通过设置五角星的大小、位置、旋转角度等属性，组合成一个五星红旗。

五角星自定义控件代码：

public partial class MyStar : Control

{

    public MyStar()

    {

        InitializeComponent();

    }

    protected override void OnPaint(PaintEventArgs pe)

    {

        base.OnPaint(pe);

        Graphics g = pe.Graphics;

        PointF[] points = new PointF[]

        {

            new PointF(Center.X, Center.Y - Radius),

            new PointF((float)(Center.X + Radius * Math.Sin( * Math.PI / )), (float)(Center.Y - Radius * Math.Cos( * Math.PI / ))),

            new PointF((float)(Center.X + Radius * Math.Sin( * Math.PI / )), (float)(Center.Y + Radius * Math.Cos(* Math.PI / ))),

            new PointF((float)(Center.X - Radius * Math.Sin( * Math.PI / )),(float)( Center.Y + Radius * Math.Cos( * Math.PI / ))),

new PointF((float)(Center.X - Radius * Math.Sin( * Math.PI / )), (float)(Center.Y - Radius * Math.Cos( * Math.PI / ))),

        };

        GraphicsPath path = new GraphicsPath(FillMode.Winding);

        path.AddLine(points[], points[]);

        path.AddLine(points[], points[]);

        path.AddLine(points[], points[]);

        path.AddLine(points[], points[]);

        path.AddLine(points[], points[]);

        path.CloseFigure();

        g.SmoothingMode = SmoothingMode.AntiAlias;

        g.RotateTransform(Angle);

        g.FillPath(new SolidBrush(ColorTranslator.FromHtml("#FFDF00")), path);

    }

    /// <summary>

    /// 中心点

    /// </summary>

    public Point Center { get; set; }

    /// <summary>

    /// 半径

    /// </summary>

    public int Radius { get; set; }

    /// <summary>

    /// 旋转角度

    /// </summary>

    public float Angle { get; set; }

}

如上的Center、Radius、Angle都是public类型暴露出来的公共属性，以便在初始化时动态的设置MyStar相关属性。

然后创建一个窗体(450*300)，并拖动一个Panel容器。

在VS中编译后会在工具栏生成MyStar控件，我们在窗体的Load事件中动态的添加MyStar控件即可。

private void Form1_Load(object sender, EventArgs e)

{

    this.panel1.BackColor = Color.Red;

    MyStar c1 = new MyStar();

    c1.Angle = 0F;

    c1.Location = new System.Drawing.Point(, );

    c1.Size = new System.Drawing.Size(, );

    c1.Center = new Point(, );

    c1.Radius = ;

    MyStar c2 = new MyStar();

    c2.Angle = 20F;

    c2.Location = new System.Drawing.Point(, -);

    c2.Size = new System.Drawing.Size(, );

    c2.Center = new Point(, );

    c2.Radius = ;

    MyStar c3 = new MyStar();

    c3.Angle = -20F;

    c3.Location = new System.Drawing.Point(, );

    c3.Size = new System.Drawing.Size(, );

    c3.Center = new Point(, );

    c3.Radius = ;

    MyStar c4 = new MyStar();

    c4.Angle = 0F;

    c4.Location = new System.Drawing.Point(, );

    c4.Size = new System.Drawing.Size(, );

    c4.Center = new Point(, );

    c4.Radius = ;

    MyStar c5 = new MyStar();

    c5.Angle = 20F;

    c5.Location = new System.Drawing.Point(, );

    c5.Size = new System.Drawing.Size(, );

    c5.Center = new Point(, );

    c5.Radius = ;

    this.panel1.Controls.Add(c1);

    this.panel1.Controls.Add(c2);

    this.panel1.Controls.Add(c3);

    this.panel1.Controls.Add(c4);

    this.panel1.Controls.Add(c5);

    this.panel1.Click += (ss, ee) => { this.Close(); };

}

效果图：

码农公寓

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