WinForms，picturebox的图像重叠自定义绘制的图纸

Question

我有一个带有图片框的自定义用户控件。然后，在Paint事件中的控件上画一个圆。

var size = TextRenderer.MeasureText(this.UnreadCount.ToString(), lblDisplayname.Font);
var rec = new Rectangle(0, 0, size.Width, size.Width);
var smallFont = new Font(lblDisplayname.Font.Name, lblDisplayname.Font.Size - 1);
StringFormat format = new StringFormat();
format.Alignment = StringAlignment.Center;
format.FormatFlags = StringFormatFlags.DirectionRightToLeft;
format.LineAlignment = StringAlignment.Center;

using (LinearGradientBrush b = new LinearGradientBrush(
    rec,
    Color.FromArgb(242, 37, 37),
    Color.FromArgb(178, 30, 30),
    45F))
{                    
    e.Graphics.FillEllipse(b, rec);                    
    e.Graphics.DrawString(this.UnreadCount.ToString(), smallFont, Brushes.White, rec, format);
}

然后，在稍后的实现中，我设置了控件图片框的图像。

MyControl ctrl = new MyControl();
ctrl.picImage.Image = Image.FromFile(imagePath);
ctrl.Refresh();

问题是：图片框的图像与绘制的圆重叠。 current issue 要求是：圆需要显示完全重叠的图像。是什么导致了我的问题？

Answer 1

下面的函数将return一个符合你要求的用户控件，贴出代码供你了解父子关系。

要么必须在图像容器的顶部绘制图形，要么在图像顶部的另一个透明容器上绘制图形。

下面的示例有 2 个面板，面板 1 和面板 2，其中面板 2 是面板的子面板。面板 1 是背景图片，面板 2 有 graphics.Hope 它有帮助。

    private UserControl create_MyControl( string  filenamepath)
    {
        //Create User Control

        UserControl MyControl = new UserControl();
        //Mention the size of control
        MyControl.Size = new Size(100, 100);
        //Create a panel to hold the background image that you wanted in the picture box
        Panel panel1 = new Panel();
        //dock the panel1 to fill the control background
        panel1.Dock = DockStyle.Fill;
        MyControl.Controls.Add(panel1);
        //Create another panel as overlay for panel1
        Panel panel2 = new Panel();
        //dock the panel2 to fill the panel1;
        panel2.Dock = DockStyle.Fill;
        //Add panel2 as child of panel1
        panel1.Controls.Add(panel2);
        //Set panel2 background as transparent 
        panel2.BackColor = Color.Transparent;
        // To replicate the variables that you have!
        Label lblDisplayname = new Label();
        lblDisplayname.Font = new Font("Arial", 24, FontStyle.Regular);
        lblDisplayname.Size = panel2.Size;
        lblDisplayname.TextAlign = ContentAlignment.TopCenter;
        lblDisplayname.Text = "25";
        lblDisplayname.Dock = DockStyle.Fill;
        panel2.Controls.Add(lblDisplayname);

        panel1.BackgroundImage = Image.FromFile(filenamepath);
        panel1.BackgroundImageLayout = ImageLayout.Stretch;

        //In Panel2 paint event put your code for stuff
        panel2.Paint += (s, e) =>
        {

            var size = TextRenderer.MeasureText("Hello", lblDisplayname.Font);
            var rec = new Rectangle(0, 0, size.Width, size.Width);

            var smallFont = new Font(lblDisplayname.Font.Name, lblDisplayname.Font.Size - 1);
            StringFormat format = new StringFormat();
            format.Alignment = StringAlignment.Center;
            format.FormatFlags = StringFormatFlags.DirectionRightToLeft;
            format.LineAlignment = StringAlignment.Center;

            using (System.Drawing.Drawing2D.LinearGradientBrush b = new System.Drawing.Drawing2D.LinearGradientBrush(
                rec,
                Color.FromArgb(242, 37, 37),
                Color.FromArgb(178, 30, 30),
                45F))
            {
                e.Graphics.FillEllipse(b, rec);
                e.Graphics.DrawString("Hello", smallFont, Brushes.White, rec, format);
            }
        };

        return MyControl;
    }

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