半透明的圆圈与文本

这是一个源自标准的自定义控件Label,可以制成半透明的.
界面是一个彩色圆圈,可以包含几个数字.

Control公开这些自定义属性:

Opacity:控件的不透明度级别BackGround [0, 255]
InnerPadding:内部矩形之间的距离,用于定义圆边界和控件边界.
FontPadding:文本和内部矩形之间的距离.

获取透明度覆盖CreateParams,然后进行设置ExStyle |= WS_EX_TRANSPARENT;

所述Control.SetStyle()方法被用来修改控制行为,添加这些的ControlStyles:

ControlStyles.Opaque防止绘制控件BackGround,因此它不受系统管理.
ControlStyles.SupportsTransparentBackColor控件接受Alpha值的BackGround颜色.

控件的直观表示:

显然,ScreenToGif忽略Pixel在完全不透明度上的变化.
它认为没有任何变化,所以它optimizes什么也没有显示出来.

注意:由于其填充,
我在这里没有使用TextRenderer.在这种情况下更难控制:垂直中心位置需要调整,并且不提供任何质量增强.

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
using System.Globalization;
using System.Windows.Forms;

[DesignerCategory("Code")]
class RoundCenterLabel : Label, INotifyPropertyChanged
{
    internal const int WS_EX_TRANSPARENT = 0x00000020;
    internal Font m_CustomFOnt= null;
    internal Color m_BackGroundColor;
    internal int m_InnerPadding = 0;
    internal int m_FOntPadding= 25;
    internal int m_Opacity = 128;
    private readonly int fOntPadding= 8;

    public event PropertyChangedEventHandler PropertyChanged;

    public RoundCenterLabel() => InitializeComponent();

    private void InitializeComponent()
    {
        this.SetStyle(ControlStyles.Opaque |
                      ControlStyles.SupportsTransparentBackColor |
                      ControlStyles.ResizeRedraw, true);
        this.SetStyle(ControlStyles.OptimizedDoubleBuffer, false);
        this.m_CustomFOnt= new Font("Segoe UI", 50, FontStyle.Regular, GraphicsUnit.Pixel);
        this.BackColor = Color.LimeGreen;
        this.ForeColor = Color.White;
    }

    private void NotifyPropertyChanged(string PropertyName)
    {
        this.Invalidate();
        this.FindForm()?.Refresh();
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(PropertyName));
    }

    public new Font Font
    {
        get => this.m_CustomFont;
        set { this.m_CustomFOnt= value;
              FontAdapter(value, this.DeviceDpi);
              NotifyPropertyChanged(nameof(this.Font));
        }
    }

    public override string Text {
        get => base.Text;
        set { base.Text = value;
              NotifyPropertyChanged(nameof(this.Text));
        }
    }

    public int InnerPadding {
        get => this.m_InnerPadding;
        set { this.m_InnerPadding = CheckValue(value, 0, this.ClientRectangle.Height - 10);
              NotifyPropertyChanged(nameof(this.InnerPadding)); }
    }

    public int FontPadding {
        get => this.m_FontPadding;
        set { this.m_FOntPadding= CheckValue(value, 0, this.ClientRectangle.Height - 10);
              NotifyPropertyChanged(nameof(this.FontPadding));
        }
    }

    public int Opacity {
        get => this.m_Opacity;
        set { this.m_Opacity = CheckValue(value, 0, 255);
              UpdateBackColor(this.m_BackGroundColor);
              NotifyPropertyChanged(nameof(this.Opacity));
        }
    }

    public override Color BackColor {
        get => this.m_BackGroundColor;
        set { UpdateBackColor(value);
              NotifyPropertyChanged(nameof(this.BackColor));
        }
    }

    protected override void OnLayout(LayoutEventArgs e)
    {
        base.OnLayout(e);
        base.AutoSize = false;
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        using (StringFormat format = new StringFormat(StringFormatFlags.LineLimit | StringFormatFlags.NoWrap, CultureInfo.CurrentUICulture.LCID))
        {
            format.LineAlignment = StringAlignment.Center;
            format.Alignment = StringAlignment.Center;

            e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
            e.Graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
            using (SolidBrush circleBrush = new SolidBrush(this.m_BackGroundColor))
            using (SolidBrush foreBrush = new SolidBrush(this.ForeColor))
            {
                this.FontAdapter(this.m_CustomFont, e.Graphics.DpiY);
                RectangleF rect = InnerRectangle();
                e.Graphics.FillEllipse(circleBrush, rect);
                e.Graphics.DrawString(this.Text, this.m_CustomFont, foreBrush, rect, format);
            };
        };
    }

    private RectangleF InnerRectangle()
    {
        Tuple refSize = GetMinMax(this.ClientRectangle.Height, this.ClientRectangle.Width);
        SizeF size = new SizeF(refSize.Item1 - (this.m_InnerPadding / 2), 
                               refSize.Item1 - (this.m_InnerPadding / 2));
        PointF position = new PointF((this.ClientRectangle.Width - size.Width) / 2,
                                     (this.ClientRectangle.Height - size.Height) / 2);
        return new RectangleF(position, size);
    }

    private void FontAdapter(Font font, float Dpi)
    {
        RectangleF rect = InnerRectangle();
        float FOntSize= CheckValue((int)(rect.Height - this.m_FontPadding), 6, 
                                    (int)(rect.Height - this.m_FontPadding)) / (Dpi / 72.0F) - fontPadding;
        using (Font customfOnt= new Font(font.FontFamily, FontSize, font.Style, GraphicsUnit.Pixel))
            this.m_CustomFOnt= (Font)customfont.Clone();
    }

    private void UpdateBackColor(Color color)
    {
        this.m_BackGroundColor = Color.FromArgb(this.m_Opacity, Color.FromArgb(color.R, color.G, color.B));
        base.BackColor = this.m_BackGroundColor;
    }

    private int CheckValue(int Value, int Min, int Max)
    {
        return (Value  Max) ? Max : Value);
    }

    private Tuple GetMinMax(ValueType Value1, ValueType Value2)
    {
        if ((Value1 is Enum) || (Value1.GetType().IsNested)) return null;
        if ((Value2 is Enum) || (Value2.GetType().IsNested)) return null;
        return new Tuple(Math.Min(Convert.ToSingle(Value1), Convert.ToSingle(Value2)),
                                       Math.Max(Convert.ToSingle(Value1), Convert.ToSingle(Value2)));
    }

    protected override CreateParams CreateParams 
    {
        get
        {
            CreateParams parameters = base.CreateParams;
            parameters.ExStyle |= WS_EX_TRANSPARENT;
            return parameters;
        }
    }
}