Pfthb

I am working on a project wherein I need to add a Circle with text in the middle. I am using the code below. But my problem is the circle is too small, when I resize it, it overlaps other control. I want to draw the circle same width as the square or how will make the back ground as transparent?

protected override void OnPaint(PaintEventArgs e)

 base.OnPaint(e);

 using (Bitmap bitmap = new Bitmap(this.Width, this.Height))
 
 using (Graphics graphics = Graphics.FromImage(bitmap))
 
 graphics.SmoothingMode = SmoothingMode.HighQuality;
 graphics.Clear(this.BackColor);

 using (SolidBrush brush = new SolidBrush(this._FillColor))
 
 graphics.FillEllipse(brush, 0x18 - 6, 0x18 - 6, (this.Width - 0x30) + 12, (this.Height - 0x30) + 12);
 

 Brush FontColor = new SolidBrush(this.ForeColor);
 SizeF MS = graphics.MeasureString(Convert.ToString(Convert.ToInt32((100 / _Maximum) * _Value)), Font);
 graphics.DrawString(Convert.ToString(Convert.ToInt32((100 / _Maximum) * _Value)), Font, FontColor, Convert.ToInt32((Width / 2 - MS.Width / 2) + 2), Convert.ToInt32((Height / 2 - MS.Height / 2) + 3));
 bitmap.MakeTransparent(this.BackColor);
 e.Graphics.DrawImage(bitmap, 0, 0);

 graphics.Dispose();
 bitmap.Dispose();
 
 

This is a Custom Control derived from a standard Label, which can be made translucent.

The interface is a colored circle which can contain a couple of numbers.

The Control exposes these custom properties:

Opacity: The level of opacity of the control BackGround [0, 255]
InnerPadding: The distance between the inner rectangle, which defines the circle bounds and the control bounds.
FontPadding: The distance between the Text and the Inner rectangle.

Transparency is obtained overriding CreateParams, then setting ExStyle |= WS_EX_TRANSPARENT;

The Control.SetStyle() method is used to modify the control behaviour, adding these ControlStyles:

ControlStyles.Opaque prevents the painting of the control BackGround, so it's not managed by the System.
ControlStyles.SupportsTransparentBackColor the control accepts Alpha values for it's BackGround color.

A visual representation of the control:

Apparently, ScreenToGif ignores the Pixel change on full opacity.

In its opinion nothing changes, so it optimizes it showing nothing.

Note:
I didn't use TextRenderer here because of its padding. It's harder to control in this context: the vertical center position needs to be adjusted and it doesn't provide any quality enhancements.

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;

 public event PropertyChangedEventHandler PropertyChanged;

 public RoundCenterLabel() => InitializeComponent();

 private void InitializeComponent()
 
 this.SetStyle(ControlStyles.Opaque 

 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 evt)
 
 base.OnLayout(evt);
 base.AutoSize = false;
 

 protected override void OnPaint(PaintEventArgs e)
 
 StringFormat format = new StringFormat(StringFormatFlags.LineLimit, CultureInfo.CurrentUICulture.LCID) 
 LineAlignment = StringAlignment.Center,
 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<decimal, decimal> refSize = GetMinMax(this.ClientRectangle.Height, this.ClientRectangle.Width);
 SizeF size = new SizeF((float)refSize.Item1 - (this.m_InnerPadding / 2), 
 (float)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);
 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 < Min) ? Min : ((Value > Max) ? Max : Value);
 

 private Tuple<decimal, decimal> GetMinMax(ValueType Value1, ValueType Value2)
 

 protected override CreateParams CreateParams 
 
 get
 = WS_EX_TRANSPARENT;
 return parameters;