As an option you can create a custom control deriving from GroupBox:
- You need to calculate a round rectangle shape. To do so, as an option you can use
AddArc method and add arcs to four corners of a rectangle in a path.
- To draw header background with hatch style, you can use a
HatchBrush. So add a property for title hatch style. This way you can use different HatchStyle values for title back-ground.
- To have a different title color and title font, add some properties to control.
- In a more complete implementation, you should implement properties in a way which setting a new value to property cause repainting the control by calling
this.Invalidate().
- To prevent flicker while resizing turn on double buffering by setting
DoubleBuffered to true in constructor.
- To have transparent background in corners, use
GroupBoxRenderer.DrawParentBackground.
Screenshot
Code
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
public class RoundPanel : GroupBox
{
public RoundPanel()
{
this.DoubleBuffered = true;
this.TitleBackColor = Color.SteelBlue;
this.TitleForeColor = Color.White;
this.TitleFont = new Font(this.Font.FontFamily, Font.Size + 8, FontStyle.Bold);
this.BackColor = Color.Transparent;
this.Radious = 25;
this.TitleHatchStyle = HatchStyle.Percent60;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
GroupBoxRenderer.DrawParentBackground(e.Graphics, this.ClientRectangle, this);
var rect = ClientRectangle;
using (var path = GetRoundRectagle(this.ClientRectangle, Radious))
{
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
rect = new Rectangle(0, 0,
rect.Width, TitleFont.Height + Padding.Bottom + Padding.Top);
if(this.BackColor!= Color.Transparent)
using (var brush = new SolidBrush(BackColor))
e.Graphics.FillPath(brush, path);
var clip = e.Graphics.ClipBounds;
e.Graphics.SetClip(rect);
using (var brush = new HatchBrush(TitleHatchStyle,
TitleBackColor, ControlPaint.Light(TitleBackColor)))
e.Graphics.FillPath(brush, path);
using (var pen = new Pen(TitleBackColor, 1))
e.Graphics.DrawPath(pen, path);
TextRenderer.DrawText(e.Graphics, Text, TitleFont, rect, TitleForeColor);
e.Graphics.SetClip(clip);
using (var pen = new Pen(TitleBackColor, 1))
e.Graphics.DrawPath(pen, path);
}
}
public Color TitleBackColor { get; set; }
public HatchStyle TitleHatchStyle { get; set; }
public Font TitleFont { get; set; }
public Color TitleForeColor { get; set; }
public int Radious { get; set; }
private GraphicsPath GetRoundRectagle(Rectangle b, int r)
{
GraphicsPath path = new GraphicsPath();
path.AddArc(b.X, b.Y, r, r, 180, 90);
path.AddArc(b.X + b.Width - r - 1, b.Y, r, r, 270, 90);
path.AddArc(b.X + b.Width - r - 1, b.Y + b.Height - r - 1, r, r, 0, 90);
path.AddArc(b.X, b.Y + b.Height - r - 1, r, r, 90, 90);
path.CloseAllFigures();
return path;
}
}
