Support rounded rectangle in Graphics class

[ghost]

Background and motivation

In modern interfaces, rounded rectangles are used in many places instead of right-angled rectangles, such as github buttons and labels.

GDI has RoundRect, but GDI+ doesn't have a direct equivalent. We can, however, do the necessary path generation in GDI+ to implement this fairly common request.

The current Graphics class provides Graphics.DrawRectangle and Graphics.FillRectangle to support drawing rectangles, but currently there is no corresponding method for drawing rounded rectangles.

API Proposal

namespace System.Drawing;

public class Graphics
{
     public void DrawRectangle(System.Drawing.Pen pen, System.DrawingRectangle rect);
     // ...
+    public void DrawRoundedRectangle(System.Drawing.Pen pen, System.Drawing.Rectangle rect, Size corner);
+    public void DrawRoundedRectangle(System.Drawing.Pen pen, System.Drawing.RectangleF rect, SizeF corner);
+    public void FillRoundedRectangle(System.Drawing.Brush brush, System.Drawing.Rectangle rect, Size corner);
+    public void FillRoundedRectangle(System.Drawing.Brush brush, System.Drawing.RectangleF rect, SizeF corner);
}

namespace System.Drawing.Drawing2D;

public class GraphicsPath
{
     public void AddRectangle(Rectangle rect);
     // ...
+    public void AddRoundedRectangle(Rectangle rect, Size corner);
+    public void AddRoundedRectangle(RectangleF rect, SizeF corner);
}

API Usage

graphics.DrawRoundedRectangle(new Pen(Color.Black), new Rectangle(0, 0, 100, 100), new Size(5, 5));
graphics.FillRoundedRectangle(new SolidBrush(Color.Black), new Rectangle(0, 0, 100, 100), new Size(5, 5));

[RussKie]

Kind of feels like you're asking for CreateRoundRectRgn...

[ghost]

Yes, it looks like this is a feature that Win32 already supports, but it's not currently included in WinForms.

[bartonjs]

• Based on the naming from GDI and from WPF, Size corner => Size radius.

namespace System.Drawing;

public class Graphics
{
     public void DrawRectangle(System.Drawing.Pen pen, System.DrawingRectangle rect);
     // ...
+    public void DrawRoundedRectangle(System.Drawing.Pen pen, System.Drawing.Rectangle rect, Size radius);
+    public void DrawRoundedRectangle(System.Drawing.Pen pen, System.Drawing.RectangleF rect, SizeF radius);
+    public void FillRoundedRectangle(System.Drawing.Brush brush, System.Drawing.Rectangle rect, Size radius);
+    public void FillRoundedRectangle(System.Drawing.Brush brush, System.Drawing.RectangleF rect, SizeF radius);
}

namespace System.Drawing.Drawing2D;

public class GraphicsPath
{
     public void AddRectangle(Rectangle rect);
     // ...
+    public void AddRoundedRectangle(Rectangle rect, Size radius);
+    public void AddRoundedRectangle(RectangleF rect, SizeF radius);
}