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Drawing Ellipses and Circles

 

Ellipses and Circles

An ellipse is a closed continuous line whose points are positioned so that two points exactly opposite each other have the exact same distant from a central point. It can be illustrated as follows:

Ellipse

Because an ellipse can fit in a rectangle, in GDI+ programming, an ellipse is defined with regards to a rectangle it would fit in. To draw an ellipse, you can use the Graphics::DrawEllipse() method that comes in four versions whose syntaxes are:

public:
    void DrawEllipse(Pen ^pen,
		     Rectangle rect);
    void DrawEllipse(Pen ^pen,
		     RectangleF rect);
    void DrawEllipse(Pen ^pen,
		     int x,
		     int y,
		     int width,
		     int height);
    void DrawEllipse(Pen ^pen,
		     float x,
		     float y,
		     float width,
		     float height);

The arguments of this method play the same roll as those of the Graphics::DrawRectangle() method:

Ellipse 2

Here is an example:

System::Void Form1_Paint(System::Object ^  sender, 
			 System::Windows::Forms::PaintEventArgs ^  e)
 {
    Pen ^penCurrent = gcnew Pen(Color::Red);
				 
    e->Graphics->DrawEllipse(penCurrent, Rectangle(20, 20, 226, 144));
}

Ellipse

 

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