Difference between DrawPath and DrawRectangle

Question

I am drawing lines using both Rectangle and graphicspath in my application and i am facing lose of width and height in drawing when using GraphicsPath rather than using Rectangle.

Below is the sample code which reproduces my issue,

protected override void OnPaint(PaintEventArgs e)
{
   int left = ClientRectangle.X + 40, right = ClientRectangle.Width -80;
   int bottom = ClientRectangle.Height - 80, top = ClientRectangle.Y + 40;
   int borderWidth = 10;

   Rectangle borderrectangle = new Rectangle(left, top, right, bottom);

   Pen pen = new Pen(Color.Black, borderWidth);

   //Draws lines using Rectangle.
   e.Graphics.DrawRectangle(pen, borderrectangle);

   Point[] points = new Point[]
   {
      new Point(left, top),
      new Point(right, top),
      new Point(right, bottom),
      new Point(left, bottom),
   };

   GraphicsPath path = new GraphicsPath();
   path.AddLines(points);
   path.CloseFigure();

   //Draws lines using Path.
   e.Graphics.DrawPath(pen, path);
}

Here is the image ,

Inner rectangle is drawn using the DrawPath and outer rectangle is drawn with DrawRectangle.

Could anyone please update me the reason for width and height lose with GraphicsPath drawing, since i have given proper points as like the rectangle?

Any help will be appreciated.

Answer 1

When you create Rectangle you are passing right and bottom coordinates as width and height. Check Rectangle constructor parameters:

public Rectangle(
    int x,
    int y,
    int width,
    int height
)

When you use Path, you are drawing it by coordinates and everything is OK. You should create rectangle this way:

Rectangle borderrectangle = new Rectangle(left, top, right-left, bottom-top);

But make sure that width and height of ClientRectangle are greater than 120

Answer 2

When you are setting the values for your Rectangle, you are setting the X and Y coordinates of the top left corner as well as width and height. However, with your GraphicsPath, you are explicitly defining every corner as a separate point. To make the GraphicsPath draw exactly what the Rectangle is, you'll either need to offset your point array coordinates to equal the width and height of the Rectangle:

Point[] points = new Point[]
{
   new Point(left, top),
   new Point(right + left, top),
   new Point(right + left, bottom + top),
   new Point(left, bottom + top),
};

or construct the Rectangle to treat the right and bottom as coordinates instead of fixed lengths:

Rectangle borderrectangle = new Rectangle(left, top, right - left, bottom - top);

Considering that you are treating the values as sides and therefore coordinates, the second option will probably give you the most consistency.