c.ClientRectangle.Width,

                          c.ClientRectangle.Height);

static extern TODO ClientRectangle(TODO);

Declare Function ClientRectangle Lib "user32.dll" (TODO) As TODO

ClientRectangle property of the System.Windows.Forms.Control class

    Dim pt As Point = picClicker.PointToScreen(New Point(picClicker.ClientRectangle.Width / 2, picClicker.ClientRectangle.Height / 2))

double fAspectRatio = (double)(this.ClientRectangle.Bottom) / (double)(this.ClientRectangle.Right);

         this.ClientRectangle.Bottom,    // So that (0,0) is at the bottom left.

         this.ClientRectangle.Right,

         -this.ClientRectangle.Bottom, // Negative so that y gets positive as you go up.