What functionality are you trying to achieve? Perhaps it should instead inherit from the Button class (asssuming WinForms), and override appropiate methods. Depending on what you need to do, you will propably get much of the lower levels of functionality in the button for free, if you do this.
To get back to your question; No, if you need to draw stuff yourself, there is no magic easy way to determine where the individual pixels should go :-) One great helper in doing this, that you should be aware of, is the Graphics.DrawString method. It lets you measure the dimensions of a given text string when drawn on the control with the selected font and size.