How to distinguish between 0 and O (0 and letter O) in the Verification code picture and print that is developed in the ASP.net project

How to distinguish between 0 and O (0 and letter O) in the Verification code picture and print that is developed in the ASP.net project

In Notepad, both the Fixedsys font and the Wst_czec to wst_swed can display 0 (0) of the middle horizontal line. To differentiate between 0 and O. But the beginning of WST, do not support Chinese, looks like Western fonts, _ after the representative of the western countries, such as Spain, Germany and so on. Fixedsys because it is not a true type font, there is no horizontal line in the middle of 0 printing. is not WYSIWYG-WYSWYG (What you see, What you). Finally, use the Consolas font to solve the problem, however, Consolas fonts need to download the installation from the Microsoft website. http://www.microsoft.com/downloads/details.aspx?familyid=22E69AE4-7E40-4807-8A86-B3D36FAB68D3&displaylang= En http://four-corner.appspot.com/