WebCaptcha control provides the following properties to configure the Captcha image:
LinesNoise – applies random noise as lines to the captcha image.
FontWarping – applies random warping to the characters on the captcha image.
BackgroundNoise – applies random noise as dots to the captcha image.
RotationNoise – applies random rotation to the characters on the captcha image.
CharacterSet – sets the characters that the captcha image is generated from. For example, if you set “0123456789” as the CharacterSet property, the generated captcha image will contain numbers only.
EnableRandomFonts – applies random font styles to each character shown on the captcha image. These fonts are taken from a predefined list of fonts, and include: Arial, Verdana, Arial Narrow, Broadway, Calibri, Cambria, Comic Sans MS, Times New Roman, Courier New, Lucida Console, and Tahoma.
TextLength – sets the number of the characters shown on the captcha image.
EnableUniqueChars – if set to True, every character generated from the captcha image is unique.
EnableCaseSensitivity – the text typed in the input box must match exactly the case of the letters on the image, otherwise validation will fail.
BackgroundColor – sets the background color of the captcha image.
TextColor – sets the color of the text shown on the captcha image.
FontStyle – sets the font style of the characters shown on the captcha image.
FontSize – sets the size of the characters shown on the captcha image.
FontName – sets the name of the font of the characters shown on the captcha image.