libgocaptcha

README

Documentation

Index

• Constants
• func AddFont(name string, f *Font)
• func Digit2Rune(d byte) rune
• func RandomDigits(length int) []byte
• func RandomId() string
• func Rune2Digit(c rune) byte
• func SelectFont(name string)
• func SetCharacterRange(rang byte)
• type Font
  • func LoadFontFromFile(fname string) *Font
• type Image
  • func NewImage(id string, digits []byte, width, height int) *Image
  • func (m *Image) WriteTo(w io.Writer) (int64, error)

Constants

const (
	// Standard width and height of a captcha image.
	StdWidth  = 240
	StdHeight = 80
)

const (
	MODULE_DIGIT = 10
	MODULE_UPPER = 36
	MODULE_LOWER = 62
)

These constants are used to set the used character ranges in the captcha image

Functions

func AddFont

func AddFont(name string, f *Font)

Add a font to the internal list of available fonts. The name is used to select the font later. The first font you add is selected automatically

func Digit2Rune

func Digit2Rune(d byte) rune

func RandomDigits

func RandomDigits(length int) []byte

RandomDigits returns a byte slice of the given length containing pseudorandom numbers in range 0-module. The slice can be used as a captcha solution.

func RandomId

func RandomId() string

RandomId returns a new random id string.

func Rune2Digit

func Rune2Digit(c rune) byte

func SelectFont

func SelectFont(name string)

Select a font by the name it was added with AddFont If no font with that name exists, the selected font remains unchanged

func SetCharacterRange

func SetCharacterRange(rang byte)

Set the desired character ranges for the captcha image. For example:

captcha.SetCharacterRange(captcha.MODULE_LOWER)

would use 0-9, A-Z and a-z The default is MODULE_UPPER which means 0-9 and A-Z

Types

type Font

type Font struct {
	// contains filtered or unexported fields
}

func LoadFontFromFile

func LoadFontFromFile(fname string) *Font

Load a font created by github.com/chenzihaojie/captcha/fontgen returns the for usage int AddFont, and an error, if the font can't be loaded.

type Image

type Image struct {
	*image.RGBA
	// contains filtered or unexported fields
}

func NewImage

func NewImage(id string, digits []byte, width, height int) *Image

NewImage returns a new captcha image of the given width and height with the given digits, where each digit must be in range 0-61.

func (*Image) WriteTo

func (m *Image) WriteTo(w io.Writer) (int64, error)

WriteTo writes captcha image in PNG format into the given writer.