README
¶
Package captcha provides an easy to use, unopinionated API for captcha generation.
Why another captcha generator?
I want a simple and framework-independent way to generate captcha. It also should be flexible, at least allow me to pick my favorite font.
install
go get github.com/steambap/captcha
usage
func handle(w http.ResponseWriter, r *http.Request) {
// create a captcha of 150x50px
data, _ := captcha.New(150, 50)
// session come from other library such as gorilla/sessions
session.Values["captcha"] = data.Text
session.Save(r, w)
// send image data to client
data.WriteImage(w)
}
sample image
Compatibility
This package uses embed package from Go 1.16. If for some reasons you have to use pre 1.16 version of Go, reference pre 1.4 version of this module in your go.mod.
Contributing
If your found a bug, please contribute! see contributing.md for more detail.
License
Documentation
¶
Overview ¶
Package captcha provides an easy to use, unopinionated API for captcha generation
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func LoadFontFromReader ¶ added in v1.0.0
LoadFontFromReader load an external font from an io.Reader interface.
Types ¶
type Data ¶
type Data struct {
// Text is captcha solution.
Text string
// contains filtered or unexported fields
}
Data is the result of captcha generation. It has a `Text` field and a private `img` field that will be used in `WriteImage` receiver.
func New ¶
New creates a new captcha. It returns captcha data and any freetype drawing error encountered.
func NewMathExpr ¶ added in v0.11.0
NewMathExpr creates a new captcha. It will generate a image with a math expression like `1 + 2`.
func (*Data) WriteGIF ¶ added in v1.1.0
WriteGIF encodes image data in GIF format and writes to an io.Writer. It returns possible error from GIF encoding.
func (*Data) WriteImage ¶ added in v1.0.0
WriteImage encodes image data and writes to an io.Writer. It returns possible error from PNG encoding.
type Options ¶
type Options struct {
// BackgroundColor is captcha image's background color.
// It defaults to color.Transparent.
BackgroundColor color.Color
// CharPreset decides what text will be on captcha image.
// It defaults to digit 0-9 and all English alphabet.
// ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
CharPreset string
// TextLength is the length of captcha text.
// It defaults to 4.
TextLength int
// CurveNumber is the number of curves to draw on captcha image.
// It defaults to 2.
CurveNumber int
// FontDPI controls DPI (dots per inch) of font.
// The default is 72.0.
FontDPI float64
// FontScale controls the scale of font.
// The default is 1.0.
FontScale float64
// Noise controls the number of noise drawn.
// A noise dot is drawn for every 28 pixel by default.
// The default is 1.0.
Noise float64
// Palette is the set of colors to chose from
Palette color.Palette
// contains filtered or unexported fields
}
Options manage captcha generation details.
Source Files
Directories