API Reference

This document provides a detailed reference for the captcha-canvas API.

CaptchaGenerator

The CaptchaGenerator class is the primary interface for creating captchas. It simplifies the process by managing the underlying Captcha canvas and its various components.

new CaptchaGenerator(options)

Creates a new CaptchaGenerator instance.

• options <Object>
  • height <number> The height of the captcha image. Default: 100.
  • width <number> The width of the captcha image. Default: 300.

.text

• Returns: <string> The text of the generated captcha.

.setDimension(height, width)

Sets the dimensions of the captcha image.

• height <number> The height of the captcha image.
• width <number> The width of the captcha image.

.setBackground(image)

Sets the background image for the captcha.

• image <string> | <Buffer> The background image for the captcha. This can be a file path, a URL, or a Buffer.

.setCaptcha(option)

Sets the options for the captcha text.

• option <SetCaptchaOption> | <SetCaptchaOption[]> An object or an array of objects containing options for the captcha text.

.setTrace(option)

Sets the options for the trace lines.

• option <SetTraceOption> An object containing options for the trace lines.

.setDecoy(option)

Sets the options for the decoy characters.

• option <SetDecoyOption> An object containing options for the decoy characters.

.generate()

Generates the captcha image asynchronously.

• Returns: <Promise<Buffer>> A Promise that resolves with the captcha image as a Buffer.

.generateSync(option)

Generates the captcha image synchronously.

• option <Object> (optional)
  • background <Image> An optional background image.
• Returns: <Buffer> The captcha image as a Buffer.

Captcha

The Captcha class provides a lower-level interface for creating captchas, giving you more control over the drawing process.

new Captcha(width, height, characters)

• width <number> The width of the captcha image.
• height <number> The height of the captcha image.
• characters <number> The number of characters in the captcha text.

.text

• Returns: <string> The text of the captcha.

.png

• Returns: <Buffer> | <Promise<Buffer>> The captcha image as a PNG Buffer. If the captcha is generated synchronously, it returns a Buffer. If generated asynchronously, it returns a Promise that resolves with a Buffer.

.drawImage(image)

Draws an image on the canvas.

• image <Image> The image to draw on the canvas.

.addDecoy(decoyOption)

Adds decoy characters to the captcha image.

• decoyOption <SetDecoyOption> Options for the decoy characters.

.drawTrace(traceOption)

Draws trace lines on the captcha image.

• traceOption <SetTraceOption> Options for the trace lines.

.drawCaptcha(captchaOption)

Draws the captcha text on the image.

• captchaOption <DrawCaptchaOption> | <DrawCaptchaOption[]> Options for the captcha text.

Type Definitions

SetCaptchaOption

An object containing options for the captcha text.

• characters <number> The number of characters in the captcha text. Default: 6.
• text <string> The captcha text. If provided, it overrides the characters option.
• color <string> The color of the captcha text (hex code). Default: #32cf7e.
• font <string> The font of the captcha text. Default: Sans.
• skew <boolean> Whether to skew the captcha text. Default: true.
• colors <string[]> An array of color hex codes. If provided, each character will have a random color from this array.
• rotate <number> The maximum rotation angle for each character (in degrees). Default: 5.
• size <number> The font size of the captcha text. Default: 40.
• opacity <number> The opacity of the captcha text. Default: 0.8.

DrawCaptchaOption

This is an alias for SetCaptchaOption when used with the Captcha.drawCaptcha method.

SetDecoyOption

An object containing options for the decoy characters.

• color <string> The color of the decoy characters (hex code). Default: #646566.
• font <string> The font of the decoy characters. Default: Sans.
• size <number> The font size of the decoy characters. Default: 20.
• opacity <number> The opacity of the decoy characters. Default: 0.8.
• total <number> The number of decoy characters to add.

SetTraceOption

An object containing options for the trace lines.

• color <string> The color of the trace lines (hex code). Default: #32cf7e.
• size <number> The width of the trace lines. Default: 3.
• opacity <number> The opacity of the trace lines. Default: 1.