import { GraphicCaptchaOptions } from '../types';
export declare class GraphicCaptcha {
    private options;
    private isVerified;
    private canvas;
    private ctx;
    private hashedCaptcha;
    private createdAt;
    private timeoutId;
    private isExpired;
    private resizeObserver;
    constructor(options: GraphicCaptchaOptions);
    private init;
    /**
     * 设置响应式监听
     */
    private setupResponsive;
    /**
     * 获取随机颜色
     */
    private getRandomColor;
    /**
     * 使用crypto API对文本进行hash加密
     */
    private hashText;
    /**
     * 调整Canvas大小以适应父容器
     */
    private resizeCanvas;
    /**
     * 绘制验证码
     */
    private drawGraphicCaptcha;
    /**
     * 生成验证码文本
     */
    private generateCaptchaText;
    /**
     * 清除超时定时器
     */
    private clearTimeout;
    /**
     * 基本公共方法：验证用户输入，刷新验证码，销毁验证码实例
     */
    verify(input?: string | number): Promise<boolean>;
    refresh(): Promise<void>;
    destroy(): void;
}