export declare class FontStyleHelper {
    static readonly defautFontFamily = "Microsoft YaHei";
    static readonly defaultFontColor = "#333";
    static readonly textBold = "bold";
    static readonly textItalic = "Italic";
    static isBold(fontStyle: string): boolean;
    static isItalic(fontStyle: string): boolean;
    static fontSize(fontStyle: string): string;
    static fontFamily(fontStyle: string): string;
    static buildFontStyle(isBold: boolean, isItalic: boolean, fontSize: string, fontFamily?: string): string;
    static getDefaultFontStyle(): string;
    static dropPx(value: string): number;
    static addPx(value: number): string;
    static updateDropdownDisplayValue(value: any, obj: any): void;
    static fontSizeValidate(value: any): {
        fontSizeError: boolean;
    };
    static limitInputIsNumber(event: any): void;
}