dragonbones-runtime/.cache/egret-core-5.1.0/src/egret/text/web/WebTextMeasurer.ts

the tools to build dragonbones file for diffrent framework

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namespace egret.web {

    /**
     * @private
     */
    let context:CanvasRenderingContext2D = null;
    /**
     * @private
     */
    let fontCache:any = {};

    /**
     * 测量文本在指定样式下的宽度。
     * @param text 要测量的文本内容。
     * @param fontFamily 字体名称
     * @param fontSize 字体大小
     * @param bold 是否粗体
     * @param italic 是否斜体
     */
    function measureText(text:string, fontFamily:string, fontSize:number, bold:boolean, italic:boolean):number {
        if(!context) {
            createContext();
        }
        let font = "";
        if (italic)
            font += "italic ";
        if (bold)
            font += "bold ";
        font += (fontSize || 12) + "px ";
        font += (fontFamily || "Arial");
        context.font = font;
        return context.measureText(text).width;
    }

    /**
     * @private
     */
    function createContext():void {
        context = sys.canvasHitTestBuffer.context;
        context.textAlign = "left";
        context.textBaseline = "middle";
    }

    sys.measureText = measureText;
}