Egret之JSZip解析图片

将图片加压到zip中,再使用JSZip和Egret将图片显示出来.

        /**
         * 将ArrayBuffer转化为Base64
         * @param {ArrayBuffer} $buffer
         * @param {smallLib.TYPE_IMAGE_FORMAT2ZIP} $img_ty (默认 : TYPE_IMAGE_FORMAT2ZIP = TYPE_IMAGE_FORMAT2ZIP._PNG)
         * @returns {string}
         */
        public static arrayBufferToBase64( $buffer : ArrayBuffer , $img_ty : TYPE_IMAGE_FORMAT2ZIP = TYPE_IMAGE_FORMAT2ZIP._PNG) : string {
            let bytes : Uint8Array = new Uint8Array( $buffer );
            const addFormat : Function = ( $base64 : string ) : string =>{
                const $base_foramt : string = `data:image/{0};base64,${$base64}`;
                switch($img_ty){
                    case TYPE_IMAGE_FORMAT2ZIP._PNG: return $base_foramt.replace(`{0}` , `png`);
                    case TYPE_IMAGE_FORMAT2ZIP._JPG: return $base_foramt.replace(`{0}`,`jpg`);
                    case TYPE_IMAGE_FORMAT2ZIP._JPEG: return $base_foramt.replace(`{0}`,`jpeg`);
                    case TYPE_IMAGE_FORMAT2ZIP._BMP: return $base_foramt.replace(`{0}`,`bmp`);
                    case TYPE_IMAGE_FORMAT2ZIP._WEBP: return $base_foramt.replace(`{0}`,`webp`);
                }
            };
            if( egret.Capabilities.runtimeType != egret.RuntimeType.WXGAME ){
                let binary : string = ‘‘;
                let len : number = bytes.byteLength;
                for (let i = 0; i < len; i++) {
                    binary += String.fromCharCode( bytes[ i ] );
                }
                return addFormat(window.btoa( binary ));
            }else{
                return addFormat(wx.arrayBufferToBase64(bytes));
            }
        }

        /**
         * 通过Base64获得图片的纹理信息
         * @param {string} $base64
         * @returns {egret.Texture}
         */
        public static getTextureByBase64( $base64 : string ) : egret.Texture{
            let img = new Image();
            img.src = $base64;
            let texture : egret.Texture = new egret.Texture();
            let bitmapdata : egret.BitmapData = new egret.BitmapData(img);
            texture._setBitmapData(bitmapdata);
            return texture;
        }

        /**
     * 图片的格式
     * @author Husz
     */
    export enum TYPE_IMAGE_FORMAT2ZIP{
        _PNG = 0,
        _JPG = 1,
        _JPEG = 2,
        _BMP = 3,
        _WEBP = 4
    }

测试 : egret引擎版本:5.2.6

一,测试环境:
①,将bg.jpg加压到bg.zip,将egret_icon.png加压到egret_icon.zip

②,将2个zip文件加到default.res.json中 , 并且删除掉bg_jpg和egret_icon.png

二,代码(修改了Main.ts中的createGameScene())如下:/=============================================================================/

    /**
     * 创建场景界面
     * Create scene interface
     */
    protected createGameScene(): void {
        // let sky = this.createBitmapByName("bg_jpg");
        // this.addChild(sky);
        let stageW = this.stage.stageWidth;
        let stageH = this.stage.stageHeight;
        // sky.width = stageW;
        // sky.height = stageH;

        let $$$zip : JSZip = new JSZip( RES.getRes("bg_zip") );
        let $$$buffer : ArrayBuffer = $$$zip.file("bg.jpg").asArrayBuffer();
        let $$$base64 : string = smallLib.CommonTool.arrayBufferToBase64($$$buffer,smallLib.TYPE_IMAGE_FORMAT2ZIP._JPG);
        let $$$sky : eui.Image = new eui.Image();
        $$$sky.source = $$$base64;
        $$$sky.width = stageW;
        $$$sky.height = stageH;
        this.addChild($$$sky);

        let topMask = new egret.Shape();
        topMask.graphics.beginFill(0x000000, 0.5);
        topMask.graphics.drawRect(0, 0, stageW, 172);
        topMask.graphics.endFill();
        topMask.y = 33;
        this.addChild(topMask);

        $$$zip = new JSZip(RES.getRes("egret_icon_zip"));
        $$$buffer = $$$zip.file("egret_icon.png").asArrayBuffer();

        $$$base64 = smallLib.CommonTool.arrayBufferToBase64($$$buffer,smallLib.TYPE_IMAGE_FORMAT2ZIP._PNG);
        // $$$base64 = this.arrayBufferToBase64($$$buffer);
        //let $$$texture : egret.Texture = this.getTextureByBase64($$$base64);
        let $$$icon : eui.Image = new eui.Image();
        $$$icon.source = $$$base64;
        $$$icon.x = 26;
        $$$icon.y = 33;

        let $$$bitmapdata : egret.BitmapData = egret.BitmapData.create(‘arraybuffer‘, $$$buffer);
        let _______texture : egret.Texture = new egret.Texture();
        _______texture.bitmapData = $$$bitmapdata;
        let $$$bitmap2Icon : egret.Bitmap = new egret.Bitmap(_______texture);
        $$$bitmap2Icon.x = 26;
        $$$bitmap2Icon.y = 33;
        this.addChild($$$bitmap2Icon);

        // let icon: egret.Bitmap = this.createBitmapByName("egret_icon_png");
        // this.addChild(icon);
        // icon.x = 26;
        // icon.y = 33;

        let line = new egret.Shape();
        line.graphics.lineStyle(2, 0xffffff);
        line.graphics.moveTo(0, 0);
        line.graphics.lineTo(0, 117);
        line.graphics.endFill();
        line.x = 172;
        line.y = 61;
        this.addChild(line);

        let colorLabel = new egret.TextField();
        colorLabel.textColor = 0xffffff;
        colorLabel.width = stageW - 172;
        colorLabel.textAlign = "center";
        colorLabel.text = "Hello Egret";
        colorLabel.size = 24;
        colorLabel.x = 172;
        colorLabel.y = 80;
        this.addChild(colorLabel);

        let textfield = new egret.TextField();
        this.addChild(textfield);
        textfield.alpha = 0;
        textfield.width = stageW - 172;
        textfield.textAlign = egret.HorizontalAlign.CENTER;
        textfield.size = 24;
        textfield.textColor = 0xffffff;
        textfield.x = 172;
        textfield.y = 135;
        this.textfield = textfield;

        let button = new eui.Button();
        button.label = "Click!";
        button.horizontalCenter = 0;
        button.verticalCenter = 0;
        this.addChild(button);
        button.addEventListener(egret.TouchEvent.TOUCH_TAP, this.onButtonClick, this);
    }

三:结果
①,在chrome下

②,在Launch Wing Player下

注意 : egret.BitmapData.create方法

四:结论
① : 使用eui.Image 直接接收base64(string)不存在兼容问题
② : 使用egret.Texture 可能在某些浏览器上无法显示
本人会持续跟踪给出答案......

原文地址：http://blog.51cto.com/aonaufly/2165614