cocos2dx-js 截屏 （原生 + H5）

1、cocos  原生截屏功能 ，保存为图片，在ios 或者java代码里可以拿到图片做分享等功能 （H5不支持saveToFile 该方法只能在原生平台上使用）

saveCanvas: function () {  
        var size = cc.director.getWinSize();  
        var fileName = "result_share.jpg";  
        var fullPath = jsb.fileUtils.getWritablePath() + fileName; //拿到可写路径，将图片保存在本地，可以在ios端或者java端读取该文件  
        if (jsb.fileUtils.isFileExist(fullPath)) {  
            jsb.fileUtils.removeFile(fullPath);  
        }  
        var texture = new cc.RenderTexture(Math.floor(size.width), Math.floor(size.height));  
        texture.setPosition(cc.p(size.width / 2, size.height / 2));  
        texture.begin();  
        cc.director.getRunningScene().visit(); //这里可以设置要截图的节点，设置后只会截取指定节点和其子节点  
        texture.end();  
        texture.saveToFile(fileName, cc.IMAGE_FORMAT_JPG);  
    }, 

//截屏保存到相册
var ret = jsb.reflection.callStaticMethod("NativeOcClass",
        "callNativeUIWithTitle:andContent:",
        "cocos2d-js",
        fileName);

@implementation NativeOcClass
+(BOOL)callNativeUIWithTitle:(NSString *) title andContent:(NSString *) content {
     
    NSString* filePath = [NSHomeDirectory() stringByAppendingFormat:@"/Documents/%@.png", content];
    UIImage *viewImage = [UIImage imageWithContentsOfFile:filePath];
    if (viewImage != nil) {
        UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
         
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title message:content delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK", nil];
        [alertView show];
    }
    return true;
}

2、H5版本 截图功能，截图得到的数据 生产图片资源，创建一个image 指向该图片资源，添加到document上 然后就支持浏览器的长按保存功能了，也可以做分享

saveCancas:function(){  
        var self = this;  
        var canvas = document.getElementById("GameCanvas");  
        var href = canvas.toDataURL("image/png");  
          
        var canvas = cc.find("Canvas").getComponent(cc.Canvas);  
        var vsbSize = cc.view.getVisibleSize();  
        var designSize = canvas.designResolution;  
        console.log("balance designSize" + designSize);  
        console.log("balance visitblSize" + vsbSize);  
        var scaleW = vsbSize.width / designSize.width;  
        var scaleH = vsbSize.height / designSize.height;  
        var fitScale = Math.max(scaleW,scaleH);  
        var gameDiv = document.getElementById('Cocos2dGameContainer');//获取div元素  
        var bigImg = document.createElement("img");//创建img元素  
        bigImg.id = 'QRCode';  
        bigImg.src = href;//给img标签添加图片源  
        bigImg.alt = 'bigImg';  
        bigImg.width = parseInt(gameDiv.style.width.replace(/px/, '')) * fitScale;  
        bigImg.height = parseInt(gameDiv.style.height.replace(/px/, '')) * fitScale;  
        bigImg.style.position = 'absolute';  
        bigImg.style.top = "0px";//y坐标  
        bigImg.style.left = parseInt(gameDiv.style.width.replace(/px/, '')) / 2 - bigImg.width / 2 + "px";//设置图片居中显示  
        gameDiv.appendChild(bigImg);  
    },