图片文件下载以及压缩剪裁操作（网页）

<script type="text/javascript">
    var time_stamp; //时间戳
    var url = 'http://img.zcool.cn/community/[email protected]'; //下载图片路径
    var compressPath = 'fs://download/compressPic'; //剪裁后的图片文件夹路径
    apiready = function() {
        time_stamp = Date.parse(new Date());
    }

    function downloadPic() {
        var fs = api.require("fs");
        //先判断文件夹是否存在，如果存在先删除再下载，否则直接下载
        fs.exist({
            path: 'fs://download'
        }, function(ret, err) {
            if (ret.exist) {
                fs.rmdir({
                    path: 'fs://download'
                }, function(ret, err) {
                    if (ret.status) {
                        downloadPicc();
                    }
                });
            } else {
                downloadPicc();
            }
        });
    }

    function downloadPicc() {
        api.download({
            url: url,
            savePath: 'fs://download/' + time_stamp + ".png",
            cache: true,
            allowResume: false
        }, function(ret, err) {
            if (ret.state == 1) {
                compressPic();
            }
        });
    }

    //进行图片剪裁压缩
    function compressPic() {
        var compress = api.require("imageFilter");
        compress.compress({
            img: 'fs://download/' + time_stamp + ".png",
            quality: 1,
            size: {
                w: 40,
                h: 40
            },
            save: {
                imgPath: compressPath,
                imgName: 'compressPic.png'
            }
        }, function(ret, err) {
            if (ret.status) {
                $api.attr($api.byId('img'), 'src', api.fsDir + '/download/compressPic/compressPic.png');
            }
        });
    }
</script>