Canvas to image base64togalary how to get url and name of the saved canvas?

i am saving canvas to image with base64togalary , while the time of saving i need to get the saved file name and location url ,how to do this?

  var dataUrl = this._CANVAS.toDataURL();//.split(';')[0].match(/jpeg|png|gif/)[0];//replace( /data:image\/png;base64,/, '' );;
    dataUrl = dataUrl;
 this.androidPermissions.requestPermissions([this.androidPermissions.PERMISSION.WRITE_EXTERNAL_STORAGE]).then(() => {
      this.base64ToGallery.base64ToGallery(dataUrl, { prefix: '_img' }).then(
        res => console.log('Saved image to gallery ', res),
        err => console.log('Error saving image to gallery ', err)