public HsImage(Stream imageStream)
{
byte[] datas = new byte[imageStream.Length];
imageStream.Seek(0, SeekOrigin.Begin);
imageStream.Read(datas, 0, datas.Length);
#region 获取图像大小
IPlatformExtension platformExtension = DependencyService.Get <IPlatformExtension>(DependencyFetchTarget.GlobalInstance);
Tuple <System.Drawing.Size, byte[]> imageData = platformExtension.ReduceImage(datas, 800);
System.Drawing.Size size = imageData.Item1;
datas = imageData.Item2;
#endregion
#region 记录元数据
byte[] metabs = new byte[METALEN];
using (MemoryStream ms = new MemoryStream(metabs))
{
//以小端方式记录元数据。
using (BinaryWriter bw = new BinaryWriter(ms, Encoding.Unicode))
{
bw.Write(ENDIAN_LITTLE); //记录第一位
bw.Write(JPG); //记录2-5位
bw.Write(size.Width); //记录6-9位
bw.Write(size.Height); //记录10-13位
}
}
#endregion
_imageData = ImageSource.FromStream(() =>
{
return(new MemoryStream(datas));
});
_imageDataString = HsBase64.ToBase64(metabs.Concat(datas).ToArray());
}
public HsImage(string imageDataString)
{
if (imageDataString.Split(',').Length > 1)
{
throw new HsException("无法识别的旧的图像格式");
}
byte[] buffers = HsBase64.FromBase64ToBytes(imageDataString);
byte[] datas = new byte[buffers.Length - METALEN];
using (MemoryStream bufferStream = new MemoryStream(buffers))
{
int endian = buffers[0];
using (BinaryReader br = new BinaryReader(bufferStream, endian == ENDIAN_BIG ? Encoding.BigEndianUnicode : Encoding.Unicode))
{
br.ReadByte(); //越过第一位
int format = br.ReadInt32(); //读取2-5位
if (format == PIXEL)
{
throw new HsException("不支持PIXEL图像格式");
}
bufferStream.Seek(METALEN, SeekOrigin.Begin);
bufferStream.Read(datas, 0, datas.Length);
}
}
this._imageDataString = imageDataString;
this._imageData = ImageSource.FromStream(() =>
{
return(new MemoryStream(datas));
});
}
private async Task downloadAndOpen(HsFile item)
{
//如果文件存在与本地，则直接打开，否则先下载再打开。
string[] cachePath = new string[] { "Cache", "Files" };
string cachefilename = $"{item.FileHash}.{item.FileName}";
IPlatformExtension pe = DependencyService.Get <IPlatformExtension>(DependencyFetchTarget.GlobalInstance);
if (!pe.FileExist(cachefilename, cachePath)) //文件不存在需要下载
{
int index = 0;
using (MemoryStream ms = new MemoryStream())
{
while (true)
{
//下载文件...
HsLabelValue result = await GetWSUtil().GetSysFileSeg(GetLoginData().ProgressId, item.FileHash, index);
if (result == null) //文件读取完毕
{
break;
}
byte[] buffer = HsBase64.FromBase64ToBytes(result.GetValueByLabel("Data"));
//数据解压缩
buffer = HsZlib.DecompressData(buffer);
ms.Write(buffer, 0, buffer.Length);
index++;
}
byte[] fileData = ms.ToArray();
Debug.WriteLine(HsMD5.EncryptionMD5(fileData));
await pe.WriteFile(cachefilename, fileData, 2, cachePath);
}
await downloadAndOpen(item);
}
else
{
List <string> previewFiletypes = new List <string>()
{
"DOC", "DOCX",
"XLS", "XLSX",
"PPT", "PPTX",
"PDF",
"TXT", "TEXT",
"JPG", "PNG"
};
if (previewFiletypes.Contains(item.FileType.ToUpper()))
{
string url = pe.GetFileURL(cachefilename, cachePath);
if (!string.IsNullOrWhiteSpace(url))
{
Panel_PreviewFile panel = new Panel_PreviewFile();
panel.Source = new UrlWebViewSource()
{
Url = url
};
await Navigation.PushAsync(panel);
}
}
else
{
pe.CallFile(cachefilename, cachePath);
}
}
}
