ASP.NET创建缩略图服务器端 [英] ASP.NET creating thumbnails server side

问题描述

使用System.Drawing在ASP.NET应用程序中创建缩略图看起来非常容易.但是 MSDN会告诉您:

It look desceptively easy to use System.Drawing to create thumbnails in your ASP.NET application. But MSDN tells you:

不支持在Windows或ASP.NET服务中使用System.Drawing命名空间中的类.尝试从这些应用程序类型之一中使用这些类可能会产生意外问题，例如服务性能下降和运行时异常.

Classes within the System.Drawing namespace are not supported for use within a Windows or ASP.NET service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions.

我在这种GDI +代码中看到间歇性的内存不足"错误.我开始怀疑这是原因.

I'm seeing intermittented 'out of memory' errors within this type of GDI+ code. I'm beginning to suspect this is the cause.

人们如何进行服务器端图像处理?任何人都可以推荐不会破坏我的服务器的任何替代方法吗?

How ARE people doing server side image manipulation? Can anyone recommend any alternative that WON'T blow up my server?

下面的相关代码.该异常间歇性地发生在System.Drawing.Graphics.DrawImage中.我刚刚继承了这个项目，所以我需要检查日志以查看它被击中的频率/我们获得异常的频率...

The relevant code below. The exception intermittently happens in System.Drawing.Graphics.DrawImage. I've just inherited this project, so I'd need to check the logs to see how often this is being hit / how often we get an exception...

public byte[] Resize(int newWidth, int newHeight, Image orignalImage)
{
    Bitmap bitmap = new Bitmap(newWidth, newHeight);
    Graphics g = Graphics.FromImage(bitmap);
    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

    Rectangle r = new Rectangle(0, 0, newWidth, newHeight);
    g.DrawImage(orignalImage, r, r.X, r.Y, orignalImage.Width, orignalImage.Height, GraphicsUnit.Pixel);

    MemoryStream stream = new MemoryStream();
    bitmap.Save(stream, ImageFormat.Jpeg);

    // clean up memory leaks
    if (bitmap != null)
    {
        bitmap.Dispose();
        bitmap = null;
    }
    if (g != null)
    {
        g.Dispose();
        g = null;
    }


    return stream.ToArray();
}

更新:我已经在整个项目中搜索了我们正在使用GDI +的任何位置，并将using() { }放在所有IDisposable周围.自从我这样做以来，我再也没有见过一个内存不足"异常.

UPDATE: I've searched thru the whole project for anywhere we are using GDI+ and put using() { } around everything that's IDisposable. I haven't seen one 'out of memory' exception since I did this.

推荐答案

假设您将对每个请求执行操作"，则问题可能是

Assuming you will be doing "stuff" per request, the issues might be

1. 处理器密集型操作:图像处理，这可能需要一些时间.

1. Processor intensive operation: manipulation of images, which could take time.

如果要保存文件，将导致磁盘问题.

In case you are saving the file, it will lead to disk issues.

您可以考虑使用处理System.Drawing对象应该是优先事项(

Disposing System.Drawing objects should be a priority(using(){} statement )

异步页面可以在此处进行探索. /p>

Asynchronous Pages can be explored here.

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