如何高效地扩展和裁剪图像在ASP.NET应用程序？ [英] How to efficiently scale and crop images in an ASP.NET app?

问题描述

我们遇到与一个ASP.NET应用程序，允许用户上传和裁剪图像的问题。图像都调整为固定尺寸之后。我们基本用完时，一个大的文件处理内存;似乎JPEG的处理是相当低效 - 我们使用System.Drawing.BitMap。你有任何一般性的建议，也许有些指向一个更高效的图像处理库？你有什么经验？

We're having problems with an ASP.NET application which allows users to upload, and crop images. The images are all scaled to fixed sizes afterwards. We basically run out of memory when a large file is processed; it seems that the handling of JPEG is rather inefficient -- we're using System.Drawing.BitMap. Do you have any general advice, and perhaps some pointers to a more efficient image handling library? What experiences do you have?

推荐答案

我有同样的问题，解决的办法是使用System.Drawing.Graphics尽快做转换和处理每一个位图对象，因为我是用它完成。下面是从我的图书馆（调整）的例子：

I had the same problem, the solution was to use System.Drawing.Graphics to do the transformations and dispose every bitmap object as soon as I was finished with it. Here's a sample from my library (resizing) :

    public Bitmap ApplyTo(Bitmap bitmap)
    {
        using (bitmap)
        {
            Bitmap newBitmap = new Bitmap(bitmap, CalculateNewSize(bitmap));

            using (Graphics graphics = Graphics.FromImage(newBitmap))
            {
                graphics.SmoothingMode =
                    SmoothingMode.None;
                graphics.InterpolationMode =
                    InterpolationMode.HighQualityBicubic;
                graphics.CompositingQuality =
                    CompositingQuality.HighQuality;

                graphics.DrawImage(
                    bitmap,
                    new Rectangle(0, 0, newBitmap.Width, newBitmap.Height));
            }

            return newBitmap;
        }
    }

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