Which free image resizing library can I use for re

问题:

I have used Umbraco and there is very nice ImageGen library there which allows to resize images 'on the fly' and cashes processed images.

Is there something similar to it I can use outside Umbraco?

(I thought I could use ImageGen without Umbraco but it looks like it is not free)

Thanks

回答1:

I realise this question is quite old, but since I still stumbled across it, I thought I should post my findings.

http://imageprocessor.org/ seems to be a relatively new library that is free and open source, and has quite a number of features too!

回答2:

I wrote the ImageResizer HttpModule, which is free, open-source, and freely supported through the StackOverflow imageresizer tag.

It has 39 plugins, some of which require a license, but all of the source code for everything is available at http://imageresizing.net/download.

It works with all .NET CMSes, including Umbraco.

Unlike ImageGen, it is designed to scale up to millions of images.

回答3:

The .NET Framework includes support for image resizing.

Below is some sample code from my book, Ultra-Fast ASP.NET:

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.IO;

namespace Samples
{
    public class ImageResizer
    {
        private static ImageCodecInfo jpgEncoder;

        public static void ResizeImage(string inFile, string outFile, double maxDimension, long level)
        {
            //
            // Load via stream rather than Image.FromFile to release the file
            // handle immediately
            //
            using (Stream stream = new FileStream(inFile, FileMode.Open))
            {
                using (Image inImage = Image.FromStream(stream))
                {
                    double width;
                    double height;

                    if (inImage.Height < inImage.Width)
                    {
                        width = maxDimension;
                        height = (maxDimension / (double)inImage.Width) * inImage.Height;
                    }
                    else
                    {
                        height = maxDimension;
                        width = (maxDimension / (double)inImage.Height) * inImage.Width;
                    }
                    using (Bitmap bitmap = new Bitmap((int)width, (int)height))
                    {
                        using (Graphics graphics = Graphics.FromImage(bitmap))
                        {
                            graphics.SmoothingMode = SmoothingMode.HighQuality;
                            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                            graphics.DrawImage(inImage, 0, 0, bitmap.Width, bitmap.Height);
                            if (inImage.RawFormat.Guid == ImageFormat.Jpeg.Guid)
                            {
                                if (jpgEncoder == null)
                                {
                                    ImageCodecInfo[] ici = ImageCodecInfo.GetImageDecoders();
                                    foreach (ImageCodecInfo info in ici)
                                    {
                                        if (info.FormatID == ImageFormat.Jpeg.Guid)
                                        {
                                            jpgEncoder = info;
                                            break;
                                        }
                                    }
                                }
                                if (jpgEncoder != null)
                                {
                                    EncoderParameters ep = new EncoderParameters(1);
                                    ep.Param[0] = new EncoderParameter(Encoder.Quality, level);
                                    bitmap.Save(outFile, jpgEncoder, ep);
                                }
                                else
                                    bitmap.Save(outFile, inImage.RawFormat);
                            }
                            else
                            {
                                //
                                // Fill with white for transparent GIFs
                                //
                                graphics.FillRectangle(Brushes.White, 0, 0, bitmap.Width, bitmap.Height);
                                bitmap.Save(outFile, inImage.RawFormat);
                            }
                        }
                    }
                }
            }
        }

        public static void GetImageSize(string inFile, out int width, out int height)
        {
            using (Stream stream = new FileStream(inFile, FileMode.Open))
            {
                using (Image src_image = Image.FromStream(stream))
                {
                    width = src_image.Width;
                    height = src_image.Height;
                }
            }
        }
    }
}