重写HttpPostedFileBase 图片压缩

遇到一个场景    文件操作模块是其他同事编写 直接通过HttpPostedFileBase来保存图片 这边不能动原来的上传流程  原来上传的图片都是没有经过压缩  导致APP加载速度会很慢

图片压缩代码

参考自：https://github.com/zkweb-framework/ZKWeb/blob/master/ZKWeb/ZKWebStandard/Extensions/ImageExtensions.cs

using MyCompanyName.Extensions.Utils;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MyCompanyName.Extensions.Extensions
{
    public static class ImageExtensions
    {

        /// <summary>
        /// Resize image
        /// </summary>
        /// <param name="image">Original image</param>
        /// <param name="width">Width</param>
        /// <param name="height">height</param>
        /// <param name="mode">Resize mode</param>
        /// <param name="background">Background default is transparent</param>
        /// <returns></returns>
        public static Image Resize(this Image image,
            int width, int height, ImageResizeMode mode, Color? background = null)
        {
            var src = new Rectangle(0, 0, image.Width, image.Height);
            var dst = new Rectangle(0, 0, width, height);
            // Calculate destination rectangle by resize mode
            if (mode == ImageResizeMode.Fixed)
            {
            }
            else if (mode == ImageResizeMode.ByWidth)
            {
                height = (int)((decimal)src.Height / src.Width * dst.Width);
                dst.Height = height;
            }
            else if (mode == ImageResizeMode.ByHeight)
            {
                width = (int)((decimal)src.Width / src.Height * dst.Height);
                dst.Width = width;
            }
            else if (mode == ImageResizeMode.Cut)
            {
                if ((decimal)src.Width / src.Height > (decimal)dst.Width / dst.Height)
                {
                    src.Width = (int)((decimal)dst.Width / dst.Height * src.Height);
                    src.X = (image.Width - src.Width) / 2; // Cut left and right
                }
                else
                {
                    src.Height = (int)((decimal)dst.Height / dst.Width * src.Width);
                    src.Y = (image.Height - src.Height) / 2; // Cut top and bottom
                }
            }
            else if (mode == ImageResizeMode.Padding)
            {
                if ((decimal)src.Width / src.Height > (decimal)dst.Width / dst.Height)
                {
                    dst.Height = (int)((decimal)src.Height / src.Width * dst.Width);
                    dst.Y = (height - dst.Height) / 2; // Padding left and right
                }
                else
                {
                    dst.Width = (int)((decimal)src.Width / src.Height * dst.Height);
                    dst.X = (width - dst.Width) / 2; // Padding top and bottom
                }
            }
            // Draw new image
            var newImage = new Bitmap(width, height);
            using (var graphics = Graphics.FromImage(newImage))
            {
                // Set smoothing mode
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                graphics.SmoothingMode = SmoothingMode.HighQuality;
                // Set background color
                graphics.Clear(background ?? Color.Transparent);
                // Render original image with the calculated rectangle
                graphics.DrawImage(image, dst, src, GraphicsUnit.Pixel);
            }
            return newImage;
        }

        /// <summary>
        /// Save to jpeg with specified quality
        /// </summary>
        /// <param name="image">Image object</param>
        /// <param name="filename">File path, will automatic create parent directories</param>
        /// <param name="quality">Compress quality, 1~100</param>
        public static void SaveJpeg(this Image image, string filename, long quality)
        {
            PathUtils.EnsureParentDirectory(filename);
            var encoder = ImageCodecInfo.GetImageEncoders().First(
                c => c.FormatID == ImageFormat.Jpeg.Guid);
            var parameters = new EncoderParameters();
            parameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
            image.Save(filename, encoder, parameters);
        }

        /// <summary>
        /// Save to icon, see
        /// http://stackoverflow.com/questions/11434673/bitmap-save-to-save-an-icon-actually-saves-a-png
        /// </summary>
        /// <param name="image">Image object</param>
        /// <param name="filename">File path, will automatic create parent directories</param>
        public static void SaveIcon(this Image image, string filename)
        {
            PathUtils.EnsureParentDirectory(filename);
            using (var stream = new FileStream(filename, FileMode.Create))
            {
                // Header (ico, 1 photo)
                stream.Write(new byte[] { 0, 0, 1, 0, 1, 0 }, 0, 6);
                // Size
                stream.WriteByte(checked((byte)image.Width));
                stream.WriteByte(checked((byte)image.Height));
                // No palette
                stream.WriteByte(0);
                // Reserved
                stream.WriteByte(0);
                // No color planes
                stream.Write(new byte[] { 0, 0 }, 0, 2);
                // 32 bpp
                stream.Write(new byte[] { 32, 0 }, 0, 2);
                // Image data length, set later
                stream.Write(new byte[] { 0, 0, 0, 0 }, 0, 4);
                // Image data offset, fixed 22 here
                stream.Write(new byte[] { 22, 0, 0, 0 }, 0, 4);
                // Write png data
                image.Save(stream, ImageFormat.Png);
                // Write image data length
                long imageSize = stream.Length - 22;
                stream.Seek(14, SeekOrigin.Begin);
                stream.WriteByte((byte)(imageSize));
                stream.WriteByte((byte)(imageSize >> 8));
                stream.WriteByte((byte)(imageSize >> 16));
                stream.WriteByte((byte)(imageSize >> 24));
            }
        }

        /// <summary>
        /// Save image by it‘s file extension
        /// Quality parameter only available for jpeg
        /// </summary>
        /// <param name="image">Image object</param>
        /// <param name="filename">File path, will automatic create parent directories</param>
        /// <param name="quality">Compress quality, 1~100</param>
        public static void SaveAuto(this Image image, string filename, long quality)
        {
            PathUtils.EnsureParentDirectory(filename);
            var extension = Path.GetExtension(filename).ToLower();
            if (extension == ".jpg" || extension == ".jpeg")
            {
                image.SaveJpeg(filename, quality);
            }
            else if (extension == ".bmp")
            {
                image.Save(filename, ImageFormat.Bmp);
            }
            else if (extension == ".gif")
            {
                image.Save(filename, ImageFormat.Gif);
            }
            else if (extension == ".ico")
            {
                image.SaveIcon(filename);
            }
            else if (extension == ".png")
            {
                image.Save(filename, ImageFormat.Png);
            }
            else if (extension == ".tiff")
            {
                image.Save(filename, ImageFormat.Tiff);
            }
            else if (extension == ".exif")
            {
                image.Save(filename, ImageFormat.Exif);
            }
            else
            {
                throw new NotSupportedException(
                    string.Format("unsupport image extension {0}", extension));
            }
        }
    }

    /// <summary>
    /// Image resize mode
    /// </summary>
    public enum ImageResizeMode
    {
        /// <summary>
        /// Resize to the specified size, allow aspect ratio change
        /// </summary>
        Fixed,
        /// <summary>
        /// Resize to the specified width, height is calculated by the aspect ratio
        /// </summary>
        ByWidth,
        /// <summary>
        /// Resize to the specified height, width is calculated by the aspect ratio
        /// </summary>
        ByHeight,
        /// <summary>
        /// Resize to the specified size, keep aspect ratio and cut the overflow part
        /// </summary>
        Cut,
        /// <summary>
        /// Resize to the specified size, keep aspect ratio and padding the insufficient part
        /// </summary>
        Padding
    }
}

　　重写HttpPostedFileBase

using MyCompanyName.Extensions.Extensions;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;

namespace MyCompanyName.Extensions.Web.Http
{
    public class ImageHttpPostedFileBase : HttpPostedFileBase
    {
        Stream stream;
        string contentType;
        string fileName;
        public int ImageQuality { get; set; }
        public Size ImageThumbnailSize { get; set; }
        public ImageResizeMode ImageResizeMode { get; set; }
        public ImageHttpPostedFileBase(Stream stream, string contentType, string fileName, Size imageThumbnailSize, int ImageQuality, ImageResizeMode imageResizeMode)
        {
            this.stream = stream;
            this.contentType = contentType;
            this.fileName = fileName;
            this.ImageQuality = ImageQuality;
            this.ImageThumbnailSize = imageThumbnailSize;
            this.ImageResizeMode = imageResizeMode;

        }

        public override int ContentLength
        {
            get { return (int)stream.Length; }
        }

        public override string ContentType
        {
            get { return contentType; }
        }

        public override string FileName
        {
            get { return fileName; }
        }

        public override Stream InputStream
        {
            get { return stream; }
        }

        public override void SaveAs(string filename)
        {
            var image = Image.FromStream(stream);
            using (var thumbnailImage = image.Resize(ImageThumbnailSize.Width, ImageThumbnailSize.Height, ImageResizeMode, Color.White))
                thumbnailImage.SaveAuto(filename, ImageQuality);

        }

    }
}

　　重写HttpPostedFileBase加入了一些自定义的属性 SoEasy

ImageHttpPostedFileBase fileBase = new ImageHttpPostedFileBase(file.InputStream, file.ContentType, file.FileName, new Size(800, 800), 90, Extensions.Extensions.ImageResizeMode.ByWidth);