自动缩放照片小程序

闲来无事，写个自动缩放照片的小程序

第一版（保存Exif）

参考：http://blog.youkuaiyun.com/ki1381/article/details/6369058

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Drawing.Imaging;
using System.Drawing;

namespace MyPhotoProcess
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            string fileURL = txtFile.Text.Trim();
            ProcessFile(fileURL);
        }

        public static void ProcessFile(string dir)
        {
            foreach (string d in Directory.GetFileSystemEntries(dir))
            {
                if (File.Exists(d))
                {
                    FileInfo fi = new FileInfo(d);
                    if (fi.Attributes.ToString().IndexOf("ReadOnly") != -1)
                        fi.Attributes = FileAttributes.Normal;
                    // 获取照片的Exif信息
                    var exif = GetImageProperties(d);
                    MakeThumbnail(d, "D:/test/process/" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".jpg", 150, 150, "EQU", exif);
                    //File.Delete(d);//直接删除其中的文件  
                }
                else
                {
                    DirectoryInfo d1 = new DirectoryInfo(d);
                    if (d1.GetFiles().Length != 0)
                    {
                        ProcessFile(d1.FullName);//递归删除子文件夹
                    }
                    //Directory.Delete(d);
                }
            }
        }

        #region 图片缩放，多种指定方式生成图片
        /// <summary>
        /// 图片缩放
        /// </summary>
        /// <param name="originalImagePath">原始图片路径，如：c:\\images\\1.gif</param>
        /// <param name="thumbnailPath">生成缩略图图片路径，如：c:\\images\\2.gif</param>
        /// <param name="width">宽</param>
        /// <param name="height">高</param>
        /// <param name="mode">EQU：指定最大高宽等比例缩放；HW：//指定高宽缩放（可能变形）；W:指定宽，高按比例；H:指定高，宽按比例；Cut：指定高宽裁减（不变形）</param>
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode, List<PropertyItem> exif)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0;
            int y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;

            if (mode == "EQU")//指定最大高宽，等比例缩放
            {
                //if(height/oh>width/ow),如果高比例多，按照宽来缩放；如果宽的比例多，按照高来缩放
                if (height * ow > width * oh)
                {
                    mode = "W";
                }
                else
                {
                    mode = "H";
                }
            }
            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形）
                    break;
                case "W"://指定宽，高按比例
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形）
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    break;
                default:
                    break;
            }

            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //清空画布并以透明背景色填充
            g.Clear(System.Drawing.Color.Transparent);

            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
                new System.Drawing.Rectangle(x, y, ow, oh),
                System.Drawing.GraphicsUnit.Pixel);
            try
            {
                // 设置EXIF  
                foreach (PropertyItem pitem in exif)
                {
                    bitmap.SetPropertyItem(pitem);
                }

                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
        #endregion


        /// <summary>
        /// 获取照片的Exif属性，存储成二进制list
        /// </summary>
        /// <param name="FileName"></param>
        /// <returns></returns>
        public static List<PropertyItem> GetImageProperties(string FileName)
        {
            if (!File.Exists(FileName)) return null;

            List<PropertyItem> rtn = new List<PropertyItem>();

            System.Drawing.Image img = null;

            try
            {
                img = System.Drawing.Image.FromFile(FileName);
                PropertyItem[] pt = img.PropertyItems;

                foreach (PropertyItem p in pt)
                {
                    rtn.Add(p);
                }
            }
            catch
            {
                rtn = null;
            }
            finally
            {
                if (img != null) img.Dispose();
            }

            return rtn;
        }

    }
}