<%@ WebHandler Language="C#" Class="ShowPic" %>

using System;
using System.Web;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;

public class ShowPic : IHttpHandler
{

    //Path Area
    protected static String MyPathIsVirtual = System.Web.Configuration.WebConfigurationManager.AppSettings["VirtualPath"];
    protected static String MyPathIsUploadBase = MyPathIsVirtual + System.Web.Configuration.WebConfigurationManager.AppSettings["PathIsUploadBase"];
    //protected static String CurrentPath = HttpContext.Current.Server.MapPath("../../upload/product/");

    public void ProcessRequest(HttpContext context)
    {
        if (context.Request.QueryString["File"] != null && context.Request.QueryString["W"] != null && context.Request.QueryString["H"] != null)
        {
            string CurrentPath = HttpContext.Current.Server.MapPath("~/upload/");
            String FileName = context.Request.QueryString["File"].Trim().Replace("../", "");
            int GetWidth = int.Parse(context.Request.QueryString["W"].Trim());
            int GetHeight = int.Parse(context.Request.QueryString["H"].Trim());

            context.Response.ContentType = "Image/JPEG";
            context.Response.Clear();
            context.Response.Cache.SetExpires(DateTime.Now.AddMinutes(43200));
            //context.Response.BufferOutput = true; //緩衝輸出, 處理完再送出

            String FileNameAndPath = CurrentPath + FileName;

            if (!System.IO.File.Exists(FileNameAndPath))
            {
                //File.WriteAllText( "C:\\log.txt" , "取得路徑為 " + FileNameAndPath + " 找不到檔案.");
            }


            //開始處理
            System.IO.FileInfo Original_FileInfo = new System.IO.FileInfo(FileNameAndPath);
            System.Drawing.Image Original_Image = System.Drawing.Image.FromFile(FileNameAndPath); //讀取圖片

            int New_Width = int.Parse(context.Request.QueryString["W"].Trim());
            int New_Height = int.Parse(context.Request.QueryString["H"].Trim());

            int x = 0;
            int y = 0;

            #region 產生圖形計算公式
            switch (context.Request.QueryString["Type"])
            {
                case "morph":   //強制寬高變形
                    New_Width = int.Parse(context.Request.QueryString["W"].Trim());
                    New_Height = int.Parse(context.Request.QueryString["H"].Trim());
                    break;

                case "Default":   //等比縮放

                default: //預設依 Width 等比縮放, 不論Height
                    New_Height = Original_Image.Height * GetWidth / Original_Image.Width;
                    if (New_Height > int.Parse(context.Request.QueryString["H"].Trim())) {
                        New_Height = int.Parse(context.Request.QueryString["H"].Trim());
                        New_Width = Original_Image.Width  * GetHeight / Original_Image.Height;
                    }
                    break;
            }

            #endregion

            //開空白畫布
            System.Drawing.Image New_Image = new System.Drawing.Bitmap(New_Width, New_Height);
            System.Drawing.Graphics ObjGraphics = System.Drawing.Graphics.FromImage(New_Image);

            #region 圖片設定

            MyWeb.global global = new MyWeb.global();

            //相關設定
            ObjGraphics.InterpolationMode = global.InterpolationMode;
            ObjGraphics.SmoothingMode = global.SmoothingMode;
            ObjGraphics.CompositingQuality = global.CompositingQuality;

            ObjGraphics.Clear(System.Drawing.Color.Transparent);    //清空Graphics, 以透明背景色填充

            //在指定位置按指定大小繪制原圖片的片段
            ObjGraphics.DrawImage(Original_Image,
                new System.Drawing.Rectangle(0, 0, New_Width, New_Height),
                new System.Drawing.Rectangle(x, y, Original_Image.Width, Original_Image.Height),
                System.Drawing.GraphicsUnit.Pixel);


            //下方設定使JPG質量
            System.Drawing.Imaging.EncoderParameters EPS = new System.Drawing.Imaging.EncoderParameters();
            System.Drawing.Imaging.EncoderParameter EP = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)global.ImageCompressionQuality);

            EPS.Param[0] = EP;


            System.Drawing.Imaging.ImageCodecInfo[] codecs = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();
            System.Drawing.Imaging.ImageCodecInfo ICI = null;

            foreach (System.Drawing.Imaging.ImageCodecInfo codec in codecs)
            {
                if (codec.MimeType == "image/jpeg") ICI = codec;
            }
            #endregion


            New_Image.Save(context.Response.OutputStream , ICI, EPS);

            //Clear
            New_Image.Dispose();
            ObjGraphics.Dispose();
            Original_Image.Dispose();


        }
    }


    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

}