using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Text.RegularExpressions;

public partial class Default2 : System.Web.UI.Page
{
    /// <summary>
    /// 图片处理
    /// http://www.lpsjj.cn/
    /// 
    /// 刘丕水 2018-11-14 创建
    /// </summary>
    public class Image
    {

        /// <summary>
        /// 图片展示完美裁剪
        /// </summary>
        /// <remarks>刘丕水 2018-11-14</remarks>
        /// <param name="fromFile">原图Stream对象</param>
        /// <param name="savePath">缩略图存放地址</param>
        /// <param name="targetWidth">指定的最大宽度</param>
        /// <param name="targetHeight">指定的最大高度</param>
        /// <param name="watermarkText">水印文字(为""表示不使用水印)</param>
        /// <param name="watermarkImage">水印图片路径(为""表示不使用水印)</param>
        public static byte[] cutPerfect(System.IO.Stream fromFile, System.Double targetWidth, System.Double targetHeight, string watermarkText, string watermarkImage)
        {
            //原始图片（获取原始图片创建对象，并使用流中嵌入的颜色管理信息）
            System.Drawing.Image initImage = System.Drawing.Image.FromStream(fromFile, true);
            MemoryStream ms = new MemoryStream();
                //缩略图宽、高计算
                double newWidth = (int)targetWidth;
                double newHeight = (int)targetHeight;
                int startX = 0;
                int startY = 0;
                if ((int)targetWidth*initImage.Height/((int)targetHeight*initImage.Width)<1) {
                    newWidth = (int)targetHeight * initImage.Width / initImage.Height;
                    startX = (int)(((int)targetWidth - newWidth) / 2);
                } else {
                    newHeight = (int)targetWidth*initImage.Height/initImage.Width;
                    startY = (int)(((int)targetHeight - newHeight) / 2);
                }
                //新建一个bmp图片
                System.Drawing.Image newImage = new System.Drawing.Bitmap((int)targetWidth, (int)targetHeight);
                //新建一个画板
                System.Drawing.Graphics newG = System.Drawing.Graphics.FromImage(newImage);
                //设置质量
                newG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                newG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                //置背景色
                newG.Clear(Color.White);
                //画图
                newG.DrawImage(initImage, new System.Drawing.Rectangle(startX, startY, (int)newWidth, (int)newHeight), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);

                //文字水印
                if (watermarkText != "")
                {
                    using (System.Drawing.Graphics gWater = System.Drawing.Graphics.FromImage(newImage))
                    {
                    int fontSizeCurr = 15;
                        System.Drawing.Font fontWater = new Font("宋体", fontSizeCurr,FontStyle.Italic);
                        System.Drawing.Brush brushWater = new SolidBrush(Color.FromArgb(150,0,0,0));
                        gWater.DrawString(watermarkText, fontWater, brushWater, (int)targetWidth-60-watermarkText.Length* fontSizeCurr, (int)targetHeight - 30- fontSizeCurr);
                        gWater.Dispose();
                    }
                }

                //透明图片水印
                if (watermarkImage != "")
                {
                    if (File.Exists(watermarkImage))
                    {
                        //获取水印图片
                        using (System.Drawing.Image wrImage = System.Drawing.Image.FromFile(watermarkImage))
                        {
                            //水印绘制条件：原始图片宽高均大于或等于水印图片
                            if (newImage.Width >= wrImage.Width && newImage.Height >= wrImage.Height)
                            {
                                Graphics gWater = Graphics.FromImage(newImage);

                                //透明属性
                                ImageAttributes imgAttributes = new ImageAttributes();
                                ColorMap colorMap = new ColorMap();
                                colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
                                colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
                                ColorMap[] remapTable = { colorMap };
                                imgAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

                                float[][] colorMatrixElements = {
                                   new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
                                   new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
                                   new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
                                   new float[] {0.0f,  0.0f,  0.0f,  0.5f, 0.0f},//透明度:0.5
                                   new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
                                };

                                ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);
                                imgAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
                                gWater.DrawImage(wrImage, new Rectangle(newImage.Width - wrImage.Width, newImage.Height - wrImage.Height, wrImage.Width, wrImage.Height), 0, 0, wrImage.Width, wrImage.Height, GraphicsUnit.Pixel, imgAttributes);
                                gWater.Dispose();
                            }
                            wrImage.Dispose();
                        }
                    }
                }

                //保存缩略图到流
                newImage.Save(ms,System.Drawing.Imaging.ImageFormat.Jpeg);
                //释放资源
                newG.Dispose();
                newImage.Dispose();
                initImage.Dispose();
                //ms流数据转换为Buffer数据;
                long fileSize = ms.Length;
                byte[] fileBuffer = new byte[fileSize];
                ms.Position = 0; //流在输出之前一定要先定位到0.否则.读出的数据全都是0
                ms.Read(fileBuffer, 0, (int)fileSize);
                //如果不写ms.Close()语句，用户在下载过程中选择取消，将不能再次下载
                ms.Close();

            return fileBuffer;
        }

        #region 其它

        /// <summary>
        /// 判断文件类型是否为WEB格式图片
        /// (注：JPG,GIF,BMP,PNG)
        /// </summary>
        /// <param name="contentType">HttpPostedFile.ContentType</param>
        /// <returns></returns>
        public static bool IsWebImage(string contentType)
        {
            if (contentType == "image/pjpeg" || contentType == "image/jpeg" || contentType == "image/gif" || contentType == "image/bmp" || contentType == "image/png")
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        #endregion

    }//end class
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.AddHeader("content-type", "image/png");
        string imgPath = HttpContext.Current.Request["path"].ToString();
        string serverPath = Server.MapPath("");
        string imgPathPre = "";
        string imgPathNext = "";
        string imgPathType = "";
        int imgSizeWidth=0;
        int imgSizeHeight=0;
        imgPathPre = imgPath.Substring(0,imgPath.LastIndexOf("_"));
        imgPathNext = imgPath.Substring(imgPath.LastIndexOf("_")+1);
        imgPathType = imgPath.Split('.')[1];
        imgSizeWidth = int.Parse(imgPathNext.Split('.')[0].Split('x')[0]);
        imgSizeHeight = int.Parse(imgPathNext.Split('.')[0].Split('x')[1]);
        Stream imgStream = File.Open(serverPath + "/" + imgPathPre + "." + imgPathType, FileMode.Open);
        byte[] imgBtye = Image.cutPerfect(imgStream, imgSizeWidth, imgSizeHeight, "刘丕水", "");
        imgStream.Close();
        Response.BinaryWrite(imgBtye);
        Response.OutputStream.Flush();
        Response.OutputStream.Close();

    }
}