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C#图片上传-加水印-自动生成缩略图的代码
来源: 互联网 发布时间:2014-08-30
本文导语: C#图片上传,加水印,自动生成缩略图 using System; using System.Data; using System.Data.SqlClient; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using...
C#图片上传,加水印,自动生成缩略图
using System; using System.Data; using System.Data.SqlClient; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Text; using System.Text.RegularExpressions; using System.Drawing; using System.Drawing.Imaging; using System.Collections; using System.ComponentModel; namespace Legalsoft.Images { /// /// News 的摘要说明 /// public class XImage { public Color tBackground; public Color tBorder; public Color tShadow; public int tQuality; public string markPosition; /// /// 图片参数预定义 /// static Hashtable htmimes = new Hashtable(); internal readonly string AllowExt = ".jpe|.jpeg|.jpg|.png|.tif|.tiff|.bmp|.gif"; public XImage() { tBackground = Color.Transparent; tBorder = Color.Transparent; tShadow = Color.Transparent; tQuality = 100; markPosition = "左下角"; #region 图片类型预定义 htmimes[".jpe"]="image/jpeg"; htmimes[".jpeg"] = "image/jpeg"; htmimes[".jpg"] = "image/jpeg"; htmimes[".png"] = "image/png"; htmimes[".tif"] = "image/tiff"; htmimes[".tiff"] = "image/tiff"; htmimes[".bmp"] = "image/bmp"; htmimes[".gif"] = "image/gif"; #endregion } #region 下载指定URL图片并保存 /// /// 下载指定URL的文件并保存到指定目录 /// /// public void DownloadImage(string strUrl, string file) { System.Net.WebClient wc = new System.Net.WebClient(); wc.DownloadFile(strUrl, file); } #endregion #region C#自动生成缩略图 /// /// 按给定名字确定颜色 /// /// /// public Color ToColor(string name) { if (name == "白色") return Color.White; if (name == "红色") return Color.Red; if (name == "蓝色") return Color.Blue; if (name == "绿色") return Color.Green; if (name == "黑色") return Color.Black; if (name == "灰色") return Color.DarkGray; if (name == "黄色") return Color.Yellow; if (name == "紫色") return Color.Cyan; if (name == "无色") return Color.Transparent; return Color.Transparent; } /// /// 按名字设置各种颜色,可以自行扩充:) /// /// /// public int ToQuality(string name) { return Int32.Parse(name.Replace("%", "")); } /// /// 获取图像编码解码器的所有相关信息 /// /// 包含编码解码器的多用途网际邮件扩充协议 (MIME) 类型的字符串 /// 返回图像编码解码器的所有相关信息 private static ImageCodecInfo GetCodecInfo(string mimeType) { ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders(); foreach (ImageCodecInfo ici in CodecInfo) { if (ici.MimeType == mimeType) return ici; } return null; } /// /// 检测扩展名的有效性 /// /// 文件名扩展名 /// 如果扩展名有效,返回true,否则返回false. private bool CheckValidExt(string sExt) { bool flag = false; string[] aExt = AllowExt.Split("|"); foreach (string filetype in aExt) { if (filetype.ToLower() == sExt) { flag = true; break; } } return flag; } /// /// 保存图片 /// /// Image 对象 /// 保存路径 /// 指定格式的编解码参数 private void SaveImage(System.Drawing.Image image, string savePath, ImageCodecInfo ici) { //设置 原图片 对象的 EncoderParameters 对象 EncoderParameters parameters = new EncoderParameters(1); parameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, ((long)tQuality)); image.Save(savePath, ici, parameters); parameters.Dispose(); } /// /// 生成缩略图 /// /// 原图片路径(相对路径) /// 生成的缩略图路径,如果为空则保存为原图片路径(相对路径) /// 缩略图的宽度(高度与按源图片比例自动生成) public void ToThumbnail(string sourceImagePath, string thumbnailImagePath, int thumbnailImageWidth, int thumbnailImageHeight ) { // 1.先检查图片格式等信息 string ThumbnailImagePath = thumbnailImagePath; string SourceImagePath = sourceImagePath; string sExt = SourceImagePath.Substring(SourceImagePath.LastIndexOf(".")).ToLower(); if (SourceImagePath.ToString() == System.String.Empty) { throw new NullReferenceException("SourceImagePath is null!"); } if (!CheckValidExt(sExt)) { throw new ArgumentException("原图片文件格式不正确,支持的格式有[ " + AllowExt + " ]", "SourceImagePath"); } // 从原图片创建 Image 对象 System.Drawing.Image image = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(SourceImagePath)); // 2.计算图片的位置、尺寸等信息 int tWidth, tHeight, tLeft, tTop; double fScale = (double)thumbnailImageHeight / (double)thumbnailImageWidth; // 高度宽度比 if (((double)image.Width * fScale) > (double)image.Height) // 如果原图比较宽 { tWidth = thumbnailImageWidth; tHeight = (int)((double)image.Height * (double)tWidth / (double)image.Width); tLeft = 0; tTop = (thumbnailImageHeight-tHeight)/2; } else { tHeight = thumbnailImageHeight; tWidth = (int)((double)image.Width * (double)tHeight / (double)image.Height); tLeft = (thumbnailImageWidth-tWidth)/2; tTop = 0; } if (tLeft < 0) tLeft = 0; if (tTop < 0) tTop = 0; if (tBorder != Color.Transparent) { tWidth -= 2; tHeight -= 2; tLeft++; tTop++; } if (tShadow != Color.Transparent) { tWidth -= 1; tHeight -= 1; } //用指定的大小和格式初始化 Bitmap 类的新实例 //Bitmap bitmap = new Bitmap(ThumbnailImageWidth, num, PixelFormat.Format32bppArgb); Bitmap bitmap = new Bitmap(thumbnailImageWidth, thumbnailImageHeight, PixelFormat.Format32bppArgb); //从指定的 Image 对象创建新 Graphics 对象 Graphics graphics = Graphics.FromImage(bitmap); //清除整个绘图面并以透明背景色填充 if (tBackground != Color.Transparent) { graphics.Clear(tBackground); } else { graphics.Clear(Color.Transparent); } // 添加阴影 if (tShadow != Color.Transparent) { Pen shPen = new Pen(tShadow); graphics.DrawLine(shPen, new Point(1, thumbnailImageHeight-1), new Point(thumbnailImageWidth-1, thumbnailImageHeight-1)); graphics.DrawLine(shPen, new Point(thumbnailImageWidth-1, 1), new Point(thumbnailImageWidth-1, thumbnailImageHeight-1)); } // 添加边框 if (tBorder != Color.Transparent) { Pen bdPen = new Pen(tBorder); if (tShadow != Color.Transparent) { graphics.DrawRectangle(bdPen, new Rectangle(0, 0, thumbnailImageWidth-2, thumbnailImageHeight-2)); } else { graphics.DrawRectangle(bdPen, new Rectangle(0, 0, thumbnailImageWidth-1, thumbnailImageHeight-1)); } } //在指定位置并且按指定大小绘制 原图片 对象 graphics.DrawImage(image, new Rectangle(tLeft, tTop, tWidth, tHeight)); image.Dispose(); try { //将此 原图片 以指定格式并用指定的编解码参数保存到指定文件 string savepath = (ThumbnailImagePath == null ? SourceImagePath : ThumbnailImagePath); SaveImage(bitmap, HttpContext.Current.Server.MapPath(savepath), GetCodecInfo((string)htmimes[sExt])); } catch (System.Exception e) { throw e; } finally { bitmap.Dispose(); graphics.Dispose(); } } #endregion #region C#给图片添加水印 public void Mark(string sourceImagePath, string markString) { // 1.先检查图片格式等信息 string markImagePath = sourceImagePath; string SourceImagePath = sourceImagePath; string sExt = SourceImagePath.Substring(SourceImagePath.LastIndexOf(".")).ToLower(); if (SourceImagePath.ToString() == System.String.Empty) { throw new NullReferenceException("SourceImagePath is null!"); } if (!CheckValidExt(sExt)) { throw new ArgumentException("原图片文件格式不正确,支持的格式有[ " + AllowExt + " ]", "SourceImagePath"); } // 从原图片创建 Image 对象 System.Drawing.Image image = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(SourceImagePath)); //用指定的大小和格式初始化 Bitmap 类的新实例 Bitmap bitmap = new Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb); //从指定的 Image 对象创建新 Graphics 对象 Graphics graphics = Graphics.FromImage(bitmap); //在指定位置并且按指定大小绘制 原图片 对象 graphics.DrawImage(image, new Rectangle(0, 0, image.Width, image.Height)); #region 绘制水印 // 设置水印字体 int fHeight = image.Height/5; if(fHeight>16) fHeight = 16; Font drawFont = new Font("Arial", fHeight); // 设置水印文字位置,默认为左下角 float x = 4; float y = image.Height - drawFont.Height - 4; if (markPosition == "左上角") { y = 4; } if (markPosition == "右上角") { x = image.Width - markString.Length * fHeight / 2 - fHeight; y = 4; } if (markPosition == "右下角") { x = image.Width - markString.Length * fHeight / 2 - fHeight; } if (markPosition == "图片中间") { x = image.Width / 2 - markString.Length * fHeight / 2; y = image.Height / 2 - fHeight / 2; } StringFormat drawFormat = new StringFormat(); drawFormat.FormatFlags = StringFormatFlags.NoWrap; // 设置水印文字颜色,先绘制一个黑色字作为阴影,再绘制白色字,这样比较显眼; SolidBrush drawBrush = new SolidBrush(Color.Black); graphics.DrawString(markString, drawFont, drawBrush, x, y, drawFormat); drawBrush.Color = Color.White; graphics.DrawString(markString, drawFont, drawBrush, x-1, y-1, drawFormat); #endregion image.Dispose(); try { //将此 原图片 以指定格式并用指定的编解码参数保存到指定文件 string savepath = SourceImagePath; SaveImage(bitmap, HttpContext.Current.Server.MapPath(savepath), GetCodecInfo((string)htmimes[sExt])); } catch (System.Exception e) { throw e; } finally { bitmap.Dispose(); graphics.Dispose(); } } #endregion } }