此文檔爲：記錄asp.net後臺上傳圖片時，根據需要對圖片的處理功能。可以對圖片進行任意比例的縮放和在圖片上添加任意水印（文字水印，圖片水印，文字+圖片）
protected void Up_load_btn_Click(object sender, EventArgs e)
{string fileUrl = "";
if (Up_load.HasFile)
{
try
{
//取得當前系統時間
string systemDateString = DateTime.Now.ToString("yyyyMMddhhmmss");
string ImageNewName = systemDateString + "_" + 2;
string path = Request.MapPath("~/attached/");
fileUrl = string.IsNullOrEmpty(this.Up_load.FileName.Trim()) ? "" : ImageNewName + System.IO.Path.GetExtension(this.Up_load.FileName); //得到名字+擴展名（例如20001265466.jpg）
if (!string.IsNullOrEmpty(fileUrl))
{
this.Up_load.PostedFile.SaveAs(path + fileUrl);//保存圖片
// MakeThumbnail(path + fileUrl, path + "xiaotu\\" + fileUrl, 100, 100, "HW");
//AddWaterText(path + fileUrl, path + "xiaotu\\" + fileUrl);
AddWaterPic(path + fileUrl, path + "xiaotu\\" + fileUrl, path +"pngYOYO.png" );
}
}
catch (Exception ex)
{
throw ex;
}
Response.Redirect("UploadImg.aspx");
}
}
/// <summary>
/// 生成縮略圖
/// </summary>
/// <param name="originalImagePath">源圖路徑（物理路徑）</param>
/// <param name="thumbnailPath">縮略圖路徑（物理路徑）</param>
/// <param name="width">縮略圖寬度</param>
/// <param name="height">縮略圖高度</param>
/// <param name="mode">生成縮略圖的方式</param>
public void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
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;
switch (mode)
{
case "HW"://指定高寬縮放（可能變形）
break;
case "W"://指定寬，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case "H"://指定高，寬按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case "Cut"://指定高寬裁減（不變形）
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;
}
//新建一個bmp圖片
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
//新建一個畫板
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
//設置高質量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//設置高質量,低速度呈現平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//清空畫布並以透明背景色填充
g.Clear(System.Drawing.Color.Transparent);
//在指定位置並且按指定大小繪製原圖片的指定部分
g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
new System.Drawing.Rectangle(x, y, ow, oh),
System.Drawing.GraphicsUnit.Pixel);
try
{
//以jpg格式保存縮略圖
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
/**/
/// <summary>
/// 在圖片上增加文字水印
/// </summary>
/// <param name="Path">原服務器圖片路徑</param>
/// <param name="Path_sy">生成的帶文字水印的圖片路徑</param>
protected void AddWaterText(string Path, string Path_sy)
{
string addText = "誠品旅行";
System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
g.DrawImage(image, 0, 0, image.Width, image.Height);
System.Drawing.Font f = new System.Drawing.Font("微軟雅黑", 12 ); //字體大小爲12
System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.White);
g.DrawString(addText, f, b, 530, 255); //字體位置爲距離左邊：530px，距離上邊：255px
g.Dispose();
string addText_1 = "www.yoyo978.com";
System.Drawing.Graphics g_1 = System.Drawing.Graphics.FromImage(image);
g_1.DrawImage(image, 0, 0, image.Width, image.Height);
System.Drawing.Font f_1 = new System.Drawing.Font("微軟雅黑", 12); //字體大小爲12
System.Drawing.Brush b_1 = new System.Drawing.SolidBrush(System.Drawing.Color.White);
g_1.DrawString(addText_1, f_1, b_1, 490, 275); //字體位置爲左上空14
g_1.Dispose();
image.Save(Path_sy);
image.Dispose();
}
/**/
/// <summary>
/// 在圖片上生成圖片水印
/// </summary>
/// <param name="Path">原服務器圖片路徑</param>
/// <param name="Path_syp">生成的帶圖片水印的圖片路徑</param>
/// <param name="Path_sypf">水印圖片路徑</param>
protected void AddWaterPic(string Path, string Path_syp, string Path_sypf)
{
System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
g.DrawImage(copyImage, new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, System.Drawing.GraphicsUnit.Pixel);
g.Dispose();
image.Save(Path_syp);
image.Dispose();
}