Question

如何在.NET平台下用C#代码实现图片的上传与裁剪和压缩、

Answer 1

using System;
using System.Data;
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.IO;
using System.Drawing;

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

}
protected void Button1_Click(object sender, EventArgs e)
{

//检查上传文件的格式是否有效
if(this.FileUpload1.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
{
Response.Write("上传图片格式无效！");
return;
}
//生成原图
Byte[] oFileByte = new byte[this.FileUpload1.PostedFile.ContentLength];
System.IO.Stream oStream = this.FileUpload1.PostedFile.InputStream;
System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);
int oWidth = oImage.Width; //原图宽度
int oHeight = oImage.Height; //原图高度
int tWidth = 100; //设置缩略图初始宽度
int tHeight = 100; //设置缩略图初始高度
//按比例计算出缩略图的宽度和高度
if(oWidth >= oHeight)
{
tHeight = (int)Math.Floor(Convert.ToDouble(oHeight) * (Convert.ToDouble(tWidth)
/ Convert.ToDouble(oWidth)));
}
else
{
tWidth = (int)Math.Floor(Convert.ToDouble(oWidth) * (Convert.ToDouble(tHeight)
/ Convert.ToDouble(oHeight)));
}

//生成缩略原图
Bitmap tImage = new Bitmap(tWidth,tHeight);
Graphics g = Graphics.FromImage(tImage);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量插值法
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//设置高质量,低速度呈现平滑程度
g.Clear(Color.Transparent); //清空画布并以透明背景色填充
g.DrawImage(oImage,new Rectangle(0,0,tWidth,tHeight),
new Rectangle(0,0,oWidth,oHeight),GraphicsUnit.Pixel);
string oFullName = Server.MapPath(".") + "/" + "o" +
DateTime.Now.ToShortDateString().Replace("-","") + DateTime.Now.Hour.ToString()
+ DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString()
+ DateTime.Now.Millisecond.ToString() + ".jpg"; //保存原图的物理路径
string tFullName = Server.MapPath(".") + "/" + "t" +
DateTime.Now.ToShortDateString().Replace("-","") + DateTime.Now.Hour.ToString()
+ DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString()
+ DateTime.Now.Millisecond.ToString() + ".jpg"; //保存缩略图的物理路径
try
{
//以JPG格式保存图片
oImage.Save(oFullName,System.Drawing.Imaging.ImageFormat.Jpeg);
tImage.Save(tFullName,System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch(Exception ex)
{
throw ex;
}
finally
{
//释放资源
oImage.Dispose();
g.Dispose();
tImage.Dispose();
}
}
}