/// <summary>
/// 为图片生成缩略图
/// </summary>
/// <param name="phyPath">原图片的路径</param>
/// <param name="width">缩略图宽</param>
/// <param name="height">缩略图高</param>
/// <returns></returns>
public System.Drawing.Image GetThumbnail(System.Drawing.Image image, int width, int height)
{
Bitmap bmp = new Bitmap(width, height);
//从Bitmap创建一个System.Drawing.Graphics
System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bmp);
//设置
gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//下面这个也设成高质量
gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
//下面这个设成High
gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
//把原始图像绘制成上面所设置宽高的缩小图
System.Drawing.Rectangle rectDestination = new System.Drawing.Rectangle(0, 0, width, height);
gr.DrawImage(image, rectDestination, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel);
return bmp;
}
调用方法
HttpPostedFile file = photoFile.PostedFile;
if (!file.ContentType.Contains("image"))
{
return "照片格式不合法";
}
string ext = Path.GetExtension(file.FileName).ToLower();
if (ext != ".jpg" && ext != ".gif" && ext != ".png" && ext != ".jpeg")
{
return "请您上传jpg、gif、png图片";
}
if (file.ContentLength > 5 * 1024 * 1024)
{
return "请您上传512字节内的图片";
}
string newName = Guid.NewGuid().ToString();
string tempPath = "upload/";
string img = tempPath + newName + ext;
string filePath = Server.MapPath(img);
if (!Directory.Exists(tempPath))
{
Directory.CreateDirectory(tempPath);
}
using (System.Drawing.Image originalImage = System.Drawing.Image.FromStream(file.InputStream))
{
GetThumbnail(originalImage, 504, 374).Save(filePath);
}