我只是想重新调整图像尺寸而不会失去质量我可以使用它吗？
[HttpPost]
public ActionResult Index(HttpPostedFileBase file)
{
WebImage img = new WebImage(file.InputStream);
if (img.Width > 1000)
img.Resize(1000, 1000);
img.Save("path");
return View();
}
或WebImage调整大小但丢失图像质量？谢谢
这是我使用的代码。在你的行动中调用ResizeImage方法。
public class Size
{
public Size(int width, int height)
{
Width = width;
Height = height;
}
public int Width { get; set; }
public int Height { get; set; }
}
public static bool ResizeImage(string orgFile, string resizedFile, ImageFormat format, int width, int height)
{
try
{
using (Image img = Image.FromFile(orgFile))
{
Image thumbNail = new Bitmap(width, height, img.PixelFormat);
Graphics g = Graphics.FromImage(thumbNail);
g.CompositingQuality = CompositingQuality.HighQuality;
g.SmoothingMode = SmoothingMode.HighQuality;
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
Rectangle rect = new Rectangle(0, 0, width, height);
g.DrawImage(img, rect);
thumbNail.Save(resizedFile, format);
}
return true;
}
catch (Exception)
{
return false;
}
}
取自http://www.codeproject.com/Tips/481015/Rename-Resize-Upload-Image-ASP-NET-MVC。
首先要创建一个图像保存类（我只是复制和粘贴）
public class ImageResult
{
public bool Success { get; set; }
public string ImageName { get; set; }
public string ErrorMessage { get; set; }
}
然后你需要另一个类保存方法（我只需要复制和粘贴）
public class ImageUpload
{
// set default size here
public int Width { get; set; }
public int Height { get; set; }
// folder for the upload, you can put this in the web.config
private readonly string UploadPath = "~/Images/Items/";
public ImageResult RenameUploadFile(HttpPostedFileBase file, Int32 counter = 0)
{
var fileName = Path.GetFileName(file.FileName);
string prepend = "item_";
string finalFileName = prepend + ((counter).ToString()) + "_" + fileName;
if (System.IO.File.Exists
(HttpContext.Current.Request.MapPath(UploadPath + finalFileName)))
{
//file exists => add country try again
return RenameUploadFile(file, ++counter);
}
//file doesn't exist, upload item but validate first
return UploadFile(file, finalFileName);
}
private ImageResult UploadFile(HttpPostedFileBase file, string fileName)
{
ImageResult imageResult = new ImageResult { Success = true, ErrorMessage = null };
var path =
Path.Combine(HttpContext.Current.Request.MapPath(UploadPath), fileName);
string extension = Path.GetExtension(file.FileName);
//make sure the file is valid
if (!ValidateExtension(extension))
{
imageResult.Success = false;
imageResult.ErrorMessage = "Invalid Extension";
return imageResult;
}
try
{
file.SaveAs(path);
Image imgOriginal = Image.FromFile(path);
//pass in whatever value you want
Image imgActual = Scale(imgOriginal);
imgOriginal.Dispose();
imgActual.Save(path);
imgActual.Dispose();
imageResult.ImageName = fileName;
return imageResult;
}
catch (Exception ex)
{
// you might NOT want to show the exception error for the user
// this is generally logging or testing
imageResult.Success = false;
imageResult.ErrorMessage = ex.Message;
return imageResult;
}
}
// you can also create an Mvc dataannotation to validate the extension of image in both server side and client side
// don't forget to add (.JPG, .JPEG or .PNG on these extension, because you can facing this type of problem
private bool ValidateExtension(string extension)
{
extension = extension.ToLower();
switch (extension)
{
case ".jpg":
return true;
case ".png":
return true;
case ".gif":
return true;
case ".jpeg":
return true;
default:
return false;
}
}
private Image Scale(Image imgPhoto)
{
float sourceWidth = imgPhoto.Width;
float sourceHeight = imgPhoto.Height;
float destHeight = 0;
float destWidth = 0;
int sourceX = 0;
int sourceY = 0;
int destX = 0;
int destY = 0;
// force resize, might distort image
if (Width != 0 && Height != 0)
{
destWidth = Width;
destHeight = Height;
}
// change size proportially depending on width or height
else if (Height != 0)
{
destWidth = (float)(Height * sourceWidth) / sourceHeight;
destHeight = Height;
}
else
{
destWidth = Width;
destHeight = (float)(sourceHeight * Width / sourceWidth);
}
Bitmap bmPhoto = new Bitmap((int)destWidth, (int)destHeight,
PixelFormat.Format32bppPArgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
//you can also add these properties to improve the quality of saved image
grPhoto.SmoothingMode = SmoothingMode.HighQuality;
grPhoto.CompositingQuality = CompositingQuality.HighQuality;
grPhoto.PixelOffsetMode = PixelOffsetMode.HighQuality;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX, destY, (int)destWidth, (int)destHeight),
new Rectangle(sourceX, sourceY, (int)sourceWidth, (int)sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
return bmPhoto;
}
//you can also create another method to verify if a saved image with similar name exist and use it in som method of controller like (Modify your account
public ImageResult VerifyUploadFile(HttpPostedFileBase file)
{
var fileName = Path.GetFileName(file.FileName);
string finalFileName = UploadPath + fileName;
// si une telle image existe déjà, renvoyer le nom du fichier et dire que le succes est faux
if (System.IO.File.Exists
(HttpContext.Current.Request.MapPath(UploadPath + finalFileName)))
{
//file exists => sucess is false
return new ImageResult { Success = false, ErrorMessage = null, ImageName =finalFileName };
}
//file doesn't exist, upload item but validate first
return RenameUploadFile(file);
}
}
您可以根据需要在控制器中使用它
[HttpPost]
public ActionResult Index(FormCollection formCollection)
{
foreach (string item in Request.Files)
{
HttpPostedFileBase file = Request.Files[item] as HttpPostedFileBase;
if (file.ContentLength == 0)
continue;
if (file.ContentLength > 0)
{
// width + height will force size, care for distortion
//Exmaple: ImageUpload imageUpload = new ImageUpload { Width = 800, Height = 700 };
// height will increase the width proportionally
//Example: ImageUpload imageUpload = new ImageUpload { Height= 600 };
// width will increase the height proportionally
ImageUpload imageUpload = new ImageUpload { Width= 600 };
// rename, resize, and upload
//return object that contains {bool Success,string ErrorMessage,string ImageName}
ImageResult imageResult = imageUpload.RenameUploadFile(file);
if (imageResult.Success)
{
//TODO: write the filename to the db
Console.WriteLine(imageResult.ImageName);
}
else
{
// use imageResult.ErrorMessage to show the error
ViewBag.Error = imageResult.ErrorMessage;
}
}
}
return View();
}
您可以根据需要使用verifyupload。
var imagePhysicalPath = @"c://image.jpg";
var newImagePhysicalPath = @"c://new-image.jpg";
var image = new System.Web.Helpers.WebImage(imagePhysicalPath)
.Resize(width + 1, height + 1, false, true)//+1 because webimage use 1px for border
.Crop(1, 1) //remove border
.Save(newImagePhysicalPath);