Question

我希望将图片尺寸减小到不超过50 kb。

这里我给出了我在申请中使用的代码。

byte[] imageSize = new byte[FileUpload1.PostedFile.ContentLength];
HttpPostedFile uploadedImage = FileUpload1.PostedFile;
uploadedImage.InputStream.Read(imageSize(int)FileUpload1.PostedFile.ContentLength);
var fileLength1 = (FileUpload1.FileContent.Length.ToString());
byte[] ImageData = GenerateThumbnails(0.005, uploadedImage.InputStream);

private byte[] GenerateThumbnails(double scaleFactor, Stream sourcePath) {
  var image = System.Drawing.Image.FromStream(sourcePath);
  var newWidth = (int)(image.Width * scaleFactor);
  var newHeight = (int)(image.Height * scaleFactor);
  var thumbnailImg = new Bitmap(newWidth, newHeight);
  var thumbGraph = Graphics.FromImage(thumbnailImg);
  thumbGraph.CompositingQuality = CompositingQuality.HighQuality;
  thumbGraph.SmoothingMode = SmoothingMode.HighQuality;
  thumbGraph.InterpolationMode = InterpolationMode.HighQualityBicubic;
  var imageRectangle = new Rectangle(0, 0, newWidth, newHeight);
  thumbGraph.DrawImage(image, imageRectangle);
  MemoryStream ms = new MemoryStream();
  image.Save(ms, ImageFormat.Jpeg);
  return ms.ToArray();    
}

这里函数GenerateThumbnails减少了图片的实际尺寸，但它非常低。假设我上传了大小为800kb的图像，该功能将从800kb减少仅40kb。影响我网站性能的图像大小。

Answer 1

你也可以使用Thumbnailimagemethod ......它似乎正是你想要的。（我没有测试压缩，但它绝对会影响图像）

Image FinalImage = Image.FromFile(@"yourPath").GetThumbnailImage(X, Y, () => false, IntPtr.Zero);

您也可以使用较低的InterpolationMode，CompositingQuality和SmoothingMode。

Answer 2

降低图像分辨率可能会导致生成低尺寸图像，

更改scaleFactor值＆lt; 0.5，在您现有的代码中。

var newWidth = (int)(image.Width * scaleFactor);
var newHeight = (int)(image.Height * scaleFactor);

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2 个答案: