c# - 如何调整图像大小并保存在文件夹中？

Question

我试过这个：

string str = System.IO.Path.GetFileName(txtImage.Text);
string pth = System.IO.Directory.GetCurrentDirectory() + "\\Subject";
string fullpath = pth + "\\" + str;

Image NewImage = clsImage.ResizeImage(fullpath, 130, 140, true);
NewImage.Save(fullpath, ImageFormat.Jpeg); 

---

public static Image ResizeImage(string file, int width, int height, bool onlyResizeIfWider)
{
    if (File.Exists(file) == false)
        return null;
    try
    {
        using (Image image = Image.FromFile(file))
        {
            // Prevent using images internal thumbnail
            image.RotateFlip(RotateFlipType.Rotate180FlipNone);
            image.RotateFlip(RotateFlipType.Rotate180FlipNone);
            if (onlyResizeIfWider == true)
            {
                if (image.Width <= width)
                {
                    width = image.Width;
                }
            }
            int newHeight = image.Height * width / image.Width;
            if (newHeight > height)
            {
                // Resize with height instead
                width = image.Width * height / image.Height;
                newHeight = height;
            }
            Image NewImage = image.GetThumbnailImage(width, newHeight, null, IntPtr.Zero);
            return NewImage;
        }
    }
    catch (Exception )
    {
        return null;
    }
}

运行上面的代码，我得到了一个 4-5 KB 大小的图像，图像质量很差。原始图像文件的大小不超过 1.5 MB。如何提高结果的图像质量？

Answer 1

我认为你应该使用Image Resizer，它免费和调整图像大小非常容易使用。

var settings = new ResizeSettings {
MaxWidth = thumbnailSize,
MaxHeight = thumbnailSize,
Format = "jpg"
};
settings.Add("quality", quality.ToString());
ImageBuilder.Current.Build(inStream, outStream, settings);
resized = outStream.ToArray(); 

您也可以使用 Nuget 包管理器安装它。

PM> Install-Package ImageResizer