图像在尝试调整大小时保持纵横比时被拉伸

Question

我正在使用以下代码调整图像大小，同时保持纵横比

 public Bitmap resizeImage(System.Drawing.Image imgToResize, SizeF size)
        {
            int sourceWidth = imgToResize.Width;
            int sourceHeight = imgToResize.Height;

            float nPercent = 0;
            float nPercentW = 0;
            float nPercentH = 0;

            nPercentW = ((float)size.Width / (float)sourceWidth);
            nPercentH = ((float)size.Height / (float)sourceHeight);

            if (nPercentH < nPercentW)
                nPercent = nPercentH;
            else
                nPercent = nPercentW;

            int destWidth = (int)(sourceWidth * nPercent);
            int destHeight = (int)(sourceHeight * nPercent);

            Bitmap b = new Bitmap(destWidth, destHeight);
            Graphics g = Graphics.FromImage((System.Drawing.Image)b);

            // Used to Prevent White Line Border 

           // g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

            g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
            g.Dispose();

            return b;
        }

但是宽度较大的图像会被压缩，内容似乎被压缩成一个小的 space.What 我试图实现的是：Resize the Large Size/Large分辨率图像，因为处理这将花费大量时间，因此当图像宽度或高度超过 1000 时，我想将图像调整为较小的尺寸 eg:1000 宽度或高度较大的一个，这样我可以节省计算time.But 当我这样做时，上面的代码似乎强行试图将图像放入 1000X1000 框

if (y.Width > 1000 || y.Height > 1000)
{

y = new Bitmap( resizeImage(y, new Size(1000, 1000)));

}

Answer 1

试试这个，它更整洁一些

public static Bitmap ResizeImage(Bitmap source, Size size)
{
   var scale = Math.Min(size.Width / (double)source.Width, size.Height / (double)source.Height);   
   var bmp = new Bitmap((int)(source.Width * scale), (int)(source.Height * scale));

   using (var graph = Graphics.FromImage(bmp))
   {
      graph.InterpolationMode = InterpolationMode.High;
      graph.CompositingQuality = CompositingQuality.HighQuality;
      graph.SmoothingMode = SmoothingMode.AntiAlias;
      graph.DrawImage(source, 0, 0, bmp.Width, bmp.Height);
   }
   return bmp;
}

图像在尝试调整大小时保持纵横比时被拉伸

Image Getting Stretched when trying to Resize It keeping the aspect Ratio

c#

.net

bitmap

gdi+

system.drawing