C# : How to resize image proportionately with max height

Question

我需要在不改变宽高比的情况下按比例调整图像大小。我有代码可以使用固定的高度和宽度调整大小，但我需要按最大高度(比如 600 像素)按比例调整图像大小。如何修改代码以满足我的要求？

public static void Main()
{
  var image = Image.FromFile(@"c:\logo.png");
  var newImage = ScaleImage(image, 300, 400);
  newImage.Save(@"c:\test.png", ImageFormat.Png);
}

public static Image ScaleImage(Image image, int maxWidth, int maxHeight)
 {
  var ratioX = (double)maxWidth / image.Width;
  var ratioY = (double)maxHeight / image.Height;
  var ratio = Math.Min(ratioX, ratioY);

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

  var newImage = new Bitmap(newWidth, newHeight);
  Graphics.FromImage(newImage).DrawImage(image, 0, 0, newWidth, newHeight);
  return newImage;
}

请提供您的宝贵意见。

Answer 1

这几乎感觉很简单，我觉得我错过了什么。无论如何，这不会奏效吗？

public static Image ScaleImage(Image image, int maxHeight) 
{ 
    var ratio = (double)maxHeight / image.Height; 

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

    var newImage = new Bitmap(newWidth, newHeight); 
    using (var g = Graphics.FromImage(newImage))
    {
        g.DrawImage(image, 0, 0, newWidth, newHeight); 
    }
    return newImage; 
}