Program & Design

You can use this class to resize images proportionally (maintaining aspect ratio), or to resize an image to an exact size and crop off excess (useful for making nice thumbnails):

public static class ImageExt {

  public static Image Resize(this Image img, int srcX, int srcY, int srcWidth, int srcHeight, int dstWidth, int dstHeight) {

    var bmp = new Bitmap(dstWidth, dstHeight);

    using(var graphics = Graphics.FromImage(bmp)) {

      graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

      graphics.CompositingMode = CompositingMode.SourceCopy;

      graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;

      using(var wrapMode = new ImageAttributes()) {

        wrapMode.SetWrapMode(WrapMode.TileFlipXY);

        var destRect = new Rectangle(0, 0, dstWidth, dstHeight);

        graphics.DrawImage(img, destRect, srcX, srcY, srcWidth, srcHeight, GraphicsUnit.Pixel, wrapMode);

      }

    }

    return bmp;

  }



  public static Image ResizeProportional(this Image img, int width, int height, bool enlarge = false) {

    double ratio = Math.Max(img.Width / (double) width, img.Height / (double) height);

    if (ratio < 1 && !enlarge) return img;

    return img.Resize(0, 0, img.Width, img.Height, M2.Round(img.Width / ratio), M2.Round(img.Height / ratio));

  }

  public static Image ResizeCropExcess(this Image img, int dstWidth, int dstHeight) {

    double srcRatio = img.Width / (double) img.Height;

    double dstRatio = dstWidth / (double) dstHeight;

    int srcX,

    srcY,

    cropWidth,

    cropHeight;

    if (srcRatio < dstRatio) // trim top and bottom 

    {

      cropHeight = dstHeight * img.Width / dstWidth;

      srcY = (img.Height - cropHeight) / 2;

      cropWidth = img.Width;

      srcX = 0;

    } else // trim left and right 

    {

      cropWidth = dstWidth * img.Height / dstHeight;

      srcX = (img.Width - cropWidth) / 2;

      cropHeight = img.Height;

      srcY = 0;

    }

    return Resize(img, srcX, srcY, cropWidth, cropHeight, dstWidth, dstHeight);

  }

}

You can use this little function to convert a decimal to any base. I use it for compacting large numbers.

Or you can use it to make a nice GUID:

This is a simple class I wrote to nicely format a JSON string. Just call it with JsonFormatter.PrettyPrint(yourJsonString)

A couple times now I’ve wanted to subtract one set (`HashSet`) from another. `HashSet` has a method ExceptWith that does just this, except that it modifies the current set in place. What if you don’t want that? You need to copy it first.

Or you could use Linq’s Except method, except that it returns `IEnumerable` instead of a `HashSet`. What if you don’t want that? You need to convert it.

So… which method is faster? Let’s find out!

On my computer, this outputs:

Linq: 1291 ms
Native: 756 ms

So, clearly the second method is faster. About 40% for you math types.

I should note that “clone” isn’t really a clone, it’s a shallow copy. Only the container class itself is “cloned”; the elements still refer their originals.