Example
// crop the image, without resizing
public static UIImage CropImage(this UIImage sourceImage, int crop_x, int crop_y, int width, int height)
{
var imgSize = sourceImage.Size;
UIGraphics.BeginImageContext(new SizeF(width, height));
var context = UIGraphics.GetCurrentContext();
var clippedRect = new RectangleF(0, 0, width, height);
context.ClipToRect(clippedRect);
var drawRect = new CGRect(-crop_x, -crop_y, imgSize.Width, imgSize.Height);
sourceImage.Draw(drawRect);
var modifiedImage = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return modifiedImage;
}
