Martin Bowlings Hacky Replacement ImageElement For MonoTouch.Dialog.cs

	
	public class ImageElement : Element {
		// The original ImageElement didn't scale the picture that was displayed as the thumbnail properly
		// this code probably needs lots of refactoring but I needed a quick solution.
		public UIImage Value;
		static RectangleF rect = new RectangleF (0, 0, dimx, dimy);
		static NSString ikey = new NSString ("ikey");
		UIImage scaled;
		
		// Apple leaks this one, so share across all.
		static UIImagePickerController picker;
		
		// Height for rows
		const int dimx = 48;
		const int dimy = 43;
		
		// radius for rounding
		const int rad = 10;
		
		// pi for image rotation
		const float M_PI = 3.141592653589793238462643f;
		
		static UIImage MakeEmpty ()
		{
			using (var cs = CGColorSpace.CreateDeviceRGB ()){
				using (var bit = new CGBitmapContext (IntPtr.Zero, dimx, dimy, 8, 0, cs, CGImageAlphaInfo.PremultipliedFirst)){
					bit.SetRGBStrokeColor (1, 0, 0, 0.5f);
					bit.FillRect (new RectangleF (0, 0, dimx, dimy));
					
					return UIImage.FromImage (bit.ToImage ());
				}
			}
		}
		
		UIImage Scale (UIImage source)
		{
			UIGraphics.BeginImageContext (new SizeF (dimx, dimy));
			var ctx = UIGraphics.GetCurrentContext ();
		
			var img = source.CGImage;
			ctx.TranslateCTM (0, dimy);
			if (img.Width > img.Height)
				ctx.ScaleCTM (1, -img.Width/dimy);
			else
				ctx.ScaleCTM (img.Height/dimx, -1);

			ctx.DrawImage (rect, source.CGImage);
			
			var ret = UIGraphics.GetImageFromCurrentImageContext ();
			UIGraphics.EndImageContext ();
			return ret;
		}
		
		UIImage Thumbnail (UIImage source)
		{
			SizeF size = source.Size; 
			float offsetY = 0;
			float offsetX = 0;
			SizeF croppedSize; 
			
			// check the size of the image, we want to make it
			// a square with sides the size of the smallest dimension
			if (size.Width  > size.Height) {
				offsetX = (size.Height - size.Width) / 2;
				croppedSize = new SizeF (size.Height, size.Height);
			} else {
				offsetY = (size.Width - size.Height) / 2;
				croppedSize = new SizeF (size.Width, size.Width);
			}
			
			// Crop the image before resize
			RectangleF clippedRect = new RectangleF (offsetX * -1 , offsetY * -1 , croppedSize.Width, croppedSize.Height);

			UIImage cropped = UIImage.FromImage(source.CGImage.WithImageInRect(clippedRect));
			// Done cropping
			
			UIGraphics.BeginImageContext (new SizeF (dimx, dimy));
			var ctx = UIGraphics.GetCurrentContext ();
			
			ctx.DrawImage (rect, cropped.CGImage);

			var ret = UIGraphics.GetImageFromCurrentImageContext ();
			UIGraphics.EndImageContext ();
			
			ret = FlipImage(ret);
			return ret;
			
		}
		
		public UIImage FlipImage(UIImage source)
		{
			UIGraphics.BeginImageContext (new SizeF (dimx, dimy));
			var ctx = UIGraphics.GetCurrentContext ();
		
		
			ctx.DrawImage (rect, source.CGImage);
			ctx.RotateCTM(M_PI);
			
			var ret = UIGraphics.GetImageFromCurrentImageContext ();
			UIGraphics.EndImageContext ();
			return ret;
		}
		
		public ImageElement (UIImage image) : base ("")
		{
			if (image == null){
				Value = MakeEmpty ();
				scaled = Value;
			} else {
				Value = image;			
				scaled = Thumbnail(Value);
			}
		}
		
		public override UITableViewCell GetCell (UITableView tv)
		{
			var cell = tv.DequeueReusableCell (ikey);
			if (cell == null){
				cell = new UITableViewCell (UITableViewCellStyle.Default, ikey);
			}
			
			if (scaled == null)
				return cell;
			
			Section psection = Parent as Section;
			bool roundTop = psection.Elements [0] == this;
			bool roundBottom = psection.Elements [psection.Elements.Count-1] == this;
			
			using (var cs = CGColorSpace.CreateDeviceRGB ()){
				using (var bit = new CGBitmapContext (IntPtr.Zero, dimx, dimy, 8, 0, cs, CGImageAlphaInfo.PremultipliedFirst)){
					// Clipping path for the image, different on top, middle and bottom.
					if (roundBottom){
						bit.AddArc (rad, rad, rad, (float) Math.PI, (float) (3*Math.PI/2), false);
					} else {
						bit.MoveTo (0, rad);
						bit.AddLineToPoint (0, 0);
					}
					bit.AddLineToPoint (dimx, 0);
					bit.AddLineToPoint (dimx, dimy);
					
					if (roundTop){
						bit.AddArc (rad, dimy-rad, rad, (float) (Math.PI/2), (float) Math.PI, false);
						bit.AddLineToPoint (0, rad);
					} else {
						bit.AddLineToPoint (0, dimy);
					}
					bit.Clip ();
					
					bit.DrawImage (rect, scaled.CGImage);
					
					cell.ImageView.Image = UIImage.FromImage (bit.ToImage ());
					cell.TextLabel.Text = "Add Photo";
					cell.Accessory = UITableViewCellAccessory.DisclosureIndicator;
				}
			}			
			return cell;
		}
		
		protected override void Dispose (bool disposing)
		{
			if (disposing){
				scaled.Dispose ();
				Value.Dispose ();
			}
			base.Dispose (disposing);
		}

		class MyDelegate : UIImagePickerControllerDelegate {
			ImageElement container;
			public MyDelegate (ImageElement container)
			{
				this.container = container;
			}
			
			public override void FinishedPickingImage (UIImagePickerController picker, UIImage image, NSDictionary editingInfo)
			{
				container.Picked (image);
			}
		}
		
		void Picked (UIImage image)
		{
			Value = image;
			scaled = Thumbnail (image);
			currentController.DismissModalViewControllerAnimated (true);
		}
		
		UIViewController currentController;
		public override void Selected (DialogViewController dvc, UITableView tableView, NSIndexPath path)
		{
			if (picker == null)
				picker = new UIImagePickerController ();
			picker.Delegate = new MyDelegate (this);
			dvc.ActivateController (picker);
			currentController = dvc;
		}
	}