private RectangleF GetRandomImageRect(Database db, Rectangle screenRect, float imgWidth, float imgHeight)
        {
            var retries     = k_randomRectRetries;
            var bestRect    = new RectangleF(0.0f, 0.0f, 0.0f, 0.0f);
            var bestOverlap = -1.0f;
            var screenRectF = screenRect;
            var oldRects    = _theme.ImageRectHistory.ToArray();

            while (retries-- > 0)
            {
                var rect = new RectangleF(
                    (float)(_rand.NextDouble() * (screenRect.Width - imgWidth)) + screenRect.X,
                    (float)(_rand.NextDouble() * (screenRect.Height - imgHeight)) + screenRect.Y,
                    imgWidth, imgHeight);

                var overlap = 0.0f;

                for (int i = 0; i < oldRects.Length; i++)
                {
                    var ratio      = (double)(i + 1) / (double)oldRects.Length;
                    var importance = Math.Pow(ratio, Math.E);

                    overlap += oldRects[i].IntersectArea(rect) * (float)importance;
                }

                if (overlap < bestOverlap || bestOverlap < 0)
                {
                    bestRect    = rect;
                    bestOverlap = overlap;
                }
            }

            _theme.AddImageRectHistory(db, bestRect, _screenRects.Count);
            return(bestRect);
        }