ComponentFactory.Krypton.Toolkit.RenderStandard.DrawRibbonTabContext C# (CSharp) Method

        protected virtual IDisposable DrawRibbonTabContext(RenderContext context,
                                                           Rectangle rect,
                                                           IPaletteRibbonGeneral paletteGeneral,
                                                           IPaletteRibbonBack paletteBack,
                                                           IDisposable memento)
        {
            if ((rect.Width > 0) && (rect.Height > 0))
            {
                Color c1 = paletteGeneral.GetRibbonTabSeparatorContextColor(PaletteState.Normal);
                Color c2 = paletteBack.GetRibbonBackColor5(PaletteState.ContextCheckedNormal);

                bool generate = true;
                MementoRibbonTabContext cache;

                // Access a cache instance and decide if cache resources need generating
                if ((memento == null) || !(memento is MementoRibbonTabContext))
                {
                    if (memento != null)
                        memento.Dispose();

                    cache = new MementoRibbonTabContext(rect, c1, c2);
                    memento = cache;
                }
                else
                {
                    cache = (MementoRibbonTabContext)memento;
                    generate = !cache.UseCachedValues(rect, c1, c2);
                }

                // Do we need to generate the contents of the cache?
                if (generate)
                {
                    // Dispose of existing values
                    cache.Dispose();

                    Rectangle borderRect = new Rectangle(rect.X - 1, rect.Y - 1, rect.Width + 2, rect.Height + 2);
                    cache.fillRect = new Rectangle(rect.X + 1, rect.Y, rect.Width - 2, rect.Height - 1);

                    LinearGradientBrush borderBrush = new LinearGradientBrush(borderRect, c1, Color.Transparent, 270f);
                    borderBrush.Blend = _ribbonGroup5Blend;
                    cache.borderPen = new Pen(borderBrush);

                    LinearGradientBrush underlineBrush = new LinearGradientBrush(borderRect, Color.Transparent, Color.FromArgb(200, c2), 0f);
                    underlineBrush.Blend = _ribbonGroup7Blend;
                    cache.underlinePen = new Pen(underlineBrush);

                    cache.fillBrush = new LinearGradientBrush(borderRect, Color.FromArgb(196, c2), Color.Transparent, 270f);
                    cache.fillBrush.Blend = _ribbonGroup6Blend;
                }

                // Draw the left and right border lines
                context.Graphics.DrawLine(cache.borderPen, rect.X, rect.Y, rect.X, rect.Bottom - 1);
                context.Graphics.DrawLine(cache.borderPen, rect.Right - 1, rect.Y, rect.Right - 1, rect.Bottom - 1);

                // Fill the inner area with a gradient context specific color
                context.Graphics.FillRectangle(cache.fillBrush, cache.fillRect);

                // Overdraw the brighter line at bottom
                context.Graphics.DrawLine(cache.underlinePen, rect.X + 1, rect.Bottom - 1, rect.Right - 2, rect.Bottom - 1);
            }

            return memento;
        }