ZForge.Controls.ExplorerBar.Expando.OnPaintDisplayRect C# (CSharp) Method

        protected void OnPaintDisplayRect(Graphics g)
        {
            // are we animating a fade
            if (this.animatingFade && this.AnimationImage != null)
            {
                // calculate the transparency value for the animation image
                float alpha = (((float) (this.Height - this.HeaderHeight)) / ((float) (this.ExpandedHeight - this.HeaderHeight)));

                float[][] ptsArray = {new float[] {1, 0, 0, 0, 0},
                                         new float[] {0, 1, 0, 0, 0},
                                         new float[] {0, 0, 1, 0, 0},
                                         new float[] {0, 0, 0, alpha, 0},
                                         new float[] {0, 0, 0, 0, 1}};

                ColorMatrix colorMatrix = new ColorMatrix(ptsArray);
                ImageAttributes imageAttributes = new ImageAttributes();
                imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);

                // work out how far up the animation image we need to start
                int y = this.AnimationImage.Height - this.PseudoClientHeight - this.Border.Bottom;

                // draw the image
                g.DrawImage(this.AnimationImage,
                    new Rectangle(0, this.HeaderHeight, this.Width, this.Height - this.HeaderHeight),
                    0,
                    y,
                    this.AnimationImage.Width,
                    this.AnimationImage.Height - y,
                    GraphicsUnit.Pixel,
                    imageAttributes);
            }
                // are we animating a slide
            else if (this.animatingSlide)
            {
                // check if we have a background image
                if (this.BackImage != null)
                {
                    // tile the backImage
                    using (TextureBrush brush = new TextureBrush(this.BackImage, WrapMode.Tile))
                    {
                        g.FillRectangle(brush, this.DisplayRectangle);
                    }
                }
                else
                {
                    // just paint the area with a solid brush
                    using (SolidBrush brush = new SolidBrush(this.BackColor))
                    {
                        g.FillRectangle(brush,
                            this.Border.Left,
                            this.HeaderHeight + this.Border.Top,
                            this.Width - this.Border.Left - this.Border.Right,
                            this.Height - this.HeaderHeight - this.Border.Top - this.Border.Bottom);
                    }
                }
            }
            else
            {
                // check if we have a background image
                if (this.BackImage != null)
                {
                    // tile the backImage
                    using (TextureBrush brush = new TextureBrush(this.BackImage, WrapMode.Tile))
                    {
                        g.FillRectangle(brush, this.DisplayRectangle);
                    }
                }
                else
                {
                    // just paint the area with a solid brush
                    using (SolidBrush brush = new SolidBrush(this.BackColor))
                    {
                        g.FillRectangle(brush, this.DisplayRectangle);
                    }
                }

                if (this.Watermark != null)
                {
                    // work out a rough location of where the watermark should go
                    Rectangle rect = new Rectangle(0, 0, this.Watermark.Width, this.Watermark.Height);
                    rect.X = this.PseudoClientRect.Right - this.Watermark.Width;
                    rect.Y = this.DisplayRectangle.Bottom - this.Watermark.Height;

                    // shrink the destination rect if necesary so that we
                    // can see all of the image

                    if (rect.X < 0)
                    {
                        rect.X = 0;
                    }

                    if (rect.Width > this.ClientRectangle.Width)
                    {
                        rect.Width = this.ClientRectangle.Width;
                    }

                    if (rect.Y < this.DisplayRectangle.Top)
                    {
                        rect.Y = this.DisplayRectangle.Top;
                    }

                    if (rect.Height > this.DisplayRectangle.Height)
                    {
                        rect.Height = this.DisplayRectangle.Height;
                    }

                    // draw the watermark
                    g.DrawImage(this.Watermark, rect);
                }
            }
        }