System.Windows.Forms.MdiClient.SizeScrollBars C# (CSharp) Method

		internal void SizeScrollBars ()
		{
			if (lock_sizing)
				return;
			
			if (!IsHandleCreated)
				return;

			if (Controls.Count == 0 || ((Form) Controls [0]).WindowState == FormWindowState.Maximized) {
				if (hbar != null)
					hbar.Visible = false;
				if (vbar != null)
					vbar.Visible = false;
				if (sizegrip != null)
					sizegrip.Visible = false;
				return;
			}

			int right = 0;
			int left = 0;
			int top = 0;
			int bottom = 0;

			foreach (Form child in Controls) {
				if (!child.Visible)
					continue;
				if (child.Right > right)
					right = child.Right;
				if (child.Left < left) {
					left = child.Left;
				}
				
				if (child.Bottom > bottom)
					bottom = child.Bottom;
				if (child.Top < 0) {
					top = child.Top;
				}
			}

			int available_width = ClientSize.Width;
			int available_height = ClientSize.Height;

			bool need_hbar = false;
			bool need_vbar = false;

			if (right - left > available_width || left < 0) {
				need_hbar = true;
				available_height -= SystemInformation.HorizontalScrollBarHeight;
			}
			if (bottom - top > available_height || top < 0) {
				need_vbar = true;
				available_width -= SystemInformation.VerticalScrollBarWidth;

				if (!need_hbar && (right - left > available_width || left < 0)) {
					need_hbar = true;
					available_height -= SystemInformation.HorizontalScrollBarHeight;
				}
			}
			
			if (need_hbar) {
				if (hbar == null) {
					hbar = new ImplicitHScrollBar ();
					Controls.AddImplicit (hbar);
				}
				hbar.Visible = true;
				CalcHBar (left, right, need_vbar);
			} else if (hbar != null)
				hbar.Visible = false;

			if (need_vbar) {
				if (vbar == null) {
					vbar = new ImplicitVScrollBar ();
					Controls.AddImplicit (vbar);
				}
				vbar.Visible = true;
				CalcVBar (top, bottom, need_hbar);
			} else if (vbar != null)
				vbar.Visible = false;

			if (need_hbar && need_vbar) {
				if (sizegrip == null) {
					sizegrip = new SizeGrip (this.ParentForm);
					Controls.AddImplicit (sizegrip);
				}
				sizegrip.Location = new Point (hbar.Right, vbar.Bottom);
				sizegrip.Visible = true;
				XplatUI.SetZOrder (sizegrip.Handle, vbar.Handle, false, false);
			} else if (sizegrip != null) {
				sizegrip.Visible = false;
			}
			
			XplatUI.InvalidateNC (Handle);
		}