Vietpad.NET.Controls.ToolStripRadioButtonMenuItem.OnPaint C# (CSharp) Method

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            // If the client sets the Image property, the selection behavior
            // remains unchanged, but the RadioButton is not displayed and the
            // selection is indicated only by the selection rectangle. 
            if (Image != null) return;

            // Determine the correct state of the RadioButton.
            RadioButtonState buttonState = RadioButtonState.UncheckedNormal;
            if (Enabled)
            {
                if (mouseDownState)
                {
                    if (Checked) buttonState = RadioButtonState.CheckedPressed;
                    else buttonState = RadioButtonState.UncheckedPressed;
                }
                else if (mouseHoverState)
                {
                    if (Checked) buttonState = RadioButtonState.CheckedHot;
                    else buttonState = RadioButtonState.UncheckedHot;
                }
                else
                {
                    if (Checked) buttonState = RadioButtonState.CheckedNormal;
                }
            }
            else
            {
                if (Checked) buttonState = RadioButtonState.CheckedDisabled;
                else buttonState = RadioButtonState.UncheckedDisabled;
            }

            // Calculate the position at which to display the RadioButton.
            Int32 offset = (ContentRectangle.Height -
                RadioButtonRenderer.GetGlyphSize(
                e.Graphics, buttonState).Height) / 2;
            Point imageLocation = new Point(
                ContentRectangle.Location.X + 4,
                ContentRectangle.Location.Y + offset);

            // If the item is selected and the RadioButton paints with partial
            // transparency, such as when theming is enabled, the check mark
            // shows through the RadioButton image. In this case, paint a 
            // non-transparent background first to cover the check mark.
            if (Checked && RadioButtonRenderer
                .IsBackgroundPartiallyTransparent(buttonState))
            {
                Size glyphSize = RadioButtonRenderer
                    .GetGlyphSize(e.Graphics, buttonState);
                glyphSize.Height--;
                glyphSize.Width--;
                Rectangle backgroundRectangle =
                    new Rectangle(imageLocation, glyphSize);
                e.Graphics.FillEllipse(
                    SystemBrushes.Control, backgroundRectangle);
            }

            RadioButtonRenderer.DrawRadioButton(
                e.Graphics, imageLocation, buttonState);
        }