protected override void DoDraw(IBatchRenderer sbatch, FRectangle bounds)
{
var radiusOuter = Height / 2f;
var radiusInner = radiusOuter * KNOB_SCALE;
var knobPosition = new FPoint(bounds.Left + radiusOuter + (Width - 2 * radiusOuter) * _knobPosition, bounds.CenterY);
var knobColor = ColorMath.Blend(ColorStateOff, ColorStateOn, _knobPosition);
var textHeight = Height / 2;
// Background
SimpleRenderHelper.DrawRoundedRect(sbatch, bounds, ColorBackground, radiusOuter);
// Text[On]
if (!string.IsNullOrWhiteSpace(TextStateOn) && _knobPosition > 0)
{
var pos = new FPoint(bounds.Left + radiusOuter / 2, bounds.CenterY);
var alpha = FloatMath.Clamp(1.5f * _knobPosition, 0f, 1f);
if (alpha > 0)
{
FontRenderHelper.DrawTextVerticallyCentered(sbatch, Font, textHeight, TextStateOn, FontColor * alpha, pos);
}
}
// Text[Off]
if (!string.IsNullOrWhiteSpace(TextStateOff) && _knobPosition < 1)
{
var pos = new FPoint(bounds.Right - radiusOuter / 2, bounds.CenterY);
var alpha = FloatMath.Clamp(1 - 1.5f * _knobPosition, 0f, 1f);
if (alpha > 0)
{
FontRenderHelper.DrawTextVerticallyCenteredRightAligned(sbatch, Font, textHeight, TextStateOff, FontColor * alpha, pos);
}
}
// Knob
sbatch.DrawCentered(StaticTextures.MonoCircle, knobPosition, radiusInner * 2, radiusInner * 2, knobColor);
}