func (p CheckboxPainter) PaintCheckbox(canvas widget.Canvas, state checkbox.PaintState) {
	if state.Bounds.IsEmpty() {
		return
	}

	colors := state.ColorScheme
	if colors == (checkbox.CheckboxColorScheme{}) {
		colors = p.resolveColors()
	}

	boxRect := flCheckboxBoxRect(state.Bounds)
	disabled := state.Disabled

	if state.Checked || state.Indeterminate {
		flPaintCheckedBox(canvas, boxRect, state, disabled, colors)
	} else {
		flPaintUncheckedBox(canvas, boxRect, state, disabled, colors)
	}

	// Label.
	if state.Label != "" {
		fg := colors.LabelColor
		if disabled {
			fg = colors.DisabledFg
		}
		labelBounds := flCheckboxLabelBounds(state.Bounds)
		canvas.DrawText(state.Label, labelBounds, flCBFontSize, fg, false, flCBTextAlignLeft)
	}

	// Focus indicator.
	if state.Focused && !disabled {
		flDrawFocusRing(canvas, boxRect, flCBCornerRadius, colors.FocusRing)
	}
}

type CheckboxPainter struct {
	Theme *Theme	// nil uses default Fluent Blue fallback
}