public void setStrokeWithGradient(final boolean STROKE_WITH_GRADIENT) {
        if (null == strokeWithGradient) {
            _strokeWithGradient = STROKE_WITH_GRADIENT;
            fireTileEvent(REDRAW_EVENT);
        } else {
            if (!strokeWithGradient.isBound()) {
                strokeWithGradient.set(STROKE_WITH_GRADIENT);
            }
        }
    }
Defines the usage of a gradient defined by gradientStops to stroke the line
in the SparklineTileSkin
@param STROKE_WITH_GRADIENT
src/main/java/eu/hansolo/tilesfx/Tile.java