public Line setPointColor(int pointColor) {
        this.pointColor = pointColor;
        if (pointColor == UNINITIALIZED) {
            this.darkenColor = ChartUtils.darkenColor(color);
        } else {
            this.darkenColor = ChartUtils.darkenColor(pointColor);
        }
        return this;
    }
Transparency of area when line is filled. *
hellocharts-library/src/lecho/lib/hellocharts/model/Line.java