Gradient fill below line

    @Override
    public void drawSeries(Canvas canvas, Paint paint, float[] points,
            SimpleSeriesRenderer seriesRenderer, float yAxisValue, int seriesIndex, int startIndex) {
        int length = points.length;
        XYSeriesRenderer renderer = (XYSeriesRenderer) seriesRenderer;
        float lineWidth = paint.getStrokeWidth();
        paint.setStrokeWidth(renderer.getLineWidth());
        if (renderer.isFillBelowLine() || renderer.isGradientEnabled()) {
            int pLength = points.length;
            float[] fillPoints = new float[pLength + 4];
            System.arraycopy(points, 0, fillPoints, 0, length);
            fillPoints[0] = points[0] + 1;
            fillPoints[length] = fillPoints[length - 2];
            fillPoints[length + 1] = yAxisValue;
            fillPoints[length + 2] = fillPoints[0];
            fillPoints[length + 3] = fillPoints[length + 1];
            float max = 0;
            for (int i = 0; i < length + 4; i += 2) {
                if (fillPoints[i + 1] < 0) {
                    fillPoints[i + 1] = 0;
                }
                else if (fillPoints[i + 1] > max) {
                    max = fillPoints[i + 1];
                }
            }
            paint.setStyle(Style.FILL);
            if (renderer.isGradientEnabled()) {
                Shader s = paint.getShader();
                // Create gradient from values set in renderer
                paint.setShader(new LinearGradient(0, (float)(renderer.getGradientStartValue() * max), 0, (float)(renderer.getGradientStopValue() * max),
                        renderer.getGradientStartColor(), renderer.getGradientStopColor(), Shader.TileMode.MIRROR));
                drawPath(canvas, fillPoints, paint, true);
                // Restore paint's shader to previous value (null)
                paint.setShader(s);
            }
            else {
                paint.setColor(renderer.getFillBelowLineColor());
                drawPath(canvas, fillPoints, paint, true);
            }
        }
        paint.setColor(seriesRenderer.getColor());
        paint.setStyle(Style.STROKE);
        drawPath(canvas, points, paint, false);
        paint.setStrokeWidth(lineWidth);
    }