protected function getChartElements(array $data)
    {
        $count = count($data);
        $step = $this->getStepWidth($count);
        $height = $this->getInnerNormalizedHeight();
        $normalizedPadding = $this->getNormalizedPadding();
        $data = $this->getDataForChartElements($data, $height);

        $pictureX1 = $pictureX2 = $normalizedPadding['left'];
        $pictureY1 = $normalizedPadding['top'] + $height - $data[0];

        $polygon = [];
        $line = [];

        // Initialize
        $polygon[] = $normalizedPadding['left'];
        $polygon[] = $normalizedPadding['top'] + $height;
        // First element
        $polygon[] = $pictureX1;
        $polygon[] = $pictureY1;
        for ($i = 1; $i < $count; ++$i) {
            $pictureX2 = $pictureX1 + $step;
            $pictureY2 = $normalizedPadding['top'] + $height - $data[$i];

            $line[] = [$pictureX1, $pictureY1, $pictureX2, $pictureY2];

            $polygon[] = $pictureX2;
            $polygon[] = $pictureY2;

            $pictureX1 = $pictureX2;
            $pictureY1 = $pictureY2;
        }
        // Last
        $polygon[] = $pictureX2;
        $polygon[] = $normalizedPadding['top'] + $height;

        return [$polygon, $line];
    }
protected function getChartElements(array $data)
    {
        $count = count($data);
        $step = $this->getStepWidth($count);
        $height = $this->getInnerNormalizedHeight();
        $normalizedPadding = $this->getNormalizedPadding();
        $data = $this->getDataForChartElements($data, $height);

        $pictureX1 = $pictureX2 = $normalizedPadding['left'];
        $pictureY1 = $normalizedPadding['top'] + $height - $data[0];

        $polygon = [];
        $line = [];

        // Initialize
        $polygon[] = $normalizedPadding['left'];
        $polygon[] = $normalizedPadding['top'] + $height;
        // First element
        $polygon[] = $pictureX1;
        $polygon[] = $pictureY1;
        for ($i = 1; $i < $count; ++$i) {
            $pictureX2 = $pictureX1 + $step;
            $pictureY2 = $normalizedPadding['top'] + $height - $data[$i];

            $line[] = [$pictureX1, $pictureY1, $pictureX2, $pictureY2];

            $polygon[] = $pictureX2;
            $polygon[] = $pictureY2;

            $pictureX1 = $pictureX2;
            $pictureY1 = $pictureY2;
        }
        // Last
        $polygon[] = $pictureX2;
        $polygon[] = $normalizedPadding['top'] + $height;

        return [$polygon, $line];
    }
@param array $data

@return array