PChart linear chart image quality : <p>I am using PChart to create linear charts. Everything goes well beside the quality of the actual lines drawn.</p>

<p>Of course, antialiasing is <em>not</em> turned off, and even explicitly turned on. </p>

<p>Here is an example of the actual image, which looks quite ugly with all these steps. </p>

<p><a href="https://i.stack.imgur.com/6NRzG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6NRzG.png" alt="enter image description here"></a></p>

<p>Is there a way to make the lines drawn smoother, without stepping?</p>

<p>The code used:</p>

<pre><code>public function linearTwoAxis($data, $fileName, $startColor = 0)
{
    $pData = new \pData();

    $i = 0;
    foreach ($data as $key =&gt; $row)
    {
        $serie = $this-&gt;translator-&gt;trans("pages.reportDefault.$key");
        $pData-&gt;addPoints($row, $serie);
        $pData-&gt;setSerieOnAxis($serie, $i);
        $pData-&gt;setSerieWeight($serie, 1);
        $pData-&gt;setAxisName($i, $serie);
        $pData-&gt;setPalette($serie, $this-&gt;colors[$startColor++]);
        $pData-&gt;setAxisDisplay($i, AXIS_FORMAT_METRIC);
        $i++;
    }
    $monthNames = array_keys($row);

    $pData-&gt;setAxisPosition(1, AXIS_POSITION_RIGHT);
    $pData-&gt;addPoints($monthNames, "Labels");
    $pData-&gt;setAbscissa("Labels");

    $pChart = new \pImage(750, 200, $pData);

    $pChart-&gt;setFontProperties(array(
        "FontName" =&gt; $this-&gt;fonts_dir . "arial.ttf",
        "FontSize" =&gt; 8)
    );

    $pChart-&gt;setGraphArea(50, 10, 700, 150);
    $pChart-&gt;Antialias = TRUE;
    $pChart-&gt;drawScale(["Mode"  =&gt; SCALE_MODE_START0]);
    $pChart-&gt;drawLineChart();
    $pChart-&gt;drawLegend(325,180,array("Style"=&gt;LEGEND_BOX,"Mode"=&gt;LEGEND_HORIZONTAL, "BoxWidth"=&gt;30,"Family"=&gt;LEGEND_FAMILY_LINE,"Alpha" =&gt; 0));

    $pChart-&gt;render($this-&gt;target_dir . $fileName);

    return $this-&gt;target_dirname . $fileName;
}
</code></pre>
