I am working on a little project on OpenCATS, developing some charts. In one of the charts, I need to add multiple plots to a PlotGroup and add Legends as well.

I have written a small function that creates the chart, however I have difficulty displaying the legends when I add them to a PlotGroup object.

Here is the code:

public function draw($format = false)
    {
            /* Make sure we have GD support. */
            if (!function_exists('imagecreatefromjpeg'))
            {
                    die();
            }

            if ($format === false)
            {
                    $format = IMG_PNG;
            }

            $group = new PlotGroup();
            $graph = new Graph($this->width, $this->height, NULL, 0, $this->width-135);

            $graph->setFormat($format);
            $graph->setBackgroundColor(new Color(0xF4, 0xF4, 0xF4));
            $graph->shadow->setSize(3);

            $graph->title->set($this->title);
            $graph->title->setFont(new Tuffy(10));
            $graph->title->setColor(new Color(0x00, 0x00, 0x8B));
            $graph->border->setColor(new Color(187, 187, 187, 15));

            $group->axis->bottom->setLabelText($this->xLabels);
            $group->axis->bottom->label->setFont(new Tuffy(8));
            $group->setPadding(25, 145, 10, 22);

            $plotcount = 0;
            $plot = array();
            foreach ($this->xValues as $xVal)
            {
                    $plotcount++;
                    $plot[$plotcount-1] = new LinePlot($xVal, LinePlot::LINE);
                    $plot[$plotcount-1]->setPadding(25, 145, 10, 22);
                    if ($plotcount % 5 ==0 )
                            $plot[$plotcount-1]->setColor(new Blue);
                    else if ($plotcount % 4 ==0 )
                            $plot[$plotcount-1]->setColor(new DarkGreen);
                    else if ($plotcount % 3 ==0 )
                            $plot[$plotcount-1]->setColor(new Red);
                    else if ($plotcount % 2 ==0 )
                            $plot[$plotcount-1]->setColor(new Orange);
                    $plot[$plotcount-1]->setThickness(2);
                    $plot[$plotcount-1]->legend->add($plot[$plotcount-1], $this->legends[$plotcount-1]);
                    $plot[$plotcount-1]->legend->setTextFont(new Tuffy(8));
                    $plot[$plotcount-1]->legend->setPadding(3, 3, 3, 3, 3);
                    $plot[$plotcount-1]->legend->setPosition(1, 0.825);
                    $plot[$plotcount-1]->legend->setBackgroundColor(new Color(0xFF, 0xFF, 0xFF));
                    $plot[$plotcount-1]->legend->border->setColor(new Color(0xD0, 0xD0, 0xD0));
                    $plot[$plotcount-1]->legend->shadow->setSize(0);

                    $group->add($plot[$plotcount-1]);
            }

            $graph->add($group);

            $graph->draw();
    }
}

If I draw only one LinePlot it works: So for instance if I change $graph->add($group); to $graph->add($plot[0]); then only one of the lines will show up with the legend next to it.