function plot_histogram($image_filename, $param)
{
extract($param);
$histo = get_histogram($image_filename);
if (empty($histo)) {
return;
}
for ($i = 0; $i < 256; $i++) {
$data[$i] = array('', $histo[$i]);
}
$p = new PHPlot_truecolor($plot_image_width, $plot_image_height);
$p->SetFileFormat('jpg');
$p->SetBgImage($image_filename, 'scale');
$p->SetDataType('text-data');
$p->SetDrawXAxis(False);
$p->SetDrawYAxis(False);
$p->SetDataValues($data);
$p->SetXDataLabelPos('none');
$p->SetXTickLabelPos('none');
$p->SetYTickLabelPos('none');
$p->SetXTickPos('none');
$p->SetYTickPos('none');
$p->SetDrawYGrid(False);
$p->SetDataColors($histogram_color, NULL, $histogram_alpha);
$p->SetPlotType('thinbarline');
if ($draw_border) {
$p->SetGridColor($border_color);
$p->SetPlotBorderType('full');
} else {
$p->SetPlotBorderType('none');
}
# Compute the position of the histogram plot within the image.
$hx0 = (int) ($hx * $plot_image_width);
$hy0 = (int) ($hy * $plot_image_height);
$hx1 = (int) ($h_width * $plot_image_width) + $hx0;
$hy1 = (int) ($h_height * $plot_image_height) + $hy0;
$p->SetPlotAreaPixels($hx0, $hy0, $hx1, $hy1);
$p->DrawGraph();
}