Specifies the miter limit. When two line segments meet at a sharp angle and miter joins have been specified for 'lineJoin', it is possible for the miter to extend far beyond the thickness of the line stroking the path. The miterLimit' imposes a limit on the ratio of the miter length to the 'lineWidth'.
Background color
 
Stroke color
 
Fill color
 
Specifies the miter limit. When two line segments meet at a sharp angle and miter joins have been specified for 'lineJoin', it is possible for the miter to extend far beyond the thickness of the line stroking the path. The miterLimit' imposes a limit on the ratio of the miter length to the 'lineWidth'.
Parameters
miterlimitintthe miter limit
function setStrokeMiterLimit($strokeColor, $fillColor, $backgroundColor)
{
    $draw = new \ImagickDraw();

    $draw->setStrokeColor($strokeColor);
    $draw->setStrokeOpacity(0.6);
    $draw->setFillColor($fillColor);
    $draw->setStrokeWidth(10);

    $yOffset = 100;

    $draw->setStrokeLineJoin(\Imagick::LINEJOIN_MITER);

    for ($y = 0; $y < 3; $y++) {
        $draw->setStrokeMiterLimit(40 * $y);

        $points = [['x' => 22 * 3, 'y' => 15 * 4 + $y * $yOffset], ['x' => 20 * 3, 'y' => 20 * 4 + $y * $yOffset], ['x' => 70 * 5, 'y' => 45 * 4 + $y * $yOffset],];

        $draw->polygon($points);
    }

    $image = new \Imagick();
    $image->newImage(500, 500, $backgroundColor);
    $image->setImageFormat("png");
    $image->drawImage($draw);

    $image->setImageType(\Imagick::IMGTYPE_PALETTE);
    //TODO - this should either be everywhere or nowhere
    $image->setImageCompressionQuality(100);
    $image->stripImage();

    header("Content-Type: image/png");
    echo $image->getImageBlob();
}