Done.

src/Element/Polyline/Polyline.php

@@ -4,9 +4,16 @@ namespace StaticMapLite\Element\Polyline;
 
 class Polyline
 {
+    /** @var string $polyline */
     protected $polyline = null;
+
+    /** @var int $colorRed */
     protected $colorRed = 0;
+
+    /** @var int $colorGreen */
     protected $colorGreen = 0;
+
+    /** @var int $colorBlue */
     protected $colorBlue = 0;
 
     public function __construct(string $polyline, int $colorRed = 0, int $colorGreen = 0, int $colorBlue = 0)

src/ElementPrinter/Polyline/PolylinePrinter.php

@@ -10,6 +10,9 @@ use StaticMapLite\Util;
 
 class PolylinePrinter
 {
+    /** @var int $thickness */
+    protected $thickness = 3;
+
     /** @var Polyline $polyline */
     protected $polyline = null;
 
@@ -40,11 +43,11 @@ class PolylinePrinter
 
             $endPoint = array_pop($pointList);
 
-            $canvas->getImage()->draw()->line($startPoint, $endPoint, $color, 3);
+            $canvas->getImage()->draw()->line($startPoint, $endPoint, $color, $this->thickness);
 
             $startPoint = $endPoint;
         }
-        
+
         return $this;
     }