feat: Turtle.CubicBezierCurve ( Fixes PoshWeb#230 )

Author: StartAutomating

Types/Turtle/CubicBezierCurve.ps1

@@ -0,0 +1,58 @@
+
+<#
+.SYNOPSIS
+    Draws a Bezier Curve
+.DESCRIPTION
+    Draws a simple Bezier curve.  
+.EXAMPLE
+    turtle @(
+        'CubicBezierCurve',
+            200,0,  # Start Control Point 
+            0,200,  # End Control Point
+            200,200 # End Point        
+    ) save ./cubic.svg
+.LINK
+    https://en.wikipedia.org/wiki/B%C3%A9zier_curve
+#>
+param(
+# The X control point
+[double]
+$ControlStartX,
+
+# The Y control point
+[double]
+$ControlStartY,
+
+# The X control point
+[double]
+$ControlEndX,
+
+# The Y control point
+[double]
+$ControlEndY,
+
+# The delta X
+[double]
+$DeltaX,
+
+# The delta Y
+[double]
+$DeltaY
+)
+
+
+
+if ($DeltaX -or $DeltaY) {
+    $this.Position = $DeltaX, $DeltaY
+    # If the pen is down
+    if ($this.IsPenDown) {
+        # draw the curve
+        $this.Steps.Add("c $ControlStartX $ControlStartY $ControlEndX $ControlEndY $DeltaX $DeltaY")
+    } else {        
+        # otherwise, move to the deltaX/deltaY
+        $this.Steps.Add("m $DeltaX $DeltaY")
+    }
+}
+
+return $this
+