'**SUMMARY**
Draw the blob contour the provided layer -- if no layer is provided, draw
to the source image.
**PARAMETERS**
* *color* - The color to render the blob.
* *alpha* - The alpha value of the rendered poly.
* *width* - The width of the drawn blob in pixels, -1 then the polygon is filled.
* *layer* - if layer is not None, the blob is rendered to the layer versus the source image.
**RETURNS**
This method either works on the original source image, or on the drawing layer provided.
The method does not modify object itself.
**EXAMPLE**
>>> img = Image("lenna")
>>> blobs = img.findBlobs()
>>> blobs[-2].drawOutline(color=Color.GREEN,width=3,alpha=128)
>>> img.show()'

def drawOutline(self, color=Color.GREEN, alpha=255, width=1, layer=None):

    if (layer is None):
        layer = self.image.dl()
    if (width < 0):
        layer.polygon(self.mContour, color, filled=True, alpha=alpha)
    else:
        lastp = self.mContour[0]
        for nextp in self.mContour[1::None]:
            layer.line(lastp, nextp, color, width=width, alpha=alpha, antialias=False)
            lastp = nextp
        layer.line(self.mContour[0], self.mContour[(-1)], color, width=width, alpha=alpha, antialias=False)
