'**SUMMARY**
Draws the bounding rectangle for the blob.
**PARAMETERS**
* *color* - The color to render the blob\'s box.
* *alpha* - The alpha value of the rendered blob 0 = transparent 255 = opaque.
* *width* - The width of the drawn blob in pixels
* *layer* - if layer is not None, the blob is rendered to the layer versus the source image.
**RETURNS**
Returns None, this operation works on the supplied layer or the source image.
**EXAMPLE**
>>> img = Image("lenna")
>>> blobs = img.findBlobs()
>>> blobs[-1].drawRect(color=Color.RED, width=-1,alpha=128)
>>> img.show()'

def drawRect(self, layer=None, color=Color.DEFAULT, width=1, alpha=128):

    if (layer is None):
        layer = self.image.dl()
    if (width < 1):
        layer.rectangle(self.topLeftCorner(), (self.width(), self.height()), color, width, filled=True, alpha=alpha)
    else:
        layer.rectangle(self.topLeftCorner(), (self.width(), self.height()), color, width, filled=False, alpha=alpha)
