Plot pie chart error (frequency distribution analysis)

2 little bugs in this block:

  1. pen size: if i set the pensize outside the block, the render is problematic (weird) and the real size is not what we expect...

  2. the x,y parameters doesn't work as expected: x,y position change while height or width change, watch this:
    if width < height:

    if width > height:

When i look into the code, the x,y position seem to be bottom/left of pie chart like this:

I've made the correction here: <<< link

Thanks! I filed a PR.