ink_rect, logical_rect = playout:GetPixelExtents()
x, y, width, and height
fields initialized.
This function just calls playout:GetExtents() followed by
two pango.ExtentsToPixels() calls, rounding ink_rect and logical_rect
such that the rounded rectangles fully contain the unrounded one (that is,
passes them as first argument to pango.ExtentsToPixels().