Get text boxes out of Ghostscript txtwrite xml

def page_get_textblocks(infile, pageno, xmltext, height):
    """Get text boxes out of Ghostscript txtwrite xml"""

    root = xmltext
    if not hasattr(xmltext, 'findall'):
        return []

    def blocks():
        for span in root.findall('.//span'):
            bbox_str = span.attrib['bbox']
            font_size = span.attrib['size']
            pts = [int(pt) for pt in bbox_str.split()]
            pts[1] = pts[1] - int(float(font_size) + 0.5)
            bbox_topdown = tuple(pts)
            bb = bbox_topdown
            bbox_bottomup = (bb[0], height - bb[3], bb[2], height - bb[1])
            yield bbox_bottomup

    def joined_blocks():
        prev = None
        for bbox in blocks():
            if prev is None:
                prev = bbox
            if bbox[1] == prev[1] and bbox[3] == prev[3]:
                gap = prev[2] - bbox[0]
                height = abs(bbox[3] - bbox[1])
                if gap < height:
                    # Join boxes
                    prev = (prev[0], prev[1], bbox[2], bbox[3])
                    continue
            # yield previously joined bboxes and start anew
            yield prev
            prev = bbox
        if prev is not None:
            yield prev

    return [block for block in joined_blocks()]