This takes an HTML document that contains a client-side image map ( and elements) and creates an SVG image based on the shapes described in the image map (since SVG's a more general-purpose format than the HTML image map).
The HTML document doesn't necessarily have to be well-formed XML (there's a fallback to the BeautifulSoup parser for documents with some weirdness in them), which might be useful.
convert.py input_filename.html image_map_id
| #!/usr/bin/env python | |
| from itertools import islice, izip | |
| from lxml import etree, html | |
| import sys | |
| """ | |
| Takes a specified HTML, reads the client-side image map at the specified ID and | |
| generates an SVG of all of those areas. | |
| """ | |
| def parse_html(input_filename): | |
| """ | |
| Takes the filename of an HTML file and returns an ElementTree representation | |
| of its contents, using the BeautifulSoup parser as a fallback if needed. | |
| """ | |
| input_file = open(input_filename, 'rb') | |
| input_contents = input_file.read() | |
| input_file.close() | |
| # Thanks to http://lxml.de/elementsoup.html#using-soupparser-as-a-fallback | |
| # for this technique. | |
| html_root = html.fromstring(input_contents) | |
| try: | |
| ignore = etree.tostring(html_root, encoding=unicode) | |
| except UnicodeDecodeError: | |
| html_root = html.soupparser.fromstring(input_contents) | |
| return html_root | |
| def group_by(input_list, n): | |
| # Thanks to http://code.activestate.com/recipes/ | |
| # 303060-group-a-list-into-sequential-n-tuples/#c5 for this technique. | |
| return izip(*[islice(input_list, i, None, n) for i in range(n)]) | |
| def area_to_path_string(area): | |
| area_type = area.get('shape') | |
| coords_string = area.get('coords') | |
| if not area_type or not coords_string: | |
| return '' # This isn't good. | |
| # Make sure we have a comma-delimited set of integral coordinates. | |
| try: | |
| coords = [int(x.strip()) for x in coords_string.split(',')] | |
| except ValueError: | |
| return '' # Non-integral coordinates | |
| if area_type == 'polygon': | |
| # Draw a polygon as multiple line segments. | |
| if len(coords) % 2 != 0: | |
| return '' # Not an even number of coordinates | |
| coord_pairs = group_by(coords, 2) | |
| return 'M %s' % ' L '.join([ | |
| '%(x)s,%(y)s' % { | |
| 'x': point[0], | |
| 'y': point[1] | |
| } for point in coord_pairs | |
| ]) | |
| elif area_type == 'circle': | |
| # Draw a circle as two arcs. | |
| if len(coords) != 3: | |
| return '' # Not enough coordinates | |
| return 'M %(x)s,%(y)s m -%(r)s,0 a %(r)s,%(r)s 0 1,0 %(d)s,0 a %(r)s,%(r)s 0 1,0 -%(d)s,0' % { | |
| 'x': coords[0], | |
| 'y': coords[1], | |
| 'r': coords[2], | |
| 'd': 2 * coords[2] | |
| } | |
| else: # 'default' or 'rect' | |
| # Draw a rectangle as four line segments (three specified plus one | |
| # close-path command). | |
| if len(coords) != 4: | |
| return '' # Not enough coordinates | |
| return 'M %(xa)s,%(ya)s L %(xb)s,%(ya)s L %(xb)s,%(yb)s L %(xa)s,%(yb)s z' % { | |
| 'xa': coords[0], | |
| 'xb': coords[1], | |
| 'ya': coords[2], | |
| 'yb': coords[3] | |
| } | |
| return path_string | |
| def main(input_filename='', map_id=''): | |
| svg_root = etree.Element('svg', xmlns='http://www.w3.org/2000/svg') | |
| input_html = parse_html(input_filename) | |
| input_map = input_html.xpath('//*[@id="%s"]' % map_id) | |
| if input_map: | |
| input_map = input_map[0] | |
| # Build a path string for each class of <area> element in the specified map. | |
| input_map_classes = {} | |
| placeholder_counter = 0 | |
| for child in input_map: | |
| path_string = area_to_path_string(child) | |
| if 'class' in child.attrib: | |
| area_class = child.get('class') | |
| else: | |
| area_class = 'area_%s' % placeholder_counter | |
| placeholder_counter += 1 | |
| if area_class in input_map_classes: | |
| input_map_classes[area_class] += ' %s' % path_string | |
| else: | |
| input_map_classes[area_class] = path_string | |
| # Build a <path> element for each class and append it to the SVG tree. | |
| for area_class in input_map_classes: | |
| area_path = etree.Element('path') | |
| area_path.set('d', input_map_classes[area_class]) | |
| area_path.set('id', area_class) | |
| area_path.set('fill', 'none') | |
| area_path.set('stroke', 'black') | |
| area_path.set('stroke-width', '1') | |
| svg_root.append(area_path) | |
| output_svg = etree.ElementTree(svg_root) | |
| output_file = open('%s.svg' % input_filename, 'w') | |
| output_svg.write(output_file, encoding='utf-8', pretty_print=True, xml_declaration=True) | |
| output_file.close() | |
| if __name__ == '__main__': | |
| if len(sys.argv) != 3: | |
| sys.stderr.write("Usage: %s input_html map_id\n" % sys.argv[0]) | |
| sys.exit(1) | |
| else: | |
| main(*sys.argv[1:]) |