def magnify_fonts(self, factor): # Magnify all font sizes defined in the book by the specified factor # First we create a restore point so that the user can undo all changes # we make. self.boss.add_savepoint('Before: Magnify fonts') container = self.current_container # The book being edited as a container object # Iterate over all style declarations in the book, this means css # stylesheets, <style> tags and style="" attributes for name, media_type in container.mime_map.items(): if media_type in OEB_STYLES: # A stylesheet. Parsed stylesheets are css_parser CSSStylesheet # objects. self.magnify_stylesheet(container.parsed(name), factor) container.dirty(name) # Tell the container that we have changed the stylesheet elif media_type in OEB_DOCS: # A HTML file. Parsed HTML files are lxml elements for style_tag in container.parsed(name).xpath('//*[local-name="style"]'): if style_tag.text and style_tag.get('type', None) in {None, 'text/css'}: # We have an inline CSS <style> tag, parse it into a # stylesheet object sheet = container.parse_css(style_tag.text) self.magnify_stylesheet(sheet, factor) style_tag.text = serialize(sheet, 'text/css', pretty_print=True) container.dirty(name) # Tell the container that we have changed the stylesheet for elem in container.parsed(name).xpath('//*[@style]'): # Process inline style attributes block = container.parse_css(elem.get('style'), is_declaration=True) self.magnify_declaration(block, factor) elem.set('style', force_unicode(block.getCssText(separator=' '), 'utf-8'))