111 lines
2.9 KiB
Python
111 lines
2.9 KiB
Python
# -*- coding: utf-8 -*-
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"""
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misc utility functions and classes
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"""
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# utils ######################################################################
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def _indent(s, level=1, tab="\t"):
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"""indent blocks"""
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indent = tab * level
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return "\n".join("%s%s" % (indent, line) for line in s.split("\n"))
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def _u(v, encoding="utf8"):
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"""provides a unicode string from anything."""
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if isinstance(v, str):
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return v
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elif isinstance(v, (list, tuple)):
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return " ".join(_u(vi, encoding) for vi in v)
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elif v is None:
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return "none"
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else:
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return str(v)
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# base classes ###############################################################
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class _Base(object):
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"""equality based on state rather than id"""
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_state_attributes = []
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def _state(self):
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return {name: getattr(self, name)
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for name in self._state_attributes}
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def __eq__(self, other):
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try:
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return other._state() == self._state()
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except AttributeError:
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return False
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def __ne__(self, other):
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return not self.__eq__(other)
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# def __hash__(self): return hash(self._state())
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def __hash__(self):
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raise RuntimeError("state is not hashable")
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class _Element(_Base):
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"""element with xml serialization support"""
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_state_attributes = ["tag"]
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attributes = []
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def __init__(self):
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super(_Element, self).__init__()
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self.id = None
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@property
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def tag(self):
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"""the svg tag that represents this element
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"""
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raise NotImplementedError # this tag is suppsed to be defined in derived classes
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def _xml(self, defs):
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"""xml serialization"""
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u = "<%s %s" % (self.tag, self._xml_attributes(defs))
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content = self._xml_content(defs)
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if content.strip():
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u += ">\n" + \
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_indent(content) + "\n" + \
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"</%s>" % self.tag
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else:
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u += "/>"
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return u
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def _xml_content(self, defs):
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"""xml serialization of content"""
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return ""
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def _xml_attributes(self, defs):
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"""xml serialization of attributes"""
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return " ".join(self._xml_attribute(name, defs) for name in self.attributes)
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def _xml_attribute(self, name, defs):
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"""unicode serialization of attribute/value pair"""
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attribute = getattr(self, name)
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if name == "href":
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name = "xlink:href"
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try:
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href = "#%s" % attribute.id
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except:
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pass
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else:
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defs.append(attribute)
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attribute = href
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try:
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u = attribute._xml_attr(defs)
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except AttributeError:
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u = _u(attribute)
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return "%s='%s'" % (name.replace("_", "-"), u) if u else ""
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def _xml_attr(self, defs):
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defs.append(self)
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return "url(#%s)" % self.id
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