Source code for pptx.util

# encoding: utf-8

"""Utility functions and classes."""

from __future__ import (
    absolute_import, division, print_function, unicode_literals
)


[docs]class Length(int): """ Base class for length classes Inches, Emu, Cm, Mm, Pt, and Px. Provides properties for converting length values to convenient units. """ _EMUS_PER_INCH = 914400 _EMUS_PER_CENTIPOINT = 127 _EMUS_PER_CM = 360000 _EMUS_PER_MM = 36000 _EMUS_PER_PT = 12700 def __new__(cls, emu): return int.__new__(cls, emu) @property def inches(self): """ Floating point length in inches """ return self / float(self._EMUS_PER_INCH) @property def centipoints(self): """ Integer length in hundredths of a point (1/7200 inch). Used internally because PowerPoint stores font size in centipoints. """ return self // self._EMUS_PER_CENTIPOINT @property def cm(self): """ Floating point length in centimeters """ return self / float(self._EMUS_PER_CM) @property def emu(self): """ Integer length in English Metric Units """ return self @property def mm(self): """ Floating point length in millimeters """ return self / float(self._EMUS_PER_MM) @property def pt(self): """ Floating point length in points """ return self / float(self._EMUS_PER_PT)
[docs]class Inches(Length): """ Convenience constructor for length in inches """ def __new__(cls, inches): emu = int(inches * Length._EMUS_PER_INCH) return Length.__new__(cls, emu)
[docs]class Centipoints(Length): """ Convenience constructor for length in hundredths of a point """ def __new__(cls, centipoints): emu = int(centipoints * Length._EMUS_PER_CENTIPOINT) return Length.__new__(cls, emu)
[docs]class Cm(Length): """ Convenience constructor for length in centimeters """ def __new__(cls, cm): emu = int(cm * Length._EMUS_PER_CM) return Length.__new__(cls, emu)
[docs]class Emu(Length): """ Convenience constructor for length in english metric units """ def __new__(cls, emu): return Length.__new__(cls, int(emu))
[docs]class Mm(Length): """ Convenience constructor for length in millimeters """ def __new__(cls, mm): emu = int(mm * Length._EMUS_PER_MM) return Length.__new__(cls, emu)
[docs]class Pt(Length): """ Convenience value class for specifying a length in points """ def __new__(cls, points): emu = int(points * Length._EMUS_PER_PT) return Length.__new__(cls, emu)
def lazyproperty(f): """ @lazyprop decorator. Decorated method will be called only on first access to calculate a cached property value. After that, the cached value is returned. """ cache_attr_name = '_%s' % f.__name__ # like '_foobar' for prop 'foobar' docstring = f.__doc__ def get_prop_value(obj): try: return getattr(obj, cache_attr_name) except AttributeError: value = f(obj) setattr(obj, cache_attr_name, value) return value return property(get_prop_value, doc=docstring)