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Source code for kivy.utils

# pylint: disable=W0611
'''
Utils
=====

The Utils module provides a selection of general utility functions and classes
that may be useful for various applications. These include maths, color,
algebraic and platform functions.

.. versionchanged:: 1.6.0
    The OrderedDict class has been removed. Use collections.OrderedDict
    instead.

'''

__all__ = ('intersection', 'difference', 'strtotuple',
           'get_color_from_hex', 'get_hex_from_color', 'get_random_color',
           'is_color_transparent', 'hex_colormap', 'colormap', 'boundary',
           'deprecated', 'SafeList',
           'interpolate', 'QueryDict',
           'platform', 'escape_markup', 'reify', 'rgba')

from os import environ
from sys import platform as _sys_platform
from re import match, split
from kivy.compat import string_types


[docs]def boundary(value, minvalue, maxvalue): '''Limit a value between a minvalue and maxvalue.''' return min(max(value, minvalue), maxvalue)
[docs]def intersection(set1, set2): '''Return the intersection of 2 lists.''' return [s for s in set1 if s in set2]
[docs]def difference(set1, set2): '''Return the difference between 2 lists.''' return [s for s in set1 if s not in set2]
[docs]def interpolate(value_from, value_to, step=10): '''Interpolate between two values. This can be useful for smoothing some transitions. For example:: # instead of setting directly self.pos = pos # use interpolate, and you'll have a nicer transition self.pos = interpolate(self.pos, new_pos) .. warning:: These interpolations work only on lists/tuples/doubles with the same dimensions. No test is done to check the dimensions are the same. ''' if type(value_from) in (list, tuple): out = [] for x, y in zip(value_from, value_to): out.append(interpolate(x, y, step)) return out else: return value_from + (value_to - value_from) / float(step)
[docs]def strtotuple(s): '''Convert a tuple string into a tuple with some security checks. Designed to be used with the eval() function:: a = (12, 54, 68) b = str(a) # return '(12, 54, 68)' c = strtotuple(b) # return (12, 54, 68) ''' # security if not match('^[,.0-9 ()\[\]]*$', s): raise Exception('Invalid characters in string for tuple conversion') # fast syntax check if s.count('(') != s.count(')'): raise Exception('Invalid count of ( and )') if s.count('[') != s.count(']'): raise Exception('Invalid count of [ and ]') r = eval(s) if type(r) not in (list, tuple): raise Exception('Conversion failed') return r
[docs]def rgba(s, *args): '''Return a Kivy color (4 value from 0-1 range) from either a hex string or a list of 0-255 values. .. versionadded:: 1.10.0 ''' if isinstance(s, string_types): return get_color_from_hex(s) elif isinstance(s, (list, tuple)): s = map(lambda x: x / 255., s) if len(s) == 3: return list(s) + [1] return s elif isinstance(s, (int, float)): s = map(lambda x: x / 255., [s] + list(args)) if len(s) == 3: return list(s) + [1] return s raise Exception('Invalid value (not a string / list / tuple)')
[docs]def get_color_from_hex(s): '''Transform a hex string color to a kivy :class:`~kivy.graphics.Color`. ''' if s.startswith('#'): return get_color_from_hex(s[1:]) value = [int(x, 16) / 255. for x in split('([0-9a-f]{2})', s.lower()) if x != ''] if len(value) == 3: value.append(1) return value
[docs]def get_hex_from_color(color): '''Transform a kivy :class:`~kivy.graphics.Color` to a hex value:: >>> get_hex_from_color((0, 1, 0)) '#00ff00' >>> get_hex_from_color((.25, .77, .90, .5)) '#3fc4e57f' .. versionadded:: 1.5.0 ''' return '#' + ''.join(['{0:02x}'.format(int(x * 255)) for x in color])
[docs]def get_random_color(alpha=1.0): '''Returns a random color (4 tuple). :Parameters: `alpha`: float, defaults to 1.0 If alpha == 'random', a random alpha value is generated. ''' from random import random if alpha == 'random': return [random(), random(), random(), random()] else: return [random(), random(), random(), alpha]
[docs]def is_color_transparent(c): '''Return True if the alpha channel is 0.''' if len(c) < 4: return False if float(c[3]) == 0.: return True return False
hex_colormap = { 'aliceblue': '#f0f8ff', 'antiquewhite': '#faebd7', 'aqua': '#00ffff', 'aquamarine': '#7fffd4', 'azure': '#f0ffff', 'beige': '#f5f5dc', 'bisque': '#ffe4c4', 'black': '#000000', 'blanchedalmond': '#ffebcd', 'blue': '#0000ff', 'blueviolet': '#8a2be2', 'brown': '#a52a2a', 'burlywood': '#deb887', 'cadetblue': '#5f9ea0', 'chartreuse': '#7fff00', 'chocolate': '#d2691e', 'coral': '#ff7f50', 'cornflowerblue': '#6495ed', 'cornsilk': '#fff8dc', 'crimson': '#dc143c', 'cyan': '#00ffff', 'darkblue': '#00008b', 'darkcyan': '#008b8b', 'darkgoldenrod': '#b8860b', 'darkgray': '#a9a9a9', 'darkgrey': '#a9a9a9', 'darkgreen': '#006400', 'darkkhaki': '#bdb76b', 'darkmagenta': '#8b008b', 'darkolivegreen': '#556b2f', 'darkorange': '#ff8c00', 'darkorchid': '#9932cc', 'darkred': '#8b0000', 'darksalmon': '#e9967a', 'darkseagreen': '#8fbc8f', 'darkslateblue': '#483d8b', 'darkslategray': '#2f4f4f', 'darkslategrey': '#2f4f4f', 'darkturquoise': '#00ced1', 'darkviolet': '#9400d3', 'deeppink': '#ff1493', 'deepskyblue': '#00bfff', 'dimgray': '#696969', 'dimgrey': '#696969', 'dodgerblue': '#1e90ff', 'firebrick': '#b22222', 'floralwhite': '#fffaf0', 'forestgreen': '#228b22', 'fuchsia': '#ff00ff', 'gainsboro': '#dcdcdc', 'ghostwhite': '#f8f8ff', 'gold': '#ffd700', 'goldenrod': '#daa520', 'gray': '#808080', 'grey': '#808080', 'green': '#008000', 'greenyellow': '#adff2f', 'honeydew': '#f0fff0', 'hotpink': '#ff69b4', 'indianred': '#cd5c5c', 'indigo': '#4b0082', 'ivory': '#fffff0', 'khaki': '#f0e68c', 'lavender': '#e6e6fa', 'lavenderblush': '#fff0f5', 'lawngreen': '#7cfc00', 'lemonchiffon': '#fffacd', 'lightblue': '#add8e6', 'lightcoral': '#f08080', 'lightcyan': '#e0ffff', 'lightgoldenrodyellow': '#fafad2', 'lightgreen': '#90ee90', 'lightgray': '#d3d3d3', 'lightgrey': '#d3d3d3', 'lightpink': '#ffb6c1', 'lightsalmon': '#ffa07a', 'lightseagreen': '#20b2aa', 'lightskyblue': '#87cefa', 'lightslategray': '#778899', 'lightslategrey': '#778899', 'lightsteelblue': '#b0c4de', 'lightyellow': '#ffffe0', 'lime': '#00ff00', 'limegreen': '#32cd32', 'linen': '#faf0e6', 'magenta': '#ff00ff', 'maroon': '#800000', 'mediumaquamarine': '#66cdaa', 'mediumblue': '#0000cd', 'mediumorchid': '#ba55d3', 'mediumpurple': '#9370db', 'mediumseagreen': '#3cb371', 'mediumslateblue': '#7b68ee', 'mediumspringgreen': '#00fa9a', 'mediumturquoise': '#48d1cc', 'mediumvioletred': '#c71585', 'midnightblue': '#191970', 'mintcream': '#f5fffa', 'mistyrose': '#ffe4e1', 'moccasin': '#ffe4b5', 'navajowhite': '#ffdead', 'navy': '#000080', 'oldlace': '#fdf5e6', 'olive': '#808000', 'olivedrab': '#6b8e23', 'orange': '#ffa500', 'orangered': '#ff4500', 'orchid': '#da70d6', 'palegoldenrod': '#eee8aa', 'palegreen': '#98fb98', 'paleturquoise': '#afeeee', 'palevioletred': '#db7093', 'papayawhip': '#ffefd5', 'peachpuff': '#ffdab9', 'peru': '#cd853f', 'pink': '#ffc0cb', 'plum': '#dda0dd', 'powderblue': '#b0e0e6', 'purple': '#800080', 'red': '#ff0000', 'rosybrown': '#bc8f8f', 'royalblue': '#4169e1', 'saddlebrown': '#8b4513', 'salmon': '#fa8072', 'sandybrown': '#f4a460', 'seagreen': '#2e8b57', 'seashell': '#fff5ee', 'sienna': '#a0522d', 'silver': '#c0c0c0', 'skyblue': '#87ceeb', 'slateblue': '#6a5acd', 'slategray': '#708090', 'slategrey': '#708090', 'snow': '#fffafa', 'springgreen': '#00ff7f', 'steelblue': '#4682b4', 'tan': '#d2b48c', 'teal': '#008080', 'thistle': '#d8bfd8', 'tomato': '#ff6347', 'turquoise': '#40e0d0', 'violet': '#ee82ee', 'wheat': '#f5deb3', 'white': '#ffffff', 'whitesmoke': '#f5f5f5', 'yellow': '#ffff00', 'yellowgreen': '#9acd32', } colormap = {k: get_color_from_hex(v) for k, v in hex_colormap.items()} DEPRECATED_CALLERS = []
[docs]def deprecated(func): '''This is a decorator which can be used to mark functions as deprecated. It will result in a warning being emitted the first time the function is used.''' import inspect import functools @functools.wraps(func) def new_func(*args, **kwargs): file, line, caller = inspect.stack()[1][1:4] caller_id = "%s:%s:%s" % (file, line, caller) # We want to print deprecated warnings only once: if caller_id not in DEPRECATED_CALLERS: DEPRECATED_CALLERS.append(caller_id) warning = ( 'Call to deprecated function %s in %s line %d.' 'Called from %s line %d' ' by %s().' % ( func.__name__, func.__code__.co_filename, func.__code__.co_firstlineno + 1, file, line, caller)) from kivy.logger import Logger Logger.warn(warning) if func.__doc__: Logger.warn(func.__doc__) return func(*args, **kwargs) return new_func
[docs]class SafeList(list): '''List with a clear() method. .. warning:: Usage of the iterate() function will decrease your performance. ''' def clear(self): del self[:] @deprecated def iterate(self, reverse=False): if reverse: return iter(reversed(self)) return iter(self)
[docs]class QueryDict(dict): '''QueryDict is a dict() that can be queried with dot. :: d = QueryDict() # create a key named toto, with the value 1 d.toto = 1 # it's the same as d['toto'] = 1 .. versionadded:: 1.0.4 ''' def __getattr__(self, attr): try: return self.__getitem__(attr) except KeyError: return super(QueryDict, self).__getattr__(attr) def __setattr__(self, attr, value): self.__setitem__(attr, value)
def format_bytes_to_human(size, precision=2): '''Format a byte value to a human readable representation (B, KB, MB...). .. versionadded:: 1.0.8 :Parameters: `size`: int Number that represents the bytes value `precision`: int, defaults to 2 Precision after the comma Examples:: >>> format_bytes_to_human(6463) '6.31 KB' >>> format_bytes_to_human(646368746541) '601.98 GB' ''' size = int(size) fmt = '%%1.%df %%s' % precision for unit in ['B', 'KB', 'MB', 'GB', 'TB']: if size < 1024.0: return fmt % (size, unit) size /= 1024.0 def _get_platform(): # On Android sys.platform returns 'linux2', so prefer to check the # presence of python-for-android environment variables (ANDROID_ARGUMENT # or ANDROID_PRIVATE). if 'ANDROID_ARGUMENT' in environ: return 'android' elif environ.get('KIVY_BUILD', '') == 'ios': return 'ios' elif _sys_platform in ('win32', 'cygwin'): return 'win' elif _sys_platform == 'darwin': return 'macosx' elif _sys_platform.startswith('linux'): return 'linux' elif _sys_platform.startswith('freebsd'): return 'linux' return 'unknown' platform = _get_platform() ''' A string identifying the current operating system. It is one of: `'win'`, `'linux'`, `'android'`, `'macosx'`, `'ios'` or `'unknown'`. You can use it as follows:: from kivy.utils import platform if platform == 'linux': do_linux_things() .. versionadded:: 1.3.0 .. versionchanged:: 1.8.0 platform is now a variable instead of a function. '''
[docs]def escape_markup(text): ''' Escape markup characters found in the text. Intended to be used when markup text is activated on the Label:: untrusted_text = escape_markup('Look at the example [1]') text = '[color=ff0000]' + untrusted_text + '[/color]' w = Label(text=text, markup=True) .. versionadded:: 1.3.0 ''' return text.replace('&', '&amp;').replace('[', '&bl;').replace(']', '&br;')
[docs]class reify(object): ''' Put the result of a method which uses this (non-data) descriptor decorator in the instance dict after the first call, effectively replacing the decorator with an instance variable. It acts like @property, except that the function is only ever called once; after that, the value is cached as a regular attribute. This gives you lazy attribute creation on objects that are meant to be immutable. Taken from the `Pyramid project <https://pypi.python.org/pypi/pyramid/>`_. To use this as a decorator:: @reify def lazy(self): ... return hard_to_compute_int first_time = self.lazy # lazy is reify obj, reify.__get__() runs second_time = self.lazy # lazy is hard_to_compute_int ''' def __init__(self, func): self.func = func self.__doc__ = func.__doc__ def __get__(self, inst, cls): if inst is None: return self retval = self.func(inst) setattr(inst, self.func.__name__, retval) return retval