# Licensed under a 3-clause BSD style license - see LICENSE.rst # This file defines the AngleFormatterLocator class which is a class that # provides both a method for a formatter and one for a locator, for a given # label spacing. The advantage of keeping the two connected is that we need to # make sure that the formatter can correctly represent the spacing requested and # vice versa. For example, a format of dd:mm cannot work with a tick spacing # that is not a multiple of one arcminute. import re import warnings import numpy as np from matplotlib import rcParams from astropy import units as u from astropy.units import UnitsError from astropy.coordinates import Angle DMS_RE = re.compile('^dd(:mm(:ss(.(s)+)?)?)?$') HMS_RE = re.compile('^hh(:mm(:ss(.(s)+)?)?)?$') DDEC_RE = re.compile('^d(.(d)+)?$') DMIN_RE = re.compile('^m(.(m)+)?$') DSEC_RE = re.compile('^s(.(s)+)?$') SCAL_RE = re.compile('^x(.(x)+)?$') # Units with custom representations - see the note where it is used inside # AngleFormatterLocator.formatter for more details. CUSTOM_UNITS = { u.degree: u.def_unit('custom_degree', represents=u.degree, format={'generic': '\xb0', 'latex': r'^\circ', 'unicode': '°'}), u.arcmin: u.def_unit('custom_arcmin', represents=u.arcmin, format={'generic': "'", 'latex': r'^\prime', 'unicode': '′'}), u.arcsec: u.def_unit('custom_arcsec', represents=u.arcsec, format={'generic': '"', 'latex': r'^{\prime\prime}', 'unicode': '″'}), u.hourangle: u.def_unit('custom_hourangle', represents=u.hourangle, format={'generic': 'h', 'latex': r'^\mathrm{h}', 'unicode': r'$\mathregular{^h}$'})} class BaseFormatterLocator: """ A joint formatter/locator """ def __init__(self, values=None, number=None, spacing=None, format=None): if len([x for x in (values, number, spacing) if x is None]) < 2: raise ValueError("At most one of values/number/spacing can be specifed") if values is not None: self.values = values elif number is not None: self.number = number elif spacing is not None: self.spacing = spacing else: self.number = 5 self.format = format @property def values(self): return self._values @values.setter def values(self, values): if not isinstance(values, u.Quantity) or (not values.ndim == 1): raise TypeError("values should be an astropy.units.Quantity array") if not values.unit.is_equivalent(self._unit): raise UnitsError("value should be in units compatible with " "coordinate units ({0}) but found {1}".format(self._unit, values.unit)) self._number = None self._spacing = None self._values = values @property def number(self): return self._number @number.setter def number(self, number): self._number = number self._spacing = None self._values = None @property def spacing(self): return self._spacing @spacing.setter def spacing(self, spacing): self._number = None self._spacing = spacing self._values = None def minor_locator(self, spacing, frequency, value_min, value_max): if self.values is not None: return [] * self._unit minor_spacing = spacing.value / frequency values = self._locate_values(value_min, value_max, minor_spacing) index = np.where((values % frequency) == 0) index = index[0][0] values = np.delete(values, np.s_[index::frequency]) return values * minor_spacing * self._unit @property def format_unit(self): return self._format_unit @format_unit.setter def format_unit(self, unit): self._format_unit = u.Unit(unit) @staticmethod def _locate_values(value_min, value_max, spacing): imin = np.ceil(value_min / spacing) imax = np.floor(value_max / spacing) values = np.arange(imin, imax + 1, dtype=int) return values class AngleFormatterLocator(BaseFormatterLocator): """ A joint formatter/locator """ def __init__(self, values=None, number=None, spacing=None, format=None, unit=None, decimal=None, format_unit=None, show_decimal_unit=True): if unit is None: unit = u.degree if format_unit is None: format_unit = unit if format_unit not in (u.degree, u.hourangle, u.hour): if decimal is False: raise UnitsError("Units should be degrees or hours when using non-decimal (sexagesimal) mode") self._unit = unit self._format_unit = format_unit or unit self._decimal = decimal self._sep = None self.show_decimal_unit = show_decimal_unit super().__init__(values=values, number=number, spacing=spacing, format=format) @property def decimal(self): decimal = self._decimal if self.format_unit not in (u.degree, u.hourangle, u.hour): if self._decimal is None: decimal = True elif self._decimal is False: raise UnitsError("Units should be degrees or hours when using non-decimal (sexagesimal) mode") elif self._decimal is None: decimal = False return decimal @decimal.setter def decimal(self, value): self._decimal = value @property def spacing(self): return self._spacing @spacing.setter def spacing(self, spacing): if spacing is not None and (not isinstance(spacing, u.Quantity) or spacing.unit.physical_type != 'angle'): raise TypeError("spacing should be an astropy.units.Quantity " "instance with units of angle") self._number = None self._spacing = spacing self._values = None @property def sep(self): return self._sep @sep.setter def sep(self, separator): self._sep = separator @property def format(self): return self._format @format.setter def format(self, value): self._format = value if value is None: return if DMS_RE.match(value) is not None: self._decimal = False self._format_unit = u.degree if '.' in value: self._precision = len(value) - value.index('.') - 1 self._fields = 3 else: self._precision = 0 self._fields = value.count(':') + 1 elif HMS_RE.match(value) is not None: self._decimal = False self._format_unit = u.hourangle if '.' in value: self._precision = len(value) - value.index('.') - 1 self._fields = 3 else: self._precision = 0 self._fields = value.count(':') + 1 elif DDEC_RE.match(value) is not None: self._decimal = True self._format_unit = u.degree self._fields = 1 if '.' in value: self._precision = len(value) - value.index('.') - 1 else: self._precision = 0 elif DMIN_RE.match(value) is not None: self._decimal = True self._format_unit = u.arcmin self._fields = 1 if '.' in value: self._precision = len(value) - value.index('.') - 1 else: self._precision = 0 elif DSEC_RE.match(value) is not None: self._decimal = True self._format_unit = u.arcsec self._fields = 1 if '.' in value: self._precision = len(value) - value.index('.') - 1 else: self._precision = 0 else: raise ValueError("Invalid format: {0}".format(value)) if self.spacing is not None and self.spacing < self.base_spacing: warnings.warn("Spacing is too small - resetting spacing to match format") self.spacing = self.base_spacing if self.spacing is not None: ratio = (self.spacing / self.base_spacing).decompose().value remainder = ratio - np.round(ratio) if abs(remainder) > 1.e-10: warnings.warn("Spacing is not a multiple of base spacing - resetting spacing to match format") self.spacing = self.base_spacing * max(1, round(ratio)) @property def base_spacing(self): if self.decimal: spacing = self._format_unit / (10. ** self._precision) else: if self._fields == 1: spacing = 1. * u.degree elif self._fields == 2: spacing = 1. * u.arcmin elif self._fields == 3: if self._precision == 0: spacing = 1. * u.arcsec else: spacing = u.arcsec / (10. ** self._precision) if self._format_unit is u.hourangle: spacing *= 15 return spacing def locator(self, value_min, value_max): if self.values is not None: # values were manually specified return self.values, 1.1 * u.arcsec else: # In the special case where value_min is the same as value_max, we # don't locate any ticks. This can occur for example when taking a # slice for a cube (along the dimension sliced). if value_min == value_max: return [] * self._unit, 0 * self._unit if self.spacing is not None: # spacing was manually specified spacing_value = self.spacing.to_value(self._unit) elif self.number is not None: # number of ticks was specified, work out optimal spacing # first compute the exact spacing dv = abs(float(value_max - value_min)) / self.number * self._unit if self.format is not None and dv < self.base_spacing: # if the spacing is less than the minimum spacing allowed by the format, simply # use the format precision instead. spacing_value = self.base_spacing.to_value(self._unit) else: # otherwise we clip to the nearest 'sensible' spacing if self.decimal: from .utils import select_step_scalar spacing_value = select_step_scalar(dv.to_value(self._format_unit)) * self._format_unit.to(self._unit) else: if self._format_unit is u.degree: from .utils import select_step_degree spacing_value = select_step_degree(dv).to_value(self._unit) else: from .utils import select_step_hour spacing_value = select_step_hour(dv).to_value(self._unit) # We now find the interval values as multiples of the spacing and # generate the tick positions from this. values = self._locate_values(value_min, value_max, spacing_value) return values * spacing_value * self._unit, spacing_value * self._unit def formatter(self, values, spacing, format='auto'): if not isinstance(values, u.Quantity) and values is not None: raise TypeError("values should be a Quantities array") if len(values) > 0: decimal = self.decimal unit = self._format_unit if unit is u.hour: unit = u.hourangle if self.format is None: if decimal: # Here we assume the spacing can be arbitrary, so for example # 1.000223 degrees, in which case we don't want to have a # format that rounds to degrees. So we find the number of # decimal places we get from representing the spacing as a # string in the desired units. The easiest way to find # the smallest number of decimal places required is to # format the number as a decimal float and strip any zeros # from the end. We do this rather than just trusting e.g. # str() because str(15.) == 15.0. We format using 10 decimal # places by default before stripping the zeros since this # corresponds to a resolution of less than a microarcecond, # which should be sufficient. spacing = spacing.to_value(unit) fields = 0 precision = len("{0:.10f}".format(spacing).replace('0', ' ').strip().split('.', 1)[1]) else: spacing = spacing.to_value(unit / 3600) if spacing >= 3600: fields = 1 precision = 0 elif spacing >= 60: fields = 2 precision = 0 elif spacing >= 1: fields = 3 precision = 0 else: fields = 3 precision = -int(np.floor(np.log10(spacing))) else: fields = self._fields precision = self._precision is_latex = format == 'latex' or (format == 'auto' and rcParams['text.usetex']) if decimal: # At the moment, the Angle class doesn't have a consistent way # to always convert angles to strings in decimal form with # symbols for units (instead of e.g 3arcsec). So as a workaround # we take advantage of the fact that Angle.to_string converts # the unit to a string manually when decimal=False and the unit # is not strictly u.degree or u.hourangle if self.show_decimal_unit: decimal = False sep = 'fromunit' if is_latex: fmt = 'latex' else: if unit is u.hourangle: fmt = 'unicode' else: fmt = None unit = CUSTOM_UNITS.get(unit, unit) else: sep = None fmt = None elif self.sep is not None: sep = self.sep fmt = None else: sep = 'fromunit' if unit == u.degree: if is_latex: fmt = 'latex' else: sep = ('\xb0', "'", '"') fmt = None else: if format == 'ascii': fmt = None elif is_latex: fmt = 'latex' else: # Here we still use LaTeX but this is for Matplotlib's # LaTeX engine - we can't use fmt='latex' as this # doesn't produce LaTeX output that respects the fonts. sep = (r'$\mathregular{^h}$', r'$\mathregular{^m}$', r'$\mathregular{^s}$') fmt = None angles = Angle(values) string = angles.to_string(unit=unit, precision=precision, decimal=decimal, fields=fields, sep=sep, format=fmt).tolist() return string else: return [] class ScalarFormatterLocator(BaseFormatterLocator): """ A joint formatter/locator """ def __init__(self, values=None, number=None, spacing=None, format=None, unit=None, format_unit=None): if unit is not None: self._unit = unit self._format_unit = format_unit or unit elif spacing is not None: self._unit = spacing.unit self._format_unit = format_unit or spacing.unit elif values is not None: self._unit = values.unit self._format_unit = format_unit or values.unit super().__init__(values=values, number=number, spacing=spacing, format=format) @property def spacing(self): return self._spacing @spacing.setter def spacing(self, spacing): if spacing is not None and not isinstance(spacing, u.Quantity): raise TypeError("spacing should be an astropy.units.Quantity instance") self._number = None self._spacing = spacing self._values = None @property def format(self): return self._format @format.setter def format(self, value): self._format = value if value is None: return if SCAL_RE.match(value) is not None: if '.' in value: self._precision = len(value) - value.index('.') - 1 else: self._precision = 0 if self.spacing is not None and self.spacing < self.base_spacing: warnings.warn("Spacing is too small - resetting spacing to match format") self.spacing = self.base_spacing if self.spacing is not None: ratio = (self.spacing / self.base_spacing).decompose().value remainder = ratio - np.round(ratio) if abs(remainder) > 1.e-10: warnings.warn("Spacing is not a multiple of base spacing - resetting spacing to match format") self.spacing = self.base_spacing * max(1, round(ratio)) elif not value.startswith('%'): raise ValueError("Invalid format: {0}".format(value)) @property def base_spacing(self): return self._format_unit / (10. ** self._precision) def locator(self, value_min, value_max): if self.values is not None: # values were manually specified return self.values, 1.1 * self._unit else: # In the special case where value_min is the same as value_max, we # don't locate any ticks. This can occur for example when taking a # slice for a cube (along the dimension sliced). if value_min == value_max: return [] * self._unit, 0 * self._unit if self.spacing is not None: # spacing was manually specified spacing = self.spacing.to_value(self._unit) elif self.number is not None: # number of ticks was specified, work out optimal spacing # first compute the exact spacing dv = abs(float(value_max - value_min)) / self.number * self._unit if self.format is not None and (not self.format.startswith('%')) and dv < self.base_spacing: # if the spacing is less than the minimum spacing allowed by the format, simply # use the format precision instead. spacing = self.base_spacing.to_value(self._unit) else: from .utils import select_step_scalar spacing = select_step_scalar(dv.to_value(self._format_unit)) * self._format_unit.to(self._unit) # We now find the interval values as multiples of the spacing and # generate the tick positions from this values = self._locate_values(value_min, value_max, spacing) return values * spacing * self._unit, spacing * self._unit def formatter(self, values, spacing, format='auto'): if len(values) > 0: if self.format is None: if spacing.value < 1.: precision = -int(np.floor(np.log10(spacing.value))) else: precision = 0 elif self.format.startswith('%'): return [(self.format % x.value) for x in values] else: precision = self._precision return [("{0:." + str(precision) + "f}").format(x.to_value(self._format_unit)) for x in values] else: return []