Source code for regions.core.core

# Licensed under a 3-clause BSD style license - see LICENSE.rst
import abc
import copy
import operator

import numpy as np

from .metadata import RegionMeta, RegionVisual
from .pixcoord import PixCoord
from .registry import RegionsRegistry

__all__ = ['Region', 'PixelRegion', 'SkyRegion']
__doctest_skip__ = ['Region.serialize', 'Region.write']


[docs]class Region(abc.ABC): """ Base class for all regions. """ _params = ()
[docs] def copy(self, **changes): """ Make an independent (deep) copy. """ fields = list(self._params) + ['meta', 'visual'] for field in fields: if field not in changes: changes[field] = copy.deepcopy(getattr(self, field)) return self.__class__(**changes)
def __repr__(self): prefix = f'{self.__class__.__name__}' cls_info = [] if self._params is not None: for param in self._params: if param == 'text': # place quotes around text value keyval = f'{param}={getattr(self, param)!r}' else: keyval = f'{param}={getattr(self, param)}' cls_info.append(keyval) cls_info = ', '.join(cls_info) return f'<{prefix}({cls_info})>' def __str__(self): cls_info = [('Region', self.__class__.__name__)] if self._params is not None: for param in self._params: if param == 'text': # place quotes around text value keyval = (param, repr(getattr(self, param))) else: keyval = (param, getattr(self, param)) cls_info.append(keyval) return '\n'.join([f'{key}: {val}' for key, val in cls_info]) def __eq__(self, other): """ Equality operator for Region. All Region properties are compared for strict equality except for Quantity parameters, which allow for different units if they are directly convertible. """ if not isinstance(other, self.__class__): return False meta_params = ['meta', 'visual'] self_params = list(self._params) + meta_params other_params = list(other._params) + meta_params # check that both have identical parameters if self_params != other_params: return False # now check the parameter values # Note that Quantity comparisons allow for different units # if they directly convertible (e.g., 1. * u.deg == 60. * u.arcmin) try: for param in self_params: # np.any is used for SkyCoord array comparisons if np.any(getattr(self, param) != getattr(other, param)): return False except TypeError: # TypeError is raised from SkyCoord comparison when they do # not have equivalent frames. Here return False instead of # the TypeError. return False return True def __ne__(self, other): """ Inequality operator for Region. """ return not (self == other)
[docs] @abc.abstractmethod def intersection(self, other): """ Return a region representing the intersection of this region with ``other``. """ raise NotImplementedError
[docs] @abc.abstractmethod def symmetric_difference(self, other): """ Return the union of the two regions minus any areas contained in the intersection of the two regions. """ raise NotImplementedError
[docs] @abc.abstractmethod def union(self, other): """ Return a region representing the union of this region with ``other``. """ raise NotImplementedError
def __and__(self, other): return self.intersection(other) def __or__(self, other): return self.union(other) def __xor__(self, other): return self.symmetric_difference(other)
[docs] @classmethod def get_formats(cls): """ Get the registered I/O formats as a Table. """ return RegionsRegistry.get_formats(Region)
[docs] def write(self, filename, format=None, overwrite=False, **kwargs): """ Write the region to a region file in the specified format. This method allows writing a file in many supported data formats, e.g.,:: >>> reg.write('new_regions.reg', format='ds9') >>> reg.write('new_regions.crtf', format='crtf') >>> reg.write('new_regions.fits', format='fits') A list of the available formats for `~regions.Region` is available using:: >>> from regions import Region >>> Region.get_formats() Parameters ---------- filename : str The filename or URL of the file to write. format : str, optional The file format specifier. overwrite : bool, optional If True, overwrite the output file if it exists. Raises an `OSError` if False and the output file exists. Default is False. **kwargs : dict, optional Keyword arguments passed to the data writer. """ return RegionsRegistry.write([self], filename, Region, format=format, overwrite=overwrite, **kwargs)
[docs] def serialize(self, format=None, **kwargs): """ Serialize the region to a region string or table. This method allows serializing regions in many supported data formats, e.g.,:: >>> reg1_str = reg.serialize(format='ds9') >>> reg2_str = reg.serialize(format='crtf') >>> reg3_tbl = reg.serialize(format='fits') A list of the available formats for `~regions.Region` is available using:: >>> from regions import Region >>> Region.get_formats() Parameters ---------- format : str, optional The file format specifier. **kwargs : dict, optional Keyword arguments passed to the data serializer. """ return RegionsRegistry.serialize([self], Region, format=format, **kwargs)
[docs]class PixelRegion(Region): """ Base class for all regions defined in pixel coordinates. """ meta = RegionMeta() visual = RegionVisual()
[docs] def intersection(self, other): """ Return a region representing the intersection of this region with ``other``. """ from .compound import CompoundPixelRegion return CompoundPixelRegion(region1=self, region2=other, operator=operator.and_)
[docs] def symmetric_difference(self, other): """ Return the union of the two regions minus any areas contained in the intersection of the two regions. """ from .compound import CompoundPixelRegion return CompoundPixelRegion(region1=self, region2=other, operator=operator.xor)
[docs] def union(self, other): """ Return a region representing the union of this region with ``other``. """ from .compound import CompoundPixelRegion return CompoundPixelRegion(region1=self, region2=other, operator=operator.or_)
[docs] @abc.abstractmethod def contains(self, pixcoord): """ Check whether a position or positions fall inside the region. Parameters ---------- pixcoord : `~regions.PixCoord` The position or positions to check. """ raise NotImplementedError
def __contains__(self, coord): if not coord.isscalar: raise ValueError(f'coord must be scalar. coord={coord}') return self.contains(coord)
[docs] @abc.abstractmethod def to_sky(self, wcs): """ Return a region defined in sky coordinates. Parameters ---------- wcs : `~astropy.wcs.WCS` The world coordinate system transformation to use to convert from pixels to sky coordinates. Returns ------- sky_region : `~regions.SkyRegion` The sky region. """ raise NotImplementedError
@property @abc.abstractmethod def area(self): """ The exact analytical area of the region shape. """ raise NotImplementedError @property @abc.abstractmethod def bounding_box(self): """ The minimal bounding box (in integer pixel coordinates) that contains the region. """ raise NotImplementedError
[docs] @abc.abstractmethod def to_mask(self, mode='center', subpixels=5): """ Return a mask for the region. Parameters ---------- mode : {'center', 'exact', 'subpixels'}, optional The method used to determine the overlap of the region on the pixel grid. Not all options are available for all region types. Note that the more precise methods are generally slower. The following methods are available: * ``'center'``: A pixel is considered to be entirely in or out of the region depending on whether its center is in or out of the region. The returned mask will contain values only of 0 (out) and 1 (in). * ``'exact'`` (default): The exact fractional overlap of the region and each pixel is calculated. The returned mask will contain values between 0 and 1. * ``'subpixel'``: A pixel is divided into subpixels (see the ``subpixels`` keyword), each of which are considered to be entirely in or out of the region depending on whether its center is in or out of the region. If ``subpixels=1``, this method is equivalent to ``'center'``. The returned mask will contain values between 0 and 1. subpixels : int, optional For the ``'subpixel'`` mode, resample pixels by this factor in each dimension. That is, each pixel is divided into ``subpixels ** 2`` subpixels. Returns ------- mask : `~regions.RegionMask` A mask for the region. """ raise NotImplementedError
@staticmethod def _validate_mode(mode, subpixels): valid_modes = ('center', 'exact', 'subpixels') if mode not in valid_modes: raise ValueError(f'Invalid mask mode: {mode} (should be one ' f'of {valid_modes}') if mode == 'subpixels': if not isinstance(subpixels, int) or subpixels <= 0: raise ValueError(f'Invalid subpixels value: {subpixels} ' '(should be a strictly positive integer)')
[docs] @abc.abstractmethod def as_artist(self, origin=(0, 0), **kwargs): """ Convert to matplotlib patch object for this region. Parameters ---------- origin : array_like, optional The ``(x, y)`` pixel position of the origin of the displayed image. **kwargs : dict Any keyword arguments accepted by `~matplotlib.patches.Patch`. Returns ------- patch : `~matplotlib.patches.Patch` A matplotlib patch. """ raise NotImplementedError
[docs] def plot(self, origin=(0, 0), ax=None, **kwargs): """ Plot the region on a matplotlib `~matplotlib.axes.Axes` instance. Parameters ---------- origin : array_like, optional The ``(x, y)`` pixel position of the origin of the displayed image. ax : `~matplotlib.axes.Axes` or `None`, optional The matplotlib axes on which to plot. If `None`, then the current `~matplotlib.axes.Axes` instance is used. **kwargs : dict Any keyword arguments accepted by `~matplotlib.patches.Patch`. Returns ------- artist : `matplotlib.artist.Artist` The matplotlib artist (typically a `~matplotlib.patches.Patch` object) for the plotted region. The artist can be used, for example, when adding a plot legend. """ import matplotlib.pyplot as plt if ax is None: ax = plt.gca() artist = self.as_artist(origin=origin, **kwargs) ax.add_artist(artist) return artist
[docs]class SkyRegion(Region): """ Base class for all regions defined in celestial coordinates. """
[docs] def intersection(self, other): """ Return a region representing the intersection of this region with ``other``. """ from .compound import CompoundSkyRegion return CompoundSkyRegion(region1=self, region2=other, operator=operator.and_)
[docs] def symmetric_difference(self, other): """ Return the union of the two regions minus any areas contained in the intersection of the two regions. """ from .compound import CompoundSkyRegion return CompoundSkyRegion(region1=self, region2=other, operator=operator.xor)
[docs] def union(self, other): """ Return a region representing the union of this region with ``other``. """ from .compound import CompoundSkyRegion return CompoundSkyRegion(region1=self, region2=other, operator=operator.or_)
[docs] def contains(self, skycoord, wcs): """ Check whether a sky coordinate falls inside the region. Parameters ---------- skycoord : `~astropy.coordinates.SkyCoord` The position or positions to check. wcs : `~astropy.wcs.WCS` The world coordinate system transformation to use to convert between sky and pixel coordinates. """ pixel_region = self.to_pixel(wcs) pixcoord = PixCoord.from_sky(skycoord, wcs) return pixel_region.contains(pixcoord)
[docs] @abc.abstractmethod def to_pixel(self, wcs): """ Return the equivalent region defined in pixel coordinates. Parameters ---------- wcs : `~astropy.wcs.WCS` The world coordinate system transformation to use to convert between sky and pixel coordinates. Returns ------- pixel_region : `~regions.PixelRegion` A pixel region. """ raise NotImplementedError