Source code for regions.shapes.rectangle

# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
This module defines rectangular regions in both pixel and sky coordinates.
"""

from astropy.coordinates import Angle
import astropy.units as u
from astropy.wcs.utils import pixel_to_skycoord
import numpy as np

from ..core.attributes import (ScalarPixCoord, PositiveScalar,
                               PositiveScalarAngle, ScalarAngle,
                               ScalarSkyCoord)
from ..core.bounding_box import RegionBoundingBox
from ..core.core import PixelRegion, SkyRegion
from ..core.mask import RegionMask
from ..core.metadata import RegionMeta, RegionVisual
from ..core.pixcoord import PixCoord
from .._geometry import rectangular_overlap_grid
from .._utils.wcs_helpers import pixel_scale_angle_at_skycoord

from .polygon import PolygonPixelRegion

__all__ = ['RectanglePixelRegion', 'RectangleSkyRegion']


[docs]class RectanglePixelRegion(PixelRegion): """ A rectangle in pixel coordinates. Parameters ---------- center : `~regions.PixCoord` The position of the center of the rectangle. width : float The width of the rectangle (before rotation) in pixels. height : float The height of the rectangle (before rotation) in pixels. angle : `~astropy.units.Quantity`, optional The rotation angle of the rectangle, measured anti-clockwise. If set to zero (the default), the width axis is lined up with the x axis. meta : `~regions.RegionMeta`, optional A dictionary that stores the meta attributes of this region. visual : `~regions.RegionVisual`, optional A dictionary that stores the visual meta attributes of this region. Examples -------- .. plot:: :include-source: from astropy.coordinates import Angle from regions import PixCoord, RectanglePixelRegion import matplotlib.pyplot as plt fig, ax = plt.subplots(1, 1) reg = RectanglePixelRegion(PixCoord(x=15, y=10), width=8, height=5, angle=Angle(30, 'deg')) patch = reg.plot(ax=ax, facecolor='none', edgecolor='red', lw=2, label='Rectangle') ax.legend(handles=(patch,), loc='upper center') ax.set_xlim(0, 30) ax.set_ylim(0, 20) ax.set_aspect('equal') """ _params = ('center', 'width', 'height', 'angle') _mpl_artist = 'Patch' center = ScalarPixCoord('The center pixel position as a |PixCoord|.') width = PositiveScalar('The width of the rectangle (before rotation) in ' 'pixels as a float.') height = PositiveScalar('The height of the rectangle (before rotation) ' 'in pixels as a float.') angle = ScalarAngle('The rotation angle measured anti-clockwise as a ' '|Quantity| angle.') def __init__(self, center, width, height, angle=0 * u.deg, meta=None, visual=None): self.center = center self.width = width self.height = height self.angle = angle self.meta = meta or RegionMeta() self.visual = visual or RegionVisual() @property def area(self): return self.width * self.height
[docs] def contains(self, pixcoord): cos_angle = np.cos(self.angle) sin_angle = np.sin(self.angle) dx = pixcoord.x - self.center.x dy = pixcoord.y - self.center.y dx_rot = cos_angle * dx + sin_angle * dy dy_rot = sin_angle * dx - cos_angle * dy in_rect = ((np.abs(dx_rot) < self.width * 0.5) & (np.abs(dy_rot) < self.height * 0.5)) if self.meta.get('include', True): return in_rect else: return np.logical_not(in_rect)
[docs] def to_sky(self, wcs): center = pixel_to_skycoord(self.center.x, self.center.y, wcs) _, pixscale, north_angle = pixel_scale_angle_at_skycoord(center, wcs) width = Angle(self.width * u.pix * pixscale, 'arcsec') height = Angle(self.height * u.pix * pixscale, 'arcsec') # region sky angles are defined relative to the WCS longitude axis; # photutils aperture sky angles are defined as the PA of the # semimajor axis (i.e., relative to the WCS latitude axis) angle = self.angle - (north_angle - 90 * u.deg) return RectangleSkyRegion(center, width, height, angle=angle, meta=self.meta.copy(), visual=self.visual.copy())
@property def bounding_box(self): w2 = self.width / 2. h2 = self.height / 2. cos_angle = np.cos(self.angle) # self.angle is a Quantity sin_angle = np.sin(self.angle) # self.angle is a Quantity dx1 = abs(w2 * cos_angle - h2 * sin_angle) dy1 = abs(w2 * sin_angle + h2 * cos_angle) dx2 = abs(w2 * cos_angle + h2 * sin_angle) dy2 = abs(w2 * sin_angle - h2 * cos_angle) dx = max(dx1, dx2) dy = max(dy1, dy2) xmin = self.center.x - dx xmax = self.center.x + dx ymin = self.center.y - dy ymax = self.center.y + dy return RegionBoundingBox.from_float(xmin, xmax, ymin, ymax)
[docs] def to_mask(self, mode='center', subpixels=5): # NOTE: assumes this class represents a single rectangle self._validate_mode(mode, subpixels) if mode == 'center': mode = 'subpixels' subpixels = 1 # Find bounding box and mask size bbox = self.bounding_box ny, nx = bbox.shape # Find position of pixel edges and recenter so that circle is at # origin xmin = float(bbox.ixmin) - 0.5 - self.center.x xmax = float(bbox.ixmax) - 0.5 - self.center.x ymin = float(bbox.iymin) - 0.5 - self.center.y ymax = float(bbox.iymax) - 0.5 - self.center.y if mode == 'subpixels': use_exact = 0 else: use_exact = 1 fraction = rectangular_overlap_grid(xmin, xmax, ymin, ymax, nx, ny, self.width, self.height, self.angle.to(u.rad).value, use_exact, subpixels) return RegionMask(fraction, bbox=bbox)
[docs] def as_artist(self, origin=(0, 0), **kwargs): """ Return a matplotlib patch object for this region (`matplotlib.patches.Rectangle`). 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.Rectangle`. These keywords will override any visual meta attributes of this region. Returns ------- artist : `~matplotlib.patches.Rectangle` A matplotlib rectangle patch. """ from matplotlib.patches import Rectangle xy = self._lower_left_xy() xy = xy[0] - origin[0], xy[1] - origin[1] width = self.width height = self.height # matplotlib expects rotation in degrees (anti-clockwise) angle = self.angle.to('deg').value mpl_kwargs = self.visual.define_mpl_kwargs(self._mpl_artist) mpl_kwargs.update(kwargs) return Rectangle(xy=xy, width=width, height=height, angle=angle, **mpl_kwargs)
def _update_from_mpl_selector(self, *args, **kwargs): xmin, xmax, ymin, ymax = self._mpl_selector.extents self.center = PixCoord(x=0.5 * (xmin + xmax), y=0.5 * (ymin + ymax)) self.width = (xmax - xmin) self.height = (ymax - ymin) self.angle = 0. * u.deg if self._mpl_selector_callback is not None: self._mpl_selector_callback(self)
[docs] def as_mpl_selector(self, ax, active=True, sync=True, callback=None, **kwargs): """ A matplotlib editable widget for this region (`matplotlib.widgets.RectangleSelector`). Parameters ---------- ax : `~matplotlib.axes.Axes` The matplotlib axes to add the selector to. active : bool, optional Whether the selector should be active by default. sync : bool, optional If `True` (the default), the region will be kept in sync with the selector. Otherwise, the selector will be initialized with the values from the region but the two will then be disconnected. callback : callable, optional If specified, this function will be called every time the region is updated. This only has an effect if ``sync`` is `True`. If a callback is set, it is called for the first time once the selector has been created. drag_from_anywhere : bool, optional If `True`, the selector can be moved by clicking anywhere within its bounds, else only at the central anchor (only available with matplotlib 3.5 upwards; default: `False`). **kwargs : dict Additional keyword arguments are passed to `matplotlib.widgets.RectangleSelector`. Returns ------- selector : `matplotlib.widgets.RectangleSelector` The matplotlib selector. Notes ----- Once a selector has been created, you will need to keep a reference to it until you no longer need it. In addition, you can enable/disable the selector at any point by calling ``selector.set_active(True)`` or ``selector.set_active(False)``. """ from matplotlib.widgets import RectangleSelector from .._utils.optional_deps import MPL_VERSION if hasattr(self, '_mpl_selector'): raise AttributeError('Cannot attach more than one selector to a region.') if self.angle.value != 0: raise NotImplementedError('Cannot create matplotlib selector for ' 'rotated rectangle.') if sync: sync_callback = self._update_from_mpl_selector else: def sync_callback(*args, **kwargs): pass rectprops = {'edgecolor': self.visual.get('color', 'black'), 'facecolor': 'none', 'linewidth': self.visual.get('linewidth', 1), 'linestyle': self.visual.get('linestyle', 'solid')} rectprops.update(kwargs.pop('props', dict())) # `rectprops` renamed `props` in mpl 3.5 and deprecated for 3.7. if MPL_VERSION < 35: kwargs.update({'rectprops': rectprops}) else: kwargs.update({'props': rectprops}) self._mpl_selector = RectangleSelector(ax, sync_callback, interactive=True, **kwargs) self._mpl_selector.extents = (self.center.x - self.width / 2, self.center.x + self.width / 2, self.center.y - self.height / 2, self.center.y + self.height / 2) self._mpl_selector.set_active(active) self._mpl_selector_callback = callback if sync and self._mpl_selector_callback is not None: self._mpl_selector_callback(self) return self._mpl_selector
@property def corners(self): """ Return the x, y coordinate pairs that define the corners. """ corners = [(-self.width / 2, -self.height / 2), (self.width / 2, -self.height / 2), (self.width / 2, self.height / 2), (-self.width / 2, self.height / 2), ] rotmat = [[np.cos(self.angle), np.sin(self.angle)], [-np.sin(self.angle), np.cos(self.angle)]] return np.dot(corners, rotmat) + np.array([self.center.x, self.center.y])
[docs] def to_polygon(self): """ Return a 4-sided polygon equivalent to this rectangle. """ x, y = self.corners.T vertices = PixCoord(x=x, y=y) return PolygonPixelRegion(vertices=vertices, meta=self.meta.copy(), visual=self.visual.copy())
def _lower_left_xy(self): """ Compute lower left ``xy`` pixel position. This is used for the conversion to matplotlib in ``as_artist``. Taken from http://photutils.readthedocs.io/en/latest/_modules/photutils/ape rture/rectangle.html#RectangularAperture.plot. """ hw = self.width / 2. hh = self.height / 2. sint = np.sin(self.angle) cost = np.cos(self.angle) dx = (hh * sint) - (hw * cost) dy = -(hh * cost) - (hw * sint) x = self.center.x + dx y = self.center.y + dy return x, y
[docs] def rotate(self, center, angle): """ Rotate the region. Positive ``angle`` corresponds to counter-clockwise rotation. Parameters ---------- center : `~regions.PixCoord` The rotation center point. angle : `~astropy.coordinates.Angle` The rotation angle. Returns ------- region : `RectanglePixelRegion` The rotated region (which is an independent copy). """ center = self.center.rotate(center, angle) angle = self.angle + angle return self.copy(center=center, angle=angle)
[docs]class RectangleSkyRegion(SkyRegion): """ A rectangle in sky coordinates. Parameters ---------- center : `~astropy.coordinates.SkyCoord` The position of the center of the rectangle. width : `~astropy.units.Quantity` The width of the rectangle (before rotation) as an angle. height : `~astropy.units.Quantity` The height of the rectangle (before rotation) as an angle. angle : `~astropy.units.Quantity`, optional The rotation angle of the rectangle, measured anti-clockwise. If set to zero (the default), the width axis is lined up with the longitude axis of the celestial coordinates. meta : `~regions.RegionMeta`, optional A dictionary that stores the meta attributes of this region. visual : `~regions.RegionVisual`, optional A dictionary that stores the visual meta attributes of this region. """ _params = ('center', 'width', 'height', 'angle') center = ScalarSkyCoord('The center position as a |SkyCoord|.') width = PositiveScalarAngle('The width of the rectangle (before rotation) ' 'as a |Quantity| angle.') height = PositiveScalarAngle('The height of the rectangle (before ' 'rotation) as a |Quantity| angle.') angle = ScalarAngle('The rotation angle measured anti-clockwise as a ' '|Quantity| angle.') def __init__(self, center, width, height, angle=0 * u.deg, meta=None, visual=None): self.center = center self.width = width self.height = height self.angle = angle self.meta = meta or RegionMeta() self.visual = visual or RegionVisual()
[docs] def to_pixel(self, wcs): center, pixscale, north_angle = pixel_scale_angle_at_skycoord( self.center, wcs) width = (self.width / pixscale).to(u.pix).value height = (self.height / pixscale).to(u.pix).value # region sky angles are defined relative to the WCS longitude axis; # photutils aperture sky angles are defined as the PA of the # semimajor axis (i.e., relative to the WCS latitude axis) angle = self.angle + (north_angle - 90 * u.deg) return RectanglePixelRegion(center, width, height, angle=angle, meta=self.meta.copy(), visual=self.visual.copy())