Source code for napari.utils.colormaps.colormap

from enum import Enum
from typing import Optional

import numpy as np
from pydantic import PrivateAttr, validator

from napari.utils.color import ColorArray
from napari.utils.colormaps.colorbars import make_colorbar
from import EventedModel
from import Array
from napari.utils.translations import trans

class ColormapInterpolationMode(str, Enum):
    """INTERPOLATION: Interpolation mode for colormaps.

    Selects an interpolation mode for the colormap.
            * linear: colors are defined by linear interpolation between
              colors of neighboring controls points.
            * zero: colors are defined by the value of the color in the
              bin between by neighboring controls points.

    LINEAR = 'linear'
    ZERO = 'zero'

[docs]class Colormap(EventedModel): """Colormap that relates intensity values to colors. Attributes ---------- colors : array, shape (N, 4) Data used in the colormap. name : str Name of the colormap. display_name : str Display name of the colormap. controls : array, shape (N,) or (N+1,) Control points of the colormap. interpolation : str Colormap interpolation mode, either 'linear' or 'zero'. If 'linear', ncontrols = ncolors (one color per control point). If 'zero', ncontrols = ncolors+1 (one color per bin). """ # fields colors: ColorArray name: str = 'custom' _display_name: Optional[str] = PrivateAttr(None) interpolation: ColormapInterpolationMode = ColormapInterpolationMode.LINEAR controls: Array[np.float32, (-1,)] = None def __init__( self, colors, display_name: Optional[str] = None, **data ) -> None: if display_name is None: display_name = data.get('name', 'custom') super().__init__(colors=colors, **data) self._display_name = display_name # controls validator must be called even if None for correct initialization @validator('controls', pre=True, always=True) def _check_controls(cls, v, values): # If no control points provided generate defaults if v is None or len(v) == 0: n_controls = len(values['colors']) + int( values['interpolation'] == ColormapInterpolationMode.ZERO ) return np.linspace(0, 1, n_controls, dtype=np.float32) # Check control end points are correct if v[0] != 0 or (len(v) > 1 and v[-1] != 1): raise ValueError( trans._( 'Control points must start with 0.0 and end with 1.0. Got {start_control_point} and {end_control_point}', deferred=True, start_control_point=v[0], end_control_point=v[-1], ) ) # Check control points are sorted correctly if not np.array_equal(v, sorted(v)): raise ValueError( trans._( 'Control points need to be sorted in ascending order', deferred=True, ) ) # Check number of control points is correct n_controls_target = len(values['colors']) + int( values['interpolation'] == ColormapInterpolationMode.ZERO ) n_controls = len(v) if n_controls != n_controls_target: raise ValueError( trans._( 'Wrong number of control points provided. Expected {n_controls_target}, got {n_controls}', deferred=True, n_controls_target=n_controls_target, n_controls=n_controls, ) ) return v def __iter__(self): yield from (self.colors, self.controls, self.interpolation) def map(self, values): values = np.atleast_1d(values) if self.interpolation == ColormapInterpolationMode.LINEAR: # One color per control point cols = [ np.interp(values, self.controls, self.colors[:, i]) for i in range(4) ] cols = np.stack(cols, axis=-1) elif self.interpolation == ColormapInterpolationMode.ZERO: # One color per bin # Colors beyond max clipped to final bin indices = np.clip( np.searchsorted(self.controls, values, side="right") - 1, 0, len(self.colors) - 1, ) cols = self.colors[indices.astype(np.int32)] else: raise ValueError( trans._( 'Unrecognized Colormap Interpolation Mode', deferred=True, ) ) return cols @property def colorbar(self): return make_colorbar(self)