Source code for pyqtgraph.colormap

# -*- coding: utf-8 -*-
import numpy as np
from .Qt import QtGui, QtCore
from .functions import mkColor, eq, colorDistance, clip_scalar, clip_array
from os import path, listdir
from import Callable, Sequence
import warnings

__all__ = ['ColorMap']

_mapCache = {}

[docs]def listMaps(source=None): """ .. warning:: Experimental, subject to change. List available color maps. Parameters ---------- source: str, optional Color map source. If omitted, locally stored maps are listed. Otherwise: - 'matplotlib' lists maps that can be imported from Matplotlib - 'colorcet' lists maps that can be imported from ColorCET Returns ------- list of str Known color map names. """ if source is None: pathname = path.join(path.dirname(__file__), 'colors','maps') files = listdir( pathname ) list_of_maps = [] for filename in files: if filename[-4:] == '.csv' or filename[-4:] == '.hex': list_of_maps.append(filename[:-4]) return list_of_maps elif source.lower() == 'matplotlib': try: import matplotlib.pyplot as mpl_plt list_of_maps = mpl_plt.colormaps() return list_of_maps except ModuleNotFoundError: return [] elif source.lower() == 'colorcet': try: import colorcet list_of_maps = list( colorcet.palette.keys() ) list_of_maps.sort() return list_of_maps except ModuleNotFoundError: return [] return []
[docs]def get(name, source=None, skipCache=False): """ .. warning:: Experimental, subject to change. Returns a ColorMap object from a local definition or imported from another library. The generated ColorMap objects are cached for fast repeated access. Parameters ---------- name: str Name of color map. In addition to the included maps, this can also be a path to a file in the local folder. See the files in the ``pyqtgraph/colors/maps/`` folder for examples of the format. source: str, optional If omitted, a locally stored map is returned. Otherwise: - 'matplotlib' imports a map defined by Matplotlib. - 'colorcet' imports a map defined by ColorCET. skipCache: bool, optional If `skipCache=True`, the internal cache is skipped and a new ColorMap object is generated. This can load an unaltered copy when the previous ColorMap object has been modified. """ if not skipCache and name in _mapCache: return _mapCache[name] if source is None: return _getFromFile(name) elif source == 'matplotlib': return getFromMatplotlib(name) elif source == 'colorcet': return getFromColorcet(name) return None
def _getFromFile(name): filename = name if filename[0] !='.': # load from built-in directory dirname = path.dirname(__file__) filename = path.join(dirname, 'colors/maps/'+filename) if not path.isfile( filename ): # try suffixes if file is not found: if path.isfile( filename+'.csv' ): filename += '.csv' elif path.isfile( filename+'.hex' ): filename += '.hex' with open(filename,'r') as fh: idx = 0 color_list = [] if filename[-4:].lower() != '.hex': csv_mode = True else: csv_mode = False for line in fh: line = line.strip() if len(line) == 0: continue # empty line if line[0] == ';': continue # comment parts = line.split(sep=';', maxsplit=1) # split into color and names/comments if csv_mode: comp = parts[0].split(',') if len( comp ) < 3: continue # not enough components given color_tuple = tuple( [ int(255*float(c)+0.5) for c in comp ] ) else: hex_str = parts[0] if hex_str[0] == '#': hex_str = hex_str[1:] # strip leading # if len(hex_str) < 3: continue # not enough information if len(hex_str) == 3: # parse as abbreviated RGB hex_str = 2*hex_str[0] + 2*hex_str[1] + 2*hex_str[2] elif len(hex_str) == 4: # parse as abbreviated RGBA hex_str = 2*hex_str[0] + 2*hex_str[1] + 2*hex_str[2] + 2*hex_str[3] if len(hex_str) < 6: continue # not enough information try: color_tuple = tuple( bytes.fromhex( hex_str ) ) except ValueError as e: raise ValueError(f"failed to convert hexadecimal value '{hex_str}'.") from e color_list.append( color_tuple ) idx += 1 # end of line reading loop # end of open cmap = ColorMap( name=name, pos=np.linspace(0.0, 1.0, len(color_list)), color=color_list) #, names=color_names) if cmap is not None: = name _mapCache[name] = cmap return cmap
[docs]def getFromMatplotlib(name): """ Generates a ColorMap object from a Matplotlib definition. Same as ``colormap.get(name, source='matplotlib')``. """ # inspired and informed by "", published by Sebastian Hoefer at # try: import matplotlib.pyplot as mpl_plt except ModuleNotFoundError: return None cmap = None col_map = mpl_plt.get_cmap(name) if hasattr(col_map, '_segmentdata'): # handle LinearSegmentedColormap data = col_map._segmentdata if ('red' in data) and isinstance(data['red'], (Sequence, np.ndarray)): positions = set() # super-set of handle positions in individual channels for key in ['red','green','blue']: for tup in data[key]: positions.add(tup[0]) col_data = np.zeros((len(positions),4 )) col_data[:,-1] = sorted(positions) for idx, key in enumerate(['red','green','blue']): positions = np.zeros( len(data[key] ) ) comp_vals = np.zeros( len(data[key] ) ) for idx2, tup in enumerate( data[key] ): positions[idx2] = tup[0] comp_vals[idx2] = tup[1] # these are sorted in the raw data col_data[:,idx] = np.interp(col_data[:,3], positions, comp_vals) cmap = ColorMap(pos=col_data[:,-1], color=255*col_data[:,:3]+0.5) # some color maps (gnuplot in particular) are defined by RGB component functions: elif ('red' in data) and isinstance(data['red'], Callable): col_data = np.zeros((64, 4)) col_data[:,-1] = np.linspace(0., 1., 64) for idx, key in enumerate(['red','green','blue']): col_data[:,idx] = np.clip( data[key](col_data[:,-1]), 0, 1) cmap = ColorMap(pos=col_data[:,-1], color=255*col_data[:,:3]+0.5) elif hasattr(col_map, 'colors'): # handle ListedColormap col_data = np.array(col_map.colors) cmap = ColorMap( name=name, pos = np.linspace(0.0, 1.0, col_data.shape[0]), color=255*col_data[:,:3]+0.5 ) if cmap is not None: = name _mapCache[name] = cmap return cmap
[docs]def getFromColorcet(name): """ Generates a ColorMap object from a colorcet definition. Same as ``colormap.get(name, source='colorcet')``. """ try: import colorcet except ModuleNotFoundError: return None color_strings = colorcet.palette[name] color_list = [] for hex_str in color_strings: if hex_str[0] != '#': continue if len(hex_str) != 7: raise ValueError(f"Invalid color string '{hex_str}' in colorcet import.") color_tuple = tuple( bytes.fromhex( hex_str[1:] ) ) color_list.append( color_tuple ) if len(color_list) == 0: return None cmap = ColorMap( name=name, pos=np.linspace(0.0, 1.0, len(color_list)), color=color_list) #, names=color_names) if cmap is not None: = name _mapCache[name] = cmap return cmap
def makeHslCycle( hue=0.0, saturation=1.0, lightness=0.5, steps=36 ): """ Returns a ColorMap object that traces a circular or spiraling path around the HSL color space. Parameters ---------- hue : float or tuple of floats Starting point or (start, end) for hue. Values can lie outside the [0 to 1] range to realize multiple cycles. For a single value, one full hue cycle is generated. The default starting hue is 0.0 (red). saturation : float or tuple of floats, optional Saturation value for the colors in the cycle, in the range of [0 to 1]. If a (start, end) tuple is given, saturation gradually changes between these values. The default saturation is 1.0. lightness : float or tuple of floats, optional Lightness value for the colors in the cycle, in the range of [0 to 1]. If a (start, end) tuple is given, lightness gradually changes between these values. The default lightness is 1.0. steps: int, optional Number of steps in the cycle. Between these steps, the color map will interpolate in RGB space. The default number of steps is 36, generating a color map with 37 stops. """ if isinstance( hue, (tuple, list) ): hueA, hueB = hue else: hueA = hue hueB = hueA + 1.0 if isinstance( saturation, (tuple, list) ): satA, satB = saturation else: satA = satB = saturation if isinstance( lightness, (tuple, list) ): lgtA, lgtB = lightness else: lgtA = lgtB = lightness hue_vals = np.linspace(hueA, hueB, num=steps+1) sat_vals = np.linspace(satA, satB, num=steps+1) lgt_vals = np.linspace(lgtA, lgtB, num=steps+1) color_list = [] for hue, sat, lgt in zip( hue_vals, sat_vals, lgt_vals): qcol = QtGui.QColor.fromHslF( hue%1.0, sat, lgt ) color_list.append( qcol ) name = f'Hue {hueA:0.2f}-{hueB:0.2f}' return ColorMap( None, color_list, name=name ) def makeMonochrome(color='neutral'): """ Returns a ColorMap object with a dark to bright ramp and adjustable tint. In addition to neutral, warm or cold grays, imitations of monochrome computer monitors are also available. The following predefined color ramps are available: `neutral`, `warm`, `cool`, `green`, `amber`, `blue`, `red`, `pink`, `lavender`. The ramp can also be specified by a tuple of float values in the range of 0 to 1. In this case `(h, s, l0, l1)` describe hue, saturation, minimum lightness and maximum lightness within the HSL color space. The values `l0` and `l1` can be omitted. They default to `l0=0.0` and `l1=1.0` in this case. Parameters ---------- color: str or tuple of floats Color description. Can be one of the predefined identifiers, or a tuple `(h, s, l0, l1)`, `(h, s)` or (`h`). 'green', 'amber', 'blue', 'red', 'lavender', 'pink' or a tuple of relative ``(R,G,B)`` contributions in range 0.0 to 1.0 """ name=f'Monochrome {color}' defaults = { 'neutral': (0.00, 0.00, 0.00, 1.00), 'warm' : (0.10, 0.08, 0.00, 0.95), 'cool' : (0.60, 0.08, 0.00, 0.95), 'green' : (0.35, 0.55, 0.02, 0.90), 'amber' : (0.09, 0.80, 0.02, 0.80), 'blue' : (0.58, 0.85, 0.02, 0.95), 'red' : (0.01, 0.60, 0.02, 0.90), 'pink' : (0.93, 0.65, 0.02, 0.95), 'lavender': (0.75, 0.50, 0.02, 0.90) } if isinstance(color, str): if color in defaults: h_val, s_val, l_min, l_max = defaults[color] else: valid = ','.join(defaults.keys()) raise ValueError(f"Undefined color descriptor '{color}', known values are:\n{valid}") else: s_val = 0.70 # set up default values l_min = 0.00 l_max = 1.00 if not hasattr(color,'__len__'): h_val = float(color) elif len(color) == 1: h_val = color[0] elif len(color) == 2: h_val, s_val = color elif len(color) == 4: h_val, s_val, l_min, l_max = color else: raise ValueError(f"Invalid color descriptor '{color}'") l_vals = np.linspace(l_min, l_max, num=16) color_list = [] for l_val in l_vals: qcol = QtGui.QColor.fromHslF( h_val, s_val, l_val ) color_list.append( qcol ) return ColorMap( None, color_list, name=name, linearize=True )
[docs]def modulatedBarData(length=768, width=32): """ Returns an NumPy array that represents a modulated color bar ranging from 0 to 1. This is used to judge the perceived variation of the color gradient. Parameters ---------- length: int Length of the data set. Values will vary from 0 to 1 over this axis. width: int Width of the data set. The modulation will vary from 0% to 4% over this axis. """ gradient = np.linspace(0.00, 1.00, length) modulation = -0.04 * np.sin( (np.pi/4) * np.arange(length) ) data = np.zeros( (length, width) ) for idx in range(width): data[:,idx] = gradient + (idx/(width-1)) * modulation clip_array(data, 0.0, 1.0, out=data) return data
[docs]class ColorMap(object): """ ColorMap(pos, color, mapping=ColorMap.CLIP) ColorMap stores a mapping of specific data values to colors, for example: | 0.0 → black | 0.2 → red | 0.6 → yellow | 1.0 → white The colors for intermediate values are determined by interpolating between the two nearest colors in RGB color space. A ColorMap object provides access to the interpolated colors by indexing with a float value: ``cm[0.5]`` returns a QColor corresponding to the center of ColorMap `cm`. """ ## mapping modes CLIP = 1 REPEAT = 2 MIRROR = 3 DIVERGING = 4 ## return types BYTE = 1 FLOAT = 2 QCOLOR = 3 enumMap = { 'clip': CLIP, 'repeat': REPEAT, 'mirror': MIRROR, 'diverging': DIVERGING, 'byte': BYTE, 'float': FLOAT, 'qcolor': QCOLOR, }
[docs] def __init__(self, pos, color, mapping=CLIP, mode=None, linearize=False, name=''): """ __init__(pos, color, mapping=ColorMap.CLIP) Parameters ---------- pos: array_like of float in range 0 to 1, or None Assigned positions of specified colors. `None` sets equal spacing. color: array_like of colors List of colors, interpreted via :func:`mkColor() <pyqtgraph.mkColor>`. mapping: str or int, optional Controls how values outside the 0 to 1 range are mapped to colors. See :func:`setMappingMode() <ColorMap.setMappingMode>` for details. The default of `ColorMap.CLIP` continues to show the colors assigned to 0 and 1 for all values below or above this range, respectively. """ = name # storing a name helps identify ColorMaps sampled by Palette if mode is not None: warnings.warn( "'mode' argument is deprecated and does nothing.", DeprecationWarning, stacklevel=2 ) if pos is None: order = range(len(color)) self.pos = np.linspace(0.0, 1.0, num=len(color)) else: self.pos = np.array(pos) order = np.argsort(self.pos) self.pos = self.pos[order] self.color = np.zeros( (len(color), 4) ) # stores float rgba values for cnt, idx in enumerate(order): self.color[cnt] = mkColor(color[idx]).getRgbF() # alternative code may be more efficient, but fails to handle lists of QColor. # self.color = np.apply_along_axis( # func1d = lambda x: np.uint8( mkColor(x).getRgb() ), # cast RGB integer values to uint8 # axis = -1, # arr = color, # )[order] self.mapping_mode = self.CLIP # default to CLIP mode if mapping is not None: self.setMappingMode( mapping ) self.stopsCache = {} if linearize: self.linearize()
[docs] def setMappingMode(self, mapping): """ Sets the way that values outside of the range 0 to 1 are mapped to colors. Parameters ---------- mapping: int or str Sets mapping mode to - `ColorMap.CLIP` or 'clip': Values are clipped to the range 0 to 1. ColorMap defaults to this. - `ColorMap.REPEAT` or 'repeat': Colors repeat cyclically, i.e. range 1 to 2 repeats the colors for 0 to 1. - `ColorMap.MIRROR` or 'mirror': The range 0 to -1 uses same colors (in reverse order) as 0 to 1. - `ColorMap.DIVERGING` or 'diverging': Colors are mapped to -1 to 1 such that the central value appears at 0. """ if isinstance(mapping, str): mapping = self.enumMap[mapping.lower()] if mapping in [self.CLIP, self.REPEAT, self.DIVERGING, self.MIRROR]: self.mapping_mode = mapping # only allow defined values else: raise ValueError(f"Undefined mapping type '{mapping}'") self.stopsCache = {}
def __str__(self): """ provide human-readable identifier """ if is None: return 'unnamed ColorMap({:d})'.format(len(self.pos)) return "ColorMap({:d}):'{:s}'".format(len(self.pos), def __getitem__(self, key): """ Convenient shorthand access to palette colors """ if isinstance(key, int): # access by color index return self.getByIndex(key) # otherwise access by map try: # accept any numerical format that converts to float float_idx = float(key) return self.mapToQColor(float_idx) except ValueError: pass return None
[docs] def linearize(self): """ Adjusts the positions assigned to color stops to approximately equalize the perceived color difference for a fixed step. """ colors = self.getColors(mode=self.QCOLOR) distances = colorDistance(colors) positions = np.insert( np.cumsum(distances), 0, 0.0 ) self.pos = positions / positions[-1] # normalize last value to 1.0 self.stopsCache = {}
[docs] def reverse(self): """ Reverses the color map, so that the color assigned to a value of 1 now appears at 0 and vice versa. This is convenient to adjust imported color maps. """ self.pos = 1.0 - np.flip( self.pos ) self.color = np.flip( self.color, axis=0 ) self.stopsCache = {}
[docs] def getSubset(self, start, span): """ Returns a new ColorMap object that extracts the subset specified by 'start' and 'length' to the full 0.0 to 1.0 range. A negative length results in a color map that is reversed relative to the original. Parameters ---------- start : float (0.0 to 1.0) Starting value that defines the 0.0 value of the new color map. span : float (-1.0 to 1.0) span of the extracted region. The orignal color map will be trated as cyclical if the extracted interval exceeds the 0.0 to 1.0 range. """ pos, col = self.getStops( mode=ColorMap.FLOAT ) start = clip_scalar(start, 0.0, 1.0) span = clip_scalar(span, -1.0, 1.0) if span == 0.0: raise ValueError("'length' needs to be non-zero") stop = (start + span) if stop > 1.0 or stop < 0.0: stop = stop % 1.0 # find indices *inside* range, start and end will be added by sampling later if span > 0: ref_pos = start # lowest position value at start idxA = np.searchsorted( pos, start, side='right' ) idxB = np.searchsorted( pos, stop , side='left' ) # + 1 # right-side element of interval wraps = bool( stop < start ) # wraps around? else: ref_pos = stop # lowest position value at stop idxA = np.searchsorted( pos, stop , side='right') idxB = np.searchsorted( pos, start, side='left' ) # + 1 # right-side element of interval wraps = bool( stop > start ) # wraps around? if wraps: # wraps around: length1 = (len(pos)-idxA) # before wrap length2 = idxB # after wrap new_length = length1 + length2 + 2 # combined; plus edge elements new_pos = np.zeros( new_length ) new_col = np.zeros( (new_length, 4) ) new_pos[ 1:length1+1] = (0 + pos[idxA:] - ref_pos) / span # starting point lie in 0 to 1 range new_pos[length1+1:-1] = (1 + pos[:idxB] - ref_pos) / span # end point wrapped to -1 to 0 range new_pos[length1] -= np.copysign(1e-6, span) # breaks degeneracy of shifted 0.0 and 1.0 values new_col[ 1:length1+1] = col[idxA:] new_col[length1+1:-1] = col[:idxB] else: # does not wrap around: new_length = (idxB - idxA) + 2 # two additional edge values will be added new_pos = np.zeros( new_length ) new_col = np.zeros( (new_length, 4) ) new_pos[1:-1] = (pos[idxA:idxB] - ref_pos) / span new_col[1:-1] = col[idxA:idxB] if span < 0: # for reversed subsets, positions now progress 0 to -1 and need to be flipped new_pos += 1.0 new_pos = np.flip( new_pos) new_col = np.flip( new_col, axis=0 ) new_pos[ 0] = 0.0 new_col[ 0] = self.mapToFloat(start) new_pos[-1] = 1.0 new_col[-1] = self.mapToFloat(stop) cmap = ColorMap( pos=new_pos, color=255.*new_col ) = f"{}[{start:.2f}({span:+.2f})]" return cmap
[docs] def map(self, data, mode=BYTE): """ map(data, mode=ColorMap.BYTE) Returns an array of colors corresponding to a single value or an array of values. Data must be either a scalar position or an array (any shape) of positions. Parameters ---------- data: float or array_like of float Scalar value(s) to be mapped to colors mode: str or int, optional Determines return format: - `ColorMap.BYTE` or 'byte': Colors are returned as 0-255 unsigned bytes. (default) - `ColorMap.FLOAT` or 'float': Colors are returned as 0.0-1.0 floats. - `ColorMap.QCOLOR` or 'qcolor': Colors are returned as QColor objects. Returns ------- array of color.dtype for `ColorMap.BYTE` or `ColorMap.FLOAT`: RGB values for each `data` value, arranged in the same shape as `data`. list of QColor objects for `ColorMap.QCOLOR`: Colors for each `data` value as Qcolor objects. """ if isinstance(mode, str): mode = self.enumMap[mode.lower()] if mode == self.QCOLOR: pos, color = self.getStops(self.FLOAT) else: pos, color = self.getStops(mode) if np.isscalar(data): interp = np.empty((color.shape[1],), dtype=color.dtype) else: if not isinstance(data, np.ndarray): data = np.array(data) interp = np.empty(data.shape + (color.shape[1],), dtype=color.dtype) if self.mapping_mode != self.CLIP: if self.mapping_mode == self.REPEAT: data = data % 1.0 elif self.mapping_mode == self.DIVERGING: data = (data/2)+0.5 elif self.mapping_mode == self.MIRROR: data = abs(data) for i in range(color.shape[1]): interp[...,i] = np.interp(data, pos, color[:,i]) # Convert to QColor if requested if mode == self.QCOLOR: if np.isscalar(data): return QtGui.QColor.fromRgbF(*interp) else: return [QtGui.QColor.fromRgbF(*x.tolist()) for x in interp] else: return interp
[docs] def mapToQColor(self, data): """Convenience function; see :func:`map() <>`.""" return, mode=self.QCOLOR)
[docs] def mapToByte(self, data): """Convenience function; see :func:`map() <>`.""" return, mode=self.BYTE)
[docs] def mapToFloat(self, data): """Convenience function; see :func:`map() <>`.""" return, mode=self.FLOAT)
[docs] def getByIndex(self, idx): """Retrieve a QColor by the index of the stop it is assigned to.""" return QtGui.QColor( *self.color[idx] )
[docs] def getGradient(self, p1=None, p2=None): """ Returns a QtGui.QLinearGradient corresponding to this ColorMap. The span and orientiation is given by two points in plot coordinates. When no parameters are given for `p1` and `p2`, the gradient is mapped to the `y` coordinates 0 to 1, unless the color map is defined for a more limited range. This is a somewhat expensive operation, and it is recommended to store and reuse the returned gradient instead of repeatedly regenerating it. Parameters ---------- p1: QtCore.QPointF, default (0,0) Starting point (value 0) of the gradient. p2: QtCore.QPointF, default (dy,0) End point (value 1) of the gradient. Default parameter `dy` is the span of ``max(pos) - min(pos)`` over which the color map is defined, typically `dy=1`. """ if p1 is None: p1 = QtCore.QPointF(0,0) if p2 is None: p2 = QtCore.QPointF(self.pos.max()-self.pos.min(),0) grad = QtGui.QLinearGradient(p1, p2) pos, color = self.getStops(mode=self.QCOLOR) if self.mapping_mode == self.MIRROR: pos_n = (1. - np.flip(pos)) / 2 col_n = np.flip( color, axis=0 ) pos_p = (1. + pos) / 2 col_p = color pos = np.concatenate( (pos_n, pos_p) ) color = np.concatenate( (col_n, col_p) ) grad.setStops(list(zip(pos, color))) if self.mapping_mode == self.REPEAT: grad.setSpread( QtGui.QGradient.Spread.RepeatSpread ) return grad
[docs] def getBrush(self, span=(0.,1.), orientation='vertical'): """ Returns a QBrush painting with the color map applied over the selected span of plot values. When the mapping mode is set to `ColorMap.MIRROR`, the selected span includes the color map twice, first in reversed order and then normal. It is recommended to store and reuse this gradient brush instead of regenerating it repeatedly. Parameters ---------- span : tuple (min, max), default (0.0, 1.0) Span of data values covered by the gradient: - Color map value 0.0 will appear at `min`, - Color map value 1.0 will appear at `max`. orientation : str, default 'vertical' Orientiation of the gradient: - 'vertical': `span` corresponds to the `y` coordinate. - 'horizontal': `span` corresponds to the `x` coordinate. """ if orientation == 'vertical': grad = self.getGradient( p1=QtCore.QPointF(0.,span[0]), p2=QtCore.QPointF(0.,span[1]) ) elif orientation == 'horizontal': grad = self.getGradient( p1=QtCore.QPointF(span[0],0.), p2=QtCore.QPointF(span[1],0.) ) else: raise ValueError("Orientation must be 'vertical' or 'horizontal'") return QtGui.QBrush(grad)
[docs] def getPen(self, span=(0.,1.), orientation='vertical', width=1.0): """ Returns a QPen that draws according to the color map based on vertical or horizontal position. It is recommended to store and reuse this gradient pen instead of regenerating it repeatedly. Parameters ---------- span : tuple (min, max), default (0.0, 1.0) Span of the data values covered by the gradient: - Color map value 0.0 will appear at `min`. - Color map value 1.0 will appear at `max`. orientation : str, default 'vertical' Orientiation of the gradient: - 'vertical' creates a vertical gradient, where `span` corresponds to the `y` coordinate. - 'horizontal' creates a horizontal gradient, where `span` correspnds to the `x` coordinate. width : int or float Width of the pen in pixels on screen. """ brush = self.getBrush( span=span, orientation=orientation ) pen = QtGui.QPen(brush, width) pen.setCosmetic(True) return pen
[docs] def getColors(self, mode=BYTE): """ Returns a list of the colors associated with the stops of the color map. The parameter `mode` can be one of - `ColorMap.BYTE` or 'byte' to return colors as RGBA tuples in byte format (0 to 255) - `ColorMap.FLOAT` or 'float' to return colors as RGBA tuples in float format (0.0 to 1.0) - `ColorMap.QCOLOR` or 'qcolor' to return a list of QColors The default is byte format. """ stops, color = self.getStops(mode=mode) return color
[docs] def getStops(self, mode=BYTE): """ Returns a tuple (stops, colors) containing a list of all stops (ranging 0.0 to 1.0) and a list of the associated colors. The parameter `mode` can be one of - `ColorMap.BYTE` or 'byte' to return colors as RGBA tuples in byte format (0 to 255) - `ColorMap.FLOAT` or 'float' to return colors as RGBA tuples in float format (0.0 to 1.0) - `ColorMap.QCOLOR` or 'qcolor' to return a list of QColors The default is byte format. """ if isinstance(mode, str): mode = self.enumMap[mode.lower()] if mode not in self.stopsCache: color = self.color if mode == self.BYTE and color.dtype.kind == 'f': color = (color*255).astype(np.ubyte) elif mode == self.FLOAT and color.dtype.kind != 'f': color = color.astype(float) / 255. elif mode == self.QCOLOR: if color.dtype.kind == 'f': factory = QtGui.QColor.fromRgbF else: factory = QtGui.QColor.fromRgb color = [factory(*x.tolist()) for x in color] self.stopsCache[mode] = (self.pos, color) return self.stopsCache[mode]
[docs] def getLookupTable(self, start=0.0, stop=1.0, nPts=512, alpha=None, mode=BYTE): """ getLookupTable(start=0.0, stop=1.0, nPts=512, alpha=None, mode=ColorMap.BYTE) Returns an equally-spaced lookup table of RGB(A) values created by interpolating the specified color stops. Parameters ---------- start: float, default=0.0 The starting value in the lookup table stop: float, default=1.0 The final value in the lookup table nPts: int, default is 512 The number of points in the returned lookup table. alpha: True, False, or None Specifies whether or not alpha values are included in the table. If alpha is None, it will be automatically determined. mode: int or str, default is `ColorMap.BYTE` Determines return type as described in :func:`map() <>`, can be either `ColorMap.BYTE` (0 to 255), `ColorMap.FLOAT` (0.0 to 1.0) or `ColorMap.QColor`. Returns ------- array of color.dtype for `ColorMap.BYTE` or `ColorMap.FLOAT`: RGB values for each `data` value, arranged in the same shape as `data`. If alpha values are included the array has shape (`nPts`, 4), otherwise (`nPts`, 3). list of QColor objects for `ColorMap.QCOLOR`: Colors for each `data` value as QColor objects. """ if isinstance(mode, str): mode = self.enumMap[mode.lower()] if alpha is None: alpha = self.usesAlpha() x = np.linspace(start, stop, nPts) table =, mode) if not alpha and mode != self.QCOLOR: return table[:,:3] else: return table
[docs] def usesAlpha(self): """Returns `True` if any stops have assigned colors with alpha < 255.""" max = 1.0 if self.color.dtype.kind == 'f' else 255 return np.any(self.color[:,3] != max)
[docs] def isMapTrivial(self): """ Returns `True` if the gradient has exactly two stops in it: Black at 0.0 and white at 1.0. """ if len(self.pos) != 2: return False if self.pos[0] != 0.0 or self.pos[1] != 1.0: return False if self.color.dtype.kind == 'f': return np.all(self.color == np.array([[0.,0.,0.,1.], [1.,1.,1.,1.]])) else: return np.all(self.color == np.array([[0,0,0,255], [255,255,255,255]]))
def __repr__(self): pos = repr(self.pos).replace('\n', '') color = repr(self.color).replace('\n', '') return "ColorMap(%s, %s)" % (pos, color) def __eq__(self, other): if other is None: return False return eq(self.pos, other.pos) and eq(self.color, other.color)