import numpy as np
from .Qt import QtGui, QtCore
from .python2_3 import basestring
from .functions import mkColor
[docs]class ColorMap(object):
"""
A ColorMap defines a relationship between a scalar value and a range of colors.
ColorMaps are commonly used for false-coloring monochromatic images, coloring
scatter-plot points, and coloring surface plots by height.
Each color map is defined by a set of colors, each corresponding to a
particular scalar value. 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 either RGB or HSV color space.
To provide user-defined color mappings, see :class:`GradientWidget <pyqtgraph.GradientWidget>`.
"""
## color interpolation modes
RGB = 1
HSV_POS = 2
HSV_NEG = 3
## boundary modes
CLIP = 1
REPEAT = 2
MIRROR = 3
## return types
BYTE = 1
FLOAT = 2
QCOLOR = 3
enumMap = {
'rgb': RGB,
'hsv+': HSV_POS,
'hsv-': HSV_NEG,
'clip': CLIP,
'repeat': REPEAT,
'mirror': MIRROR,
'byte': BYTE,
'float': FLOAT,
'qcolor': QCOLOR,
}
[docs] def __init__(self, pos, color, mode=None):
"""
=============== ==============================================================
**Arguments:**
pos Array of positions where each color is defined
color Array of colors.
Values are interpreted via
:func:`mkColor() <pyqtgraph.mkColor>`.
mode Array of color modes (ColorMap.RGB, HSV_POS, or HSV_NEG)
indicating the color space that should be used when
interpolating between stops. Note that the last mode value is
ignored. By default, the mode is entirely RGB.
=============== ==============================================================
"""
self.pos = np.array(pos)
order = np.argsort(self.pos)
self.pos = self.pos[order]
self.color = np.apply_along_axis(
func1d = lambda x: mkColor(x).getRgb(),
axis = -1,
arr = color,
)[order]
if mode is None:
mode = np.ones(len(pos))
self.mode = mode
self.stopsCache = {}
[docs] def map(self, data, mode='byte'):
"""
Return an array of colors corresponding to the values in *data*.
Data must be either a scalar position or an array (any shape) of positions.
The *mode* argument determines the type of data returned:
=========== ===============================================================
byte (default) Values are returned as 0-255 unsigned bytes.
float Values are returned as 0.0-1.0 floats.
qcolor Values are returned as an array of QColor objects.
=========== ===============================================================
"""
if isinstance(mode, basestring):
mode = self.enumMap[mode.lower()]
if mode == self.QCOLOR:
pos, color = self.getStops(self.BYTE)
else:
pos, color = self.getStops(mode)
# don't need this--np.interp takes care of it.
#data = np.clip(data, pos.min(), pos.max())
# Interpolate
# TODO: is griddata faster?
# interp = scipy.interpolate.griddata(pos, color, data)
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)
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(*interp)
else:
return [QtGui.QColor(*x) for x in interp]
else:
return interp
[docs] def mapToQColor(self, data):
"""Convenience function; see :func:`map() <pyqtgraph.ColorMap.map>`."""
return self.map(data, mode=self.QCOLOR)
[docs] def mapToByte(self, data):
"""Convenience function; see :func:`map() <pyqtgraph.ColorMap.map>`."""
return self.map(data, mode=self.BYTE)
[docs] def mapToFloat(self, data):
"""Convenience function; see :func:`map() <pyqtgraph.ColorMap.map>`."""
return self.map(data, mode=self.FLOAT)
[docs] def getGradient(self, p1=None, p2=None):
"""Return a QLinearGradient object spanning from QPoints p1 to p2."""
if p1 == None:
p1 = QtCore.QPointF(0,0)
if p2 == None:
p2 = QtCore.QPointF(self.pos.max()-self.pos.min(),0)
g = QtGui.QLinearGradient(p1, p2)
pos, color = self.getStops(mode=self.BYTE)
color = [QtGui.QColor(*x) for x in color]
g.setStops(list(zip(pos, color)))
#if self.colorMode == 'rgb':
#ticks = self.listTicks()
#g.setStops([(x, QtGui.QColor(t.color)) for t,x in ticks])
#elif self.colorMode == 'hsv': ## HSV mode is approximated for display by interpolating 10 points between each stop
#ticks = self.listTicks()
#stops = []
#stops.append((ticks[0][1], ticks[0][0].color))
#for i in range(1,len(ticks)):
#x1 = ticks[i-1][1]
#x2 = ticks[i][1]
#dx = (x2-x1) / 10.
#for j in range(1,10):
#x = x1 + dx*j
#stops.append((x, self.getColor(x)))
#stops.append((x2, self.getColor(x2)))
#g.setStops(stops)
return g
[docs] def getColors(self, mode=None):
"""Return list of all color stops converted to the specified mode.
If mode is None, then no conversion is done."""
if isinstance(mode, basestring):
mode = self.enumMap[mode.lower()]
color = self.color
if mode in [self.BYTE, self.QCOLOR] 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.
if mode == self.QCOLOR:
color = [QtGui.QColor(*x) for x in color]
return color
def getStops(self, mode):
## Get fully-expanded set of RGBA stops in either float or byte mode.
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.
## to support HSV mode, we need to do a little more work..
#stops = []
#for i in range(len(self.pos)):
#pos = self.pos[i]
#color = color[i]
#imode = self.mode[i]
#if imode == self.RGB:
#stops.append((x,color))
#else:
#ns =
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'):
"""
Return an RGB(A) lookup table (ndarray).
=============== =============================================================================
**Arguments:**
start The starting value in the lookup table (default=0.0)
stop The final value in the lookup table (default=1.0)
nPts 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 Determines return type: 'byte' (0-255), 'float' (0.0-1.0), or 'qcolor'.
See :func:`map() <pyqtgraph.ColorMap.map>`.
=============== =============================================================================
"""
if isinstance(mode, basestring):
mode = self.enumMap[mode.lower()]
if alpha is None:
alpha = self.usesAlpha()
x = np.linspace(start, stop, nPts)
table = self.map(x, mode)
if not alpha and mode != self.QCOLOR:
return table[:,:3]
else:
return table
[docs] def usesAlpha(self):
"""Return True if any stops have an alpha < 255"""
max = 1.0 if self.color.dtype.kind == 'f' else 255
return np.any(self.color[:,3] != max)
[docs] def isMapTrivial(self):
"""
Return 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)