diff --git a/pykat/utilities/plotting/colormap.py b/pykat/utilities/plotting/colormap.py new file mode 100644 index 0000000000000000000000000000000000000000..2ea25b8d8310eed4c7fbd340d01a105e02c61ab3 --- /dev/null +++ b/pykat/utilities/plotting/colormap.py @@ -0,0 +1,324 @@ + +import numpy as np +import matplotlib +BACKEND = 'Qt4Agg' +matplotlib.use(BACKEND) +from matplotlib import rc +import matplotlib.pyplot as plt + +# ============================================================================= +# ====================== The Class ColorMapCreator ============================ +# ============================================================================= + +class ColorMapCreator: + """ + Class ColorMapCreator: + Create diverging colormaps from RGB1 to RGB2 using the method of Moreland + or a simple CIELAB-interpolation. numColors controls the number of color + values to output (odd number) and divide gives the possibility to output + RGB-values from 0.0-1.0 instead of 0-255. If a filename different than + "" is given, the colormap will be saved to this file, otherwise a simple + output using print will be given. + """ + + # ======================== Global Variables =============================== + + # Reference white-point D65 + Xn, Yn, Zn = [95.047, 100.0, 108.883] # from Adobe Cookbook + + # Transfer-matrix for the conversion of RGB to XYZ color space + transM = np.array([[0.4124564, 0.2126729, 0.0193339], + [0.3575761, 0.7151522, 0.1191920], + [0.1804375, 0.0721750, 0.9503041]]) + + + # ============================= Functions ================================= + + + def __init__(self, RGB1, RGB2, numColors = 257., divide = 255., + method = "moreland", filename = ""): + + # create a class variable for the number of colors + self.numColors = numColors + + # assert an odd number of points + assert np.mod(numColors,2) == 1, \ + "For diverging colormaps odd numbers of colors are desireable!" + + # assert a known method was specified + knownMethods = ["moreland", "lab"] + assert method in knownMethods, "Unknown method was specified!" + + if method == knownMethods[0]: + #generate the Msh diverging colormap + self.colorMap = self.generateColorMap(RGB1, RGB2, divide) + elif method == knownMethods[1]: + # generate the Lab diverging colormap + self.colorMap = self.generateColorMapLab(RGB1, RGB2, divide) + + def getMap(self): + return self.colorMap + + def showMap(self): + #rc('text', usetex=False) + a=np.outer(np.arange(0,1,0.01),np.ones(10)) + fig=plt.figure(99,figsize=(10,2)) + plt.axis("off") + cm = matplotlib.colors.ListedColormap(self.colorMap) + pm=plt.imshow(a,aspect='auto',cmap=cm,origin="lower") + plt.clim(0,1) + fig.colorbar(pm) + plt.draw() + + + def rgblinear(self, RGB): + """ + Conversion from the sRGB components to RGB components with physically + linear properties. + """ + + # initialize the linear RGB array + RGBlinear = np.zeros((3,)) + + # calculate the linear RGB values + for i,value in enumerate(RGB): + value = float(value) / 255. + if value > 0.04045 : + value = ( ( value + 0.055 ) / 1.055 ) ** 2.4 + else : + value = value / 12.92 + RGBlinear[i] = value * 100. + return RGBlinear + #- + + def sRGB(self, RGBlinear): + """ + Back conversion from linear RGB to sRGB. + """ + + # initialize the sRGB array + RGB = np.zeros((3,)) + + # calculate the sRGB values + for i,value in enumerate(RGBlinear): + value = float(value) / 100. + + if value > 0.00313080495356037152: + value = (1.055 * np.power(value,1./2.4) ) - 0.055 + else : + value = value * 12.92 + + RGB[i] = round(value * 255.) + return RGB + #- + + def rgb2xyz(self, RGB): + """ + Conversion of RGB to XYZ using the transfer-matrix + """ + return np.dot(self.rgblinear(RGB), self.transM) + #- + + def xyz2rgb(self, XYZ): + """ + Conversion of RGB to XYZ using the transfer-matrix + """ + #return np.round(np.dot(XYZ, np.array(np.matrix(transM).I))) + return self.sRGB(np.dot(XYZ, np.array(np.matrix(self.transM).I))) + #- + + def rgb2Lab(self, RGB): + """ + Conversion of RGB to CIELAB + """ + + # convert RGB to XYZ + X, Y, Z = (self.rgb2xyz(RGB)).tolist() + + # helper function + def f(x): + limit = 0.008856 + if x> limit: + return np.power(x, 1./3.) + else: + return 7.787*x + 16./116. + + # calculation of L, a and b + L = 116. * ( f(Y/self.Yn) - (16./116.) ) + a = 500. * ( f(X/self.Xn) - f(Y/self.Yn) ) + b = 200. * ( f(Y/self.Yn) - f(Z/self.Zn) ) + return np.array([L, a, b]) + #- + + def Lab2rgb(self, Lab): + """ + Conversion of CIELAB to RGB + """ + + # unpack the Lab-array + L, a, b = Lab.tolist() + + # helper function + def finverse(x): + xlim = 0.008856 + a = 7.787 + b = 16./116. + ylim = a*xlim+b + if x > ylim: + return np.power(x, 3) + else: + return ( x - b ) / a + + # calculation of X, Y and Z + X = self.Xn * finverse( (a/500.) + (L+16.)/116. ) + Y = self.Yn * finverse( (L+16.)/116. ) + Z = self.Zn * finverse( (L+16.)/116. - (b/200.) ) + + # conversion of XYZ to RGB + return self.xyz2rgb(np.array([X,Y,Z])) + #- + + def Lab2Msh(self, Lab): + """ + Conversion of CIELAB to Msh + """ + + # unpack the Lab-array + L, a, b = Lab.tolist() + + # calculation of M, s and h + M = np.sqrt(np.sum(np.power(Lab, 2))) + s = np.arccos(L/M) + h = np.arctan2(b,a) + return np.array([M,s,h]) + #- + + def Msh2Lab(self, Msh): + """ + Conversion of Msh to CIELAB + """ + + # unpack the Msh-array + M, s, h = Msh.tolist() + + # calculation of L, a and b + L = M*np.cos(s) + a = M*np.sin(s)*np.cos(h) + b = M*np.sin(s)*np.sin(h) + return np.array([L,a,b]) + #- + + def rgb2Msh(self, RGB): + """ Direct conversion of RGB to Msh. """ + return self.Lab2Msh(self.rgb2Lab(RGB)) + #- + + def Msh2rgb(self, Msh): + """ Direct conversion of Msh to RGB. """ + return self.Lab2rgb(self.Msh2Lab(Msh)) + #- + + def adjustHue(self, MshSat, Munsat): + """ + Function to provide an adjusted hue when interpolating to an + unsaturated color in Msh space. + """ + + # unpack the saturated Msh-array + Msat, ssat, hsat = MshSat.tolist() + + if Msat >= Munsat: + return hsat + else: + hSpin = ssat * np.sqrt(Munsat**2 - Msat**2) / \ + (Msat * np.sin(ssat)) + if hsat > -np.pi/3: + return hsat + hSpin + else: + return hsat - hSpin + #- + + def interpolateColor(self, RGB1, RGB2, interp): + """ + Interpolation algorithm to automatically create continuous diverging + color maps. + """ + + # convert RGB to Msh and unpack + Msh1 = self.rgb2Msh(RGB1) + M1, s1, h1 = Msh1.tolist() + Msh2 = self.rgb2Msh(RGB2) + M2, s2, h2 = Msh2.tolist() + + # If points saturated and distinct, place white in middle + if (s1>0.05) and (s2>0.05) and ( np.abs(h1-h2) > np.pi/3. ): + Mmid = max([M1, M2, 88.]) + if interp < 0.5: + M2 = Mmid + s2 = 0. + h2 = 0. + interp = 2*interp + else: + M1 = Mmid + s1 = 0. + h1 = 0. + interp = 2*interp-1. + + # Adjust hue of unsaturated colors + if (s1 < 0.05) and (s2 > 0.05): + h1 = self.adjustHue(np.array([M2,s2,h2]), M1) + elif (s2 < 0.05) and (s1 > 0.05): + h2 = self.adjustHue(np.array([M1,s1,h1]), M2) + + # Linear interpolation on adjusted control points + MshMid = (1-interp)*np.array([M1,s1,h1]) + \ + interp*np.array([M2,s2,h2]) + + return self.Msh2rgb(MshMid) + #- + + def generateColorMap(self, RGB1, RGB2, divide): + """ + Generate the complete diverging color map using the Moreland-technique + from RGB1 to RGB2, placing "white" in the middle. The number of points + given by "numPoints" controls the resolution of the colormap. The + optional parameter "divide" gives the possibility to scale the whole + colormap, for example to have float values from 0 to 1. + """ + + # calculate + scalars = np.linspace(0., 1., self.numColors) + RGBs = np.zeros((self.numColors, 3)) + for i,s in enumerate(scalars): + RGBs[i,:] = self.interpolateColor(RGB1, RGB2, s) + return RGBs/divide + #- + + def generateColorMapLab(self, RGB1, RGB2, divide): + """ + Generate the complete diverging color map using a transition from + Lab1 to Lab2, transitioning true RGB-white. The number of points + given by "numPoints" controls the resolution of the colormap. The + optional parameter "divide" gives the possibility to scale the whole + colormap, for example to have float values from 0 to 1. + """ + + # convert to Lab-space + Lab1 = self.rgb2Lab(RGB1) + Lab2 = self.rgb2Lab(RGB2) + LabWhite = np.array([100., 0., 0.]) + + # initialize the resulting arrays + Lab = np.zeros((self.numColors ,3)) + RGBs = np.zeros((self.numColors ,3)) + N2 = np.floor(self.numColors/2.) + + # calculate + for i in range(3): + Lab[0:N2+1, i] = np.linspace(Lab1[i], LabWhite[i], N2+1) + Lab[N2:, i] = np.linspace(LabWhite[i], Lab2[i], N2+1) + for i,l in enumerate(Lab): + RGBs[i,:] = self.Lab2rgb(l) + return RGBs/divide + #- +