pyx/color.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2004, 2006, 2013 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2003-2006 Michael Schindler <m-schindler@users.sourceforge.net>
   6 # Copyright (C) 2002-2011 André Wobst <wobsta@users.sourceforge.net>
   7 #
   8 # This file is part of PyX (http://pyx.sourceforge.net/).
   9 #
  10 # PyX is free software; you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation; either version 2 of the License, or
  13 # (at your option) any later version.
  14 #
  15 # PyX is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19 #
  20 # You should have received a copy of the GNU General Public License
  21 # along with PyX; if not, write to the Free Software
  22 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  23
  24 import binascii, colorsys, logging, math, struct
  25 from . import attr, style, pdfwriter
  26
  27 logger = logging.getLogger("pyx")
  28
  29 # device-dependent (nonlinear) functions for color conversion
  30 # UCRx : [0,1] -> [-1, 1] UnderColorRemoval (removes black from c, y, m)
  31 # BG   : [0,1] -> [0, 1]  BlackGeneration (generate the black from the nominal k-value)
  32 # as long as we have no further knowledge we define them linearly with constants 1
  33 def _UCRc(x): return x
  34 def _UCRm(x): return x
  35 def _UCRy(x): return x
  36 def _BG(x): return x
  37
  38 def set(UCRc=None, UCRm=None, UCRy=None, BG=None):
  39     global _UCRc
  40     global _UCRm
  41     global _UCRy
  42     global _BG
  43
  44     if UCRc is not None:
  45         _UCRc = UCRc
  46     if UCRm is not None:
  47         _UCRm = UCRm
  48     if UCRy is not None:
  49         _UCRy = UCRy
  50     if BG is not None:
  51         _BG = BG
  52
  53
  54 class color(attr.exclusiveattr, style.strokestyle, style.fillstyle):
  55     """base class for all colors"""
  56     def __init__(self):
  57         super().__init__(color)
  58
  59     def processSVGattrs(self, attrs, writer, context, registry):
  60         if context.strokeattr:
  61             context.strokecolor = self.rgb().tohexstring()
  62         if context.fillattr:
  63             context.fillcolor = self.rgb().tohexstring()
  64
  65
  66 clear = attr.clearclass(color)
  67
  68
  69 class gray(color):
  70
  71     """grey tones"""
  72
  73     def __init__(self, g=0.0):
  74         super().__init__()
  75         if g<0 or g>1:
  76             raise ValueError("Value g out of range [0,1]")
  77         self.g = g
  78
  79     def processPS(self, file, writer, context, registry):
  80         file.write("%f setgray\n" % self.g)
  81
  82     def processPDF(self, file, writer, context, registry):
  83         if context.strokeattr:
  84             file.write("%f G\n" % self.g)
  85         if context.fillattr:
  86             file.write("%f g\n" % self.g)
  87
  88     def cmyk(self):
  89         return cmyk(0, 0, 0, 1 - self.g)
  90
  91     def gray(self):
  92         return gray(self.g)
  93     grey = gray
  94
  95     def hsb(self):
  96         return hsb(0, 0, self.g)
  97
  98     def rgb(self):
  99         return rgb(self.g, self.g, self.g)
 100
 101     def colorspacestring(self):
 102         return "/DeviceGray"
 103
 104     def to8bitbytes(self):
 105         return bytes((int(self.g*255),))
 106
 107 gray.black = gray(0.0)
 108 gray.white = gray(1.0)
 109 grey = gray
 110
 111
 112 class rgb(color):
 113
 114     """rgb colors"""
 115
 116     def __init__(self, r=0.0, g=0.0, b=0.0):
 117         super().__init__()
 118         if r<0 or r>1:
 119             raise ValueError("Value r out of range [0,1]")
 120         if g<0 or g>1:
 121             raise ValueError("Value g out of range [0,1]")
 122         if b<0 or b>1:
 123             raise ValueError("Value b out of range [0,1]")
 124         self.r = r
 125         self.g = g
 126         self.b = b
 127
 128     def processPS(self, file, writer, context, registry):
 129         file.write("%f %f %f setrgbcolor\n" % (self.r, self.g, self.b))
 130
 131     def processPDF(self, file, writer, context, registry):
 132         if context.strokeattr:
 133             file.write("%f %f %f RG\n" % (self.r, self.g, self.b))
 134         if context.fillattr:
 135             file.write("%f %f %f rg\n" % (self.r, self.g, self.b))
 136
 137     def cmyk(self):
 138         # conversion to cmy
 139         c, m, y = 1 - self.r, 1 - self.g, 1 - self.b
 140         # conversion from cmy to cmyk with device-dependent functions
 141         k = min([c, m, y])
 142         return cmyk(min(1, max(0, c - _UCRc(k))),
 143                     min(1, max(0, m - _UCRm(k))),
 144                     min(1, max(0, y - _UCRy(k))),
 145                     _BG(k))
 146
 147     def gray(self):
 148         return gray(0.3*self.r + 0.59*self.g + 0.11*self.b)
 149     grey = gray
 150
 151     def hsb(self):
 152         h, s, b = colorsys.rgb_to_hsv(self.r, self.g, self.b)
 153         return hsb(h, s, b)
 154
 155     def rgb(self):
 156         return rgb(self.r, self.g, self.b)
 157
 158     def colorspacestring(self):
 159         return "/DeviceRGB"
 160
 161     def to8bitbytes(self):
 162         return struct.pack("BBB", int(self.r*255), int(self.g*255), int(self.b*255))
 163
 164     def tohexstring(self, cssstrip=1, addhash=1):
 165         hexstring = binascii.b2a_hex(self.to8bitbytes()).decode('ascii')
 166         if cssstrip and hexstring[0] == hexstring[1] and hexstring[2] == hexstring[3] and hexstring[4] == hexstring[5]:
 167             hexstring = "".join([hexstring[0], hexstring[2], hexstring[4]])
 168         if addhash:
 169             hexstring = "#" + hexstring
 170         return hexstring
 171
 172
 173 def rgbfromhexstring(hexstring):
 174     hexstring = hexstring.strip().lstrip("#")
 175     if len(hexstring) == 3:
 176         hexstring = "".join([hexstring[0], hexstring[0], hexstring[1], hexstring[1], hexstring[2], hexstring[2]])
 177     elif len(hexstring) != 6:
 178         raise ValueError("3 or 6 digit hex number expected (with optional leading hash character)")
 179     return rgb(*[value/255.0 for value in struct.unpack("BBB", binascii.a2b_hex(hexstring))])
 180
 181 rgb.red   = rgb(1, 0, 0)
 182 rgb.green = rgb(0, 1, 0)
 183 rgb.blue  = rgb(0, 0, 1)
 184 rgb.white = rgb(1, 1, 1)
 185 rgb.black = rgb(0, 0, 0)
 186
 187
 188 class hsb(color):
 189
 190     """hsb colors"""
 191
 192     def __init__(self, h=0.0, s=0.0, b=0.0):
 193         super().__init__()
 194         if h<0 or h>1:
 195             raise ValueError("Value h out of range [0,1]")
 196         if s<0 or s>1:
 197             raise ValueError("Value s out of range [0,1]")
 198         if b<0 or b>1:
 199             raise ValueError("Value b out of range [0,1]")
 200         self.h = h
 201         self.s = s
 202         self.b = b
 203
 204     def processPS(self, file, writer, context, registry):
 205         file.write("%f %f %f sethsbcolor\n" % (self.h, self.s, self.b))
 206
 207     def processPDF(self, file, writer, context, registry):
 208         self.rgb().processPDF(file, writer, context, registry)
 209
 210     def cmyk(self):
 211         return self.rgb().cmyk()
 212
 213     def gray(self):
 214         return self.rgb().gray()
 215     grey = gray
 216
 217     def hsb(self):
 218         return hsb(self.h, self.s, self.b)
 219
 220     def rgb(self):
 221         r, g, b = colorsys.hsv_to_rgb(self.h, self.s, self.b)
 222         return rgb(r, g, b)
 223
 224     def colorspacestring(self):
 225         raise RuntimeError("colorspace string not available for hsb colors")
 226
 227
 228 class cmyk(color):
 229
 230     """cmyk colors"""
 231
 232     def __init__(self, c=0.0, m=0.0, y=0.0, k=0.0):
 233         super().__init__()
 234         if c<0 or c>1:
 235             raise ValueError("Value c out of range [0,1]")
 236         if m<0 or m>1:
 237             raise ValueError("Value m out of range [0,1]")
 238         if y<0 or y>1:
 239             raise ValueError("Value y out of range [0,1]")
 240         if k<0 or k>1:
 241             raise ValueError("Value k out of range [0,1]")
 242         self.c = c
 243         self.m = m
 244         self.y = y
 245         self.k = k
 246
 247     def processPS(self, file, writer, context, registry):
 248         file.write("%f %f %f %f setcmykcolor\n" % (self.c, self.m, self.y, self.k))
 249
 250     def processPDF(self, file, writer, context, registry):
 251         if context.strokeattr:
 252             file.write("%f %f %f %f K\n" % (self.c, self.m, self.y, self.k))
 253         if context.fillattr:
 254             file.write("%f %f %f %f k\n" % (self.c, self.m, self.y, self.k))
 255
 256     def cmyk(self):
 257         return cmyk(self.c, self.m, self.y, self.k)
 258
 259     def gray(self):
 260         return gray(1 - min([1, 0.3*self.c + 0.59*self.m + 0.11*self.y + self.k]))
 261     grey = gray
 262
 263     def hsb(self):
 264         return self.rgb().hsb()
 265
 266     def rgb(self):
 267         # conversion to cmy:
 268         c = min(1, self.c + self.k)
 269         m = min(1, self.m + self.k)
 270         y = min(1, self.y + self.k)
 271         # conversion from cmy to rgb:
 272         return rgb(1 - c, 1 - m, 1 - y)
 273
 274     def colorspacestring(self):
 275         return "/DeviceCMYK"
 276
 277     def to8bitbytes(self):
 278         return struct.pack("BBBB", int(self.c*255), int(self.m*255), int(self.y*255), int(self.k*255))
 279
 280 cmyk.GreenYellow    = cmyk(0.15, 0, 0.69, 0)
 281 cmyk.Yellow         = cmyk(0, 0, 1, 0)
 282 cmyk.Goldenrod      = cmyk(0, 0.10, 0.84, 0)
 283 cmyk.Dandelion      = cmyk(0, 0.29, 0.84, 0)
 284 cmyk.Apricot        = cmyk(0, 0.32, 0.52, 0)
 285 cmyk.Peach          = cmyk(0, 0.50, 0.70, 0)
 286 cmyk.Melon          = cmyk(0, 0.46, 0.50, 0)
 287 cmyk.YellowOrange   = cmyk(0, 0.42, 1, 0)
 288 cmyk.Orange         = cmyk(0, 0.61, 0.87, 0)
 289 cmyk.BurntOrange    = cmyk(0, 0.51, 1, 0)
 290 cmyk.Bittersweet    = cmyk(0, 0.75, 1, 0.24)
 291 cmyk.RedOrange      = cmyk(0, 0.77, 0.87, 0)
 292 cmyk.Mahogany       = cmyk(0, 0.85, 0.87, 0.35)
 293 cmyk.Maroon         = cmyk(0, 0.87, 0.68, 0.32)
 294 cmyk.BrickRed       = cmyk(0, 0.89, 0.94, 0.28)
 295 cmyk.Red            = cmyk(0, 1, 1, 0)
 296 cmyk.OrangeRed      = cmyk(0, 1, 0.50, 0)
 297 cmyk.RubineRed      = cmyk(0, 1, 0.13, 0)
 298 cmyk.WildStrawberry = cmyk(0, 0.96, 0.39, 0)
 299 cmyk.Salmon         = cmyk(0, 0.53, 0.38, 0)
 300 cmyk.CarnationPink  = cmyk(0, 0.63, 0, 0)
 301 cmyk.Magenta        = cmyk(0, 1, 0, 0)
 302 cmyk.VioletRed      = cmyk(0, 0.81, 0, 0)
 303 cmyk.Rhodamine      = cmyk(0, 0.82, 0, 0)
 304 cmyk.Mulberry       = cmyk(0.34, 0.90, 0, 0.02)
 305 cmyk.RedViolet      = cmyk(0.07, 0.90, 0, 0.34)
 306 cmyk.Fuchsia        = cmyk(0.47, 0.91, 0, 0.08)
 307 cmyk.Lavender       = cmyk(0, 0.48, 0, 0)
 308 cmyk.Thistle        = cmyk(0.12, 0.59, 0, 0)
 309 cmyk.Orchid         = cmyk(0.32, 0.64, 0, 0)
 310 cmyk.DarkOrchid     = cmyk(0.40, 0.80, 0.20, 0)
 311 cmyk.Purple         = cmyk(0.45, 0.86, 0, 0)
 312 cmyk.Plum           = cmyk(0.50, 1, 0, 0)
 313 cmyk.Violet         = cmyk(0.79, 0.88, 0, 0)
 314 cmyk.RoyalPurple    = cmyk(0.75, 0.90, 0, 0)
 315 cmyk.BlueViolet     = cmyk(0.86, 0.91, 0, 0.04)
 316 cmyk.Periwinkle     = cmyk(0.57, 0.55, 0, 0)
 317 cmyk.CadetBlue      = cmyk(0.62, 0.57, 0.23, 0)
 318 cmyk.CornflowerBlue = cmyk(0.65, 0.13, 0, 0)
 319 cmyk.MidnightBlue   = cmyk(0.98, 0.13, 0, 0.43)
 320 cmyk.NavyBlue       = cmyk(0.94, 0.54, 0, 0)
 321 cmyk.RoyalBlue      = cmyk(1, 0.50, 0, 0)
 322 cmyk.Blue           = cmyk(1, 1, 0, 0)
 323 cmyk.Cerulean       = cmyk(0.94, 0.11, 0, 0)
 324 cmyk.Cyan           = cmyk(1, 0, 0, 0)
 325 cmyk.ProcessBlue    = cmyk(0.96, 0, 0, 0)
 326 cmyk.SkyBlue        = cmyk(0.62, 0, 0.12, 0)
 327 cmyk.Turquoise      = cmyk(0.85, 0, 0.20, 0)
 328 cmyk.TealBlue       = cmyk(0.86, 0, 0.34, 0.02)
 329 cmyk.Aquamarine     = cmyk(0.82, 0, 0.30, 0)
 330 cmyk.BlueGreen      = cmyk(0.85, 0, 0.33, 0)
 331 cmyk.Emerald        = cmyk(1, 0, 0.50, 0)
 332 cmyk.JungleGreen    = cmyk(0.99, 0, 0.52, 0)
 333 cmyk.SeaGreen       = cmyk(0.69, 0, 0.50, 0)
 334 cmyk.Green          = cmyk(1, 0, 1, 0)
 335 cmyk.ForestGreen    = cmyk(0.91, 0, 0.88, 0.12)
 336 cmyk.PineGreen      = cmyk(0.92, 0, 0.59, 0.25)
 337 cmyk.LimeGreen      = cmyk(0.50, 0, 1, 0)
 338 cmyk.YellowGreen    = cmyk(0.44, 0, 0.74, 0)
 339 cmyk.SpringGreen    = cmyk(0.26, 0, 0.76, 0)
 340 cmyk.OliveGreen     = cmyk(0.64, 0, 0.95, 0.40)
 341 cmyk.RawSienna      = cmyk(0, 0.72, 1, 0.45)
 342 cmyk.Sepia          = cmyk(0, 0.83, 1, 0.70)
 343 cmyk.Brown          = cmyk(0, 0.81, 1, 0.60)
 344 cmyk.Tan            = cmyk(0.14, 0.42, 0.56, 0)
 345 cmyk.Gray           = cmyk(0, 0, 0, 0.50)
 346 cmyk.Grey           = cmyk.Gray
 347 cmyk.Black          = cmyk(0, 0, 0, 1)
 348 cmyk.White          = cmyk(0, 0, 0, 0)
 349 cmyk.white          = cmyk.White
 350 cmyk.black          = cmyk.Black
 351
 352
 353 class palette(attr.changelist):
 354     """color palettes
 355
 356     A color palette is a discrete, ordered list of colors"""
 357
 358 palette.clear = attr.clearclass(palette)
 359
 360 #
 361 # gradients
 362 #
 363
 364 class gradient(attr.changeattr):
 365
 366     """base class for color gradients
 367
 368     A gradient is a continuous collection of colors with a single parameter ranging from 0 to 1
 369     to address them"""
 370
 371     def getcolor(self, param):
 372         """return color corresponding to param"""
 373         pass
 374
 375     def select(self, index, n_indices):
 376         """return a color corresponding to an index out of n_indices"""
 377         if n_indices == 1:
 378             param = 0
 379         else:
 380             param = index / (n_indices - 1.0)
 381         return self.getcolor(param)
 382
 383 gradient.clear = attr.clearclass(gradient)
 384
 385 #
 386 # gradient with arbitrary non-linear dependency
 387 #
 388
 389 class functiongradient_gray(gradient):
 390
 391     """arbitrary non-linear gradients of gray colors
 392
 393     f_gray: a function mapping [0,1] to the gray value
 394     """
 395
 396     def __init__(self, f_gray):
 397         super().__init__()
 398         self.f_gray = f_gray
 399
 400     def getcolor(self, param):
 401         return gray(self.f_gray(param))
 402
 403
 404 class functiongradient_cmyk(gradient):
 405
 406     """arbitrary non-linear gradients of cmyk colors
 407
 408     f_c: a function mapping [0,1] to the c component
 409     f_m: a function mapping [0,1] to the m component
 410     f_y: a function mapping [0,1] to the y component
 411     f_k: a function mapping [0,1] to the k component
 412     """
 413
 414     def __init__(self, f_c, f_m, f_y, f_k):
 415         super().__init__()
 416         self.f_c = f_c
 417         self.f_m = f_m
 418         self.f_y = f_y
 419         self.f_k = f_k
 420
 421     def getcolor(self, param):
 422         return cmyk(self.f_c(param), self.f_m(param), self.f_y(param), self.f_k(param))
 423
 424
 425 class functiongradient_hsb(gradient):
 426
 427     """arbitrary non-linear gradients of hsb colors
 428
 429     f_h: a function mapping [0,1] to the h component
 430     f_s: a function mapping [0,1] to the s component
 431     f_b: a function mapping [0,1] to the b component
 432     """
 433
 434     def __init__(self, f_h, f_s, f_b):
 435         super().__init__()
 436         self.f_h = f_h
 437         self.f_s = f_s
 438         self.f_b = f_b
 439
 440     def getcolor(self, param):
 441         return hsb(self.f_h(param), self.f_s(param), self.f_b(param))
 442
 443
 444 class functiongradient_rgb(gradient):
 445
 446     """arbitrary non-linear gradients of rgb colors
 447
 448     f_r: a function mapping [0,1] to the r component
 449     f_g: a function mapping [0,1] to the b component
 450     f_b: a function mapping [0,1] to the b component
 451     """
 452
 453     def __init__(self, f_r, f_g, f_b):
 454         super().__init__()
 455         self.f_r = f_r
 456         self.f_g = f_g
 457         self.f_b = f_b
 458
 459     def getcolor(self, param):
 460         return rgb(self.f_r(param), self.f_g(param), self.f_b(param))
 461
 462 #
 463 # factory functions for gradients interpolating linearly between two colors
 464 #
 465
 466 def lineargradient_cmyk(mincolor, maxcolor):
 467      return functiongradient_cmyk(lambda x:maxcolor.c * x + mincolor.c * (1-x),
 468                                   lambda x:maxcolor.m * x + mincolor.m * (1-x),
 469                                   lambda x:maxcolor.y * x + mincolor.y * (1-x),
 470                                   lambda x:maxcolor.k * x + mincolor.k * (1-x))
 471
 472 def lineargradient_gray(mincolor, maxcolor):
 473      return functiongradient_gray(lambda x:maxcolor.g * x + mincolor.g * (1-x))
 474
 475 def lineargradient_hsb(mincolor, maxcolor):
 476      return functiongradient_hsb(lambda x:maxcolor.h * x + mincolor.h * (1-x),
 477                                  lambda x:maxcolor.s * x + mincolor.s * (1-x),
 478                                  lambda x:maxcolor.b * x + mincolor.b * (1-x))
 479
 480 def lineargradient_rgb(mincolor, maxcolor):
 481      return functiongradient_rgb(lambda x:maxcolor.r * x + mincolor.r * (1-x),
 482                                  lambda x:maxcolor.g * x + mincolor.g * (1-x),
 483                                  lambda x:maxcolor.b * x + mincolor.b * (1-x))
 484
 485
 486 #
 487 # gradients converted into other color spaces
 488 #
 489
 490 class rgbgradient(gradient):
 491
 492     "a gradient, which takes another gradient and returns rgb colors"
 493
 494     def __init__(self, gradient):
 495         super().__init__()
 496         self.gradient = gradient
 497
 498     def getcolor(self, param):
 499         return self.gradient.getcolor(param).rgb()
 500
 501
 502 class cmykgradient(gradient):
 503
 504     "a gradient, which takes another gradient and returns cmyk colors"
 505
 506     def __init__(self, gradient):
 507         super().__init__()
 508         self.gradient = gradient
 509
 510     def getcolor(self, param):
 511         return self.gradient.getcolor(param).cmyk()
 512
 513
 514 gradient.Gray           = lineargradient_gray(gray.white, gray.black)
 515 gradient.Grey           = gradient.Gray
 516 gradient.ReverseGray    = lineargradient_gray(gray.black, gray.white)
 517 gradient.ReverseGrey    = gradient.ReverseGray
 518 gradient.BlackYellow    = functiongradient_rgb( # compare this with reversegray above
 519     f_r=lambda x: 2*x*(1-x)**5 + 3.5*x**2*(1-x)**3 + 2.1*x*x*(1-x)**2 + 3.0*x**3*(1-x)**2 + x**0.5*(1-(1-x)**2),
 520     f_g=lambda x: 1.5*x**2*(1-x)**3 - 0.8*x**3*(1-x)**2 + 2.0*x**4*(1-x) + x**4,
 521     f_b=lambda x: 5*x*(1-x)**5 - 0.5*x**2*(1-x)**3 + 0.3*x*x*(1-x)**2 + 5*x**3*(1-x)**2 + 0.5*x**6)
 522 gradient.YellowBlack    = functiongradient_rgb(
 523     f_r=lambda x: 2*(1-x)*x**5 + 3.5*(1-x)**2*x**3 + 2.1*(1-x)*(1-x)*x**2 + 3.0*(1-x)**3*x**2 + (1-x)**0.5*(1-x**2),
 524     f_g=lambda x: 1.5*(1-x)**2*x**3 - 0.8*(1-x)**3*x**2 + 2.0*(1-x)**4*x + (1-x)**4,
 525     f_b=lambda x: 5*(1-x)*x**5 - 0.5*(1-x)**2*x**3 + 0.3*(1-x)*(1-x)*x**2 + 5*(1-x)**3*x**2 + 0.5*(1-x)**6)
 526 gradient.RedGreen       = lineargradient_rgb(rgb.red, rgb.green)
 527 gradient.RedBlue        = lineargradient_rgb(rgb.red, rgb.blue)
 528 gradient.GreenRed       = lineargradient_rgb(rgb.green, rgb.red)
 529 gradient.GreenBlue      = lineargradient_rgb(rgb.green, rgb.blue)
 530 gradient.BlueRed        = lineargradient_rgb(rgb.blue, rgb.red)
 531 gradient.BlueGreen      = lineargradient_rgb(rgb.blue, rgb.green)
 532 gradient.RedBlack       = lineargradient_rgb(rgb.red, rgb.black)
 533 gradient.BlackRed       = lineargradient_rgb(rgb.black, rgb.red)
 534 gradient.RedWhite       = lineargradient_rgb(rgb.red, rgb.white)
 535 gradient.WhiteRed       = lineargradient_rgb(rgb.white, rgb.red)
 536 gradient.GreenBlack     = lineargradient_rgb(rgb.green, rgb.black)
 537 gradient.BlackGreen     = lineargradient_rgb(rgb.black, rgb.green)
 538 gradient.GreenWhite     = lineargradient_rgb(rgb.green, rgb.white)
 539 gradient.WhiteGreen     = lineargradient_rgb(rgb.white, rgb.green)
 540 gradient.BlueBlack      = lineargradient_rgb(rgb.blue, rgb.black)
 541 gradient.BlackBlue      = lineargradient_rgb(rgb.black, rgb.blue)
 542 gradient.BlueWhite      = lineargradient_rgb(rgb.blue, rgb.white)
 543 gradient.WhiteBlue      = lineargradient_rgb(rgb.white, rgb.blue)
 544 gradient.Rainbow        = lineargradient_hsb(hsb(0, 1, 1), hsb(2.0/3.0, 1, 1))
 545 gradient.ReverseRainbow = lineargradient_hsb(hsb(2.0/3.0, 1, 1), hsb(0, 1, 1))
 546 gradient.Hue            = lineargradient_hsb(hsb(0, 1, 1), hsb(1, 1, 1))
 547 gradient.ReverseHue     = lineargradient_hsb(hsb(1, 1, 1), hsb(0, 1, 1))
 548 rgbgradient.Rainbow        = rgbgradient(gradient.Rainbow)
 549 rgbgradient.ReverseRainbow = rgbgradient(gradient.ReverseRainbow)
 550 rgbgradient.Hue            = rgbgradient(gradient.Hue)
 551 rgbgradient.ReverseHue     = rgbgradient(gradient.ReverseHue)
 552 cmykgradient.Rainbow        = cmykgradient(gradient.Rainbow)
 553 cmykgradient.ReverseRainbow = cmykgradient(gradient.ReverseRainbow)
 554 cmykgradient.Hue            = cmykgradient(gradient.Hue)
 555 cmykgradient.ReverseHue     = cmykgradient(gradient.ReverseHue)
 556 def jet_r(x):
 557     if x < 0.38: return 0
 558     elif x < 0.62: return (x-0.38)/(0.62-0.38)
 559     elif x < 0.87: return 1
 560     else: return 0.5 + 0.5*(1-x)/(1-0.87)
 561 def jet_g(x):
 562     if x < 0.13: return 0
 563     elif x < 0.38: return (x-0.13)/(0.38-0.13)
 564     elif x < 0.62: return 1
 565     elif x < 0.87: return (0.87-x)/(0.87-0.62)
 566     else: return 0
 567 def jet_b(x):
 568     if x < 0.13: return 0.5 + 0.5*x/0.13
 569     elif x < 0.38: return 1
 570     elif x < 0.62: return 1-(x-0.38)/(0.62-0.38)
 571     else: return 0
 572 gradient.Jet = functiongradient_rgb(f_r=jet_r, f_g=jet_g, f_b=jet_b)
 573 gradient.ReverseJet = functiongradient_rgb(f_r=lambda x: jet_r(1-x), f_g=lambda x: jet_g(1-x), f_b=lambda x: jet_b(1-x))
 574 cmykgradient.Jet = cmykgradient(gradient.Jet)
 575 cmykgradient.ReverseJet = cmykgradient(gradient.ReverseJet)
 576
 577
 578
 579 class PDFextgstate(pdfwriter.PDFobject):
 580
 581     def __init__(self, name, extgstate, registry):
 582         pdfwriter.PDFobject.__init__(self, "extgstate", name)
 583         registry.addresource("ExtGState", name, self)
 584         self.name = name
 585         self.extgstate = extgstate
 586
 587     def write(self, file, writer, registry):
 588         file.write("%s\n" % self.extgstate)
 589
 590
 591 class transparency(attr.exclusiveattr, style.strokestyle, style.fillstyle):
 592
 593     def __init__(self, value):
 594         self.value = 1-value
 595         attr.exclusiveattr.__init__(self, transparency)
 596
 597     def processPS(self, file, writer, context, registry):
 598         logger.warning("Transparency not available in PostScript, proprietary ghostscript extension code inserted.")
 599         file.write("%f .setshapealpha\n" % self.value)
 600
 601     def processPDF(self, file, writer, context, registry):
 602         if context.strokeattr and context.fillattr:
 603             registry.add(PDFextgstate("Transparency-%f" % self.value,
 604                                       "<< /Type /ExtGState /CA %f /ca %f >>" % (self.value, self.value), registry))
 605             file.write("/Transparency-%f gs\n" % self.value)
 606         elif context.strokeattr:
 607             registry.add(PDFextgstate("Transparency-Stroke-%f" % self.value,
 608                                       "<< /Type /ExtGState /CA %f >>" % self.value, registry))
 609             file.write("/Transparency-Stroke-%f gs\n" % self.value)
 610         elif context.fillattr:
 611             registry.add(PDFextgstate("Transparency-Fill-%f" % self.value,
 612                                       "<< /Type /ExtGState /ca %f >>" % self.value, registry))
 613             file.write("/Transparency-Fill-%f gs\n" % self.value)
 614
 615     def processSVGattrs(self, attrs, writer, context, registry):
 616         if context.strokeattr:
 617             context.strokeopacity = self.value
 618         if context.fillattr:
 619             context.fillopacity = self.value
 620