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