1 import Image, ImageDraw
   2 import math
   3 
   4 def yuv2rgb(Y,U,V):
   5     R = 1.164*(Y - 16) + 1.596*(V - 128)
   6     G = 1.164*(Y - 16) - 0.813*(V - 128) - 0.391*(U - 128)
   7     B = 1.164*(Y - 16) + 2.018*(U - 128)
   8     return tuple(map(int, (R,G,B)))
   9 
  10 def rgb2yuv(R,G,B):
  11     Y = (0.257 * R) + (0.504 * G) + (0.098 * B) + 16
  12     U = -(0.148 * R) - (0.291 * G) + (0.439 * B) + 128
  13     V = (0.439 * R) - (0.368 * G) - (0.071 * B) + 128
  14     return tuple(map(int, (Y,U,V)))
  15 
  16 def evalue2rgb(evalue):
  17     n = -math.log(evalue)/math.log(10)
  18     if n > 70:
  19         v = 255
  20     elif n < 5:
  21         v = 0
  22     else:
  23         v = int((n-5)*255/65)
  24     print evalue, n, v
  25     return yuv2rgb(10,50,v)
  26 
  27 def makeSampleImage():
  28     img = Image.new('RGB', (80,140), (255,255,255))
  29     draw = ImageDraw.Draw(img)
  30     for yline in range(128):
  31         color = yuv2rgb(10, 50, 255-yline*2)
  32         draw.line((5, yline+5, 35, yline+5), fill=color)
  33     draw.text((40, 2), '1e-70', fill='black')
  34     draw.text((40, 60), '1e-32', fill='black')
  35     draw.text((40, 126), '1e-5', fill='black')
  36     img.save('test.png',type='PNG')
  37 
  38 def makeEvalueDistribution():
  39     img = Image.new('RGB', (80,140), (255,255,255))
  40     draw = ImageDraw.Draw(img)
  41     y = 10
  42     for evalue in (1e-3, 1e-5, 1e-10, 1e-34, 1e-68, 1e-70, 1e-80):
  43         draw.rectangle((50, y, 70, y+10),fill=evalue2rgb(evalue))
  44         y+=15
  45     img.save('test.png',type='PNG')
  46 
  47 if __name__=='__main__':
  48     #makeSampleImage()
  49     makeEvalueDistribution()