1 """GradationEffect for BLAST expect value distribution, It uses PIL
   2 """
   3 import Image, ImageDraw
   4 import math
   5 
   6 def yuv2rgb(Y,U,V):
   7     R = 1.164*(Y - 16) + 1.596*(V - 128)
   8     G = 1.164*(Y - 16) - 0.813*(V - 128) - 0.391*(U - 128)
   9     B = 1.164*(Y - 16) + 2.018*(U - 128)
  10     return tuple(map(int, (R,G,B)))
  11 
  12 def rgb2yuv(R,G,B):
  13     Y = (0.257 * R) + (0.504 * G) + (0.098 * B) + 16
  14     U = -(0.148 * R) - (0.291 * G) + (0.439 * B) + 128
  15     V = (0.439 * R) - (0.368 * G) - (0.071 * B) + 128
  16     return tuple(map(int, (Y,U,V)))
  17 
  18 def evalue2rgb(evalue):
  19     try:
  20         n = -math.log(evalue)/math.log(10)
  21     except OverflowError:
  22         n = 71
  23     if n > 70:
  24         v = 255
  25     elif n < 5:
  26         v = 0
  27     else:
  28         v = int((n-5)*255/65)
  29     print evalue, n, v
  30     return yuv2rgb(10,50,v)
  31 
  32 def makeSampleImage():
  33     img = Image.new('RGB', (80,140), (255,255,255))
  34     draw = ImageDraw.Draw(img)
  35     for yline in range(128):
  36         color = yuv2rgb(10, 50, 255-yline*2)
  37         draw.line((5, yline+5, 35, yline+5), fill=color)
  38     draw.text((40, 2), '1e-70', fill='black')
  39     draw.text((40, 60), '1e-32', fill='black')
  40     draw.text((40, 126), '1e-5', fill='black')
  41     img.save('test.png',type='PNG')
  42 
  43 def makeEvalueDistribution():
  44     img = Image.new('RGB', (80,140), (255,255,255))
  45     draw = ImageDraw.Draw(img)
  46     y = 10
  47     for evalue in (1e-3, 1e-5, 1e-10, 1e-34, 1e-68, 1e-70, 1e-80):
  48         draw.rectangle((50, y, 70, y+10),fill=evalue2rgb(evalue))
  49         y+=15
  50     img.save('test.png',type='PNG')
  51 
  52 if __name__=='__main__':
  53     #makeSampleImage()
  54     makeEvalueDistribution()