00001 #!/usr/bin/env python
00002 #
00003 # Copyright 2004
00004 # by
00005 # The Board of Trustees of the
00006 # Leland Stanford Junior University.
00007 # All rights reserved.
00008 #
00009
00010 __facility__ = "Online"
00011 __abstract__ = "GLAST Online Event Display color selector"
00012 __author__ = "R. Claus <Claus@SLAC.Stanford.edu> SLAC - GLAST LAT I&T/Online"
00013 __date__ = "10/14/04"
00014 __version__ = "$Revision: 1.3 $"
00015 __release__ = "$Name: R04-12-00 $"
00016 __credits__ = "SLAC"
00017
00018 import LATTE.copyright_SLAC
00019
00020
00021 def colorScale(value):
00022 """\brief Method for returning a color scale RGB tuple given a percentage.
00023
00024 Return a tuple giving the RGB values for a color chosen from a color scale:
00025 black for value < 0.0
00026 blue (cold) for value >= 0.0
00027 .
00028 .
00029 .
00030 red (hot) for value <= 1.0
00031 white for value > 1.0
00032
00033 \param value - A number between 0.0 and 1.0
00034 \return A tuple containing the RGB values corresponding to the input value
00035 """
00036
00037 if value < 0.0: return (0, 0, 0)
00038 if value > 1.0: return (255, 255, 255)
00039
00040 r = 1.0
00041 g = 1.0
00042 b = 1.0
00043
00044 dv = 1.0
00045 vmin = 0.0
00046 v = value
00047
00048 if (v < (vmin + 0.25 * dv)):
00049 r = 0
00050 g = 4 * (v - vmin) / dv
00051 elif (v < (vmin + 0.5 * dv)):
00052 r = 0
00053 b = 1 + 4 * (vmin + 0.25 * dv - v) / dv
00054 elif (v < (vmin + 0.75 * dv)):
00055 r = 4 * (v - vmin - 0.5 * dv) / dv
00056 b = 0
00057 else:
00058 g = 1 + 4 * (vmin + 0.75 * dv - v) / dv
00059 b = 0
00060
00061 red = int( r * 255. )
00062 green = int( g * 255. )
00063 blue = int( b * 255. )
00064
00065 assert ( red < 256 and green < 256 and blue < 256 )
00066 return ( red, green, blue )
