Color Objects

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#####################################################################
#
# Colour by object
#
#####################################################################

def color_obj(rainbow=0):

        """
        
AUTHOR 

        Gareth Stockwell

USAGE

        color_obj(rainbow=0)

	This function colours each object currently in the PyMOL heirarchy
	with a different colour.  Colours used are either the 22 named
	colours used by PyMOL (in which case the 23rd object, if it exists,
	gets the same colour as the first), or are the colours of the rainbow

        """

	# Process arguments
	rainbow = int(rainbow)

        # Get names of all PyMOL objects
	obj_list = cmd.get_names('models')

	if rainbow:

           print "\nColouring objects as rainbow\n"

	   nobj = len(obj_list)

	   # Create colours starting at blue(240) to red(0), using intervals
	   # of 240/(nobj-1)
	   for j in range(nobj):
	      hsv = (240-j*240/(nobj-1), 1, 1)
	      # Convert to RGB
	      rgb = hsv_to_rgb(hsv)
	      # Define the new colour
	      cmd.set_color("col" + str(j), rgb)
	      print obj_list[j], rgb
	      # Colour the object
	      cmd.color("col" + str(j), obj_list[j])

	else:

	   print "\nColouring objects using PyMOL defined colours\n"

	   # List of available colours
	   colours = ['red', 'green', 'blue', 'yellow', 'violet', 'cyan',    \
           'salmon', 'lime', 'pink', 'slate', 'magenta', 'orange', 'marine', \
	   'olive', 'purple', 'teal', 'forest', 'firebrick', 'chocolate',    \
	   'wheat', 'white', 'grey' ]
	   ncolours = len(colours)

	   # Loop over objects
	   i = 0
	   for obj in obj_list:
	      print "  ", obj, colours[i]
	      cmd.color(colours[i], obj)
	      i = i+1
	      if(i == ncolours):
	         i = 0


# HSV to RGB routine taken from Robert L. Campbell's color_b.py script
#   See http://pldserver1.biochem.queensu.ca/~rlc/work/pymol/
# Original algorithm from: http://www.cs.rit.edu/~ncs/color/t_convert.html
def hsv_to_rgb(hsv):

        h = float(hsv[0])
        s = float(hsv[1])
        v = float(hsv[2])

        if( s == 0 ) :
                #achromatic (grey)
                r = g = b = v

        else:
                # sector 0 to 5
                h = h/60.            
                i = int(h)
                f = h - i                       # factorial part of h
                #print h,i,f
                p = v * ( 1 - s )
                q = v * ( 1 - s * f )
                t = v * ( 1 - s * ( 1 - f ) )

                if i == 0:
                        (r,g,b) = (v,t,p)
                elif i == 1:
                        (r,g,b) = (q,v,p)
                elif i == 2:
                        (r,g,b) = (p,v,t)
                elif i == 3:
                        (r,g,b) = (p,q,v)
                elif i == 4:
                        (r,g,b) = (t,p,v)
                elif i == 5:
                        (r,g,b) = (v,p,q)
                else:
                        (r,g,b) = (v,v,v)
                        print "error, i not equal 1-5"

        return [r,g,b]

 

# Add color_obj to the PyMOL command list 
cmd.extend("color_obj",color_obj)