reactos/lib/3rdparty/freetype/src/tools/cordic.py

   1 # compute arctangent table for CORDIC computations in fttrigon.c
   2 import sys, math
   3
   4 #units  = 64*65536.0   # don't change !!
   5 units  = 180 * 2**16
   6 scale  = units/math.pi
   7 shrink = 1.0
   8 comma  = ""
   9
  10 print ""
  11 print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units"
  12
  13 for n in range(1,32):
  14
  15     x = 0.5**n                      # tangent value
  16
  17     angle  = math.atan(x)           # arctangent
  18     angle2 = round(angle*scale)     # arctangent in FT_Angle units
  19
  20     if angle2 <= 0:
  21         break
  22
  23     sys.stdout.write( comma + repr( int(angle2) ) )
  24     comma = ", "
  25
  26     shrink /= math.sqrt( 1 + x*x )
  27
  28 print
  29 print "shrink factor    = " + repr( shrink )
  30 print "shrink factor 2  = " + repr( int( shrink * (2**32) ) )
  31 print "expansion factor = " + repr( 1/shrink )
  32 print ""
  33