diff -r f3840de881bd -r 915436ff64ab misc/libfreetype/src/tools/cordic.py --- a/misc/libfreetype/src/tools/cordic.py Thu Jul 25 23:16:06 2013 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,79 +0,0 @@ -# compute arctangent table for CORDIC computations in fttrigon.c -import sys, math - -#units = 64*65536.0 # don't change !! -units = 256 -scale = units/math.pi -shrink = 1.0 -comma = "" - -def calc_val( x ): - global units, shrink - angle = math.atan(x) - shrink = shrink * math.cos(angle) - return angle/math.pi * units - -def print_val( n, x ): - global comma - - lo = int(x) - hi = lo + 1 - alo = math.atan(lo) - ahi = math.atan(hi) - ax = math.atan(2.0**n) - - errlo = abs( alo - ax ) - errhi = abs( ahi - ax ) - - if ( errlo < errhi ): - hi = lo - - sys.stdout.write( comma + repr( int(hi) ) ) - comma = ", " - - -print "" -print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units" - -# compute range of "i" -r = [-1] -r = r + range(32) - -for n in r: - - if n >= 0: - x = 1.0/(2.0**n) # tangent value - else: - x = 2.0**(-n) - - angle = math.atan(x) # arctangent - angle2 = angle*scale # arctangent in FT_Angle units - - # determine which integer value for angle gives the best tangent - lo = int(angle2) - hi = lo + 1 - tlo = math.tan(lo/scale) - thi = math.tan(hi/scale) - - errlo = abs( tlo - x ) - errhi = abs( thi - x ) - - angle2 = hi - if errlo < errhi: - angle2 = lo - - if angle2 <= 0: - break - - sys.stdout.write( comma + repr( int(angle2) ) ) - comma = ", " - - shrink = shrink * math.cos( angle2/scale) - - -print -print "shrink factor = " + repr( shrink ) -print "shrink factor 2 = " + repr( shrink * (2.0**32) ) -print "expansion factor = " + repr(1/shrink) -print "" -