test/experimental/test_bezier.py

   1 #!/usr/bin/env python
   2 import sys; sys.path.insert(0, "../..")
   3
   4 import math
   5 from random import Random
   6
   7 from pyx import *
   8 from pyx import normpath
   9 from pyx.deformer import controldists_from_endgeometry_pt
  10 from pyx.normpath import _epsilon
  11
  12 def test_reproductions(seed, n_tests, xmax, ymax, accuracy): # <<<
  13     # insert xmax, ymax, accuracy in pt!
  14
  15     r = Random(seed)
  16     n_testpoints = 20
  17     testparams = [i / (n_testpoints - 1.0) for i in range(n_testpoints)]
  18
  19     # a canvas for drawing
  20     can = canvas.canvas()
  21     xpos = 0
  22     ypos = 0
  23
  24     # loop over many different cases
  25     n_failures = 0
  26     n_successes = 0
  27     for cnt in range(n_tests):
  28
  29         # the original curve
  30         a = r.uniform(0,xmax), r.uniform(0,ymax)
  31         b = r.uniform(0,xmax), r.uniform(0,ymax)
  32         c = r.uniform(0,xmax), r.uniform(0,ymax)
  33         d = r.uniform(0,xmax), r.uniform(0,ymax)
  34         origcurve = normpath.normcurve_pt(a[0], a[1], b[0], b[1], c[0], c[1], d[0], d[1])
  35         tbeg, tend = origcurve.rotation([0, 1])
  36         cbeg, cend = origcurve.curvature_pt([0, 1])
  37         # raise an error if one of the params is invalid:
  38         tbeg, tend, cbeg, cend
  39         tbeg, tend = tbeg.apply_pt(1, 0), tend.apply_pt(1, 0)
  40
  41         # the reproduced curve
  42         controldistpairs = controldists_from_endgeometry_pt(a, d, tbeg, tend, cbeg, cend, _epsilon)
  43         reprocurves = []
  44         for controldistpair in controldistpairs:
  45             alpha, beta = controldistpair
  46             reprocurves.append(normpath.normcurve_pt(
  47               a[0], a[1],
  48               a[0] + alpha * tbeg[0], a[1] + alpha * tbeg[1],
  49               d[0] - beta * tend[0], d[1] - beta * tend[1],
  50               d[0], d[1]))
  51
  52         # analyse the quality of the reproduction
  53         minmaxdist = float("inf")
  54         minindex = -1
  55         maxdists = []
  56         for i, reprocurve in enumerate(reprocurves):
  57             maxdist = max([math.hypot(p[0]-q[0], p[1]-q[1])
  58               for p,q in zip(origcurve.at_pt(testparams), reprocurve.at_pt(testparams))])
  59             if maxdist < minmaxdist:
  60                 minmaxdist = maxdist
  61                 minindex = i
  62             maxdists.append(maxdist)
  63
  64         # print complaints for too bad reproductions
  65         if minindex != 0 or minmaxdist > accuracy:
  66             n_failures += 1
  67
  68             if minmaxdist > accuracy:
  69                 print "%4d Smallest distance is %f" % (cnt, minmaxdist)
  70
  71             if minindex == -1:
  72                 print "%4d Failure: no solution found" % (cnt)
  73
  74             if minindex > 0:
  75                 print "%4d Wrong sorting: entry %d is the smallest" % (cnt, minindex)
  76
  77             if minindex >=0 and not (controldistpairs[minindex][0] >= 0 and controldistpairs[minindex][1] >= 0):
  78                 print "%4d Failure: signs are wrong" % (cnt)
  79
  80             # selectively draw the curves:
  81             #if minindex == -1:
  82             #if minindex > 0:
  83             if minmaxdist > accuracy:
  84                 # draw the failure curves
  85                 can.stroke(path.rect_pt(0,0,xmax,ymax), [trafo.translate_pt(xpos, ypos)])
  86                 can.draw(normpath.normpath([normpath.normsubpath([origcurve])]),  [trafo.translate_pt(xpos, ypos), deco.stroked([style.linewidth.THIck]), deco.shownormpath()])
  87                 if minindex != -1:
  88                     can.stroke(normpath.normpath([normpath.normsubpath([reprocurves[minindex]])]), [trafo.translate_pt(xpos, ypos), color.rgb.red])
  89                 can.text(0, 0, r"(%d)" % (cnt), [trafo.translate_pt(xpos+0.5*xmax, ypos), text.halign.center, text.vshift(2.0)])
  90                 xpos += 1.1*xmax
  91                 if xpos > 11*xmax:
  92                     xpos = 0
  93                     ypos -= 1.1*ymax
  94                     ypos -= 15
  95         else:
  96             n_successes += 1
  97
  98     print "failures, successes = ", n_failures, ", ", n_successes
  99     can.writeEPSfile("test_bezier")
 100 # >>>
 101
 102 test_reproductions(43, 10000, 100, 100, 1.0e-2)
 103
 104
 105 # vim:foldmethod=marker:foldmarker=<<<,>>>