manual/connector.py

   1 from math import *
   2 from pyx import *
   3 try:
   4     from math import radians, degrees
   5 except ImportError:
   6     # fallback implementation for Python 2.1
   7     def radians(x): return x*pi/180
   8     def degrees(x): return x*180/pi
   9
  10 startbox = box.polygon(corners=[[0,-0.6], [0.5,0.1], [-0.25,0.1]])
  11 endbox = box.polygon(corners=[[4.5,3.9], [5.5,4.0], [5.2,3.4]])
  12
  13 # the arc connector <<<
  14 c1 = canvas.canvas()
  15 for b in [startbox, endbox]:
  16     c1.stroke(b.path(), [style.linewidth.Thick, style.linejoin.round])
  17     c1.fill(path.circle_pt(b.center[0], b.center[1], 2))
  18 absangle = degrees(atan2(endbox.center[1] - startbox.center[1], endbox.center[0] - startbox.center[0]))
  19 relangle = 60
  20 len = 2
  21
  22 # the direct connection
  23 direct = path.line_pt(startbox.center[0], startbox.center[1], endbox.center[0], endbox.center[1])
  24 c1.stroke(direct, [style.linestyle.dashed])
  25
  26 # the arc connector
  27 l = connector.arc(startbox, endbox, relangle=relangle, boxdists=[0.0,0.0])
  28 c1.stroke(l, [style.linewidth.Thick, color.rgb.red, deco.earrow.Large])
  29
  30 # the relangle parameter
  31 comp1 = path.path(path.moveto(*direct.atbegin()),
  32                   path.rlineto(len*cos(radians(absangle + relangle)), len*sin(radians(absangle + relangle))))
  33 c1.stroke(comp1)
  34 ang = path.path(path.arc(direct.atbegin()[0], direct.atbegin()[1], 0.8*len, absangle, absangle+relangle))
  35 c1.stroke(ang, [deco.earrow.large])
  36 pos = ang.at(0.5*ang.arclen())
  37 c1.text(pos[0], pos[1], r"~relangle", [text.halign.left])
  38
  39 # the bulge parameter
  40 bulge = 0.5 * direct.arclen() * tan(0.5*radians(relangle))
  41 bul = path.path(path.moveto(*direct.at(0.5*direct.arclen())),
  42                 path.rlineto(bulge * cos(radians(absangle+90)), bulge * sin(radians(absangle+90))))
  43 c1.stroke(bul, [deco.earrow.large])
  44 pos = bul.at(0.5*bul.arclen())
  45 c1.text(pos[0], pos[1], r"~(rel)bulge", [text.halign.left])
  46
  47 # >>>
  48
  49 # the curve connector <<<
  50 c2 = canvas.canvas()
  51 for b in [startbox, endbox]:
  52     c2.stroke(b.path(), [style.linewidth.Thick, style.linejoin.round])
  53     c2.fill(path.circle_pt(b.center[0], b.center[1], 2))
  54 absangle = degrees(atan2(endbox.center[1] - startbox.center[1], endbox.center[0] - startbox.center[0]))
  55 relangle1 = 60
  56 relangle2 = 30
  57 absbulge = 0
  58 relbulge = 0.5
  59 len = 2
  60
  61 # the direct connection
  62 direct = path.line_pt(startbox.center[0], startbox.center[1], endbox.center[0], endbox.center[1])
  63 c2.stroke(direct, [style.linestyle.dashed])
  64
  65 # the arc connector
  66 l = connector.curve(startbox, endbox, relangle1=relangle1, relangle2=relangle2, absbulge=absbulge, relbulge=relbulge, boxdists=[0.0,0.0])
  67 #l = connector.curve(startbox, endbox, absangle1=absangle+relangle1, absangle2=absangle+relangle2, absbulge=absbulge, relbulge=relbulge, boxdists=[0.0,0.0])
  68 c2.stroke(l, [style.linewidth.Thick, color.rgb.red, deco.earrow.Large])
  69
  70 # the relangle parameters
  71 # relangle1
  72 c2.stroke(path.path(path.moveto(*direct.atbegin()),
  73                    path.rlineto(len*cos(radians(absangle + relangle1)),
  74                                 len*sin(radians(absangle + relangle1)))))
  75 ang = path.path(path.arc(direct.atbegin()[0], direct.atbegin()[1], 0.8*len, absangle, absangle+relangle1))
  76 c2.stroke(ang, [deco.earrow.large])
  77 pos = ang.at(0.5*ang.arclen())
  78 c2.text(pos[0], pos[1], r"~relangle1", [text.halign.left])
  79
  80 # absangle1
  81 c2.stroke(path.path(path.moveto(*direct.atbegin()), path.rlineto(len, 0)))
  82 ang = path.path(path.arc(direct.atbegin()[0], direct.atbegin()[1], 0.5*len, 0, absangle+relangle1))
  83 c2.stroke(ang, [deco.earrow.large])
  84 pos = ang.at(0.2*ang.arclen())
  85 c2.text(pos[0], pos[1], r"~absangle1", [text.halign.left])
  86
  87 # relangle2
  88 c2.stroke(path.path(path.moveto(*direct.atend()),
  89                    path.rlineto(len*cos(radians(absangle)),
  90                                 len*sin(radians(absangle)))))
  91 c2.stroke(path.path(path.moveto(*direct.atend()),
  92                    path.rlineto(len*cos(radians(absangle + relangle2)),
  93                                 len*sin(radians(absangle + relangle2)))))
  94 ang = path.path(path.arc(direct.atend()[0], direct.atend()[1],
  95                          0.8*len, absangle, absangle+relangle2))
  96 c2.stroke(ang, [deco.earrow.large])
  97 pos = ang.at(0.5*ang.arclen())
  98 c2.text(pos[0], pos[1], r"~relangle2", [text.halign.left])
  99
 100 # the bulge parameter
 101 bulge = absbulge + direct.arclen() * relbulge
 102 bul = path.path(path.moveto(*direct.atbegin()),
 103                 path.rlineto(bulge * cos(radians(absangle+relangle1)), bulge * sin(radians(absangle+relangle1))))
 104 c2.stroke(bul, [deco.earrow.large])
 105 pos = bul.at(0.7*bul.arclen())
 106 c2.text(pos[0], pos[1], r"~(rel)bulge", [text.halign.left])
 107
 108 bul = path.path(path.moveto(*direct.atend()),
 109                 path.rlineto(-bulge * cos(radians(absangle+relangle2)), -bulge * sin(radians(absangle+relangle2))))
 110 c2.stroke(bul, [deco.earrow.large])
 111 pos = bul.at(0.7*bul.arclen())
 112 c2.text(pos[0], pos[1], r"~(rel)bulge", [text.halign.left, text.vshift(1)])
 113 # >>>
 114
 115
 116 # write everything
 117 c1.insert(c2, [trafo.translate(6.5, 0)])
 118 c1.writePDFfile()
 119
 120 # vim:foldmethod=marker:foldmarker=<<<,>>>