projects.mako.cc - yourule/blob - ruler.py

   1 # define the length of things
   2 from __future__ import division
   3 import SVGdraw
   4
   5 class Ruler:
   6     def __init__(self, scale=None, units=None,
   7                  ruler_height=None, ruler_length=None):
   8
   9         # default values come from OLPC
  10         self.scale = scale or 78.740
  11         self.units = units or 'centimeters'
  12         self.ruler_height = ruler_height or 200
  13         self.ruler_length = ruler_length or 15
  14
  15         font_height = 22
  16
  17         self.drawing = SVGdraw.drawing()
  18         self.svg = SVGdraw.svg()
  19
  20         # create the body of the ruler
  21         body = SVGdraw.rect(0, 0,
  22                             (self.scale * self.ruler_length),
  23                             self.ruler_height, "white", "black", 2)
  24         self.svg.addElement(body)
  25
  26         # add a units label
  27         units = SVGdraw.text((self.scale / 2),
  28                              (self.ruler_height - self.scale / 5),
  29                              self.units, font_height)
  30         self.svg.addElement(units)
  31
  32         self.point = 0.0
  33
  34
  35         # find the appropriate subunit marker
  36         self.subunit_marks = 1
  37
  38         while self.scale / self.subunit_marks >= font_height * 3:
  39             if self.subunit_marks == 1:
  40                 self.subunit_marks += 3
  41             else:
  42                 self.subunit_marks = self.subunit_marks * 2
  43
  44         # for every unit
  45         for i in range(self.ruler_length):
  46
  47             # place subunit marks
  48             for i2 in range(self.subunit_marks):
  49                 self.__drawline(0.3)
  50
  51             self.__drawline(0.6)
  52             self.svg.addElement(SVGdraw.text((self.point - font_height * 1.4),
  53                            (self.ruler_height * 0.6 - 5),
  54                             str(i + 1), font_height))
  55
  56
  57         self.drawing.setSVG(self.svg)
  58
  59     def output(self):
  60         import cStringIO
  61         xml = cStringIO.StringIO()
  62         xml.write("<?xml version='1.0' encoding='UTF-8'?>\n")
  63         xml.write("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" \"http://www .w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd \">\n")
  64         self.svg.toXml(0,xml)
  65
  66         return(xml.getvalue())
  67
  68     def write_svg_to_file(self, filename='output.svg'):
  69         self.drawing.toXml(filename)
  70
  71     def __drawline(self, size):
  72
  73         self.point = self.point + (self.scale / (1 + self.subunit_marks))
  74         line = SVGdraw.line(self.point, 0, self.point,
  75                             (self.ruler_height * size), "black", 2)
  76         self.svg.addElement(line)
  77
  78