pyx/graph/axis/positioner.py

   1 # -*- coding: ISO-8859-1 -*-
   2 #
   3 #
   4 # Copyright (C) 2005 André Wobst <wobsta@users.sourceforge.net>
   5 #
   6 # This file is part of PyX (http://pyx.sourceforge.net/).
   7 #
   8 # PyX is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # PyX is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with PyX; if not, write to the Free Software
  20 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  21
  22 import math
  23 from pyx import path, unit
  24
  25
  26 class _positioner:
  27     """interface definition of axis tick position methods
  28     - these methods are used for the postitioning of the ticks
  29       when painting an axis"""
  30     # TODO: should we add a local transformation (for label text etc?)
  31     #       (this might replace tickdirection (and even tickposition?))
  32
  33     def vbasepath(self, v1=None, v2=None):
  34         """return the basepath as a path
  35         - like basepath, but for graph coordinates"""
  36
  37     def vgridpath(self, v):
  38         """return the gridpath as a path for a given position v
  39         in graph coordinates
  40         - might return None when no gridpath is available"""
  41         return None
  42
  43     def vtickpoint_pt(self, v):
  44         """return tick position (x, y) in pts for a tick at position v in graph coordinates"""
  45
  46     def vtickdirection(self, v):
  47         """return direction tuple (dx, dy) for a tick at position v in graph coordinates"""
  48
  49
  50 class pathpositioner(_positioner):
  51     """axis tick position methods along an arbitrary path"""
  52
  53     def __init__(self, p, direction=1):
  54         self.path = p
  55         self.normpath = p.normpath()
  56         self.arclen_pt = self.normpath.arclen_pt()
  57         self.arclen = self.arclen_pt * unit.t_pt
  58         self.direction = direction
  59
  60     def vbasepath(self, v1=None, v2=None):
  61         if v1 is None:
  62             if v2 is None:
  63                 return self.path
  64             else:
  65                 return self.normpath.split(self.normpath.arclentoparam(v2 * self.arclen))[0]
  66         else:
  67             if v2 is None:
  68                 return self.normpath.split(self.normpath.arclentoparam(v1 * self.arclen))[1]
  69             else:
  70                 return self.normpath.split(*self.normpath.arclentoparam([v1 * self.arclen, v2 * self.arclen]))[1]
  71
  72     def vtickpoint_pt(self, v):
  73         return self.normpath.at_pt(self.normpath.arclentoparam(v * self.arclen))
  74
  75     def vtickdirection(self, v):
  76         return self.normpath.rotation(self.normpath.arclentoparam(v * self.arclen)).apply_pt(0, self.direction)
  77
  78
  79 class lineaxispos_pt:
  80     """an axispos linear along a line with a fix direction for the ticks"""
  81
  82     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt, fixtickdirection, vgridpathfunction):
  83         self.x1_pt = x1_pt
  84         self.y1_pt = y1_pt
  85         self.x2_pt = x2_pt
  86         self.y2_pt = y2_pt
  87         self.fixtickdirection = fixtickdirection
  88         self.vgridpathfunction = vgridpathfunction
  89
  90     def vbasepath(self, v1=None, v2=None):
  91         if v1 is None:
  92             v1 = 0
  93         if v2 is None:
  94             v2 = 1
  95         return path.line_pt((1-v1)*self.x1_pt+v1*self.x2_pt,
  96                             (1-v1)*self.y1_pt+v1*self.y2_pt,
  97                             (1-v2)*self.x1_pt+v2*self.x2_pt,
  98                             (1-v2)*self.y1_pt+v2*self.y2_pt)
  99
 100     def vgridpath(self, v):
 101         return self.vgridpathfunction(v)
 102
 103     def vtickpoint_pt(self, v):
 104         return (1-v)*self.x1_pt+v*self.x2_pt, (1-v)*self.y1_pt+v*self.y2_pt
 105
 106     def vtickdirection(self, v):
 107         return self.fixtickdirection
 108