notebook for Boundary testing matplotlib.path.Path.contains_point

gistfile1.json

{
 "metadata": {
  "name": "Boundary testing matplotlib.path.Path.contains_point"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "import numpy as np\nfrom matplotlib.path import Path\n#counter-clockwise path (unclosed)...\npath1 = Path([[0,0], [1,0], [1,1], [0,1]])\n#clockwise path (unclosed)...\npath2 = Path([[0,0], [0,1], [1,1], [1,0]])\n#CCW path (closed)...\npath3 = Path([[0,0], [1,0], [1,1], [0,1], [0,0]])\nall_paths = (path1, path2, path3)",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#path direction seems irrelevant at first.  All contain (0.5, 0.5)...\npt = (0.5, 0.5)\nfor path in all_paths:\n    print path.contains_point(pt),",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "1 1 1\n"
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#Set up a simple path testing function...\ndef test_paths(paths, test_points, r = 0.0):\n    for i, path in enumerate(paths, 1):\n        print \"path%d:\" % i,\n        for pt in test_points:\n            print path.contains_point(pt, radius=r),\n        print",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#Check what happens for points running up the y axis...\ny_axis_points = [[0, y] for y in np.linspace(0, 1, 11)]\ntest_paths(all_paths, y_axis_points)\n#Why is 0,0 not a hit?\n#why is y-axis not hit at all for CW path?",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "path1: 0 1 1 1 1 1 1 1 1 1 1\npath2: 0 0 0 0 0 0 0 0 0 0 0\npath3: 0 1 1 1 1 1 1 1 1 1 1\n"
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#Check the x axis...\nx_axis_points = [[x, 0] for x in np.linspace(0, 1, 11)]\ntest_paths(all_paths, x_axis_points)\n#No hits for CW or CCW -- we clearly have to be careful with boundaries!",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "path1: 0 0 0 0 0 0 0 0 0 0 0\npath2: 0 0 0 0 0 0 0 0 0 0 0\npath3: 0 0 0 0 0 0 0 0 0 0 0\n"
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#Check if adding a radius helps...\nr = 0.1\nprint \"X axis tests with r=%.2f\" % r\ntest_paths(all_paths, x_axis_points, r)\nprint \"\\nY axis tests with r=%.2f\" % r\ntest_paths(all_paths, y_axis_points, r)\n#strange! adding a big radius causes x-axis to be hit\n#for CCW paths, but not for the CW path!!?\n#CW path can't seem to hit on a boundary at all, even\n#with a radius.",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "X axis tests with r=0.10\npath1: 1 1 1 1 1 1 1 1 1 1 1\npath2: 0 0 0 0 0 0 0 0 0 0 0\npath3: 1 1 1 1 1 1 1 1 1 1 1\n\nY axis tests with r=0.10\npath1: 1 1 1 1 1 1 1 1 1 1 1\npath2: 0 0 0 0 0 0 0 0 0 0 0\npath3: 1 1 1 1 1 1 1 1 1 1 1\n"
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#Sanity check a real offset by shifting test points...\nx = 1e-100\noffset_y_axis_pts = [[x, y] for y in np.linspace(0, 1, 11)]\ntest_paths(all_paths, offset_y_axis_pts, 0)\n#X axis still not detected (no surprise), and a tiny\n#offset from y axis does get detection.\n#it seems that radius is not working properly?",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "path1: 0 1 1 1 1 1 1 1 1 1 1\npath2: 0 1 1 1 1 1 1 1 1 1 1\npath3: 0 1 1 1 1 1 1 1 1 1 1\n"
      }
     ],
     "prompt_number": 7
    }
   ],
   "metadata": {}
  }
 ]
}