René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Doubling of coordinates in polygon clipping","articleBody":"The following code snippet takes coordinates for a hand, and clips it to a rectangular window.  Of the returned polygon, the endpoints are duplicated.\n\n```\nfrom matplotlib import path, transforms\nimport matplotlib.pyplot as plt\nimport numpy as np\n\nhand = np.array(\n    [[ 1.64516129,  1.16145833 ],\n     [ 1.64516129,  1.59375    ],\n     [ 1.35080645,  1.921875   ],\n     [ 1.375     ,  2.18229167 ],\n     [ 1.68548387,  1.9375     ],\n     [ 1.60887097,  2.55208333 ],\n     [ 1.68548387,  2.69791667 ],\n     [ 1.76209677,  2.56770833 ],\n     [ 1.83064516,  1.97395833 ],\n     [ 1.89516129,  2.75       ],\n     [ 1.9516129 ,  2.84895833 ],\n     [ 2.01209677,  2.76041667 ],\n     [ 1.99193548,  1.99479167 ],\n     [ 2.11290323,  2.63020833 ],\n     [ 2.2016129 ,  2.734375   ],\n     [ 2.25403226,  2.60416667 ],\n     [ 2.14919355,  1.953125   ],\n     [ 2.30645161,  2.36979167 ],\n     [ 2.39112903,  2.36979167 ],\n     [ 2.41532258,  2.1875     ],\n     [ 2.1733871 ,  1.703125   ],\n     [ 2.07782258,  1.16666667 ]])\n\n(r0, c0, r1, c1) = (1.0, 1.5, 2.1, 2.5)\n\npoly = path.Path(np.vstack((hand[:, 1], hand[:, 0])).T, closed=True)\nclip_rect = transforms.Bbox([[r0, c0], [r1, c1]])\npoly_clipped = poly.clip_to_bbox(clip_rect).to_polygons()[0]\n\nprint(len(poly_clipped[:, 0]), len(poly_clipped[:, 1]))\n\nplt.plot(hand[:, 0], hand[:, 1], 'r-')\nplt.plot(poly_clipped[:, 1], poly_clipped[:, 0], 'go-')\nplt.show()\n\nprint(poly_clipped[-2:, :])\n```\n","author":{"url":"https://github.com/stefanv","@type":"Person","name":"stefanv"},"datePublished":"2015-12-14T09:08:36.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/5670/matplotlib/issues/5670"}