mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-29 09:06:25 +08:00
Stefan van der Walt
73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
/* `pnpoly` is from
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http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
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Copyright (c) 1970-2003, Wm. Randolph Franklin
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Permission is hereby granted, free of charge, to any person
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obtaining a copy of this software and associated documentation
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files (the "Software"), to deal in the Software without
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restriction, including without limitation the rights to use, copy,
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modify, merge, publish, distribute, sublicense, and/or sell copies
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of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimers.
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2. Redistributions in binary form must reproduce the above
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copyright notice in the documentation and/or other materials
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provided with the distribution.
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3. The name of W. Randolph Franklin may not be used to endorse or
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promote products derived from this Software without specific
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prior written permission.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE. */
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#ifdef __cplusplus
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extern "C" {
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#endif
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unsigned char pnpoly(int nr_verts, double *xp, double *yp, double x, double y)
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{
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int i, j;
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unsigned char c = 0;
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for (i = 0, j = nr_verts-1; i < nr_verts; j = i++) {
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if ((((yp[i]<=y) && (y<yp[j])) ||
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((yp[j]<=y) && (y<yp[i]))) &&
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(x < (xp[j] - xp[i]) * (y - yp[i]) / (yp[j] - yp[i]) + xp[i]))
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c = !c;
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}
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return c;
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}
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void npnpoly(int nr_verts, double *xp, double *yp,
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int nr_points, double *x, double *y,
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unsigned char *result)
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/*
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* For N provided points, calculate whether they are in
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* the polygon defined by vertices *xp, *yp.
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*
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* nr_verts : number of vertices
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* *xp, *yp : x and y coordinates of vertices
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* nr_points : number of data points provided
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* *x, *y : data points
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*/
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{
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unsigned char n = 0;
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for (n = 0; n < nr_points; n++) {
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result[n] = pnpoly(nr_verts, xp, yp, x[n], y[n]);
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}
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}
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#ifdef __cplusplus
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}
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#endif
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