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Diffstat (limited to 'src/silx/gui/plot/utils/intersections.py')
-rw-r--r-- | src/silx/gui/plot/utils/intersections.py | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/silx/gui/plot/utils/intersections.py b/src/silx/gui/plot/utils/intersections.py new file mode 100644 index 0000000..53f2546 --- /dev/null +++ b/src/silx/gui/plot/utils/intersections.py @@ -0,0 +1,101 @@ +# coding: utf-8 +# /*########################################################################## +# +# Copyright (c) 2017-2018 European Synchrotron Radiation Facility +# +# Permission is hereby granted, free of charge, to any person obtaining a copy +# of this software and associated documentation files (the "Software"), to deal +# in the Software without restriction, including without limitation the rights +# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +# copies of the Software, and to permit persons to whom the Software is +# furnished to do so, subject to the following conditions: +# +# The above copyright notice and this permission notice shall be included in +# all copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +# THE SOFTWARE. +# +# ###########################################################################*/ +"""This module contains utils class for axes management. +""" + +__authors__ = ["H. Payno", ] +__license__ = "MIT" +__date__ = "18/05/2020" + + +import numpy + + +def lines_intersection(line1_pt1, line1_pt2, line2_pt1, line2_pt2): + """ + line segment intersection using vectors (Computer Graphics by F.S. Hill) + + :param tuple line1_pt1: + :param tuple line1_pt2: + :param tuple line2_pt1: + :param tuple line2_pt2: + :return: Union[None,numpy.array] + """ + dir_line1 = line1_pt2[0] - line1_pt1[0], line1_pt2[1] - line1_pt1[1] + dir_line2 = line2_pt2[0] - line2_pt1[0], line2_pt2[1] - line2_pt1[1] + dp = line1_pt1 - line2_pt1 + + def perp(a): + b = numpy.empty_like(a) + b[0] = -a[1] + b[1] = a[0] + return b + + dap = perp(dir_line1) + denom = numpy.dot(dap, dir_line2) + num = numpy.dot(dap, dp) + if denom == 0: + return None + return ( + (num / denom.astype(float)) * dir_line2[0] + line2_pt1[0], + (num / denom.astype(float)) * dir_line2[1] + line2_pt1[1]) + + +def segments_intersection(seg1_start_pt, seg1_end_pt, seg2_start_pt, + seg2_end_pt): + """ + Compute intersection between two segments + + :param seg1_start_pt: + :param seg1_end_pt: + :param seg2_start_pt: + :param seg2_end_pt: + :return: numpy.array if an intersection exists, else None + :rtype: Union[None,numpy.array] + """ + intersection = lines_intersection(line1_pt1=seg1_start_pt, + line1_pt2=seg1_end_pt, + line2_pt1=seg2_start_pt, + line2_pt2=seg2_end_pt) + if intersection is not None: + max_x_seg1 = max(seg1_start_pt[0], seg1_end_pt[0]) + max_x_seg2 = max(seg2_start_pt[0], seg2_end_pt[0]) + max_y_seg1 = max(seg1_start_pt[1], seg1_end_pt[1]) + max_y_seg2 = max(seg2_start_pt[1], seg2_end_pt[1]) + + min_x_seg1 = min(seg1_start_pt[0], seg1_end_pt[0]) + min_x_seg2 = min(seg2_start_pt[0], seg2_end_pt[0]) + min_y_seg1 = min(seg1_start_pt[1], seg1_end_pt[1]) + min_y_seg2 = min(seg2_start_pt[1], seg2_end_pt[1]) + + min_tmp_x = max(min_x_seg1, min_x_seg2) + max_tmp_x = min(max_x_seg1, max_x_seg2) + min_tmp_y = max(min_y_seg1, min_y_seg2) + max_tmp_y = min(max_y_seg1, max_y_seg2) + if (min_tmp_x <= intersection[0] <= max_tmp_x and + min_tmp_y <= intersection[1] <= max_tmp_y): + return intersection + else: + return None |