118 lines
3.7 KiB
Python
118 lines
3.7 KiB
Python
import numpy as np
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from math import degrees
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from matplotlib import cbook
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import math
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def atan2(dy, dx):
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if dx == 0 and dy == 0:
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cbook._warn_external("dx and dy are 0")
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return 0
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else:
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return math.atan2(dy, dx)
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# FIXME : The current algorithm seems to return incorrect angle when the line
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# ends at the boundary.
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def clip(xlines, ylines, x0, clip="right", xdir=True, ydir=True):
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clipped_xlines = []
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clipped_ylines = []
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_pos_angles = []
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xsign = 1 if xdir else -1
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ysign = 1 if ydir else -1
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for x, y in zip(xlines, ylines):
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if clip in ["up", "right"]:
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b = (x < x0).astype("i")
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db = b[1:] - b[:-1]
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else:
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b = (x > x0).astype("i")
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db = b[1:] - b[:-1]
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if b[0]:
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ns = 0
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else:
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ns = -1
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segx, segy = [], []
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for (i,) in np.argwhere(db):
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c = db[i]
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if c == -1:
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dx = (x0 - x[i])
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dy = (y[i+1] - y[i]) * (dx / (x[i+1] - x[i]))
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y0 = y[i] + dy
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clipped_xlines.append(np.concatenate([segx, x[ns:i+1], [x0]]))
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clipped_ylines.append(np.concatenate([segy, y[ns:i+1], [y0]]))
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ns = -1
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segx, segy = [], []
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if dx == 0. and dy == 0:
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dx = x[i+1] - x[i]
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dy = y[i+1] - y[i]
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a = degrees(atan2(ysign*dy, xsign*dx))
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_pos_angles.append((x0, y0, a))
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elif c == 1:
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dx = (x0 - x[i])
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dy = (y[i+1] - y[i]) * (dx / (x[i+1] - x[i]))
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y0 = y[i] + dy
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segx, segy = [x0], [y0]
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ns = i+1
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if dx == 0. and dy == 0:
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dx = x[i+1] - x[i]
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dy = y[i+1] - y[i]
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a = degrees(atan2(ysign*dy, xsign*dx))
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_pos_angles.append((x0, y0, a))
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if ns != -1:
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clipped_xlines.append(np.concatenate([segx, x[ns:]]))
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clipped_ylines.append(np.concatenate([segy, y[ns:]]))
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return clipped_xlines, clipped_ylines, _pos_angles
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def clip_line_to_rect(xline, yline, bbox):
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x0, y0, x1, y1 = bbox.extents
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xdir = x1 > x0
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ydir = y1 > y0
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if x1 > x0:
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lx1, ly1, c_right_ = clip([xline], [yline], x1,
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clip="right", xdir=xdir, ydir=ydir)
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lx2, ly2, c_left_ = clip(lx1, ly1, x0,
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clip="left", xdir=xdir, ydir=ydir)
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else:
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lx1, ly1, c_right_ = clip([xline], [yline], x0,
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clip="right", xdir=xdir, ydir=ydir)
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lx2, ly2, c_left_ = clip(lx1, ly1, x1,
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clip="left", xdir=xdir, ydir=ydir)
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if y1 > y0:
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ly3, lx3, c_top_ = clip(ly2, lx2, y1,
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clip="right", xdir=ydir, ydir=xdir)
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ly4, lx4, c_bottom_ = clip(ly3, lx3, y0,
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clip="left", xdir=ydir, ydir=xdir)
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else:
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ly3, lx3, c_top_ = clip(ly2, lx2, y0,
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clip="right", xdir=ydir, ydir=xdir)
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ly4, lx4, c_bottom_ = clip(ly3, lx3, y1,
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clip="left", xdir=ydir, ydir=xdir)
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c_left = [((x, y), (a + 90) % 180 - 90) for x, y, a in c_left_
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if bbox.containsy(y)]
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c_bottom = [((x, y), (90 - a) % 180) for y, x, a in c_bottom_
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if bbox.containsx(x)]
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c_right = [((x, y), (a + 90) % 180 + 90) for x, y, a in c_right_
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if bbox.containsy(y)]
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c_top = [((x, y), (90 - a) % 180 + 180) for y, x, a in c_top_
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if bbox.containsx(x)]
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return list(zip(lx4, ly4)), [c_left, c_bottom, c_right, c_top]
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