215 lines
6.8 KiB
Python
215 lines
6.8 KiB
Python
"""
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Contains a classes for generating hatch patterns.
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"""
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import numpy as np
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from matplotlib.path import Path
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class HatchPatternBase:
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"""
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The base class for a hatch pattern.
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"""
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pass
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class HorizontalHatch(HatchPatternBase):
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def __init__(self, hatch, density):
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self.num_lines = int((hatch.count('-') + hatch.count('+')) * density)
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self.num_vertices = self.num_lines * 2
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def set_vertices_and_codes(self, vertices, codes):
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steps, stepsize = np.linspace(0.0, 1.0, self.num_lines, False,
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retstep=True)
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steps += stepsize / 2.
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vertices[0::2, 0] = 0.0
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vertices[0::2, 1] = steps
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vertices[1::2, 0] = 1.0
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vertices[1::2, 1] = steps
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codes[0::2] = Path.MOVETO
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codes[1::2] = Path.LINETO
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class VerticalHatch(HatchPatternBase):
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def __init__(self, hatch, density):
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self.num_lines = int((hatch.count('|') + hatch.count('+')) * density)
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self.num_vertices = self.num_lines * 2
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def set_vertices_and_codes(self, vertices, codes):
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steps, stepsize = np.linspace(0.0, 1.0, self.num_lines, False,
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retstep=True)
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steps += stepsize / 2.
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vertices[0::2, 0] = steps
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vertices[0::2, 1] = 0.0
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vertices[1::2, 0] = steps
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vertices[1::2, 1] = 1.0
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codes[0::2] = Path.MOVETO
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codes[1::2] = Path.LINETO
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class NorthEastHatch(HatchPatternBase):
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def __init__(self, hatch, density):
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self.num_lines = int((hatch.count('/') + hatch.count('x') +
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hatch.count('X')) * density)
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if self.num_lines:
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self.num_vertices = (self.num_lines + 1) * 2
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else:
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self.num_vertices = 0
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def set_vertices_and_codes(self, vertices, codes):
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steps = np.linspace(-0.5, 0.5, self.num_lines + 1)
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vertices[0::2, 0] = 0.0 + steps
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vertices[0::2, 1] = 0.0 - steps
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vertices[1::2, 0] = 1.0 + steps
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vertices[1::2, 1] = 1.0 - steps
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codes[0::2] = Path.MOVETO
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codes[1::2] = Path.LINETO
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class SouthEastHatch(HatchPatternBase):
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def __init__(self, hatch, density):
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self.num_lines = int((hatch.count('\\') + hatch.count('x') +
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hatch.count('X')) * density)
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self.num_vertices = (self.num_lines + 1) * 2
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if self.num_lines:
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self.num_vertices = (self.num_lines + 1) * 2
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else:
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self.num_vertices = 0
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def set_vertices_and_codes(self, vertices, codes):
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steps = np.linspace(-0.5, 0.5, self.num_lines + 1)
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vertices[0::2, 0] = 0.0 + steps
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vertices[0::2, 1] = 1.0 + steps
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vertices[1::2, 0] = 1.0 + steps
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vertices[1::2, 1] = 0.0 + steps
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codes[0::2] = Path.MOVETO
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codes[1::2] = Path.LINETO
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class Shapes(HatchPatternBase):
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filled = False
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def __init__(self, hatch, density):
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if self.num_rows == 0:
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self.num_shapes = 0
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self.num_vertices = 0
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else:
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self.num_shapes = ((self.num_rows // 2 + 1) * (self.num_rows + 1) +
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(self.num_rows // 2) * (self.num_rows))
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self.num_vertices = (self.num_shapes *
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len(self.shape_vertices) *
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(1 if self.filled else 2))
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def set_vertices_and_codes(self, vertices, codes):
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offset = 1.0 / self.num_rows
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shape_vertices = self.shape_vertices * offset * self.size
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if not self.filled:
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inner_vertices = shape_vertices[::-1] * 0.9
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shape_codes = self.shape_codes
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shape_size = len(shape_vertices)
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cursor = 0
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for row in range(self.num_rows + 1):
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if row % 2 == 0:
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cols = np.linspace(0, 1, self.num_rows + 1)
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else:
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cols = np.linspace(offset / 2, 1 - offset / 2, self.num_rows)
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row_pos = row * offset
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for col_pos in cols:
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vertices[cursor:cursor + shape_size] = (shape_vertices +
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(col_pos, row_pos))
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codes[cursor:cursor + shape_size] = shape_codes
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cursor += shape_size
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if not self.filled:
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vertices[cursor:cursor + shape_size] = (inner_vertices +
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(col_pos, row_pos))
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codes[cursor:cursor + shape_size] = shape_codes
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cursor += shape_size
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class Circles(Shapes):
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def __init__(self, hatch, density):
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path = Path.unit_circle()
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self.shape_vertices = path.vertices
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self.shape_codes = path.codes
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Shapes.__init__(self, hatch, density)
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class SmallCircles(Circles):
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size = 0.2
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def __init__(self, hatch, density):
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self.num_rows = (hatch.count('o')) * density
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Circles.__init__(self, hatch, density)
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class LargeCircles(Circles):
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size = 0.35
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def __init__(self, hatch, density):
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self.num_rows = (hatch.count('O')) * density
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Circles.__init__(self, hatch, density)
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class SmallFilledCircles(SmallCircles):
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size = 0.1
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filled = True
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def __init__(self, hatch, density):
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self.num_rows = (hatch.count('.')) * density
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Circles.__init__(self, hatch, density)
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class Stars(Shapes):
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size = 1.0 / 3.0
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filled = True
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def __init__(self, hatch, density):
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self.num_rows = (hatch.count('*')) * density
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path = Path.unit_regular_star(5)
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self.shape_vertices = path.vertices
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self.shape_codes = np.full(len(self.shape_vertices), Path.LINETO,
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dtype=Path.code_type)
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self.shape_codes[0] = Path.MOVETO
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Shapes.__init__(self, hatch, density)
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_hatch_types = [
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HorizontalHatch,
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VerticalHatch,
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NorthEastHatch,
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SouthEastHatch,
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SmallCircles,
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LargeCircles,
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SmallFilledCircles,
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Stars
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]
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def get_path(hatchpattern, density=6):
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"""
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Given a hatch specifier, *hatchpattern*, generates Path to render
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the hatch in a unit square. *density* is the number of lines per
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unit square.
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"""
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density = int(density)
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patterns = [hatch_type(hatchpattern, density)
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for hatch_type in _hatch_types]
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num_vertices = sum([pattern.num_vertices for pattern in patterns])
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if num_vertices == 0:
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return Path(np.empty((0, 2)))
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vertices = np.empty((num_vertices, 2))
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codes = np.empty(num_vertices, Path.code_type)
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cursor = 0
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for pattern in patterns:
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if pattern.num_vertices != 0:
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vertices_chunk = vertices[cursor:cursor + pattern.num_vertices]
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codes_chunk = codes[cursor:cursor + pattern.num_vertices]
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pattern.set_vertices_and_codes(vertices_chunk, codes_chunk)
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cursor += pattern.num_vertices
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return Path(vertices, codes)
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