"""
Contains a classes for generating hatch patterns.
"""
import numpy as np
from matplotlib.path import Path
class HatchPatternBase:
"""
The base class for a hatch pattern.
"""
pass
class HorizontalHatch(HatchPatternBase):
def __init__(self, hatch, density):
self.num_lines = (hatch.count('-') + hatch.count('+')) * density
self.num_vertices = self.num_lines * 2
def set_vertices_and_codes(self, vertices, codes):
steps = np.linspace(0.0, 1.0, self.num_lines, False)
vertices[0::2, 0] = 0.0
vertices[0::2, 1] = steps
vertices[1::2, 0] = 1.0
vertices[1::2, 1] = steps
codes[0::2] = Path.MOVETO
codes[1::2] = Path.LINETO
class VerticalHatch(HatchPatternBase):
def __init__(self, hatch, density):
self.num_lines = (hatch.count('|') + hatch.count('+')) * density
self.num_vertices = self.num_lines * 2
def set_vertices_and_codes(self, vertices, codes):
steps = np.linspace(0.0, 1.0, self.num_lines, False)
vertices[0::2, 0] = steps
vertices[0::2, 1] = 0.0
vertices[1::2, 0] = steps
vertices[1::2, 1] = 1.0
codes[0::2] = Path.MOVETO
codes[1::2] = Path.LINETO
class NorthEastHatch(HatchPatternBase):
def __init__(self, hatch, density):
self.num_lines = (hatch.count('/') + hatch.count('x') + hatch.count('X')) * density
self.num_vertices = self.num_lines * 4
def set_vertices_and_codes(self, vertices, codes):
steps = np.linspace(0.0, 1.0, self.num_lines, False)
rev_steps = 1.0 - steps
vertices[0::4, 0] = 0.0
vertices[0::4, 1] = steps
vertices[1::4, 0] = rev_steps
vertices[1::4, 1] = 1.0
vertices[2::4, 0] = rev_steps
vertices[2::4, 1] = 0.0
vertices[3::4, 0] = 1.0
vertices[3::4, 1] = steps
codes[0::2] = Path.MOVETO
codes[1::2] = Path.LINETO
class SouthEastHatch(HatchPatternBase):
def __init__(self, hatch, density):
self.num_lines = (hatch.count('\\') + hatch.count('x') + hatch.count('X')) * density
self.num_vertices = self.num_lines * 4
def set_vertices_and_codes(self, vertices, codes):
steps = np.linspace(0.0, 1.0, self.num_lines, False)
vertices[0::4, 0] = 1.0
vertices[0::4, 1] = steps
vertices[1::4, 0] = steps
vertices[1::4, 1] = 1.0
vertices[2::4, 0] = steps
vertices[2::4, 1] = 0.0
vertices[3::4, 0] = 0.0
vertices[3::4, 1] = steps
codes[0::2] = Path.MOVETO
codes[1::2] = Path.LINETO
class Shapes(HatchPatternBase):
filled = False
def __init__(self, hatch, density):
if self.num_rows == 0:
self.num_shapes = 0
self.num_vertices = 0
else:
self.num_shapes = ((self.num_rows / 2 + 1) * (self.num_rows + 1) +
(self.num_rows / 2) * (self.num_rows))
self.num_vertices = (self.num_shapes *
len(self.shape_vertices) *
(self.filled and 1 or 2))
def set_vertices_and_codes(self, vertices, codes):
offset = 1.0 / self.num_rows
shape_vertices = self.shape_vertices * offset * self.size
if not self.filled:
inner_vertices = shape_vertices[::-1] * 0.9
shape_codes = self.shape_codes
shape_size = len(shape_vertices)
cursor = 0
for row in xrange(self.num_rows + 1):
if row % 2 == 0:
cols = np.linspace(0.0, 1.0, self.num_rows + 1, True)
else:
cols = np.linspace(offset / 2.0, 1.0 - offset / 2.0, self.num_rows, True)
row_pos = row * offset
for col_pos in cols:
vertices[cursor:cursor+shape_size] = shape_vertices + (col_pos, row_pos)
codes[cursor:cursor+shape_size] = shape_codes
cursor += shape_size
if not self.filled:
vertices[cursor:cursor+shape_size] = inner_vertices + (col_pos, row_pos)
codes[cursor:cursor+shape_size] = shape_codes
cursor += shape_size
class Circles(Shapes):
def __init__(self, hatch, density):
path = Path.unit_circle()
self.shape_vertices = path.vertices
self.shape_codes = path.codes
Shapes.__init__(self, hatch, density)
class SmallCircles(Circles):
size = 0.2
def __init__(self, hatch, density):
self.num_rows = (hatch.count('o')) * density
Circles.__init__(self, hatch, density)
class LargeCircles(Circles):
size = 0.35
def __init__(self, hatch, density):
self.num_rows = (hatch.count('O')) * density
Circles.__init__(self, hatch, density)
class SmallFilledCircles(SmallCircles):
size = 0.1
filled = True
def __init__(self, hatch, density):
self.num_rows = (hatch.count('.')) * density
Circles.__init__(self, hatch, density)
class Stars(Shapes):
size = 1.0 / 3.0
filled = True
def __init__(self, hatch, density):
self.num_rows = (hatch.count('*')) * density
path = Path.unit_regular_star(5)
self.shape_vertices = path.vertices
self.shape_codes = np.ones(len(self.shape_vertices)) * Path.LINETO
self.shape_codes[0] = Path.MOVETO
Shapes.__init__(self, hatch, density)
_hatch_types = [
HorizontalHatch,
VerticalHatch,
NorthEastHatch,
SouthEastHatch,
SmallCircles,
LargeCircles,
SmallFilledCircles,
Stars
]
def get_path(hatchpattern, density=6):
"""
Given a hatch specifier, *hatchpattern*, generates Path to render
the hatch in a unit square. *density* is the number of lines per
unit square.
"""
size = 1.0
density = int(density)
patterns = [hatch_type(hatchpattern, density) for hatch_type in _hatch_types]
num_vertices = sum([pattern.num_vertices for pattern in patterns])
if num_vertices == 0:
return Path(np.empty((0, 2)))
vertices = np.empty((num_vertices, 2))
codes = np.empty((num_vertices,), np.uint8)
cursor = 0
for pattern in patterns:
if pattern.num_vertices != 0:
vertices_chunk = vertices[cursor:cursor + pattern.num_vertices]
codes_chunk = codes[cursor:cursor + pattern.num_vertices]
pattern.set_vertices_and_codes(vertices_chunk, codes_chunk)
cursor += pattern.num_vertices
return Path(vertices, codes)
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