369 lines
13 KiB
Python
369 lines
13 KiB
Python
from .pack_algo import PackingAlgorithm
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from .geometry import Rectangle
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import itertools
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import operator
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class Guillotine(PackingAlgorithm):
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"""Implementation of several variants of Guillotine packing algorithm
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For a more detailed explanation of the algorithm used, see:
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Jukka Jylanki - A Thousand Ways to Pack the Bin (February 27, 2010)
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"""
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def __init__(self, width, height, rot=True, merge=True, *args, **kwargs):
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"""
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Arguments:
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width (int, float):
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height (int, float):
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merge (bool): Optional keyword argument
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"""
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self._merge = merge
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super(Guillotine, self).__init__(width, height, rot, *args, **kwargs)
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def _add_section(self, section):
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"""Adds a new section to the free section list, but before that and if
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section merge is enabled, tries to join the rectangle with all existing
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sections, if successful the resulting section is again merged with the
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remaining sections until the operation fails. The result is then
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appended to the list.
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Arguments:
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section (Rectangle): New free section.
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"""
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section.rid = 0
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plen = 0
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while self._merge and self._sections and plen != len(self._sections):
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plen = len(self._sections)
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self._sections = [s for s in self._sections if not section.join(s)]
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self._sections.append(section)
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def _split_horizontal(self, section, width, height):
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"""For an horizontal split the rectangle is placed in the lower
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left corner of the section (section's xy coordinates), the top
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most side of the rectangle and its horizontal continuation,
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marks the line of division for the split.
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+-----------------+
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+-------+---------+
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|#######| |
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|#######| |
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|#######| |
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+-------+---------+
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If the rectangle width is equal to the the section width, only one
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section is created over the rectangle. If the rectangle height is
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equal to the section height, only one section to the right of the
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rectangle is created. If both width and height are equal, no sections
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are created.
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"""
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# First remove the section we are splitting so it doesn't
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# interfere when later we try to merge the resulting split
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# rectangles, with the rest of free sections.
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#self._sections.remove(section)
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# Creates two new empty sections, and returns the new rectangle.
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if height < section.height:
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self._add_section(Rectangle(section.x, section.y+height,
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section.width, section.height-height))
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if width < section.width:
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self._add_section(Rectangle(section.x+width, section.y,
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section.width-width, height))
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def _split_vertical(self, section, width, height):
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"""For a vertical split the rectangle is placed in the lower
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left corner of the section (section's xy coordinates), the
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right most side of the rectangle and its vertical continuation,
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marks the line of division for the split.
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+-------+---------+
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+-------+ |
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|#######| |
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|#######| |
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|#######| |
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+-------+---------+
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If the rectangle width is equal to the the section width, only one
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section is created over the rectangle. If the rectangle height is
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equal to the section height, only one section to the right of the
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rectangle is created. If both width and height are equal, no sections
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are created.
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"""
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# When a section is split, depending on the rectangle size
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# two, one, or no new sections will be created.
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if height < section.height:
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self._add_section(Rectangle(section.x, section.y+height,
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width, section.height-height))
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if width < section.width:
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self._add_section(Rectangle(section.x+width, section.y,
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section.width-width, section.height))
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def _split(self, section, width, height):
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"""
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Selects the best split for a section, given a rectangle of dimmensions
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width and height, then calls _split_vertical or _split_horizontal,
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to do the dirty work.
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Arguments:
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section (Rectangle): Section to split
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width (int, float): Rectangle width
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height (int, float): Rectangle height
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"""
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raise NotImplementedError
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def _section_fitness(self, section, width, height):
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"""The subclass for each one of the Guillotine selection methods,
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BAF, BLSF.... will override this method, this is here only
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to asure a valid value return if the worst happens.
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"""
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raise NotImplementedError
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def _select_fittest_section(self, w, h):
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"""Calls _section_fitness for each of the sections in free section
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list. Returns the section with the minimal fitness value, all the rest
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is boilerplate to make the fitness comparison, to rotatate the rectangles,
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and to take into account when _section_fitness returns None because
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the rectangle couldn't be placed.
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Arguments:
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w (int, float): Rectangle width
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h (int, float): Rectangle height
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Returns:
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(section, was_rotated): Returns the tuple
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section (Rectangle): Section with best fitness
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was_rotated (bool): The rectangle was rotated
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"""
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fitn = ((self._section_fitness(s, w, h), s, False) for s in self._sections
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if self._section_fitness(s, w, h) is not None)
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fitr = ((self._section_fitness(s, h, w), s, True) for s in self._sections
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if self._section_fitness(s, h, w) is not None)
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if not self.rot:
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fitr = []
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fit = itertools.chain(fitn, fitr)
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try:
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_, sec, rot = min(fit, key=operator.itemgetter(0))
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except ValueError:
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return None, None
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return sec, rot
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def add_rect(self, width, height, rid=None):
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"""
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Add rectangle of widthxheight dimensions.
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Arguments:
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width (int, float): Rectangle width
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height (int, float): Rectangle height
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rid: Optional rectangle user id
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Returns:
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Rectangle: Rectangle with placemente coordinates
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None: If the rectangle couldn be placed.
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"""
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assert(width > 0 and height >0)
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# Obtain the best section to place the rectangle.
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section, rotated = self._select_fittest_section(width, height)
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if not section:
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return None
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if rotated:
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width, height = height, width
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# Remove section, split and store results
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self._sections.remove(section)
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self._split(section, width, height)
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# Store rectangle in the selected position
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rect = Rectangle(section.x, section.y, width, height, rid)
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self.rectangles.append(rect)
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return rect
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def fitness(self, width, height):
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"""
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In guillotine algorithm case, returns the min of the fitness of all
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free sections, for the given dimension, both normal and rotated
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(if rotation enabled.)
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"""
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assert(width > 0 and height > 0)
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# Get best fitness section.
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section, rotated = self._select_fittest_section(width, height)
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if not section:
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return None
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# Return fitness of returned section, with correct dimmensions if the
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# the rectangle was rotated.
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if rotated:
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return self._section_fitness(section, height, width)
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else:
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return self._section_fitness(section, width, height)
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def reset(self):
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super(Guillotine, self).reset()
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self._sections = []
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self._add_section(Rectangle(0, 0, self.width, self.height))
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class GuillotineBaf(Guillotine):
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"""Implements Best Area Fit (BAF) section selection criteria for
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Guillotine algorithm.
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"""
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def _section_fitness(self, section, width, height):
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if width > section.width or height > section.height:
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return None
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return section.area()-width*height
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class GuillotineBlsf(Guillotine):
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"""Implements Best Long Side Fit (BLSF) section selection criteria for
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Guillotine algorithm.
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"""
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def _section_fitness(self, section, width, height):
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if width > section.width or height > section.height:
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return None
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return max(section.width-width, section.height-height)
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class GuillotineBssf(Guillotine):
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"""Implements Best Short Side Fit (BSSF) section selection criteria for
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Guillotine algorithm.
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"""
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def _section_fitness(self, section, width, height):
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if width > section.width or height > section.height:
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return None
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return min(section.width-width, section.height-height)
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class GuillotineSas(Guillotine):
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"""Implements Short Axis Split (SAS) selection rule for Guillotine
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algorithm.
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"""
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def _split(self, section, width, height):
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if section.width < section.height:
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return self._split_horizontal(section, width, height)
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else:
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return self._split_vertical(section, width, height)
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class GuillotineLas(Guillotine):
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"""Implements Long Axis Split (LAS) selection rule for Guillotine
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algorithm.
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"""
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def _split(self, section, width, height):
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if section.width >= section.height:
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return self._split_horizontal(section, width, height)
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else:
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return self._split_vertical(section, width, height)
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class GuillotineSlas(Guillotine):
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"""Implements Short Leftover Axis Split (SLAS) selection rule for
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Guillotine algorithm.
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"""
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def _split(self, section, width, height):
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if section.width-width < section.height-height:
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return self._split_horizontal(section, width, height)
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else:
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return self._split_vertical(section, width, height)
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class GuillotineLlas(Guillotine):
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"""Implements Long Leftover Axis Split (LLAS) selection rule for
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Guillotine algorithm.
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"""
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def _split(self, section, width, height):
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if section.width-width >= section.height-height:
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return self._split_horizontal(section, width, height)
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else:
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return self._split_vertical(section, width, height)
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class GuillotineMaxas(Guillotine):
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"""Implements Max Area Axis Split (MAXAS) selection rule for Guillotine
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algorithm. Maximize the larger area == minimize the smaller area.
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Tries to make the rectangles more even-sized.
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"""
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def _split(self, section, width, height):
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if width*(section.height-height) <= height*(section.width-width):
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return self._split_horizontal(section, width, height)
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else:
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return self._split_vertical(section, width, height)
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class GuillotineMinas(Guillotine):
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"""Implements Min Area Axis Split (MINAS) selection rule for Guillotine
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algorithm.
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"""
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def _split(self, section, width, height):
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if width*(section.height-height) >= height*(section.width-width):
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return self._split_horizontal(section, width, height)
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else:
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return self._split_vertical(section, width, height)
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# Guillotine algorithms GUILLOTINE-RECT-SPLIT, Selecting one
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# Axis split, and one selection criteria.
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class GuillotineBssfSas(GuillotineBssf, GuillotineSas):
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pass
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class GuillotineBssfLas(GuillotineBssf, GuillotineLas):
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pass
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class GuillotineBssfSlas(GuillotineBssf, GuillotineSlas):
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pass
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class GuillotineBssfLlas(GuillotineBssf, GuillotineLlas):
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pass
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class GuillotineBssfMaxas(GuillotineBssf, GuillotineMaxas):
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pass
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class GuillotineBssfMinas(GuillotineBssf, GuillotineMinas):
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pass
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class GuillotineBlsfSas(GuillotineBlsf, GuillotineSas):
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pass
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class GuillotineBlsfLas(GuillotineBlsf, GuillotineLas):
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pass
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class GuillotineBlsfSlas(GuillotineBlsf, GuillotineSlas):
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pass
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class GuillotineBlsfLlas(GuillotineBlsf, GuillotineLlas):
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pass
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class GuillotineBlsfMaxas(GuillotineBlsf, GuillotineMaxas):
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pass
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class GuillotineBlsfMinas(GuillotineBlsf, GuillotineMinas):
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pass
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class GuillotineBafSas(GuillotineBaf, GuillotineSas):
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pass
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class GuillotineBafLas(GuillotineBaf, GuillotineLas):
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pass
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class GuillotineBafSlas(GuillotineBaf, GuillotineSlas):
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pass
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class GuillotineBafLlas(GuillotineBaf, GuillotineLlas):
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pass
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class GuillotineBafMaxas(GuillotineBaf, GuillotineMaxas):
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pass
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class GuillotineBafMinas(GuillotineBaf, GuillotineMinas):
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pass
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