140 lines
4 KiB
Python
140 lines
4 KiB
Python
from .geometry import Rectangle
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class PackingAlgorithm(object):
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"""PackingAlgorithm base class"""
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def __init__(self, width, height, rot=True, bid=None, *args, **kwargs):
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"""
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Initialize packing algorithm
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Arguments:
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width (int, float): Packing surface width
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height (int, float): Packing surface height
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rot (bool): Rectangle rotation enabled or disabled
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bid (string|int|...): Packing surface identification
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"""
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self.width = width
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self.height = height
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self.rot = rot
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self.rectangles = []
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self.bid = bid
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self._surface = Rectangle(0, 0, width, height)
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self.reset()
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def __len__(self):
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return len(self.rectangles)
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def __iter__(self):
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return iter(self.rectangles)
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def _fits_surface(self, width, height):
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"""
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Test surface is big enough to place a rectangle
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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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Returns:
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boolean: True if it could be placed, False otherwise
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"""
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assert(width > 0 and height > 0)
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if self.rot and (width > self.width or height > self.height):
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width, height = height, width
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if width > self.width or height > self.height:
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return False
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else:
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return True
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def __getitem__(self, key):
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"""
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Return rectangle in selected position.
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"""
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return self.rectangles[key]
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def used_area(self):
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"""
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Total area of rectangles placed
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Returns:
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int, float: Area
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"""
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return sum(r.area() for r in self)
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def fitness(self, width, height, rot = False):
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"""
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Metric used to rate how much space is wasted if a rectangle is placed.
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Returns a value greater or equal to zero, the smaller the value the more
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'fit' is the rectangle. If the rectangle can't be placed, returns None.
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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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rot (bool): Enable rectangle rotation
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Returns:
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int, float: Rectangle fitness
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None: Rectangle can't be placed
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"""
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raise NotImplementedError
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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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raise NotImplementedError
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def rect_list(self):
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"""
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Returns a list with all rectangles placed into the surface.
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Returns:
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List: Format [(x, y, width, height, rid), ...]
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"""
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rectangle_list = []
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for r in self:
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rectangle_list.append((r.x, r.y, r.width, r.height, r.rid))
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return rectangle_list
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def validate_packing(self):
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"""
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Check for collisions between rectangles, also check all are placed
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inside surface.
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"""
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surface = Rectangle(0, 0, self.width, self.height)
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for r in self:
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if not surface.contains(r):
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raise Exception("Rectangle placed outside surface")
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rectangles = [r for r in self]
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if len(rectangles) <= 1:
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return
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for r1 in range(0, len(rectangles)-2):
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for r2 in range(r1+1, len(rectangles)-1):
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if rectangles[r1].intersects(rectangles[r2]):
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raise Exception("Rectangle collision detected")
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def is_empty(self):
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# Returns true if there is no rectangles placed.
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return not bool(len(self))
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def reset(self):
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self.rectangles = [] # List of placed Rectangles.
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