rectpack - 2D Rectangle Packing

0.2.2 verified Sat May 09 auth: no python

A Python library for packing 2D rectangles into a bin using various algorithms (MaxRects, Guillotine, etc.). Supports rotation, sorting, and multiple packing modes. Current version 0.2.2, maintained infrequently.

pip install rectpack

Common errors

error AttributeError: module 'rectpack' has no attribute 'Packer' ↓

cause Importing 'import rectpack' then trying 'rectpack.Packer' works, but if you use 'from rectpack import *' and then 'Packer', it may not be included if __all__ is missing. But typical wrong import is 'import Packer'.

fix

Use 'from rectpack import Packer'.

error AttributeError: 'Packer' object has no attribute 'pack_algo' ↓

cause The 'pack_algo' attribute is set after creation; may be due to spelling (pack_algo vs pack_algo) or setting it before calling pack.

fix

Ensure you assign packer.pack_algo = MaxRectsBssf() (note: 'pack_algo' not 'pack_algorithm').

Warnings

gotcha The library does not check if a rectangle fits before packing. If no bin can accommodate, the rectangle is silently left unpacked. Always check packer.rect_list() against your input. ↓

fix After packing, iterate packer.rect_list() and compare with input counts to detect unplaced rectangles.

deprecated The attribute 'pack_algo' is being replaced by 'pack_algo' usage as a property. In older examples, they assigned the algorithm class directly; now use an instance. ↓

fix Use: packer.pack_algo = MaxRectsBssf() (with parentheses)

gotcha Rectangles added without 'rid' will be assigned a default id (e.g., 'rect_0'). If multiple rectangles have the same rid, later ones overwrite earlier ones in internal dictionary. Use unique rid per rectangle to avoid data loss. ↓

fix Always provide unique rid strings, e.g., f'rect_{i}'.

Imports

Packer
wrong
```
import Packer
```
correct
```
from rectpack import Packer
```
Wrong import causes ModuleNotFoundError.
MaxRectsBssf
wrong
```
from rectpack.maxrects import MaxRectsBssf
```
correct
```
from rectpack import MaxRectsBssf
```
Direct submodule import fails; all packers are exposed at package level.

GuillotineBssfSas

wrong

from rectpack.guillotine import GuillotineBssfSas

correct

from rectpack import GuillotineBssfSas

Same as above; use package-level imports.

Quickstart

Basic packing of two rectangles into a 100x100 bin using MaxRects BSSF algorithm.

from rectpack import Packer, MaxRectsBssf
from rectpack import SORT_AREA

packer = Packer()
# Use a packing algorithm
packer.add_bin(100, 100)
packer.add_rect(50, 30, rid='rect1')
packer.add_rect(20, 40, rid='rect2')
packer.pack_algo = MaxRectsBssf()
packer.sort_algo = SORT_AREA
packer.pack()
for rect in packer.rect_list():
    print('Rectangle:', rect)
# Alternatively, get a summary
print('Bins:', packer.bins)  # list of Bin objects
print('Unpacked:', packer.unused_areas())