"""Helper to get paper sizes."""
from typing import NamedTuple
class Dimensions(NamedTuple):
width: int
height: int
[docs]class PaperSize:
"""(width, height) of the paper in portrait mode in pixels at 72 ppi."""
# Notes how to calculate it:
# 1. Get the size of the paper in mm
# 2. Convert it to inches (25.4 millimeters are equal to 1 inches)
# 3. Convert it to pixels ad 72dpi (1 inch is equal to 72 pixels)
# All Din-A paper sizes follow this pattern:
# 2xA(n-1) = A(n)
# So the height of the next bigger one is the width of the smaller one
# The ratio is always approximately the ratio 1:2**0.5
# Additionally, A0 is defined to have an area of 1 m**2
# Be aware of rounding issues!
A0 = Dimensions(2384, 3370) # 841mm x 1189mm
A1 = Dimensions(1684, 2384)
A2 = Dimensions(1191, 1684)
A3 = Dimensions(842, 1191)
A4 = Dimensions(
595, 842
) # Printer paper, documents - this is by far the most common
A5 = Dimensions(420, 595) # Paperback books
A6 = Dimensions(298, 420) # Post cards
A7 = Dimensions(210, 298)
A8 = Dimensions(147, 210)
# Envelopes
C4 = Dimensions(649, 918)
_din_a = (
PaperSize.A0,
PaperSize.A1,
PaperSize.A2,
PaperSize.A3,
PaperSize.A4,
PaperSize.A5,
PaperSize.A6,
PaperSize.A7,
PaperSize.A8,
)