53 lines
1.4 KiB
Python
53 lines
1.4 KiB
Python
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"""Helper to get paper sizes."""
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from typing import NamedTuple
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class Dimensions(NamedTuple):
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width: int
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height: int
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class PaperSize:
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"""(width, height) of the paper in portrait mode in pixels at 72 ppi."""
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# Notes of how to calculate it:
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# 1. Get the size of the paper in millimeters
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# 2. Convert it to inches (25.4 millimeters is equal to 1 inch)
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# 3. Convert it to pixels at 72dpi (1 inch is equal to 72 pixels)
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# All Din-A paper sizes follow this pattern:
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# 2 x A(n - 1) = A(n)
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# So the height of the next bigger one is the width of the smaller one
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# The ratio is always approximately 1:2**0.5
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# Additionally, A0 is defined to have an area of 1 m**2
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# https://en.wikipedia.org/wiki/ISO_216
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# Be aware of rounding issues!
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A0 = Dimensions(2384, 3370) # 841mm x 1189mm
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A1 = Dimensions(1684, 2384)
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A2 = Dimensions(1191, 1684)
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A3 = Dimensions(842, 1191)
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A4 = Dimensions(
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595, 842
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) # Printer paper, documents - this is by far the most common
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A5 = Dimensions(420, 595) # Paperback books
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A6 = Dimensions(298, 420) # Postcards
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A7 = Dimensions(210, 298)
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A8 = Dimensions(147, 210)
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# Envelopes
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C4 = Dimensions(649, 918)
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_din_a = (
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PaperSize.A0,
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PaperSize.A1,
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PaperSize.A2,
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PaperSize.A3,
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PaperSize.A4,
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PaperSize.A5,
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PaperSize.A6,
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PaperSize.A7,
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PaperSize.A8,
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)
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