3 ms·
PDF spec itself give bit more context: In PDF versions earlier than PDF 1.6, the size of the default user space unit is fixed at 1 ⁄ 72 inch. In Acroba
by zokier 3y ago
PDF spec itself give bit more context:
In PDF versions earlier than PDF 1.6, the size of the default user space
unit is fixed at 1 ⁄ 72 inch. In Acrobat viewers earlier than version 4.0, the
minimum allowed page size is 72 by 72 units in default user space (1 by 1
inch); the maximum is 3240 by 3240 units (45 by 45 inches). In Acrobat
versions 5.0 and later, the minimum allowed page size is 3 by 3 units (ap-
proximately 0.04 by 0.04 inch); the maximum is 14,400 by 14,400 units
(200 by 200 inches).
Beginning with PDF 1.6, the size of the default user space unit may be set
with the UserUnit entry of the page dictionary. Acrobat 7.0 supports a
maximum UserUnit value of 75,000, which gives a maximum page dimen-
sion of 15,000,000 inches (14,400 * 75,000 * 1 ⁄ 72). The minimum
UserUnit value is 1.0 (the default).
15 million inches happens to be exactly 381 km
- userbinator 3y agoDoes anyone else find those to be very odd limiting values? 1/72" is a standard unit in typesetting, but 3240 looks quite arbitrary, 14400 is 200 * 72 or a slightly more "computerish" 900 * 16, and 75000 is definitely more arbitrary than the nearest "round" limit of 65535. As a relevant contrast, Knuth's TeX internally uses units of "scaled points" for dimensions, or 1/65536 of a point, and its point is defined as 1/72.27 inch so its precision is approximately 5.36um, and the maximum dimension of a page is 1073741823 scaled points, or approximately 5.758m.
- maxnoe 3y ago1 scaled point is 5.36 nm, nano, not micro https://www.wolframalpha.com/input?i=1+inch+%2F+72+%2F+2%5E16 https://www.wolframalpha.com/input?i=1+inch+%2F+72+%2F+2%5E1...