fixed values
relationships defined
by a series of relative measurements
90mm
78mm
half an em dash
There is NO relationship between the em and en and the capitals 'M' and 'N'
same as the pt size of the type
1/2 an em
1/3 an em
pauses in speech
nested clauses and stand in for 'to'
10–11 or 1975–1981
hyphenated words
'half-tone'
measuring lines of type
equal to 12 points
6 picas / inch
72 points / inch
A pixel is a single square 'picture element' (hence pix-el),
A 10x10 image is made up of a set of pixels in
a grid 10 wide by 10 high, totaling 100 pixels.
there are two predominant systems in use today. They are the international and North American systems.
the International Standard - ISO216
the North American System
The basis for the whole system is the A0 format which has an area of one square meter.
has an aspect ratio equal to the square root of two (1:4142) which makes it simple to enlarge or reduce a document for printing on another ISO paper format.
sizes are based on traditional formats with arbitrary aspect ratios
2008
2015
2021
With a huge number of device targets and screen sizes across the Windows 10 ecosystem, rather than optimizing your UI for each device, we recommended designing for a few key width categories (also called “breakpoints“):
2021
hot / active space
cool / passive space