| Author |
Peter Edberg |
| Date |
2019-05-21 |
| Status |
Proposal |
| Feedback to |
pedberg (at) unicode (dot) org |
| Bugs |
CLDR-9996 Add units for pixels , ems, and display resolution
CLDR-8076 Proposal: add units for dot density and pixel density |
This is a proposal to add 7 units related to graphics, imaging, typography.
| unit |
abbr (en) |
proposed category
|
notes |
pixel
megapixel |
px
MP |
new category? |
A pixel is the smallest resolvable element of a bitmap image. In many usages it does not have a fixed size, and is just used for counting (e.g. an image has 360 pixels vertically and 480 horizontally). In some graphic usages it is specifically 1/96 inch. In CSS it is the smallest resolvable element on a display, but specifically means 1/96 inch on a printer. Thus sometimes it is a property associated with an image, and sometimes with a device. |
dots-per-inch
dots-per-centimeter |
dpi
dpcm |
new category?
or concentr |
A dot is the smallest displayable element on a device, typically used for printers. Measurements using dots per inch or centimeter are used to indicate printer resolution, and are a kind of linear density. |
pixels-per-inch
pixels-per-centimeter |
ppi
ppcm |
new category?
or concentr |
Measurements using pixels per inch or centimeter are sometimes used to indicate display resolution, and are a kind of linear density. |
| em |
em |
new category?
or length |
A typographic em is a unit of length that corresponds to the point size of a font (so it does not have a fixed size). |
We could consider adding a new category for these, say “graphics”; otherwise some of them do not fit reasonably into any existing category.
Per TC meeting 2019-05-22: - Use singular for the internal key name, e.g. “dot-per-inch”
- Put all of these in a new category “graphics”
Some reference material:
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