IRIS

Intelligent Roadway Information System

Fonts

A font is a set of bitmapped glyphs for displaying text on a DMS.

API Resources 🕵️

iris/api/font (primary)
iris/tfon/{name}.tfon

Access	Primary
👁️ View	name, font_number

A number of fonts are included in the /var/lib/iris/tfon directory:

Name	Number	Height	Line Spacing	3-Lines	Notes
`F07-C`	5	7 px	—	—	5 px width
`F07`	7	7 px	3 px	27 px
`F08`	8	8 px	2 px	28 px
`F09`	9	9 px	3 px	33 px
`F10`	10	10 px	3 px	36 px
`F11`	11	11 px	3 px	39 px
`F12`	12	12 px	3 px	42 px
`F12-A`	112 †	12 px	(2 px)	—	full ASCII
`F12-B`	212 †	12 px	(4 px)	—	bold
`F13`	13	13 px	4 px	47 px
`F14`	14	14 px	4 px	50 px
`F14-A`	114 †	14 px	(6 px)	—	full ASCII
`F15`	15	15 px	4 px	53 px
`F16`	16	16 px	4 px	56 px
`F18`	18	18 px	5 px	64 px
`F20`	20	20 px	6 px	72 px
`F22`	22	22 px	7 px	80 px
`F24`	24	24 px	8 px	88 px
`F26`	26	26 px	8 px	94 px

† Normally font number is the same as pixel height, but variations use 1xx or 2xx.

Numbers 1-4 are reserved for permanent fonts used by some signs.

Non-ASCII Characters

Since NTCIP 1203 does not support Unicode, ASCII characters must be used as surrogates for arrows, diamonds, etc:

Character	Code Point	ASCII	Fonts
^ND	38	&	`F14-A`
◊	42	*	`F07`, `F26`
↖	94	^	`F14-A`
█	96	`	`F14-A`
↙	123	{	`F07`, `F14-A`
↘	125	}	`F07`, `F14-A`

Choosing Fonts

When choosing a font, a few parameters must be considered, such as pixel pitch, desired character height, and font weight. Pixel pitch varies from 70 mm down to 20 mm or smaller.

For legibility, text on freeway signs should be about 380 mm tall (15 in). See the table below for optimal character heights based on pixel pitch.

Pixel Pitch	Font Height	Character Height
70 mm	7 px	420 mm (16.5 in)
66 mm	7 px	396 mm (15.6 in)
63 mm	7 px	378 mm (14.9 in)
50 mm	8 px	350 mm (13.8 in)
43 mm	9 px	387 mm (15.2 in)
33 mm	12 px	363 mm (14.3 in)
20 mm	20 px	380 mm (15.0 in)

Upper-case only fonts are recommended for larger pixel pitch, but fonts with lower-case characters can be used if pitch is below 50 mm. If a message containing lower-case characters is used with an upper-case only font, it will be converted to upper-case.

Importing

Fonts in tfon format can be imported into the IRIS database using tfon_import.py (in the bin directory):

tfon_import.py [font file] | psql tms

Also, each font file must be copied to the /var/lib/iris/web/tfon/ directory to make it available in the REST API.

Send and Query Fonts

The status tab of the DMS properties dialog contains two settings buttons. Pressing Send Settings will cause all necessary fonts to be sent to the sign. Query Settings will read all fonts currently on the sign, and store them in the /var/lib/iris/web/tfon/{sign_name} directory.