Length & Angle Units

Prince supports the following length and angle units:

Absolute Length Units

The absolute length units correspond to exact distances in the PDF file.

Absolute length units
cm	centimeters
mm	millimeters
q	quarter-millimeters
in	inches
pc	picas
pt	points

Font Length Units

The font length units are relative to the font-size property.

Font length units
em	font size of the element
rem	font size of the root element
ex	x-height in the current font
rex	x-height in the font of the root element
Line height units
lh	line height of the element
rlh	line height of the root element
Character units
ch	width of the "0" (zero) glyph in the current font
rch	width of the "0" (zero) glyph in the font of the root element
CapHeight units
cap	nominal height of capital letters in the current font
rcap	nominal height of capital letters in the font of the root element
Ideographic units
ic	width of the "水" glyph (CJK water ideograph, U+6C34) in the current font
ric	of the "水" glyph (CJK water ideograph, U+6C34) in the font of the root element

Viewport Length Units

The viewport length units are relative to the @page area: the unit vw is equal to 1% of the width of the page area, i.e. the page size minus the margin area (and minus border and padding), while the unit vh is equal to 1% of its height.

The values pvw and pvh are equal to respectively 1% of the width and height of the entire page, as defined by the page size.

Please note that these values cannot be used with elements for which a viewport, such as the root element, has not been established.

Viewport length Units
vw	content area width
vh	content area height
vmin	the smaller length of vw or vh
vmax	the larger length of vw or vh
pvw	page width
pvh	page height
pvmin	the smaller length of pvw or pvh
pvmax	the larger length of pvw or pvh

Pixel Unit

The pixel unit is relative to the de-facto standard of 96dpi (or rather, 96 pixel per inch) for compatibility with browsers.

Pixel unit
px	pixel

tip

This can be changed with the command-line option --css-dpi.

Fractional Length Unit

CSS grids require a flexible length, expressed as a fraction of the leftover space in a grid container.

Fractional length unit
fr	fraction of the leftover space in the grid container

Angle Units

Furthermore, Prince supports the four angle units deg, grad, rad and turn on the following properties:

• the CSS transform property has rotate, skew and skewx/skewy operators;
• linear gradients have an angle;
• HSL colors have a hue angle;
• the hue-rotate filter takes an angle;
• the @page -prince-rotate-body descriptor takes multiples of 90deg.