[css-inline] Controlling half-leading

One of the problems that keeps coming up for quality typesetting
is the way half-leading works in CSS. There are a handful of issues,
but one of the major ones is that authors cannot control the amount
of leading (which is effectively extra space between the content of
the line and the content edge of the box) at the top or bottom of
a box (particularly one which is made visible, e.g. through backgrounds
or borders) or fragmentainer.

[If I understand correctly, the half-leading model was chosen for CSS
in order to handle blocks that don't have such visible boundaries,
e.g. consecutive paragraphs.]

Dave Cramer and I discussed the possibility of adding a property to
control whether half-leading is added at the top/bottom of a block
so that authors can get the control they need at the top of the page
etc.

It would look something like

   leading: always | auto | never

where

   always - always add half-leading above/below the line box (default)
   never  - never add half-leading above the first line box or below
            the last line box
   auto   - as 'never' for boxes that establish a new formatting context
            (i.e. flex items or other BFC roots) or boxes that have
            borders or padding [similar rules to margin collapsing]

~fantasai

Received on Tuesday, 10 May 2016 06:41:05 UTC