* Refactor \kern, proper \mkern support, add \hskip
* Move \kern, \mkern into functions directory
* Add \hskip, \mskip support (but without supporting plus/minus)
* Properly separate \kern, \hskip from \mkern, \mskip.
(The former work in both modes, and don't support mu units.
The latter work only in math mode and only support mu units.)
* Render \kern etc. using MathML <mspace>
* Implement \TeX macro
* Implement \LaTeX
* New KaTeX logo \katex
* Rename hskip.js -> kern.js
* Tweak katex \kern to 0.16em
* \katex kern -.17em
* Compute A raise height in \LaTeX and \katex
* Switch mu unit errors to warnings
* LaTeX screenshot test
* Replace \KaTeX with macro definition
* Update screenshots with \KaTeX in them
* Fix font selection for \*TeX macros
TeX and CSS treat line heights in fundamentally different ways. In
TeX, every character is treated as a box of its precise height and
depth; the line height (\baselineskip) applies after characters have
been assembled into lines. In CSS, in contrast, every character
creates a "line box" corresponding to the accompanying font. When
characters of different fonts and sizes are placed into the same
span, the resulting line box contains the line boxes of all children.
This is unfortunate because, for example, we want `\frac{1}{2}` to
behave in vertical spacing contexts like it is exactly as tall and
deep as the visible fraction (which is the TeX behavior). Given CSS
constraints, though, in most contexts the fraction has extra vertical
space: the line boxes for the numerator and denominator create
padding. For small boxes, this isn't so bad. To really see the
problem put a tall rule in the denominator of a fraction, or check
out the VerticalSpacing screenshotter test, which has way more space
than it should.
Solving this problem in CSS is difficult. There is no easy way to get
rid of the extra line boxes.
But there is *a* way, namely tables. A table-cell with vertical-align
top, bottom, or middle is ignored for the purposes of line height
calculation.
So in this commit, makeVList puts its contents into a
vertical-align:bottom table-cell (to clear unwanted line boxes), with
an extra row used to represent depth.
Many Chrome screenshotter tests change. This is because Chrome rounds
table dimensions to integral numbers of pixels, while it uses
sub-pixel positioning for non-table displayed tabs. That makes many
vlists a fraction of a pixel wider than they used to be.
When rebasing for 2e002ff37a I forgot to
re-create the screenshots based on the new parent. As a consequence, the
font testing images from fd2d58fd80 were not
updated for Firefox and not even included for Chrome.
We still have the strange issue that Lap can result in one of two possible
screenshots, and while the previous commit recreated one of them, this one
here recreates the other.
