* Fix interaction between styles and sizes by implementing styles as sizes.
Rather than having both `textstyle` CSS classes and `size5` CSS classes
affect the font size (and step on each other), implement sizes more the
way TeX does: a command like `\displaystyle` changes the current size.
This is actually a simplification, since now only `size` affects the size.
Simplifies CSS and computation. Many screenshotter tests change; they
change to be more like TeX. For instance, `\sqrt` fixes some
discrepancies in size treatment.
Also:
Remove the `Options.withX()` methods in favor of `.havingX()`, which
might return the same `options`.
Remove `Style.cls()` and `Style.reset()`.
Remove `Options.reset()`. You should never modify an `Options`; they
should change only by the `havingX()` methods.
* Implement TeX sizing for scriptsize/scriptscriptsize.
At every size level. Also make the sizes match TeX to the last decimal.
* Review comments.
The previous code incorrectly implemented TeXbook rules. First off,
the font metrics at issue should be those for the superscript/
subscript style, not the main style. Secondly, the metrics should be
scaled by the font size.
This changes some screenshotter tests (and they look more like TeX
now).
Summary:
FONTDIM metrics include metrics like sup2, sup3, etc. which are used for
position sub/super-scripts, fractions, delimiters, etc. TeX uses three
different font styles: textfont2 (DISPLAY & TEXT), scriptfont2 (SCRIPT), and
scriptscriptfont2 (SCRIPTSCRIPT) and has different sets of metrics for each.
This diff adds style specific metrics for better TeX compliance.
Notable squashed commits:
- Recreated screenshots (martin)
- fix getEmPerEx to use getXHeight
- regularize how we access options.style, remove unnecessary newlines
- use var style = options.style in more places in buildHTML
The combination of jspngopt and pako should eliminate possible causes for
different PNG encodings, although the core reason for #325 remains unknown.
Pako has poorer compression rates than native libz, but optimization can
counter that effect, and actually reduce the size of the screenshots.
The screenshots for LimitControls and UnsupportedCmds on Firefox used to
exhibit subpixel rendering before, for reasons unknown. The regenerated
versions don't exhibit this. See #324 for a discussion.
Summary:
Update the MathJaxFonts `Dockerfile` to enable the use of
`ttfautohint` which hints our fonts better. Also, fix the location that
batik is downloaded from, update some formatting in the `Dockerfile`,
and update the fonts and metrics.
Test Plan:
- Compare a rendered `= - A z 4 \Longrightarrow \Sigma \Biggl(` in
Chrome on Windows at font sizes 10px to 20px before and after this
change.
- See that characters look about the same, or better.
- See that the screenshot tests didn't change in firefox (maybe firefox
runs the same autohinting algorithm that we do?), and don't visually
change in chrome
Reviewers: kevinb, alpert
Reviewed By: kevinb, alpert
Differential Revision: https://phabricator.khanacademy.org/D18977
