Improve fonts generation: remove unused codes

[ylemkimon]

This PR is part of #12.

• Remove CSS generation: CSS is generated by fonts.less
• Remove EOT and SVG font generation
  • EOT was removed in remove EOT font files #8
  • SVG was never used. In fact, SVG generation never worked since dependencies were not installed
  • Both font types are not needed in browsers that is supported by KaTeX
• Remove skew data generation: skew data was never used
• Remove Greek and Windows fonts: they were never used
• Remove install target: copying font files is handled by buildFonts.sh
• Remove fonts and pack target in src/Makefile
• Remove unused dependencies and variables

[edemaine]

I haven't looked at this yet, but what do you mean by "skew generation isn't used"? Don't we need this for italic correction/spreading out (in \mathit)?

[kevinbarabash]

@ylemkimon this is awesome! Thanks for starting to simplify font creation.

[ylemkimon]

@edemaine We have different method of calculating skew in metrics generation.

[ylemkimon]

@kevinbarabash Of course, tests fail because KaTeX/KaTeX#1267 was not merged. Why didn't I think of that before 😄 Tested with latest KaTeX: KaTeX/KaTeX#1494.

[kevinbarabash]

@edemaine We have different method of calculating skew in metrics generation.

@ylemkimon can you link to where this is being done?

[ylemkimon]

@kevinbarabash

katex-fonts/src/metrics/extract_tfms.py

Lines 96 to 100 in e641de5

	skewkern = 0.0
	if (font_skewchar[font] and
	font_skewchar[font] in tfm_char.kern_table):
	skewkern = round(
	tfm_char.kern_table[font_skewchar[font]], 5)

[edemaine]

Another question: Should we support SVG fonts? This seems relevant to KaTeX one day supporting SVG output (KaTeX/KaTeX#375).

Ah, never mind: SVG fonts seem to have poor support in general, e.g., support for them was removed from Chrome. SVG can use any CSS-accessible fonts, at least in the browser.

[ylemkimon]

This PR does not change contents of fonts. (Checked with ttx)

[edemaine]

Wow, this is substantial cleanup. The code changes look good to me.

However, I just tried running ./buildFonts.sh on this branch and (several minutes later) the font files seem to have changed (all of them). You seem to have had the opposite experience. I'm not sure how to do diffs for TTF/WOFF[2] files. Any thoughts on how to debug this discrepancy? (Or maybe it's because another PR merged since?)

[update] Or is your point that I should run ttx to dump the fonts and then compare?

[ylemkimon]

@edemaine Without #54, font binaries will change due to timestamps. Yes, it is possible dump the font file to XML using ttx and compare them.

[edemaine]

OK, given that you checked this already, I'm happy to approve.