Add \smash, laps, spaces, and phantoms #833

ronkok · 2017-08-29T23:06:42Z

Support \smash, including the optional argument from AMS.
Change \llap and \rlap so that they render in text style. Repeat: This changes KaTeX behavior.
Add \mathllap and \mathrlap. These will act as they do in mathtools and as in previous KaTeX versions of \llap and \rlap.
Add \mathclap and \clap.
Add \hphantom and \vphantom.
Add \thinspace, \medspace, \thickspace
Add \hspace.

This work will resolve issue #270 and parts of #50 and #164.

A. Perlis has written a concise description of items 1 thru 5. Except for \smash's optional argument. It's described in the AMS User's Guide.

Item 6 also comes from the AMS User's Guide.

1. Support `\smash`, including the optional argument from AMS. 2. Change `\llap` and `\rlap` so that they render in text style. Repeat: This *changes* KaTeX behavior. 3. Add `\mathllap` and `\mathrlap`. These will act as they do in `mathtools` and as in previous KaTeX versions of `\llap` and `\rlap`. 4. Add `\mathclap` and `\clap`. 5. Add `\hphantom` and \vphantom`. 6. Add `\thinspace`, `\medspace`, `\thickspace` 7. Add `\hspace`. This work will resolve issue #270 and parts of #50 and #164. A. Perlis has written a [concise description](https://www.math.lsu.edu/~aperlis/publications/mathclap/perlis_mathclap_24Jun2003.pdf) of items 1 thru 5. Except for `\smash`'s optional argument. It's described in the [AMS User's Guide](http://texdoc.net/texmf-dist/doc/latex/amsmath/amsldoc.pdf). Item 6 also comes from the AMS User's Guide.

ronkok · 2017-08-29T23:10:06Z

My apologies for the disconnectedness in this PR. And @edemaine thank you for the help in getting restarted.

@kohler I haven't yet looked into your comment about calling makeVList from groupTypes.smash. I'll do that later this evening.

ronkok · 2017-08-29T23:45:04Z

@kohler, I've taken your advice and exploited makeVList. I've applied it to \smash and \hphantom. That should be enough shouldn't it?

update smash and phantom screenshots for chrome

kevinbarabash · 2017-08-30T20:10:29Z

src/buildCommon.js

+    "\\thickspace": {
+        size: "0.277778em",
+        className: "thickspace",
+    },


Are these separate commands or would it make sense to use defineMacro to define \thickspace in terms of \;?

Using defineMacro would work very well. I'll change it.

kevinbarabash · 2017-08-30T20:29:46Z

static/katex.less

+    .clap > .inner  > span {
+        margin-left: -50%;
+        margin-right: 50%;
+    }


I feel like there might be an easier way to center things. I'll check out the branch and experiment.

I never got around to experimenting. This does the trick and anything else would be marginally smaller so I'm going to merge this as is.

kevinbarabash · 2017-08-30T20:30:25Z

test/katex-spec.js

@@ -715,7 +715,7 @@ describe("A text parser", function() {
    const textExpression = "\\text{a b}";
    const noBraceTextExpression = "\\text x";
    const nestedTextExpression =
-        "\\text{a {b} \\blue{c} \\textcolor{#fff}{x} \\llap{x}}";
+        "\\text{a {b} \\blue{c} \\textcolor{#fff}{x} \\mathllap{x}}";


Why change all \laps in this file to \mathlaps?

It seemed to me that \mathllap is a core command. I found \llap to be less interesting. But your point is well taken. This line is supposed to be testing a text parser. I'll change it back.

Well, now I have a better answer to your question about the test. Since \lap is a test mode function, we should not expect it to work properly when given math mode arguments, such as \left. So the tests really should be revised to test \mathllap and not \lllap.

kevinbarabash · 2017-08-30T20:32:20Z

test/screenshotter/ss_data.yaml

@@ -107,7 +107,7 @@ KaTeX: \KaTeX
 Kern:
    tex: \frac{a\kern{1em}b}{c}a\kern{1em}b\kern{1ex}c\kern{-0.25em}d
    nolatex: LaTeX fails to typeset this, “Missing number, treated as zero.”
-Lap: ab\llap{f}cd\rlap{g}h
+Lap: ab\mathllap{f}cd\mathrlap{g}h


We should probably also verify the changed behavior of llap et al.

I'll add some tests.

kevinbarabash · 2017-08-30T20:39:52Z

src/functions.js

    numArgs: 1,
    allowedInText: true,
 }, function(context, args) {
    const body = args[0];
    return {
-        type: context.funcName.slice(1),
+        type: "lap",
+        className: context.funcName.slice(5),


I'd like to avoid including CSS specifics at this level, maybe this could be called alignment.

kevinbarabash · 2017-08-30T20:44:05Z

src/buildMathML.js

+    const inner = buildExpression(group.value.value, options);
+    const node = new mathMLTree.MathNode("mphantom", inner);
+    node.setAttribute("width", "0px");
+    return node;


Thanks for your attention to detail with this.

kevinbarabash · 2017-08-30T20:45:09Z

src/buildHTML.js

+        // ref: amsmath: \renewcommand{\smash}[1][tb]{%
+        //               def\mb@t{\ht}\def\mb@b{\dp}\def\mb@tb{\ht\z@\z@\dp}%
+        smashHeight = /t/.test(group.value.tb);
+        smashDepth = /b/.test(group.value.tb);


I see, the tb optional param is used to "smash" the top and/or the bottom of the group.

These tests could be moved into functions.js so that we don't have repeat the here and in buildMathML.js.

I'll do that.

kevinbarabash · 2017-08-30T20:57:09Z

src/functions.js

+    };
+});
+
+// smash, with optional [bt], as in AMS


nit: the comment uses bt but everywhere else it's tb

kevinbarabash · 2017-08-30T20:59:38Z

src/functions.js

        body: body,
+        tb: tb,


smashHeight: /t/.test(tbArg), smashDepth: /b/.test(tbArg),

Do we care if there are other values in tbArg?

Yes, I suppose we do care. I just checked and AMS LaTeX ignores the \smash if I put another character in there. Here's an example and the first exponent has \smash[tab]{2}

I'll change the code to act in the same way.

\llap is fundamentally a text-mode function. We should not expect it to work correctly when given math-mode arguments. So test \mathllap instead.

A correction. The previous macro returned an error if given an argument with math-mode content, such as x^2. The corrected macro will not return an error. It will instead return well rendered math, but letters are in `\mathrm` font.

kevinbarabash · 2017-09-02T15:31:31Z

@ronkok I've updated the \llap, \clap, and \rlap to use textrm instead of mathrm. The unit tests are passing now. I'll regenerate the Lap screenshots.

update Lap screenshots

kevinbarabash

LGTM. Thanks for making changes.

ronkok · 2017-10-15T15:20:45Z

@kevinbarabash, It just occurred to me that there is another breaking change in release 0.9.0-alpha, one that is not yet listed in the release notes.

The \llap and \rlap functions now render in text style, which follows LaTeX behavior. Also, KaTeX now has functions \mathllap and \mathrlap. These will act as they do in mathtools and as in previous KaTeX versions of \llap and \rlap.

My current draft of the function support page has been so updated. But I did not emphasize the change as much as I did when \color changed. If you want that draft revised, let me know.

kevinbarabash · 2017-10-15T16:37:32Z

Good call. I can up date the release notes.

kevinbarabash · 2017-10-15T16:39:45Z

I've updated the release notes.

ronkok added 2 commits August 29, 2017 16:12

Fix test spec

0b8b3ab

Exploit makeVList for smash

de8e8b8

kevinbarabash and others added 2 commits August 29, 2017 22:17

update smash and phantom screenshots for chrome

c8e557c

Merge pull request #1 from Khan/smash_screenshots_2

bce39ca

update smash and phantom screenshots for chrome

kevinbarabash mentioned this pull request Aug 30, 2017

group all \phantom code, group all delimsizing code, and add introduce flow type checking #766

Merged

kevinbarabash reviewed Aug 30, 2017

View reviewed changes

ronkok and others added 7 commits August 31, 2017 10:43

Pick up review comments

a63a994

Merge branch 'master' into master

a810d58

Change test from \llap to \mathlap

b57a6f6

\llap is fundamentally a text-mode function. We should not expect it to work correctly when given math-mode arguments. So test \mathllap instead.

Merge remote-tracking branch 'upstream/master'

4d3bb30

Merge branch 'master' of https://github.com/ronkok/KaTeX

ffd3b65

Correct \llap macro

fea19fe

A correction. The previous macro returned an error if given an argument with math-mode content, such as x^2. The corrected macro will not return an error. It will instead return well rendered math, but letters are in `\mathrm` font.

update \llap, \rlap, \clap macros to use \textrm

655d3c3

kevinbarabash and others added 2 commits September 2, 2017 11:39

update Lap screenshots

bdc0c0a

Merge pull request #2 from Khan/lap_screenshots

476f9fe

update Lap screenshots

kevinbarabash approved these changes Sep 2, 2017

View reviewed changes

kevinbarabash merged commit 092aa0c into KaTeX:master Sep 2, 2017

ronkok mentioned this pull request Sep 7, 2017

mhchem extension support #50

Closed

edemaine mentioned this pull request Nov 19, 2017

Horizontal spacing commands: \>, \hfill #164

Closed

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Add \smash, laps, spaces, and phantoms #833

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Add \smash, laps, spaces, and phantoms #833

Add \smash, laps, spaces, and phantoms #833

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