)]}'
{
  "commit": "cd24d80daa22a2a720f3ce67d038086be9ee9cfd",
  "tree": "00e97ddd130632e1fcd53dfa4d48e64e261f2ab5",
  "parents": [
    "a926747b7ae5d6140314089e84ed73d87551b03a"
  ],
  "author": {
    "name": "Karl Schaefer",
    "email": "karlgschaefer@gmail.com",
    "time": "Fri Sep 30 14:23:27 2016 -0400"
  },
  "committer": {
    "name": "Karl Schaefer",
    "email": "karlgschaefer@gmail.com",
    "time": "Fri Sep 30 14:23:27 2016 -0400"
  },
  "message": "Add \\overleftrightarrow command.\n\nThis is simply another Style command with custom CSS to make a line with an\narrowhead at each end.\n\nThere were a couple of small issues here:\n1. :after is used to fill empty blocks, but I need :after for the right\n   arrowhead.\n\n   This was resolved by using min-width and min-height.  Both are extremely\n   common CSS at this point.\n\n2. The original \\overleftarrow and \\overrightarrow work upon which this is\n   based do not scale well.\n\n   I made no effort to fix the scaling issue.  The current arrows misalign with\n   the line if the font-size changes even slightly.  Using \\overleftarrow in\n   the visual test page, where the base font is .8em causes issues.\n\n   Without using JavaScript to alter inline styles, I think that end users will\n   have to write custom styles if they are using non-standard font sizes.  This\n   is no worse than the original implementation, so I feel confident that the\n   \\overleftrightarrow is as good as what currently exists for the other arrow\n   types.\n\n3. The collapsed arrowheads for \\overleftrightarrow collapse on top of one\n   another when the block is empty.  It looks like an asterisk.\n\n   The min-width could be made larger.  This is part of a set of geometric\n   markers that need at least two identifiers underneath.  No line segment,\n   ray, or line can be defined without at least two points.\n\n   Given that the current \\over* markers do not have enough space when empty\n   for two characters, I concluded that two space was not necessary here\n   either.  The difference, however, is that the single-arrowhead lines do not\n   present a visual miscue when collapsed to a single character width.\n\n   This would be an easy change.  Given the variable width nature of Symbola, I\n   recommend that the min-width be set to 1.5em if this change is desired.\n   Our custom CSS that we apply on top of MathQuill\u0027s base CSS for our product\n   does use the 1.5em min-width.\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "7d7cc3167b6b2cd3c9d2b2133b593701b417a6cc",
      "old_mode": 33188,
      "old_path": "src/commands/math/commands.js",
      "new_id": "20a18acd199fe763cd542dc54716c17ca0a5d8cc",
      "new_mode": 33188,
      "new_path": "src/commands/math/commands.js"
    },
    {
      "type": "modify",
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      "old_mode": 33188,
      "old_path": "src/css/math.less",
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      "new_path": "src/css/math.less"
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}