Meaning of fields in exported JSON

[smolck]

In trying to use this library (just the binary for now), I've been successful in getting some things rendered from a generated font atlas, but I'm running into some issues that I think stem at least in part from not knowing what the different values in the exported JSON (from the file outputted when running the binary with -json <output.json>) mean.

For reference, here's part of the JSON for the font atlas I'm working with atm:

{
  "atlas": {
    "type": "msdf",
    "distanceRange": 2,
    "size": 33.0625,
    "width": 104,
    "height": 104,
    "yOrigin": "bottom"
  },
  "metrics": {
    "emSize": 1,
    "lineHeight": 1.2090000000000001,
    "ascender": 0.96799999999999997,
    "descender": -0.24099999999999999,
    "underlineY": -0.20100000000000001,
    "underlineThickness": 0.095000000000000001
  },
  "glyphs": [
    {
      "unicode": 72,
      "advance": 0.746,
      "planeBounds": {
        "left": 0.025173913043478272,
        "bottom": -0.044817580340264687,
        "right": 0.72082608695652173,
        "top": 0.7718175803402646
      },
      "atlasBounds": {
        "left": 36.5,
        "bottom": 8.5,
        "right": 59.5,
        "top": 35.5
      }
    }
  ]
}

The values in the atlas and metrics objects I'm not so confused about (although an explanation or link to one of what exactly they mean/what units they're in, etc., would be helpful), but I don't really know what the advance, planeBounds, and atlasBounds fields in each of the objects in glyphs mean, what their units are, etc.? I've tried to figure it out through looking at the source code and also an exported shadron script, but I'm still unsure.

Thanks!

[Chlumsky]

See #2 (comment). The units are pixels for size and atlasBounds and EMs for everything else. Feel free to ask more specifically if something still isn't clear.

[smolck]

Ah, I didn't see that; thank you!