Help with Deneb/Vega Gantt visual x-axis

Deneb Showcase
6

Hi @KN1

(I know that posting to solved threads is discouraged, but thought I’d add results from a small investigation that might help you.)

I’ve posted my Vega-Lite take on an enhanced Gantt Chart here that may be of some interest:

To take what I’d learned in Vega-Lite and see if I can find anything to answer your question for Vega, I started with the example given on the Vega-Lite website,

When I used the “View this example in the online editor” link, played around a bit with the “labelExpr” line in the “x\axis” block, and used the “Compiled Vega” tab in the online editor, it seems that both Vega-Lite and Vega seem to use the same syntax, albeit in different locations.

  • in Vega-Lite, the code is housed in the “labelExpr” key:value pair in the “axis” block in the “x” encoding block
  • in Vega, the code is housed in the “signal” key:value pair in the “labels\update\text” section of the “x” scale block
  • in both cases, the 2-line labels are composed of a 2-value array

Here’s the compiled Vega for the Vega-Lite example (I’ve added a couple of comments to indicate the location in case its helpful):

	{
      "scale": "x",
      "orient": "bottom",
      "grid": false,
      "title": "date",
      "labelAlign": "left",
      "labelOffset": 4,
      "labelPadding": -24,
      "tickCount": 8,
      "tickSize": 30,
      "labelFlush": true,
      "labelOverlap": true,
      "encode": {
        "ticks": {
          "update": {
            "strokeDash": [
              {
                "test": "time(datetime(2012, month(datum[\"value\"]), 1, 0, 0, 0, 0))===time(datetime(2012, 0, 1, 0, 0, 0, 0))",
                "value": []
              },
              {"value": [2, 2]}
            ]
          }
        },
// START - UPDATE THE FOLLOWING AS DESIRED //		
        "labels": {
          "update": {
            "text": {
              "signal": "[timeFormat(datum.value, '%b'), timeFormat(datum.value, '%m') == '01' ? timeFormat(datum.value, '%Y') : '']"
            }
          }
        }
// END - UPDATE THE PRECEDING AS DESIRED //		
      },
      "zindex": 0
    },

I often use the D3 online reference for the time formats (both Vega-Lite and Vega are abstractions of D3); here’s the link:

Taking another look at Davide’s Vega code, I think you might be able to modify it to suit your needs if
https://vega.github.io/editor/#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

I had some success when I adjusted the format string in the “timeFormat” lines in the "encode\labels\update\text\signal" of the [Day axis] (line 1119) and [Month axis] (line 1141) blocks in the “axes” block. Here’s the target sections of Davide’s code, again with comments added to indicate the location in case its helpful:

      "axes": [
        {
          "description": "Day axis",
          "ticks": true,
          "labelPadding": -12,
          "scale": "xDays",
          "tickSize": 15,
          "orient": "top",
          "bandPosition": 0,
          "grid": false,
          "zindex": 1,
          "encode": {
            "labels": {
              "update": {
                "text": [
                  {
// START - UPDATE THE FOLLOWING AS DESIRED //				  
                    "signal": "timeFormat(timeParse(datum.label,'%d/%m/%y'),'%d')"
// END - UPDATE THE PRECEDING AS DESIRED //                 
				  }
                ]
              }
            }
          }
        },
        {
          "description": "Month axis",
          "scale": "xDays",
          "domain": false,
          "orient": "top",
          "offset": 0,
          "tickSize": 25,
          "labelFontSize": 12,
          "bandPosition": 0,
          "grid": false,
          "zindex": 0,
          "encode": {
            "ticks": {
              "update": {
                "strokeOpacity": [
                  {
                    "test": "timeFormat(timeParse(datum.label,'%d/%m/%y'),'%d')   == '01'",
                    "value": 1
                  },
                  {"value": 0}
                ]
              }
            },
            "labels": {
              "update": {
                "text": [
                  {
                    "test": "timeFormat(timeParse(datum.label,'%d/%m/%y'),'%d')   == '15'",
// START - UPDATE THE FOLLOWING AS DESIRED //					
                    "signal": "timeFormat(timeParse(datum.label,'%d/%m/%y'),'%B')"
// END - UPDATE THE PRECEDING AS DESIRED // 					
                  },
                  {"value": ""}
                ]
              }
            }
          }
        },

Hope this helps.
Greg