How to apply color gradient for bubble inside custom visualization developed using Deneb

[Junato47]

@giammariam hi could you help me in this code, i would like to swap the axis, but more than that the color of the bubble should change not as per the size of the bubble, but instead we should use a color gradient. For eg:"If the residual Impact is "Very Low" and residual probability is "Very Low" it should be Green and if it is high it should be Red. i will show you an example

Here i have used a background, but i want the color change inside the bubble and the backgroud should be white. For the visualisation i used i have made the bubble fill color as transperent. Is it possible to change the colors of the bubble just like the background.

Here is the Link for the sample data set

https://docs.google.com/spreadsheets/d/1e65EUJxRDijyh4DXcasRJrZmetQxvvGe/edit?usp=sharing&ouid=11288...

[giammariam · Accepted solution]

Hey @Junato47, because of the limited clippath settings available, I could not figure out a way to have the gradient be confined to just the circles. However, I was able to calaculate a single color for each bubble with a close match of the gradient based on the position in the matrix. Let me know if the following will suffice.

If this is enough to get you going please consider liking this reply and choosing it as the solution. Otherwise, I'm happy to help further.

Interactive gist 
spec:

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "width": 800,
  "height": 800,
  "transform": [
    {
      "aggregate": [{"op": "count", "as": "count_of_risk_id"}],
      "groupby": ["Residual Impact", "Residual Probability"]
    },
    {"window": [{"op": "row_number", "as": "index"}]},
    {
      "calculate": "indexof(x_domain, datum['Residual Probability'])",
      "as": "x_index"
    },
    {
      "calculate": "indexof(y_domain, datum['Residual Impact'])",
      "as": "y_index"
    },
    {"calculate": "datum['y_index']+datum['x_index']", "as": "gradient_index"},
    {
      "joinaggregate": [
        {"op": "min", "field": "gradient_index", "as": "min_gradient_index"},
        {"op": "max", "field": "gradient_index", "as": "max_gradient_index"}
      ]
    },
    {
      "calculate": "datum['gradient_index']/(gradient_index_domain_max-gradient_index_domain_min)",
      "as": "color_percentage"
    },
    {
      "calculate": "datum['gradient_index']===gradient_index_domain_min ? 0 : datum['gradient_index'] === gradient_index_domain_max ? length(color_domain) - 1 : datum['color_percentage'] <= 0.25 ? 1 : datum['color_percentage'] >= 0.75 ? length(color_domain) - 2 : 2",
      "as": "color_index"
    },
    {"calculate": "color_range[datum['color_index']]", "as": "color"}
  ],
  "params": [
    {
      "name": "x_domain",
      "value": ["Very Low", "Low", "Medium", "High", "Very High"]
    },
    {
      "name": "y_domain",
      "value": ["Very Low", "Low", "Medium", "High", "Very High"]
    },
    {"name": "gradient_index_domain_min", "value": 0},
    {
      "name": "gradient_index_domain_max",
      "expr": "length(x_domain) + length(y_domain) - 2"
    },
    {
      "name": "color_range",
      "value": [
        "rgb(0,255,0)",
        "rgb(165,255,0)",
        "rgb(255,255,0)",
        "rgb(255,165,0)",
        "rgb(255,0,0)"
      ]
    },
    {"name": "color_domain", "expr": "sequence(0,length(color_range), 1)"}
  ],
  "encoding": {
    "x": {
      "field": "Residual Probability",
      "type": "ordinal",
      "axis": {"labelAngle": 0},
      "scale": {"domain": {"expr": "x_domain"}}
    },
    "y": {
      "field": "Residual Impact",
      "type": "nominal",
      "scale": {"domain": {"expr": "y_domain"}, "reverse": true}
    }
  },
  "layer": [
    {
      "mark": {"type": "point", "size": 1000, "tooltip": true, "filled": true},
      "encoding": {
        "size": {
          "field": "count_of_risk_id",
          "legend": null,
          "scale": {"rangeMax": 15000},
          "type": "quantitative"
        },
        "color": {"field": "color", "legend": null, "scale": null}
      }
    },
    {
      "mark": {
        "type": "text",
        "fontSize": 16,
        "fontWeight": 400,
        "color": "black"
      },
      "encoding": {
        "text": {"field": "count_of_risk_id", "type": "quantitative"}
      }
    }
  ],
  "data": {
    "name": "dataset",
    "values": [
      {
        "Risk ID": "1",
        "Residual Impact": "Low",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "2",
        "Residual Impact": "Very High",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "3",
        "Residual Impact": "Medium",
        "Residual Probability": "Very Low"
      },
      {
        "Risk ID": "4",
        "Residual Impact": "Medium",
        "Residual Probability": "Very Low"
      },
      {
        "Risk ID": "5",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "6",
        "Residual Impact": "Medium",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "7",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "8",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "9",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "10",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "11",
        "Residual Impact": "Low",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "12",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "13",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "14",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "15",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "16",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "17",
        "Residual Impact": "Medium",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "18",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "19",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "20",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "21",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "22",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "23",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "24",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "25",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "26",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "27",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "28",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "29",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "30",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "31",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "32",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "33",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "34",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "35",
        "Residual Impact": "High",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "36",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "37",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "38",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "39",
        "Residual Impact": "High",
        "Residual Probability": "Medium"
      },
      {
        "Risk ID": "40",
        "Residual Impact": "Medium",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "41",
        "Residual Impact": "Medium",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "42",
        "Residual Impact": "Low",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "43",
        "Residual Impact": "Medium",
        "Residual Probability": "Low"
      },
      {
        "Risk ID": "44",
        "Residual Impact": "Medium",
        "Residual Probability": "Very High"
      },
      {
        "Risk ID": "45",
        "Residual Impact": "Medium",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "46",
        "Residual Impact": "Medium",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "47",
        "Residual Impact": "Medium",
        "Residual Probability": "High"
      },
      {
        "Risk ID": "48",
        "Residual Impact": "Very High",
        "Residual Probability": "Very High"
      },
      {
        "Risk ID": "49",
        "Residual Impact": "Very Low",
        "Residual Probability": "Very Low"
      }
    ]
  }
}

[Belabw00]

 Hello, I would like to input an variable horizontal line into a bubble chart and I do not have a glue how to do it. For example the horizontal line for the green category should be at the y axes level of 40 and for category red on the lebel of 20. Could you help me with that question ? Best regards Benjamin

[Junato47]

Thanks @giammariam This would work fine for me