Custom Color Formatting for Groups

[Anonymous]

Good day!

I am trying to add custom coloring to my visual, but I have trouble implementing this with grouping. 

Situation:

The data consists of multiple projects, which in turn have multiple milestones. Basically it's a line graph, with a line for each milestone. The user has two options:
1) Draw all milestones from only one project. The user can change the color of each milestone. (This already works)

2) Draw all milestones from all projects inside one graph. In this situation all milestones within one project have the same color (works). The user should be able to change the color of a project with custom formatting. (This doesn't work)

snippet from capabilities.json:

  "dataRoles": [
    {
      "displayName": "Date",
      "name": "date",
      "kind": "Grouping"
    },
    {
      "displayName": "Milestones",
      "name": "milestones",
      "kind": "Measure"
    },
    {
      "displayName": "Project Name",
      "name": "project",
      "kind": "Grouping"
    }
  ],
  "dataViewMappings": [
    {
      "categorical": {
        "categories": {
          "for": {
            "in": "date"
          }
        },
        "values": {
          "group": {
            "by": "project",
            "select": [
              {
                "for": {
                  "in": "milestones"
                }
              }
            ]
          }
        }
      }
    }
  ],

snippet from enumerateObjectInstances function:

objectEnumeration.push({
  objectName: objectName,
  displayName: project.name,
  properties: {
    lineColor: ms.colorLine
  },
  propertyInstanceKind: {
    fill: VisualEnumerationInstanceKinds.ConstantOrRule
  },
  selector: selectionId.getSelector()
});

Problem:

I can't implement Situation 2). I think the problem is the selector. Among others I tried the following: 

A) selectionId = host.createSelectionIdBuilder().withCategory(categories, i).createSelectionId();

B) selectionId = host.createSelectionIdBuilder().withMeasure(ms.source.groupName.toString()).createSelectionId();

C) selector = {metadata: column.queryName};

A) The color is saved in categories. However, this only works if there are equal or more categories than groups (not guaranteed). This was just a workaround by me trying to understand how selectors work. I was hoping for a better solution than this.

B) This doesn't work. Changing a color doesn't seem to be saved anywhere in dataViews

After changing a color . The selector looks like this:

{
    "metadata": "Name of the Group/Project"
}

C) Using this selector changes the color of the milestones (independ of project). E. g. all milestone1 of all projects will be green, all milestone2 will be red...

Does anybody have an idea how I can implement custom formatting of the milestones based on the project? Maybe I also have to change the data model?

Thank you for any help!

[Anonymous · Accepted solution]

Hello Internet,

I think I managed to make it work. It was rather simple:

Basic example

1. Get values grouped

const groups = dataViews[0].categorical.values.grouped()

2. Set selectionId for each group:

values = dataViews[0].categorical.values;
groups.forEach(group => {
  selectionIdGroup = host.createSelectionIdBuilder().withSeries(values, group).createSelectionId()
}

3. Set selectionId for each measure:

selectionIdMeasure = host.createSelectionIdBuilder().withMeasure(dataViewColumn.source.queryName).createSelectionId()

4. You can then access these in formatting pane:

let groupColor: powerbi.visuals.FormattingGroup = {
    displayName: "Colors",
    uid: "colors",
    slices: {
        displayName: group.name,
        uid: "colors_" + group.name,
        control: {
            type: powerbi.visuals.FormattingComponent.ColorPicker,
            properties: {
                descriptor: {
                    objectName: "series",
                    propertyName: "line",
                    selector: group.selectionId.getSelector()
                },
                value: { value: group.colorLine },
            }
        }
    }
};

Hope it helps anyone 🙂

[v-shex-msft]

HI @Anonymous,

According to your description, I don't think your requirement can be achieved based on the code in the custom color formatting groups. They should be more suitable to use condition formatting in visuals based on Dax expressions.

Apply conditional table formatting in Power BI - Power BI | Microsoft Docs

You can use dax expressions to look up correspond records based on current row context and apply color code.
BTW, they can be also pre-declared in a table then you can use DAX expression to load these color code settings from that table.

Regards,

Xiaoxin Sheng