Column / Measure Context Modifier Functions for Tooltips, Especially Table and Matrix

Abstract

Adding three new functions, HOVERCONTEXT, HOVERCONTEXTNAME, and ISHOVERCONTEXT, would enable developers to create more nuanced tooltips on all visuals.

Explanation

The SELECTEDMEAURE family of functions (SELECTEDMEASURE, SELECTEDMEASURENAME, ISSELECTEDMEASURE, SELECTEDMEASUREFORMATSTRING) currently provide information on the current measure when dealing with calculation items or dynamic format strings. This concept could be carried over to tooltips, though probably not by overloading the same functions.

I propose a set of functions like HOVERCONTEXT to pass through information about the source of the displayed value in context for the hovered region. This would be a reference to a measure or sometimes a column. These functions could then be interpreted by the measures used in the tooltip to display finer-grained context per the hovered region.

Example

Consider the following table visual (headers are the fully-qualified reference, not the display name, except that the table is removed from measure references):

If we hover over the cell containing "4", we would see the following behavior in the tooltip:

• HOVERCONTEXTNAME returns 'Table'[SumMeasure]
• HOVERCONTEXT evaluates [SumMeasure], filtered to the provided row context (per existing behavior) and returns "4"
• ISHOVERCONTEXT returns TRUE for ISHOVERCONTEXT('Table'[Category], [SumMeasure]) and FALSE for ISHOVERCONTEXT('Table'[SubCategory], [AvgMeasure])

If we hover over the cell containing "ii", we would see the following behavior in the tooltip:

• HOVERCONTEXTNAME returns 'Table'[SubCategory]
• HOVERCONTEXT evaluates SELECTEDVALUE('Table'[SubCategory]), filtered to the provided row context (per existing behavior) and returns "ii"
• ISHOVERCONTEXT returns FALSE for ISHOVERCONTEXT('Table'[Category], [SumMeasure]) and TRUE for ISHOVERCONTEXT('Table'[SubCategory], [AvgMeasure])

Extension to other visuals

This behavior is similar to what we see with the default tooltip options. In the first example above, hovering with the tooltip page set to "Auto" would display "Category: A; SumMeasure: 4". The same is true of other visuals. Here is a sampling of visuals and the field well from which HOVERCONTEXT would draw its values:

• Stacked / Clustered Bar Chart: X-axis
• Stacked / Clustered Column Chart: Y-axis
• Area / Line Chart: Y-Axis
• Waterfall: Y-axis
• Funnel: Values
• Scatter Chart: Y Axis
• Pie / Donut Chart: Values
• Treemap: Values
• Gauge: Value

If you have read to the end, I'd also like to open up a discussion as to the best way to deal with implicit measures under this system. Feel free to put any recommendations in the comments.