SVG Visuals

SVG Visuals via DAX Measures (PBIR)

Use pbir for every report mutation. The pbir-format skill is read-only schema context. If the CLI is unavailable or lacks an operation, stop and report the gap.

Generate inline SVG graphics using DAX measures that return SVG markup strings. These render as images in table, matrix, card, image, and slicer visuals. Store as extension measures in reportExtensions.json.

How It Works

1. A DAX measure returns an SVG string prefixed with data:image/svg+xml;utf8,
2. The measure's dataCategory is set to ImageUrl
3. Power BI renders the SVG as an image in supported visuals

Supported Visuals

• Table (tableEx): grid.imageHeight / grid.imageWidth -- references/svg-table-matrix.md
• Matrix (pivotTable): same as table -- references/svg-table-matrix.md
• Image (image): sourceType='imageData' + sourceField -- references/svg-image-visual.md
• Card/New (cardVisual): the image object (image area) or cardImage (callout image) -- references/svg-template-matrix.md, patterns in references/svg-card-slicer.md
• Slicer/New (advancedSlicerVisual): one image per button through the image "Select from data" slot -- references/svg-template-matrix.md

Start From a Template

Before writing DAX by hand, check references/svg-template-matrix.md: it maps each pattern (bullet, progress, pill, sparkline, dumbbell, diverging, delta, pin, gauge) to the hosts it fits (an SVG on its own goes in an image visual, a card is for a number), shows the verified PBIR wiring per host, and gives the one-step pbir visuals svg / pbir add gauge-card commands that write the pattern as a thin report measure and wire it in. Hand-write SVG DAX only for a shape no template covers.

Workflow: Creating an SVG Measure

Step 0: Design and Preview

Before writing DAX, design the SVG visually:

1. Query the model first -- use DAX Studio or Tabular Editor CLI to get actual values with the intended filter context. Use real numbers, not placeholders.
2. Write static SVG to a temp file -- save to /tmp/mockup.svg and open it in a browser to preview layout, colors, and proportions.
3. Ask for feedback before converting to DAX -- iterating on static SVG is far easier than on DAX string concatenation.
4. Colors must be hex codes with # -- e.g., fill='#2B7A78'. Never use %23 URL encoding or named colors. Always hex.

Step 1: Create the Extension Measure

Create the extension measure in reportExtensions.json manually (see the pbir-format skill in the pbip plugin for JSON structure).

# Example using pbir_object_model (if available):
report.add_extension_measure(
    table="Orders",
    name="Sparkline SVG",
    expression='''
        VAR _Prefix = "data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 30'>"
        VAR _Bar = "<rect x='0' y='0' width='50' height='30' fill='#2196F3'/>"
        VAR _Suffix = "</svg>"
        RETURN _Prefix & _Bar & _Suffix
    ''',
    data_type="Text",
    data_category="ImageUrl",
    display_folder="SVG Charts",
)
report.save()

Step 1b: Review

Before presenting the measure to the user, dispatch the svg-reviewer agent to validate syntax and provide design feedback.

Step 2: Bind to a Visual

Extension measures use "Schema": "extension" in the SourceRef:

{
  "field": {
    "Measure": {
      "Expression": {
        "SourceRef": {"Schema": "extension", "Entity": "Orders"}
      },
      "Property": "Sparkline SVG"
    }
  }
}

For image visuals, bind the SVG measure through pbir add visual image --image; see references/svg-image-visual.md.

Step 3: Validate

Validate with pbir validate "Report.Report" --all and inspect bindings with pbir visuals bind "...Visual" --show.

Prefer UDF Libraries Over Custom DAX

Before writing a custom SVG measure from scratch, check whether an existing UDF library already provides the chart type:

• PowerofBI.IBCS (Andrzej Leszkiewicz) -- IBCS-compliant bar, column, waterfall, pin, small multiples, and P&L charts. Preferred for business reporting with AC/PY/BU/FC comparisons. Install from https://daxlib.org/package/PowerofBI.IBCS/
• DaxLib.SVG (Jake Duddy) -- general-purpose sparklines, bars, boxplots, heatmaps, jitter, violin, progress bars, pills. Install from https://daxlib.org/package/DaxLib.SVG/ -- source at https://github.com/daxlib/dev-daxlib-svg
• PowerBI MacGuyver Toolbox (Stepan Resl / Data Goblins) -- C# scripts that generate SVG measures via Tabular Editor

To check if a library is installed, look for functions/measures starting with PowerofBI.IBCS., Viz., Compound., or Element.. Only write custom SVG DAX when no library function covers the required visualization. See references/community-examples.md for full function listings and additional libraries.

Installing UDF libraries

UDF libraries are installed into the semantic model, not the report. Use one of these tools:

• Tabular Editor CLI (te command) -- use the te-docs skill for guidance
• Power BI MCP server -- if available, use it to modify the model directly
• connect-pbid skill -- connect to Power BI Desktop's local Analysis Services instance via TOM/PowerShell
• tmdl skill -- edit TMDL files directly in a PBIP project (last resort)

DAX SVG Conventions

Measure Structure (VAR Pattern)

Every SVG measure must follow a strict VAR-based structure. Organize code into clearly separated regions:

SVG Measure =
-- CONFIG: Input fields and visual parameters
VAR _Actual = [Sales Amount]
VAR _Target = [Sales Target]
VAR _Scope = ALLSELECTED ( 'Product'[Category] )

-- CONFIG: Colors
VAR _BarColor = "#5B8DBE"
VAR _TargetColor = "#333333"

-- NORMALIZATION: Scale values to SVG coordinate space
VAR _AxisMax = CALCULATE( MAXX( _Scope, [Sales Amount] ), REMOVEFILTERS( 'Product'[Category] ) ) * 1.1
VAR _AxisRange = 100
VAR _ActualNormalized = DIVIDE( _Actual, _AxisMax ) * _AxisRange

-- SVG ELEMENTS: One VAR per visual element
VAR _SvgPrefix = "data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 25'>"
VAR _Sort = "<desc>" & FORMAT( _Actual, "000000000000" ) & "</desc>"
VAR _Bar = "<rect x='0' y='5' width='" & _ActualNormalized & "' height='15' fill='" & _BarColor & "'/>"
VAR _TargetLine = "<rect x='" & DIVIDE( _Target, _AxisMax ) * _AxisRange & "' y='2' width='2' height='21' fill='" & _TargetColor & "'/>"
VAR _SvgSuffix = "</svg>"

-- ASSEMBLY: Combine in rendering order (back to front)
VAR _SVG = _SvgPrefix & _Sort & _Bar & _TargetLine & _SvgSuffix

RETURN _SVG

Key conventions:

• CONFIG section first -- input measures, scope column, colors, font settings. Users change only this section.
• NORMALIZATION section -- scale raw values to SVG coordinate space (see below)
• SVG ELEMENTS -- one VAR per <rect>, <circle>, <text>, <line>, etc.
• ASSEMBLY -- concatenate elements in document order (first = back layer, last = front)
• <desc> sort trick -- embed FORMAT(_Actual, "000000000000") in a <desc> tag so the table/matrix can sort by the SVG column

Axis Normalization (Critical)

SVG coordinates must be normalized to a fixed range. Raw measure values (e.g., 1,234,567) cannot be used directly as pixel coordinates. The standard pattern:

-- 1. Define the SVG coordinate range
VAR _BarMin = 0       -- leftmost position (or offset for labels)
VAR _BarMax = 100     -- rightmost position

-- 2. Find the maximum value across all rows in the visual's filter context
VAR _Scope = ALLSELECTED( 'Table'[GroupColumn] )
VAR _MaxInScope = CALCULATE( MAXX( _Scope, [Measure] ), REMOVEFILTERS( 'Table'[GroupColumn] ) )
VAR _AxisMax = _MaxInScope * 1.1   -- 10% padding

-- 3. Normalize each value to the SVG range
VAR _AxisRange = _BarMax - _BarMin
VAR _Normalized = DIVIDE( _Actual, _AxisMax ) * _AxisRange

Use ALLSELECTED for the scope when the chart should respond to slicer context. Use ALL for a fixed axis across all filter contexts. The * 1.1 padding prevents bars from touching the edge.

HASONEVALUE Guard

Table/matrix SVG measures must guard against subtotal/total rows where multiple categories are in scope:

IF( HASONEVALUE( 'Table'[GroupColumn] ),
    -- SVG code here
)

Without this guard, the measure evaluates on grand total rows with meaningless aggregated values.

Escaping and Color Rules

• Single quotes for SVG attributes -- avoids DAX double-quote escaping: fill='#2196F3'
• Double quotes in DAX: escape as "" (DAX convention)
• viewBox for responsive scaling: viewBox='0 0 100 25'
• xmlns required on <svg> element
• Hex colors with # only -- e.g., fill='#2196F3'. %23 URL encoding causes errors in image visuals. Never use named colors.
• No JavaScript -- SVG must be purely declarative

SVG Coordinate System

• Y=0 is at the top -- invert values for charts: _Height - _Value
• Use viewBox with a 0-100 range for normalized coordinates
• Elements render in document order (first = back, last = front)

CONCATENATEX for Series Data

For sparklines and multi-point charts, build coordinate strings with CONCATENATEX:

VAR _Points = CONCATENATEX(
    _SparklineTable,
    [X] & "," & (100 - [Y]),
    " ",
    [Date], ASC
)
-- Produces: "0,80 10,60 20,40 30,20"
-- Use in: <polyline points='...'/>