svg-visuals

# SVG Visuals via DAX Measures (PBIR)

> **Report modification requires tooling.** Two paths exist:
> 1. **`pbir` CLI (preferred)** -- use the `pbir` command and the `pbir-cli` skill. Install with `uv tool install pbir-cli` or `pip install pbir-cli`. Check availability with `pbir --version`.
> 2. **Direct JSON modification** -- if `pbir` is not available, use the `pbir-format` skill (pbip plugin) for PBIR JSON structure and patterns. Validate every change with `jq empty <file.json>`.
>
> If neither the `pbir-cli` skill nor the `pbir-format` skill is loaded, ask the user to install the appropriate plugin before proceeding with report modifications.

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`): `callout.imageFX` -- `references/svg-card-slicer.md`
- Slicer/New (`advancedSlicerVisual`): header images -- `references/svg-card-slicer.md`

## 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).

```python
# 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:

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

For **image visuals**, set `sourceType='imageData'` with `sourceField` in the visual.json (see `references/svg-image-visual.md`).

### Step 3: Validate

Validate JSON syntax with `jq empty <reportExtensions.json>` and inspect the file to confirm measure definitions and data categories.

## 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:

```dax
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 = "<