R Visuals

R Visuals in Power BI (PBIR)

Use pbir for every report mutation. Read PBIR metadata only for diagnosis. If pbir is unavailable or lacks an operation, stop and report the gap; never edit report JSON directly.

R visuals execute R scripts (primarily ggplot2) to render static PNG images on the Power BI canvas. ggplot2 is the preferred library -- its grammar of graphics approach produces clean, publication-quality statistical visualizations with less code. R is particularly strong for statistical visualizations.

Visual Identity

• visualType: scriptVisual
• Data role: Values (columns and measures, multiple allowed)
• Data variable: dataset (data.frame, auto-injected)
• Row limit: 150,000 rows
• Output: Static PNG at 72 DPI -- no interactivity

Workflow: Creating an R Visual

Step 1: Add the Visual

pbir add visual scriptVisual "Report.Report/Page.Page" --name RevenueByDateR \
  --data "Values:Sales.Date" --data "Values:Sales.Revenue"

Step 2: Write the Script

library(ggplot2)

p <- ggplot(dataset, aes(x=Date, y=Sales)) +
  geom_col(fill="#5B8DBE") +
  theme_minimal(base_size=12) +
  theme(panel.grid.major.x=element_blank())

print(p)  # MANDATORY for ggplot2

Critical rules:

• print(p) is mandatory for ggplot2 objects -- they do not auto-display in Power BI
• dataset is auto-injected as a data.frame; do not create it
• Access columns by index (dataset[,1]) to avoid name escaping issues
• Use backticks for column names with spaces: dataset$`Order Lines`

Step 2b: Review

Before presenting the script to the user, dispatch the r-reviewer agent to validate correctness and provide design feedback.

Step 3: Inject the Script

pbir visuals r "Report.Report/Page.Page/RevenueByDateR.Visual" --script-file chart.r

The CLI handles PBIR string escaping.

Step 4: Validate

pbir visuals bind "Report.Report/Page.Page/RevenueByDateR.Visual" --show
pbir validate "Report.Report" --all

PBIR Format

For read-only diagnosis, scripts are stored in visual.objects.script[0].properties:

{
  "source": {"expr": {"Literal": {"Value": "'library(ggplot2)\\n...\\nprint(p)'"}}},
  "provider": {"expr": {"Literal": {"Value": "'R'"}}}
}

Identical structure to Python visuals except visualType is scriptVisual and provider is 'R'.

Supported Packages

Power BI Service (R 4.3.3)

~1000 CRAN packages available. Not supported: packages requiring networking (RgoogleMaps, mailR).

Full package list: https://learn.microsoft.com/power-bi/connect-data/service-r-packages-support

Desktop

Any locally installed R package works without restriction. R must be installed separately.

Best Practices

1. Always call print(p) -- ggplot2 objects require explicit printing
2. Guard against empty data -- if (nrow(dataset) == 0) { plot.new(); text(0.5, 0.5, "No data") }
3. Use index-based column access -- dataset[,1] avoids name escaping issues
4. Use theme_minimal() -- clean aesthetic that works well with Power BI
5. Factor categorical variables -- control sort order explicitly with factor()
6. Use hex colors matching the report theme
7. Set margins -- plot.margin=margin(t, r, b, l) to prevent clipping
8. Keep scripts concise -- 5-min timeout Desktop, 1-min Service

Limitations

Script Structure Template

library(ggplot2)

# 1. Guard against empty data
if (nrow(dataset) == 0) {
  plot.new()
  text(0.5, 0.5, "No data available", cex=1.5)
} else {
  # 2. Data preparation (index-based access)
  df <- data.frame(
    category = dataset[,1],
    value = dataset[,2]
  )

  # 3. Create visualization
  p <- ggplot(df, aes(x=reorder(category, -value), y=value)) +
    geom_col(fill="#5B8DBE", width=0.7) +
    theme_minimal(base_size=12) +
    theme(
      panel.grid.major.x = element_blank(),
      axis.title = element_blank()
    )

  # 4. Render
  print(p)
}

R vs Python Syntax Reference

For the language-choice decision, see the "When to Use a Script Visual" section above. This table covers only mechanical syntax differences for scripts already committed to R:

When to Use a Script Visual

Reach for an R visual only when all of the following hold:

• The chart has no native equivalent and no reasonable Deneb spec
• The value is in a statistical computation that must run at render time (model fit, kernel density, forecast band), not just a shape Vega could draw
• The visual does not need to be a cross-filter source, hover tooltips, publish-to-web, or app-owns-data embed
• The report is served in a Pro/PPU or higher capacity with a Fabric-enabled region

If interactivity or cross-filtering matters, use Deneb (a static PNG cannot be a selection source). If the need is a small inline mark (sparkline, bar, status pill), use an SVG measure (no row cap, no timeout, no licensing/region gate, renders under publish-to-web). The script visual's niche is narrow: compute-at-render statistical plots for internal or org consumption.

R vs Python once a script visual is the right call: use R for publication-quality statistical defaults and packages with no Python peer (forecast, corrplot, pheatmap, ridgeline/violin). Use Python when the computation leans on scikit-learn, statsmodels, or scipy, or when surrounding report logic is already Python. Where equal, default to whichever language the report's other scripts use; mixing doubles the publish-time package surface to validate.

Do not default to a script visual because a chart type "looks statistical." A box plot, lollipop, or dumbbell is an SVG-measure or Deneb job; reserve scripts for charts that genuinely compute.

References

• references/data-model.md -- dataset grouping mechanic, row/byte caps, forcing per-row input, and R-specific traps (Time type, text rendering flags, CJK fonts)
• references/community-examples.md -- R Graph Gallery examples organized by chart type (distribution, correlation, ranking, evolution, flow)
• references/ggplot2-patterns.md -- Common ggplot2 chart patterns (bar, donut, line, heatmap, bullet)
• examples/script/ -- Standalone R scripts (bar-chart, trend-line) -- ready to inject into visual.json after escaping
• examples/visual/bullet-chart.json -- PBIR visual.json: bullet chart with conditional coloring, error handling, and extensive escaping
• examples/visual/bar-chart.json -- PBIR visual.json: horizontal bar with PY comparison lines and colored account labels
• examples/visual/trend-line.json -- PBIR visual.json: area chart with ribbon plot and month factor handling

Fetching Docs

To retrieve current R visual / package support docs, use microsoft_docs_search + microsoft_docs_fetch (MCP) if available, otherwise mslearn search + mslearn fetch (CLI). Search based on the user's request and run multiple searches as needed to ensure sufficient context before proceeding.

Related Skills

• pbi-report-design -- Layout and design best practices
• python-visuals -- Python Script visuals (same concept, different language)
• deneb-visuals -- Vega/Vega-Lite visuals (interactive, vector-based alternative)
• svg-visuals -- SVG via DAX measures (lightweight inline graphics)
• pbir-format (pbip plugin) -- PBIR JSON format reference

Source: data-goblin/power-bi-agentic-development → plugins/custom-visuals/skills/r-visuals/SKILL.md