Loom Paginated Report Editor — Fabric-parity spec

Comparative positioning note

This document is written from the perspective of Microsoft Azure, Cloud Scale Analytics, and CSA Loom. Any description of third-party or competing products, services, pricing, or capabilities is derived from publicly available documentation and sources believed accurate at the time of writing, and is provided for general comparison only. We do not claim expertise in, or authority over, any non-Microsoft product or service; the respective vendor's official documentation is the authoritative source for their offerings, which may change over time. Nothing here is intended to disparage any vendor — where a competing product has genuine advantages, we aim to note them honestly. Verify all third-party details against the vendor's current official documentation before making decisions.

Captured 2026-05-26 by catalog agent fabric-parity-loop. Source: Microsoft Learn — Power BI Report Builder (/power-bi/paginated-reports/paginated-reports-report-design-view, report-builder-power-bi, web-authoring/paginated-formatted-table, paginated-reports-edit-service) and Report Definition Language (/power-bi/paginated-reports/report-definition-language).

A Paginated Report is an RDL-based pixel-perfect report — an XML report definition (.rdl) authored in Power BI Report Builder (Windows desktop) or the paginated report web authoring experience (Power BI service, currently Preview, limited to formatted tables on a single semantic model). Paginated reports are designed for printable / multi-page / fixed-layout output (invoices, statements, regulatory PDFs), in contrast to interactive Power BI (.pbix) reports.

UI components

Ribbon (Report Builder desktop)

• File menu — New · Open · Save · Save As · Publish (to Power BI service workspace) · Account · Options · Enable/Disable preview features · Recent
• Home tab — Run (preview) · Paste · Cut/Copy · Font · Paragraph · Border · Number format (Default / Currency / Percent / Scientific / Custom) · Layout · Placeholder style toggle (Sample Values / Field Names)
• Insert tab — Table · Matrix · List · Chart · Gauge · Map · Data Bar · Sparkline · Indicator · Image · Text Box · Line · Rectangle · Subreport · Header · Footer · Page Break · Page Number
• View tab — Show/Hide group: Report Data · Properties · Grouping · Parameters · Ruler · Tooltips
• Run (preview mode) tab — Print · Print Layout · Page Setup · Export (PDF, Word, Excel, PowerPoint, CSV, XML, MHTML, TIFF, JSON) · First/Previous/Next/Last page · Refresh · Stop · Document Map · Parameters · Find

Report Data pane (left)

• Built-in Fields — ExecutionTime, ReportName, ReportFolder, OverallPageNumber, OverallTotalPages, PageNumber, TotalPages, UserID, Language
• Parameters — define typed parameters (Boolean / DateTime / Integer / Float / String); single-value or multi-value; available values list (static / query); default values
• Images — embedded image resources
• Data Sources — connection definitions to SQL Server, Azure SQL, Synapse, Power BI semantic models (XMLA), Power BI dataflows, OData, Oracle, Teradata, Snowflake (via Power Query), Databricks (via Power Query), files
• Datasets — query against a data source (T-SQL, DAX, MDX, M / Power Query Mashup); field list with data types

Report design surface (center)

• WYSIWYG canvas with page boundaries and margins drawn
• Header / Body / Footer bands (right-click → Add Page Header / Add Page Footer)
• Rulers (top + left)
• Drag-drop report items: Table / Matrix / List / Chart / Gauge / Map / Image / Text Box / Line / Rectangle / Subreport / Tablix
• Right-click context menus on body / header / footer / item → Properties dialog
• Snap-to-grid alignment

Properties pane (right)

• Categorized / Alphabetized property list for the selected item
• Sections: Action, Border, Fill, Font, General, Layout, Visibility, Misc
• Every value supports literal OR <Expression> (VB.NET expression editor with Fields!, Parameters!, Globals!, User!, custom code)
• Property Pages button → opens the full Properties dialog for the item

Grouping pane (bottom)

• Row groups + column groups for the active Tablix
• Drag fields to create groups; right-click → Group Properties (group on expression, sort, filters, page breaks)
• Adjacent vs nested grouping

Parameters pane (top, optional)

• Visual layout of report parameters as displayed at run time
• Drag to reposition; add/remove columns and rows
• Right-click parameter → Parameter Properties (visibility, data type, available values, default values, prompt label)

Tablix / Chart wizards

• Table wizard / Matrix wizard / Chart wizard / Map wizard — guided creation: choose dataset → drag fields to row/column/value buckets → pick layout → pick style → finish
• Map wizard supports SQL spatial, ESRI shapefile, Bing map tiles

Expression editor

• VB.NET-based expression language
• IntelliSense for Fields collection, Parameters, Globals, User, ReportItems
• Categories: Constants, Built-in Fields, Parameters, Fields, Datasets, Operators, Common Functions (Text, Date & Time, Math, Inspection, Program Flow, Aggregate, Financial, Conversion, Miscellaneous)
• Custom Code tab (Report Properties > Code) for embedded VB.NET helper functions; Reference tab for assembly references

Report Properties dialog

• Page Setup (size, margins, orientation, columns)
• Code (custom VB.NET)
• References (.NET assemblies)
• Variables (report-scoped variables)

Run / Preview mode

• Renders the report inline with the configured rendering extension
• Parameter prompts at top
• Document Map navigation (for grouped reports)
• Find / Find Next
• Page navigation toolbar
• Export to: PDF, Microsoft Word, Microsoft Excel, Microsoft PowerPoint, CSV, XML, Data Feed, MHTML / Web Archive, TIFF, JSON

Web authoring experience (Preview, Power BI service)

• Browser-based editor, available in any workspace (no capacity required)
• Limited to a single Power BI semantic model as the source
• Build pane — Format tab (style dropdown), Fields tab, Filters tab
• Editor ribbon — Insert tab (text box, image, header, footer), Format tab
• Inline column rename, resize, sort
• Save / Publish back to the same workspace
• "Edit in Power BI Report Builder" hand-off

What Loom has

• PaginatedReportEditor (apps/fiab-console/lib/editors/phase3-editors.tsx:1639) — wraps the shared ReportLikeEditor with kind="paginated", listPath="/api/items/paginated-report"
• Workspace picker, left tree of paginated reports, refresh button
• Right-side metadata card: name, reportType (defaults to PaginatedReport), datasetId, modified date/by, "Open in Power BI" link
• "Embed preview" placeholder card explicitly labeled v2.1: showing metadata only — full embed via Power BI Embed SDK lands in v2.2
• C-grade verdict — listing + metadata works, no design surface, no parameter pane, no run/preview, no RDL edit, no publish

Gaps for parity

1. No design surface — neither the Report Builder canvas nor the web-authoring canvas is present
2. No Report Data pane (Built-in Fields / Parameters / Images / Data Sources / Datasets)
3. No Properties pane for selected items
4. No Grouping pane
5. No Parameters pane for at-runtime parameter layout
6. No ribbon (Home / Insert / View / Run)
7. No RDL XML editor for direct edit-the-source workflow
8. No expression editor
9. No Run / Preview — cannot render the report
10. No export to PDF / Word / Excel / PowerPoint / CSV / XML / TIFF / JSON
11. No parameter prompt UI
12. No "Edit in Report Builder" hand-off (deep link to launch desktop Report Builder with the rdl pre-loaded)
13. No publish-back flow for an edited RDL
14. No web-authoring create-from-scratch flow

Backend mapping

• List paginated reports: GET /v1.0/myorg/groups/{groupId}/reports?$filter=reportType eq 'PaginatedReport' (Loom already calls this through /api/items/paginated-report)
• Get report: GET /v1.0/myorg/groups/{groupId}/reports/{reportId} — returns webUrl, embedUrl, datasetId, reportType
• Download RDL: GET /v1.0/myorg/groups/{groupId}/reports/{reportId}/Export → returns .rdl file bytes
• Upload / Update RDL: POST /v1.0/myorg/groups/{groupId}/imports?datasetDisplayName={name}.rdl&nameConflict=Overwrite with multipart body containing the rdl bytes
• Clone report: POST /v1.0/myorg/groups/{groupId}/reports/{reportId}/Clone
• Delete report: DELETE /v1.0/myorg/groups/{groupId}/reports/{reportId}
• Update data source bindings: POST /v1.0/myorg/groups/{groupId}/reports/{reportId}/Default.UpdateDatasources with updateDetails array
• Embed paginated report (for run/preview): generate embed token via POST /v1.0/myorg/groups/{groupId}/reports/{reportId}/GenerateToken, then render via powerbi-client SDK with type: 'report' + reportType: 'PaginatedReport' (the SDK supports paginated embed)
• Export to file (server-side render): POST /v1.0/myorg/groups/{groupId}/reports/{reportId}/ExportTo with {format: 'PDF' | 'WORD' | 'EXCEL' | 'PPTX' | 'CSV' | 'XML' | 'IMAGE' | 'MHTML'} → returns export id; poll GET .../exports/{exportId} until status Succeeded, then GET .../exports/{exportId}/file for the binary
• "Edit in Report Builder" deep link: pbirsrb://... URI scheme; web-authoring URL is https://app.powerbi.com/groups/{groupId}/rdlreports/{reportId}/edit
• RDL schema is XML validated against the Microsoft RDL XSD — Loom can generate / mutate RDL using any XML library; the schema is documented on Microsoft Learn

Required Azure resources / tenant settings

• Power BI Pro license OR Premium-Per-User OR a workspace on a Power BI Premium / Fabric capacity for non-My-Workspace publishing
• Tenant setting Paginated reports = enabled
• Tenant setting Service principals can use Power BI APIs = enabled
• Tenant setting Export reports as PDF / Word / Excel / PowerPoint / CSV / XML / Image = enabled (individual toggles)
• Workspace role: Contributor or higher to publish; Build permission on the source semantic model
• For data-gateway-bound sources (on-prem SQL, file shares): an On-premises data gateway registered and bound to the data source
• For Snowflake / Databricks / Oracle via Power Query: the VNet data gateway (for cloud sources behind a VNet) or the on-prem gateway

Estimated effort

4-5 sessions.

• Phase 1 (1 session) — Embed the rendered paginated report via powerbi-client SDK + GenerateToken (read-only Run/Preview parity). Replace the metadata placeholder card.
• Phase 2 (1 session) — Wire ExportTo for PDF / Word / Excel / PowerPoint exports; surface as ribbon actions; show export-job progress.
• Phase 3 (1-2 sessions) — Build a parameter prompt panel by reading parameter definitions from the rdl XML (<ReportParameters>); pass values into embed config.
• Phase 4 (1 session) — "Edit in Report Builder" deep-link + an "Edit in Web Authoring" iframe redirect to app.powerbi.com/.../rdlreports/{id}/edit. Document that Loom does not attempt to reimplement Report Builder's design surface.
• Phase 5 (optional) — Direct RDL XML editor with Monaco + schema validation against the RDL XSD for power users.

Notes

• Loom will not reimplement Report Builder — the desktop tool is a large WPF application with no realistic web port; even Microsoft's web authoring is limited to single-table formatted tables on a single semantic model
• The realistic Loom parity story is: list + embed-preview + parameter prompts + ExportTo + deep-link to Report Builder for edit, plus an optional Monaco-based RDL XML editor for advanced users
• The web-authoring experience is currently Preview with a narrow scope (single semantic model, single formatted table) — Loom should embed it where available rather than replicate