---
title: Extensions
summary: API reference for Extensions.
status: draft
owner: SAIF Doc Gen
last_reviewed: 2026-09-17
library: PdfAPI.Core
reference_type: package
---

# Extensions

`Extensions` is a static class defined in `PdfFormat.cs` offering a single display-formatting extension method for `PdfFormat`. Its name is very generic for a public extension class shipped from a package, since it gives no indication of what it extends.*

## Purpose
- Renders a `PdfFormat` value as its display string (`"pdf"` or `"pdf/a"`) for use in user-facing or logged output.

## Context
- Namespace: `PdfAPI.Core`
- Assembly/package: `PdfAPI.Core`

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| ToDisplay(PdfFormat) | `static string ToDisplay(this PdfFormat format)` | Converts `PdfFormat.Pdf` to `"pdf"` and `PdfFormat.PdfA` to `"pdf/a"`. |

## Behavioral notes
- Being a public, generically-named static class, `Extensions` could collide with an identically-named extension class from another referenced library if both are imported in the same file.*

## Constraints and usage notes
- Import the `PdfAPI.Core` namespace to bring `ToDisplay` into scope as an extension method on `PdfFormat`.

> **Note:** Statements marked with `*` were inferred from code structure, naming
> conventions, or contextual evidence where direct confirmation was not available
> in source artifacts.

## Related documentation
- [Index](../../index.md)
- [Overview](../../overview.md)
- [Architecture](../../architecture.md)
- [Dependencies](../../dependencies.md)
- [Operations and processes](../../operations-processes.md)
- [Business rules](../../business-rules.md)
- [Security and authorization](../../security-authorization.md)
- [API reference](../index.md)

## Sources
- `PdfAPI.Core\PdfFormat.cs`