What is MIME type "application/x-font-printer-metric"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

The MIME type application/x-font-printer-metric indicates a file that holds printer font metric data. It defines numeric details like character spacing, dimensions, and baseline information. This data is crucial for ensuring that text prints with proper alignment and spacing.

Files using this MIME type, such as PFM files, are typically used in environments where accurate font rendering in print output is needed. They often work alongside other font files to complete the visual presentation of printed text.

Main Use Case: Provides font metrics that printers use to lay out text precisely.
Additional Use Cases:
- Support for desktop publishing software.
- Assisting legacy Windows systems with traditional font technologies.
- Improving compatibility with font rendering engines.

For further reading on printer font metrics, check out Wikipedia: Font Metrics.

Associated file extensions

.pfm

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-font-printer-metric

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-font-printer-metric">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/x-font-printer-metric');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.pfm

FAQs

What is the application/x-font-printer-metric MIME type used for?

This MIME type identifies PFM (Printer Font Metrics) files, which are binary files containing spacing and kerning data for PostScript Type 1 fonts. Unlike standard font files that hold character shapes, files served as application/x-font-printer-metric only provide the measurements required to align text correctly during printing.

Can I use files with this MIME type as web fonts?

No, modern web browsers do not support PFM files for displaying text on websites. To use a font on the web, you should convert the source font to WOFF or WOFF2 formats and use standard types like font/woff2 instead of application/x-font-printer-metric.

How do I configure Apache to serve PFM files correctly?

You can enable support for this file type by adding the following line to your .htaccess file or main configuration: AddType application/x-font-printer-metric .pfm. This ensures that when a user or application downloads the file, the server declares it as printer metric data rather than a generic binary stream.

Why does a font need a separate PFM file?

In the legacy PostScript Type 1 architecture, the font data is split into two files: a PFB (Printer Font Binary) for the glyph shapes and a PFM for the metrics. The file associated with application/x-font-printer-metric is essential because without it, the operating system does not know how much space to leave between characters.

How do I add this MIME type to an Nginx server?

To configure Nginx, open your mime.types file or specific server block and insert the mapping inside the types block. Use the syntax: application/x-font-printer-metric pfm; to link the extension to the content type.

Is application/x-font-printer-metric an official IANA standard?

No, the x- prefix indicates that this is a non-standard or private MIME type. While it is widely recognized by legacy software and font managers for handling PFM files, it is not part of the modern standard registry.

What happens if this MIME type is missing on my server?

If a server is not configured for application/x-font-printer-metric, it may serve PFM files as application/octet-stream. While browsers will simply download the file, specific font management software or automated scripts relying on the Content-Type header might fail to process the file correctly.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.