Why does macOS prefer using PDF files for icons or UI elements?

2•damiaozi•8mo ago

Running `find /System/Library/ -name "*.pdf"` reveals that macOS uses many .pdf files as icons or UI elements. For example, the VPN connection animation in the menu bar seems to cycle through a sequence of .pdf files located at:

/System/Library/CoreServices/Menu Extras/VPN.menu/Contents/Resources/VPN[0-4].pdf

Why PDF, instead of more traditional formats like PNG or SVG? Is this due to Quartz/CoreGraphics rendering benefits, vector scaling efficiency, or something else?

Comments

neximo64•8mo ago

its a more efficient vector format than PNG or SVG.

runjake•8mo ago

This is the correct answer.

And to add to it: macOS (and its derivatives, such as iOS) descends from an operating system called OPENSTEP (formerly NeXTSTEP), which used Display Postscript for on-screen rendering.

Apple later replaced Display PostScript with a more modern reimplementation called Quartz 2D[1], which switched from Postscript to PDF.

Why not PNG? Because PNG is a bitmap format and Quartz 2D is designed to be resolution-independent.

Why not SVG? Probably because Quartz 2D relies heavily on the PDF specification throughout and it would be too much work to reimplement, and for what? PDF is still a common and well-regarded format.

1. https://en.wikipedia.org/wiki/Quartz_2D

How were the NIST ECDSA curve parameters generated? (2023)

AI, networks and Mechanical Turks (2025)

Goto Considered Awesome [video]

Show HN: I Built a Free AI LinkedIn Carousel Generator

Implementing Auto Tiling with Just 5 Tiles

Open Challange (Get all Universities involved

Apple Tried to Tamper Proof AirTag 2 Speakers – I Broke It [video]

Show HN: Vibe as a Code / VaaC – new approach to vibe coding

Show HN: More beautiful and usable Hacker News

Toledo Derailment Rescue [video]

War Department Cuts Ties with Harvard University

Show HN: LocalGPT – A local-first AI assistant in Rust with persistent memory

A Bid-Based NFT Advertising Grid

AI readability score for your documentation

NASA Study: Non-Biologic Processes Don't Explain Mars Organics

I inhaled traffic fumes to find out where air pollution goes in my body

X said it would give $1M to a user who had previously shared racist posts

155M US land parcel boundaries

Private Inference

Font Rendering from First Principles

Show HN: Seedance 2.0 AI video generator for creators and ecommerce

Wally: A fun, reliable voice assistant in the shape of a penguin

Rewriting Pycparser with the Help of an LLM

Lobsters Vibecoding Challenge

E-Commerce vs. Social Commerce

Avoiding Modern C++ – Anton Mikhailov [video]

Show HN: AegisMind–AI system with 12 brain regions modeled on human neuroscience

Zig – Package Management Workflow Enhancements

AI-powered text correction for macOS

AppSecMaster – Learn Application Security with hands on challenges