Andrew Pangborn
Principal Software Engineer — Color, HDR & UI Compositing at Apple Inc.
16 years of experience developing and supporting features on 2+ billion active devices — specializing in color, HDR, and display pipeline design from SoC integration through the display compositor and developer UI frameworks. I'm passionate about bringing hardware and software together to build delightful user experiences at scale.
Experience
Apple Inc.
Cupertino, CA
CoreAnimation · Senior / Principal Software Engineer
2014 – Present
- Brought ICC color management to iOS, enabling wide gamut (P3) displays and laying the foundation for HDR and professional color features. Leveraged specialized hardware to achieve minimal performance impact on existing sRGB content. Deployed to all active iPhone & iPad users.
- End-to-end HDR support across iOS, macOS, and tvOS: designed & implemented the HDR compositing architecture (Extended Dynamic Range). HDR photo rendering, video playback for DolbyVision, HDR10(+), and HLG. GPU and specialized SoC acceleration of display mapping for OLED, LCD, miniLED, and external TVs.
- HDR UI effects in Liquid Glass and Icons.
- Specialized color management via 'Reference Mode' on iPad Pro to enable review-and-approve workflows used by many Hollywood Studios.
- Reference presets on Pro Display XDR, MacBook Pro XDR, and Studio XDR Displays — used by professional video editors, photographers, and graphics creatives. Detailed precision, pipeline analysis, and debugging to ensure presets meet industry standards.
- Led color & HDR issue triage for 6+ years; recently built AI agent tooling to automate GPU and SoC color pipeline analysis, and domain-specific code review — applying LLMs to specialized systems debugging at scale.
- Transitioned the macOS window server and compositing engine to Apple Silicon, supporting all Macs shipped since 2020.
- Lossless compression throughout compositor and media playback to reduce DRAM traffic by ~50% and provide significant power savings (additional 4 hours of video playback, 1 hour Safari browsing).
- Integrated SoC features from Display, GPU, Camera, Video, and Sensor hardware teams into compositor across 12 years of iPhone, iPad, Apple TV, and Apple Watch products and 6 years of Apple Silicon Macs.
- Content-aware brightness control on iPhone enables seamless transitions for HDR content viewing on OLED and miniLED displays with minimal power impact. Required tight sensor, UI rendering, display hardware, and display calibration integration.
- External display support on iPad and iPhone, including AppleLog output to enable "Shot on iPhone" production for Apple Keynotes and Hollywood movies such as "28 Years Later".
ImageIO & CoreGraphics · Software Engineer
2010 – 2014
- Accelerated JPEG decoding by integrating a dedicated SoC hardware decoder.
- Performance optimization and bug fixes on the GPU-accelerated CoreGraphics rendering stack powering WebKit.
- Text rendering improvements for languages like Hindi with overlapping glyphs.
- Security hardening, new APIs, and full support for XMP, EXIF, and IPTC image metadata.
- Maintenance and integration of open source image codecs: libPNG, libTIFF, libGIF.
- Added JPEG2000 image format support.
Patents
Content Dependent Brightness Management System
US 12,230,191
Dual-control brightness management integrating fast intra-frame and slow multi-frame luminance adjustments to achieve higher display brightness while managing power consumption.
Graphics Engine and Environment for Efficient Real Time Rendering of Graphics that are Not Pre-Known
US 9,679,346
On-the-fly reordering of GPU rendering commands into optimized buffers for real-time display of unpredictable graphics content.