Jot - A Cross-Platform Drawing and Annotation App
By
John Phung

Jot is an innovative drawing and annotation application developed for both macOS and Windows, designed by Espresso to boost productivity and creativity for users of their portable touchscreens. As a software engineer on this project, I contributed significantly to its development, utilising my expertise in cross-platform engineering to deliver a high-performance, user-friendly tool that integrates seamlessly with Espresso's hardware ecosystem.
You can find this app on the Mac App Store and Windows Store.
Tech Stack
Jot was built using a robust set of technologies to ensure top performance and a native experience on each platform:
- macOS Development:
- Swift and SwiftUI: Utilized to create a modern, responsive user interface that adheres to macOS design standards and supports touch interactions.
- CoreGraphics: Employed for precise drawing and annotation, leveraging Appleâs native graphics framework for smooth and accurate pen input handling.
- Windows Development:
- C# and WinUI: Used to develop a polished, high-performance interface that integrates deeply with the Windows ecosystem, providing a native look and feel.
- Open-Source Drawing API: Implemented alongside WinUI to enable high-quality graphics rendering and annotation features, likely utilizing DirectX for optimised performance.
- Cross-Platform Features:
- Custom Inter-Application Communication: Developed modules to facilitate seamless interaction with other applications, enabling screenshot annotation and content sharing across workflows.
This tech stack showcases my proficiency in both macOS and Windows development, highlighting my versatility and technical depth.
Challenges
Developing Jot required overcoming several technical obstacles with creative solutions:
- Cross-Platform Consistency:
- I ensured a uniform user experience across macOS and Windows by designing shared core logic and adapting it to platform-specific toolsâSwiftUI for macOS and WinUI with C# for Windowsâwhile respecting each operating systemâs distinct design and input conventions.
- Precise Input Handling:
- Capturing detailed pen inputs, such as pressure and tilt, demanded accuracy. For macOS, I used CoreGraphics to optimize drawing precision. On Windows, I integrated the open-source drawing API within the WinUI framework, using C# to tailor it to the platformâs strengths.
- Performance Optimisation:
- Jot needed to run efficiently across diverse hardware, from desktops to portable devices. I optimised the drawing enginesâCoreGraphics for macOS and the open-source API with WinUI for Windowsâto balance functionality with minimal resource usage, delivering a seamless experience.
- Inter-Application Integration:
- A standout feature of Jot is its ability to annotate screenshots and share them across apps. For Windows, I implemented a custom clipboard system and overlay rendering using C# and WinUI, addressing the complexities of cross-program data transfer.
These challenges highlight my ability to solve intricate technical problems and deliver a refined, efficient product.
Motivation
Jot was created to offer a powerful, intuitive tool that enables users to capture ideas, provide visual feedback, and collaborate effortlessly, maximizing the value of Espressoâs portable touchscreens. Distributed for free, Jot enhances the appeal of Espressoâs hardware, fostering user loyalty and driving adoption. My efforts focused on streamlining workflows and igniting creativity, aligning with Espressoâs mission to advance workplace productivity and innovation.
Key Contributions
My contributions to Jot underscore my technical skills and problem-solving prowess:
- Cross-Platform Drawing Engine:
- I designed and implemented the drawing engine using CoreGraphics for macOS and an open-source API within the WinUI framework for Windows, coded in C#, ensuring consistent, responsive performance across platforms.
- âMagic Jotâ Feature:
- I spearheaded this feature, enabling users to draw over any screen content and transfer annotations between apps. On Windows, I leveraged C# and WinUI to achieve seamless functionality, mirroring the capability I built with SwiftUI on macOS.
- Hardware Performance Optimisation:
- I optimised graphics rendering for both CoreGraphics and the open-source API with WinUI, ensuring Jot performed efficiently across a range of devices, enhancing user satisfaction.
Jot exemplifies my ability to deliver impactful software solutions. By combining technical expertise with a user-centric focus, I helped create a tool that empowers creative professionals and showcases Espressoâs innovation at the intersection of software and hardware. This project reflects my readiness to contribute to cutting-edge initiatives and stand out to recruiters with my skills and dedication.