# Effect Maker

Published articles for Effect Maker.

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## Canvas2D: WatchUI Demo

DevFeed: [Canvas2D: WatchUI Demo](<https://devfeed.tech/articles/canvas2d-watchui-demo-58802.md>)

Original publisher: [Read original article](<https://www.qt.io/blog/canvas2d-watchui-demo>)

Author: kaj.gronholm@qtcompany.onmicrosoft.com (Kaj Grönholm)

Published: 2026-09-23T10:31:29Z

Content type: article

Language: en

Sources: [Qt](<https://devfeed.tech/sources/qt-blog.md>)

Topics: [Qt](<https://devfeed.tech/topics/qt.md>), [Canvas](<https://devfeed.tech/topics/canvas.md>), [JavaScript](<https://devfeed.tech/topics/javascript.md>), [GPU](<https://devfeed.tech/topics/gpu.md>), [3D](<https://devfeed.tech/topics/3d.md>), [shaders](<https://devfeed.tech/topics/shaders.md>)

Tags: [c-plus-plus](<https://devfeed.tech/tags/c-plus-plus.md>), [canvas](<https://devfeed.tech/tags/canvas.md>), [canvas-painter](<https://devfeed.tech/tags/canvas-painter.md>), [canvas2d](<https://devfeed.tech/tags/canvas2d.md>), [dev-loop](<https://devfeed.tech/tags/dev-loop.md>), [effect-maker](<https://devfeed.tech/tags/effect-maker.md>), [gpu](<https://devfeed.tech/tags/gpu.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [prototyping](<https://devfeed.tech/tags/prototyping.md>), [qml](<https://devfeed.tech/tags/qml.md>), [qt](<https://devfeed.tech/tags/qt.md>), [qt-quick](<https://devfeed.tech/tags/qt-quick.md>)

### AI overview

This article presents WatchUI, a smartwatch demo built with Qt Canvas2D, Qt Quick Effect Maker, QML, JavaScript, and shaders. It explains how Canvas2D handles geometry and shader effects handle per-pixel visuals, enabling high-performance interfaces without custom C++ code and supporting rapid hot-reload iteration.

### Source excerpt

In the previous blog post I introduced Canvas2D, the new QML item in Qt 6.12 that lets you paint with JavaScript using the GPU through Qt Canvas Painter. That post was about the API: what it is, how it compares to Qt Quick Canvas and to the QCanvasPainter C++ API, and how fast it is. But that post might have left someone wondering what a real UI built with it could actually look like. So, while testing Canvas2D (and QQEM) in preparation for the Qt 6.12.0 release, I spent a few days building a demo application to give some ideas. WatchUI is a smartwatch demo with six swipeable views, running on a 3D watch model. This is based on the smartwatch demo that was built a while back for the Qt 6.5 release. But the content of the watch screen has been reimplemented using not just QQEM effects but also Canvas2D. The demo looks like this: