Microsoft Edge Ink input latency is reduced by 240%

In Microsoft Edge Dev and Canary builds, Microsoft has begun testing ink enhancements that the company claims reduced latency by 240%. This means that Edge users can now draw quickly and smoothly in the browser. To give the changes a try, you need the latest versions of Microsoft Edge Dev and Windows 11 Insider Preview.

Note: At the moment of this writing, the latest build of Edge Dev is 94.0.982.2, and the latest Windows 11 build is 22000.132.

Microsoft has done this significant improvement with creating a special top-level Ink API. In its blog, the company details how to get started using this API in existing web applications.

Microsoft cuts Edge inking latency by 240%

Green color shows how much the latency has improved compared to the old implementation.

Some technical details:

In Chromium-based browsers today, pen events are first sent to the browser process, which in turn forwards these events to a web application’s JavaScript event loop. The time delay between when the browser process receives these events and when they reach the application can sometimes be significant, depending on the rest of the main thread, resulting in the latency seen when inking.

To improve this, behind the scenes of the InkPresenter implementation on Windows 11, Microsoft Edge is using a new Windows API that will work directly with the operating system’s compositor to draw additional ink strokes outside of Microsoft Edge’s application loop. Thanks to this API, instead of waiting to deliver the event to the web application via JavaScript, we can take these points and provide them to the operating system compositor as soon as we receive them. The compositor can then connect the points with ink strokes and draw these strokes in the next frame that is to be presented to the screen, dramatically reducing latency.

It is important to note that Microsoft "returns" this change back to the Chromium project. This means that improvements to handwriting will come to other browsers that use Chromium.