--- breadcrumbs: - - /teams - Teams - - /teams/animations - Animations Team - - /teams/animations/highlights-archive - Highlights Archive page_name: september-2020---code-heath-animation-timelines-smoothness-metrics-animation-event-handlers-and-more title: September 2020 - Code Heath, Animation Timelines, Smoothness Metrics, Animation event handlers and more! ---

September 2020 | Chrome Interactions Highlights | Archives: go/interactions-team-highlights

| Code health |  |  |  | kevers@ presented a graph to show the progress of bug fixing. |  | In this sprint we closed a lot of bugs, but more were opened than closed. |  | We now have breakdowns by priority. Nice to see that we did not lose ground on P0s or P1s. |  | xidachen@ removed the usage of setTimeout in animations layout test, and replaced them with rAF. |  | setTimeout can easily cause flakiness, especially on debug bots. |  | Animations are driven by animation frames, using rAF leads to more robust tests. |  |  |  | Mutable timelines |  | kevers@ has been working on scroll timelines and the above demo showcases mutable timelines, which are required for supporting css animation-timeline. |  | The demo illustrates updating the animation timeline via the web-animation API. |  | Presently it is behind the scroll-timeline feature flag. |  | kevers@ showed another fun demo for scroll timelines, which uses scroll position to drive a paint worklet animation.. |  |  |
| Smoothness metrics |  |  |  | xidachen@ improved fps meter by making it account for page loading. |  | The fps meter will reset itself at first contentful paint (which is regarded as loading completed). |  | The stats before first contentful paint will be discarded when we report to UMA. |  | Animation event handlers |  | gtsteel@ landed the implementation for ontrasition\* event handler properties. Along with that, gtsteel@ also fixed animationcancel event so that it doesn’t fire after animationend. |  | Zooming no longer breaks transitions |  | gtsteel@ fixed a bug where zooming would cause transition event listeners to fire. |  | Previously, we compared zoomed values when starting transitions, then transitionend based on computed value. |  | Now we calculate and compare computed values (as per spec) if zoom changed. |  |
| Web tests ⇒ WPT |  | liviutinta@ shared a sheet that lists input related layout tests that we would like to move to wpt/. The spreadsheet also tracks the progress. |  | WebDriver Actions API Spec |  | lanwei@ has landed spec change that adds wheel input to the webdriver action API. |  |

Chrome Interactions Highlights | September 2020 | go/interactions-team