I’m extremely pleased to announce the release of Scroll-Driven Animations Debugger, a DevTools extension to visualize and debug Scroll-Driven Animations.
The extension adds a new pane named “Scroll-Driven Animations” to Chrome DevTools’s Elements Panel. To use it, inspect an Element as you’d normally do and select the “Scroll-Driven Animations” pane. When selected, you’ll see a visualization of the Scroll-Driven Animations that are added to the inspected element. The visualization is a live representation of the scroller, animated element, and – in case of a ViewTimeline – tracked subject: as you scroll in the document, the visualization also updates.
Use the top toolbar to switch between multiple animations (if more than one) or to set the visualization’s scale factor. Typically you don’t need to set the scale factor, as the visualization automatically adapts itself to the available space. Also included in the top toolbar are an indicator telling you which type of scroll timeline you are dealing with, and some progress numbers: total scroll progress, effect progress, actual scroll offset (in pixels).
Use the “Edit Values” toggle at the bottom to bring up a range editor. Once the editor is shown, the visualization also shows indicators for the start and end range. In case of a ScrollTimeline these are two lines on the scroller’s contents. In case of a ViewTimeline these are two boxes representing the areas for the set animation-range-* values. Change the values using the dropdown and/or the inputs. Note that the inputs do not live-update (for now); after changing click somewhere outside the field to update the value.