1627365 - Make WidgetEvent::mRefPoint floating-point to avoid rounding errors with synthesized events

Status: NEW

(Core :: Widget, task)

Description

[Botond Ballo [:botond]]

As of bug 1556556, WidgetEvent::mRefPoint is stored in visual coordinates, which can include an arbitrary floating-point resolution in the presence of pinch-zooming.

For synthesized events, particularly those generated by tests, the coordinates originate as layout coordinates (e.g. using getBoundingClientRect()) and are therefore round-tripped through visual coordinates before targeting elements inside zoomed content.

The fact that mRefPoint is an IntPoint means this round-tripping can introduce rounding errors. To avoid this, it would be nice to make mRefPoint store floating-point coordinates.