Bug 201770 – PointerEvent.buttons incorrect on touch move

• Component: UI Events
• Status: RESOLVED DUPLICATE

Created attachment 378752 [details]
Small example reproducing the issue

In the iOS13 iPhone simulator at least, the value of the 'buttons' property of a pointermove event generated by a moving touch is 0, but according to the W3C spec it should be 1. It appears to be 1 in Chrome (android simulator and on desktop in touch simulation mode). 

Example attached. 

This discrepancy leads to a project bug in the simulator that matches a bug on an iPad running 13.1. (I'll confirm its the same issue once I get a chance to plug the device in.)

In iPad OS 13.1 on a 2018 iPad pointermove.buttons also reads as 0 when caused by a touch. 

Also in the iOS13 iPhone simulator, pointermove events are dispatched continuously even if the mouse isn't moving. This is not the case in 13.1 on the iPad.

[Radar WebKit Bug Importer]

<rdar://problem/55394548>

[Antoine Quint]

This *should* work but clearly doesn't.

static unsigned short buttonsForType(const AtomString& type)
{
    // We have contact with the touch surface for most events except when we've released the touch or canceled it.
    return (type == eventNames().pointerupEvent || type == eventNames().pointeroutEvent || type == eventNames().pointerleaveEvent || type == eventNames().pointercancelEvent) ? 0 : 1;
}

This should return 1 for pointermove.

[Antoine Quint]

This actually works on ToT, this is a dupe of https://bugs.webkit.org/show_bug.cgi?id=199910. However, this landed too late to make it into iOS 13. It will be picked up for an upcoming software update, but I can't comment as to when.

*** This bug has been marked as a duplicate of bug 199910 ***