[Qt] Improve the tap gesture recognizer

• Component: WebKit2
• Status: RESOLVED FIXED

[Kenneth Rohde Christiansen]

The current code is messy and it emits single taps in cases where it shouldn't

[Kenneth Rohde Christiansen]

Created attachment 135547 [details]
Patch

[Simon Hausmann]

Comment on attachment 135547 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=135547&action=review

r=me

We really need unit tests for this state machine though :(

> Source/WebKit2/UIProcess/qt/QtTapGestureRecognizer.cpp:71
> +            if (!withinDistance(touchPoint, maxDoubleTapDistance)) {
> +                reset(); // Received a new tap, that is unrelated to the previous one. Ignore previous.
>                  m_tapState = SingleTapStarted;
> -            }
> -        } else
> -            m_tapState = SingleTapStarted;
> -        m_touchBeginEventForTap = adoptPtr(new QTouchEvent(*event));
> +            } else
> +                m_tapState = DoubleTapCandidate;

I kind of like logic the "positive" way, i.e.

if (withinDistance(touchPoint, ...)
    m_tapState = DoubleTapCandidate;
} else {
    reset();
    m_tapState = SingleTapStarted;
}

But that's also a kind of nitpick which you can freely ignore if you want :)

[Kenneth Rohde Christiansen]

Landed in 113165