Pointer Events

vs.

Touch Events

in Blink

Rick Byers - Nov 4, 2014

Problems

Why introduce pointer events?

Problems

• Developers want to be able to use the same code for multiple input devices.

Demo

Code sharing

Problems

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if ('ontouchstart' in window)

element.addEventListener('touchstart', activate);

else

element.addEventListener('mousedown', activate);

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• Assumptions that touch event support is mobile only

Problems

• Interoperability issues��

examples

Problems

• Scrolling always blocks on touchstart

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demo

Pointer Events?

Are they a good fit for blink priorities?

Blink Priorities

• Mobile first

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Interoperability with Safari is critical

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Touch events are the best hope for a single API

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Easily adapting mouse code is no longer our goal

Blink Priorities

• Apps as rich as on Android/iOS

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Performance

Richness

Rationality

Blink Priorities

• Performance

Minor in practice - disadvantage in principle

2.5% frame hit-test penalty

Risk of double event dispatch

Evolving

Touch Events

Another way to address the problems

Evolving Touch Events

• Improve interoperability on mobile

Converging behavior while scrolling

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Details in Chrome, Safari, IE

Evolving Touch Events

• Fix device confusion issues

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Evangelism

Interaction media queries

Event de-duplication

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Evolving Touch Events

• Enable touch event API all the time�

Evolving Touch Events

• Non-blocking scroll opt-in

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touch-action

+

scroll-delay

Evolving Touch Events

• Improve mouse/stylus support on Android

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TouchEvent.pointerType

TouchEvent.buttons

touchhover

Element.setTouchCapture

...

Evolving Touch Events

• Universal touch events opt-in?

Debate

What should we be doing differently?