Re: Scrolling two elements in parallel

Is scroll customization necessary here at all?  I thought this was just a
"scroll response" effect, so all you need is compositor worker.  As such
the use case is already listed here
<https://github.com/w3c/css-houdini-drafts/blob/master/composited-scrolling-and-animation/UseCases.md#linked-scrollers>
.

On Mon, Mar 7, 2016 at 8:07 AM, Timothy Dresser <tdresser@chromium.org>
wrote:

> Scroll customization
> <https://docs.google.com/document/d/1VnvAqeWFG9JFZfgG5evBqrLGDZYRE5w6G5jEDORekPY/edit?pli=1#heading=h.kd0gtwwz5bf9> on
> compositor worker would solve this problem cleanly, though it's still quite
> speculative.
>
> Feel free to submit a pull request here
> <https://github.com/RByers/css-houdini-drafts/blob/master/css-scroll-api/UseCases.md> adding
> this use case.
>
> Tim
>
>
> On Mon, Mar 7, 2016 at 3:31 AM Dmitry Sagalovskiy <dmitry@getgrist.com>
> wrote:
>
>> I am responding to the call for input here:
>> https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Scroll-linked_effects
>> .
>>
>> One effect that I am interested in is to synchronize the scrolling of two
>> elements. (An example is the "frozen columns" feature of spreadsheets,
>> where two panes are in separate side-by-side containers but should scroll
>> in parallel.)
>>
>> The straightforward way of listening to 'scroll' event on each container,
>> and updating scrollTop of the other is somewhat janky with synchronous
>> scrolling, and visibly out-of-sync with asynchronous scrolling.
>>
>> From reading that page and scanning some of the linked pages, I didn't
>> find any recommendations for how to achieve a smooth parallel scroll
>> effect. (Perhaps "Compositor worker"?) Is there anything that can be used
>> to achieve this today?
>>
>> Dmitry
>>
>