Scroll multiplier doesn't work with float numbers and looks laggy

[Kendzi-x]

Describe the bug
Scrolling config doesn't work with float numbers and looks laggy with a mouse wheel or trackpad (even with multiplier: 1 it's not smooth).

Code
For example we can check: https://github.com/neuronetio/gantt-schedule-timeline-calendar/blob/master/examples/complex-1/index.js with this scroll config:

scroll: {
  vertical: { precise: true, multiplier: 0.5 },
  horizontal: { precise: true, multiplier: 0.5 }
},

Scrolling works smoothly with the scrollbars (grabbing them and move) , but laggy with a mouse wheel or trackpad.

gantt-schedule-timeline-calendar version
3.33.16

[Kendzi-x]

under "laggy" I mean that when you scroll with a mouse wheel or trackpad, the scroll always jump to the next/previous row

[neuronetio]

So we need to implement a different scrolling mechanism. We will most likely add some setting that will change the default scroll behavior and will work based on pixels and not rows. We will try to implement it as soon as possible and will leave info here when we are done.

[neuronetio]

New functionality has been added in version 3.34.0.
To use it, you need to set the byPixels: true option for each scroll configuration.

const config = {
/* ... */
scroll: {
      horizontal: {
        multiplier: 0.3,
        precise: true,
        byPixels: true,
      },
      vertical: {
        multiplier: 0.3,
        precise: true,
        byPixels: true,
      },
    },
/* ... */
};

But there is a little catch. If you use api.setScrollLeft or api.setScrollTop anywhere in your code, you must pass an absolute offset (not rowId or dataIndex as in normal mode) as an argument.
So when byPixels is set to false - nothing changes, but when set to true then setScrollLeft and setScrollTop work in offset mode (in pixels).

Example setScrollLeft with byPixels enabled:

const configScroll = this.state.get('config.scroll.horizontal');
const scrollLeft = this.api.getScrollLeft();
if (configScroll.byPixels) {
  this.api.setScrollLeft(scrollLeft.absolutePosPx + 1); // offset + 1 pixel
} else {
  this.api.setScrollLeft(scrollLeft.dataIndex + 1); // offset + one date
}

[PichlerJoh06]

@neuronetio , thank you very much for your quick reaction!

[Kendzi-x]

Works like a charm, thanks