Web-bugs: app.avocode.com - site is not usable

[webcompat-bot]

URL: https://app.avocode.com/

Browser / Version: Firefox 59.0
Operating System: Linux
Tested Another Browser: Yes

Problem type: Site is not usable
Description: Scroll don't work properly
Steps to Reproduce:

Just open an design to inspect

_From webcompat.com with ❤️_

[adamopenweb]

Tested in Firefox 60 for OSX, scrolling around a PSD file is pretty slow with a mouse wheel, it's fine with a Apple touchpad.

With Chrome for OSX, scrolling is very quick and smooth with a mouse wheel.

To test this site you need to create an account and upload a file (like a PSD).

Setting as needs diagnosis.

[karlcow]

I wonder if it's related to the same type of issues than #8012 and https://bugzilla.mozilla.org/show_bug.cgi?id=1392460
ping @wisniewskit

[wisniewskit]

This is another instance of Firefox providing per-line wheel event deltas, but the script expects them to be per-pixel (warning! gigantic JS file!):

key: "getWheelEventDelta",
value: function(e) {
    var t = e.deltaX, 
        n = e.deltaY;
    if (e.shiftKey && 0 === e.deltaX && Math.abs(e.deltaY) > 20) {
        var r = [n, t];
        t = r[0], n = r[1]
    }
    return {
        x: t,
        y: n
    }
}

Despite the spec saying the default should be pixels, I consider this site error as browsers don't always use the default (for instance Chrome sometimes uses per-page, as per the info in the Firefox bug I cited).

They should alter their code as such:

var h = getWheelDeltaInPixels(e);
var t = e.deltaX * h,
    n = e.deltaY * h;

Where getWheelDeltaInPixels can be a function like this:

function getWheelDeltaInPixels(e) {
  switch (e.deltaMode) {
    case WheelEvent.DOM_DELTA_PIXEL: return 1;
    case WheelEvent.DOM_DELTA_LINE:  return parseFloat(window.getComputedStyle(e.target).getPropertyValue('line-height'));
    case WheelEvent.DOM_DELTA_PAGE:  return document.scrollingElement.offsetHeight;
  }
}

[adamopenweb]

Thanks @wisniewskit. Let's try reaching them on Twitter.
https://twitter.com/AdamOpenWeb/status/961387043027935232

[jankuca]

Hello from Avocode,

We are going to incorporate this fix into some of our next releases. Thank you for the tip. <3

[softvision-sergiulogigan]

I think that the issue is still reproducible on my side.
I need to scroll 6 times in Nightly, with the mouse wheel, in order to fully scroll vertically on a picture. In Chrome I can almost do it with only one scroll.

Tested with:
Browser / Version: Firefox Nightly 70.0a1 (2019-08-06)
Operating System: MacOS 10.14.5

[softvision-oana-arbuzov]

Note: Trial account has expired.

@jankuca does the issue still occurs on your side?