Infinite scrolling display issue

[wattsbn]

I started using the infinite scrolling feature and it works pretty well so far. However, I do see that right after a new page is loaded there is a display issue. If you look at the image below you can see that there is a fairly large gap between the column headers and the first visible row.
You can reproduce this using the doc example (212). Scroll down to around row 80-85 and look for the new page to load. Be careful not to scroll after the new page is loaded because that will make the display issue go away.

[jcompagner]

is this the same as what you also can see here:

http://ui-grid.info/docs/#/tutorial/212_infinite_scroll

when you keep scrolling down? If you do that a bit fast then suddenly only a portion of the screen is really filled with data (so below it not above it like this case)

somehow it seems the calculation of the viewport is not correct. i am trying to dive into this and make a patch, any idea where this can happen (+/-)?

[jcompagner]

i tracked the problem

GridRenderContainer.prototype.adjustRows

is being called by the scrollbar event , then scrollPercentage is given as an argument.

But when new rows are coming in modifyRows has a promise that also calls it and then the scrollPercentage is not given. then it is calculated, but when the scroll is a bit large already that one doesn't really calculate to the right value and it is becoming out of sync (only a small variation alreayd results in a quite bad offset)

if i just remember the scollPercentage of the last time it was given:

if ((typeof(scrollPercentage) === 'undefined' || scrollPercentage === null) && scrollTop) {
if (self.scrollPercentage) {
scrollPercentage = self.scrollPercentage;
}
else {
scrollPercentage = scrollTop / self.getVerticalScrollLength();
}
}
else {
self.scrollPercentage = scrollPercentage;
}

the scrolling works. and i can't reproduce it anymore on the tutorial site (i just inject/change the code through the developer tools)

[jcompagner]

i think this one can be closed right now.
I patched it yesterday because the code in GridRenderContainer.prototype.adjustRows, if the scrollPercentage was not given, was then hitting the code:

  if (self.prevScrollTop < scrollTop && rowIndex < self.prevRowScrollIndex + self.grid.options.scrollThreshold && rowIndex < maxRowIndex) {

        return;
      }

and that return would hit. Because of that self.updateViewableRowRange(newRange); was not called and the currentRow (or the viewable range) was wrong.

So what i did was create a patch that if the scrollPercentage was not given i just make sure that updateViewableRowRange was called. so i skipped the checks that those ifs do (when scrolling up or down)

But today i noticed that with the latest code out of master that if was not hit anyway
Because the first part: self.prevScrollTop < scrollTop
seems to be always false now (they are the same value)

So something fixed this that or the prevScrollTop is set already to the right value before this call or the scrollTop is now a bit different.

I can't also reporduce it anymore in the tutorial/sample i guess the urls now already are updated to the latest code from master?

[jcompagner]

#2357 is the one that did fix the issue also this case is describing (its a duplicate)

Problem is that for me now an other issue appears, and that is that the rows are not updating at all anymore when inserts are being done above the viewport

[wattsbn]

Closing this issue since I can no longer reproduce it. @jcompagner, sounds like you should make a different issue for the insert problem you are seeing.

[jcompagner]

i made a pull request: #2379 for the regression #2357 did introduce