improve table horizontal scroll experience

[mroswell]

Wide tables aren't a huge problem if you know to click and drag right. But it's not at all obvious to do that. (it also tends to blue-select any content as it's dragging.) Depending on column widths, public users might entirely miss all the columns to the right.

There is a scrollbar at the bottom of the table, but I'm displaying ALL my records because it's the only way for datasette-vega to make accurate charts. So that bottom scrollbar is likely to be missed. I wonder if some sort of javascript-y mouseover to an arrow might help, similar to those seen in image carousels. Ah: here's a perfect example:

1. Visit http://google.com
2. Search for: animals endangered
3. Note the 'g-right-button' (in the code) that looks like a right-facing caret in a circle.
4. Click on that and the carousel scrolls right (and 'g-left-button' appears on the left).

Might be tricky to do that on a table, rather than a one-row carousel, but it's worth experimenting with.

Another option is just to put the scrollbars at the top of the table, too.

Meantime, I'm trying to build a button like the "View/hide all columns on https://salaries.news.baltimoresun.com/salaries-be494cf/2019+Maryland+state+salaries Might be nice to have that available by default, with settings in the metadata showing which are on by default.

(I saw some other closed issues related to horizontal scrolling, and admit I don't entirely understand them. For instance, the animated gif at https://github.com/simonw/datasette/issues/998#issuecomment-714117534 confuses me. )

[dracos]

My suggestions, originally made on twitter, but might be better here now:

1. Could have a CSS shadow (one of the comments on https://stackoverflow.com/questions/44793453/how-do-i-add-a-top-and-bottom-shadow-while-scrolling-but-only-when-needed is a codepen for horizontal instead of vertical);

2. Could give the table a max-height (either the window or work out the available space) so that it is both vertically/horizontally scrollable and you don't have to scroll to the bottom in order to see this;

3. On a desktop browser, what I think I'd want is an absolute grid to work with - left query/filters, TR chart (or map), BR table. No problem with scrolling then. Here is a mockup I made when this was about the map plugin:

[mroswell]

@dracos I appreciate your ideas!

1. Ooh, I like this: https://codepen.io/astro87/pen/LYRQNbd?editors=1100 (That's the codepen from your linked stackoverflow.)
2. I worry that a max height will be a problem when my facets are open. (I've got 35 active ingredients, and so I've set the default_facet_size to 35.)
3. I don't understand this one. I'm observing the screenshot... very helpful! (Ah, okay, TR = Top Right and BR = Bottom Right. Absolute grid refers to position style.) All the scroll bars look a little wonky to me. I've also got a lot of facets, and prefer the extra horizontal space so that not as many facets disappear below the fold. My site also has end users... some will be on mobile... not sure what the absolute grid would do there...
4. (I still think a hover-arrow that scrolls upon click would help, too...)

But meanwhile, I'm going to go ahead and see if I can apply that shadow. (Never would've thought of that.) Hmmm... I'm not an SCSS person. This looks helpful! https://jsonformatter.org/scss-to-css

[dracos]

2. Max height would still let you scroll the page to underneath the facets to the table, but would mean the table would never take up more than your window size, so the horizontal scrollbar would be visible as soon as the table took up the size of the window.
3. Yes, this wouldn't be for mobile :) It'd be desktop-only styling. On mobile you can scroll much more easily with touch, anyway. In your case, perhaps better would be the whole top half would be facets, bottom left quadrant chart, bottom right table. Depends upon the particular use case, as you say.

[llimllib]

user report: I found this issue because the first time I tried to use datasette for real, I displayed a large table, and thought there was no horizontal scroll bar at all. I didn't even consider that I had to scroll all the way to the end of the page to find it.

Just chipping in to say that this confused me, and I didn't even find the scroll bar until after I saw this issue. I don't know what the right answer is, but IMO the UI should suggest to the user that there is a way to view the data that's hidden to the right.