Xterm.js: No scroll bar on terminal

[Tyriar]

It would be great if a virtual scroll bar was provided.

[parisk]

The terminal scrolling definitely needs an enhancement and physical scrolling with a scrollbar would be a great addition. The only tricky thing to do there is handling switching back and forth with curses applications like Vim.

[Tyriar]

hterm handles the scrollbar really well but only has the currently displayed viewport in the DOM. We should see how they implement it.

[Tyriar]

https://chromium.googlesource.com/apps/libapps/+/HEAD/hterm/js/hterm_scrollport.js

[Tyriar]

I'm going to work on this as part of vscode 1.5.0, the current rough plan/approach is:

• Detect row height and set height and line-height explicitly on .xterm-rows (will resolve #149)
• Wrap .xterm-rows in a .xterm-viewport element which has overflow-y: scroll
• Create an .xterm-scroll-area element which sizes based on the total number of rows in the buffer, this will be invisible but will position itself based on y, ybase and ydisp

[parisk]

Sounds 👍 . What is the purpose of .xterm-scroll-area element though? Will it be used for the displaying of the scroll bar?

[Tyriar]

@parisk yes, it's a large element that's programmatically sized and is used for the scrollbar. After playing with this implementation I ended up getting it working but needed to pull .xterm-rows out of .xterm-viewport, otherwise every refresh would recall the scroll method. That made it very difficult to handle the 3 scroll cases; wheel, drag and drop scroll bar and up/down arrows.

I'll probably put out a PR later today.