Table: Make UpdateViewport() have constant runtime, not depending on …

[pja237]

…number of rows in a table.

Related issue: #276

Since there was no feedback on the issue, i tried the following approach to solve the problem of table becoming pretty much useless for a large number of rows.

Instead of rendering the whole table, i limited the rendering to only rows from: m.cursor-m.viewport.Height to: m.cursor+m.viewport.Height. This approach gives the constant runtime (see below) making table act snappy and responsive independent on the number of rows in it.

Results, timed by measuring time to execute a MoveDown(1):

		// DOWN
		case key.Matches(msg, keybindings.DefaultKeyMap.Down):
			t := time.Now()
			m.Log.Printf("Update: Move down\n")
			activeTable.MoveDown(1)
			m.Log.Printf("Update: Move down finished in: %.3f sec\n", time.Since(t).Seconds())

Rows: 36932


SC: 14:34:19.346611 update.go:396: Update: Move down
debug 2022/11/04 14:34:19 rows: 36932 start: 0 end: 51 cursor: 1 height: 50 range: 51
SC: 14:34:19.351719 update.go:398: Update: Move down finished in: 0.005 sec

SC: 14:34:19.507794 update.go:396: Update: Move down
debug 2022/11/04 14:34:19 rows: 36932 start: 0 end: 52 cursor: 2 height: 50 range: 52
SC: 14:34:19.511653 update.go:398: Update: Move down finished in: 0.004 sec

SC: 14:34:19.675428 update.go:396: Update: Move down
debug 2022/11/04 14:34:19 rows: 36932 start: 0 end: 53 cursor: 3 height: 50 range: 53
SC: 14:34:19.679369 update.go:398: Update: Move down finished in: 0.004 sec


Rows: 12

SC: 14:34:31.174864 update.go:396: Update: Move down
debug 2022/11/04 14:34:31 rows: 12 start: 0 end: 12 cursor: 1 height: 50 range: 12
SC: 14:34:31.176839 update.go:398: Update: Move down finished in: 0.002 sec

SC: 14:34:31.344683 update.go:396: Update: Move down
debug 2022/11/04 14:34:31 rows: 12 start: 0 end: 12 cursor: 2 height: 50 range: 12
SC: 14:34:31.345428 update.go:398: Update: Move down finished in: 0.001 sec

SC: 14:34:31.514059 update.go:396: Update: Move down
debug 2022/11/04 14:34:31 rows: 12 start: 0 end: 12 cursor: 3 height: 50 range: 12
SC: 14:34:31.514577 update.go:398: Update: Move down finished in: 0.001 sec

This code works fine in my app , although i'm not sure if it might have any adverse effect in some other table code-paths?
Can't see any for now. If you spot anything, let me know! 😺

[maaslalani]

Thank you @pja237, this is super appreciated. Nice work!

[maaslalani]

One thing I noticed when playing around with this is that the cursor is not working properly when scrolling. The cursor should behave like the first table where it is on the last / first row depending on whether it is scrolling down / up.

Screen.Recording.2022-11-04.at.10.26.08.AM.mov

[pja237]

👍 haven't noticed that, thanks!
It's back to the drawing board, maths is hard 😄

[maaslalani]

Thanks! This is a great improvement, really looking forward to see it merged!

[pja237]

Hey @maaslalani ,
sorry again for the sloppy original PR, got excited by "how easy it was" 😆
Now, i've tried to cover the corner cases that arise from this approach (bending table to misuse viewport), and it seems better. Please give it a try and let me know what you think.

[maaslalani]

I think we can get rid of this renderedLines struct and replace it as end and start on the model. What do you think?

[pja237]

Absolutely fine with me, was just a distinction between original table struct and added values, pushed a commit with change

[maaslalani]

Tested this out and it works great! Thank you so much @pja237. Great work!

[pja237]

You're very welcome!
👍 for your amazing responsiveness! 🥇

[muesli]

@maaslalani Anything blocking this or can we merge?

[pja237]

To keep this alive and let you know, i've been in contact with @maaslalani on discord regarding this pr and we concluded that it's good to go, but of course, we should wait for him on this. Just posting this so it doesn't fizzle out, would love to see this merged

[maaslalani]

Yep, this one is good to go!

[maaslalani]

Thanks @pja237 for the awesome work ❤️