ui-speedspacechart: fix speedlimittags layer blinking

[Synar]

Close #427

There were 2 issues I could find leading to the blinking :

• the store object was used as a dependency of useEffect, which means it was triggered every time
• the tooltip computation and the canvas drawing were tied together in a single function, despite the tooltip computation depending on the cursor position (and we don't want the canvas to be redrawn whenever the cursor moves)

There seems to be an overreliance on the store object in the code, but it may take a major refactor to fix it.

[Synar]

Close #427 on osrd-ui

Therefore fix half of OpenRailAssociation/osrd#8853 on osrd

[Yohh]

very nice!

a few comments before reviewing deeper

[Yohh]

I can see a little unwanted space at the end of some rects, depending on the zoom level:

[Yohh]

I take the liberty of assigning @Caracol3 , he has a pending PR that will have many conflicts after this one

[Synar]

I can see a little unwanted space at the end of some rects, depending on the zoom level:

Is this behavior that wasn't present before the pr? I tried not to touch the drawing code and dimension computations at all, so if something changed there I messed up

[Yohh]

I can see a little unwanted space at the end of some rects, depending on the zoom level:

Is this behavior that wasn't present before the pr? I tried not to touch the drawing code and dimension computations at all, so if something changed there I messed up

you're right, it's not your work, that was already present

[emersion]

There were 2 issues I could find leading to the blinking

Next time, if you're feeling up for it, would be easier for reviewers if these two changes were split into separate commits!

[Synar]

I take the liberty of assigning @Caracol3 , he has a pending PR that will have many conflicts after this one

Thanks! I'll confess I did not notice there was another PR on this component. But I don't mind being the one to do the conflict resolution

[emersion]

I'm mostly nitpicking at this point. Feel free to discard/ignore comments you disagree with.