Add ability to limit area of scrolling text. Scrolling enhance

[StarveTheEgo]

Is your feature request related to a problem? Please describe.
I would like to add scrolling text via video.add_text function (this is currently possible)
I would like to have this text to scroll on some limited area. Like, i can dedicate some part of screen for this and scroll text only in that small part of screen. Currently text is scrolling on the full width of frame, so the thing i want to achieve is impossible currently

Describe the solution you'd like
Probably add arguments:
width - scrolling width / text area width. Default value is frame width
height - scrolling height / text area height. Default value is... font size? Not sure tho

And maybe replace speed with:
x_speed - scrolling speed on X axis. Default value is 0
y_speed - scrolling speed on Y axis. Default value is 0
^ In order to allow vertical scrolling too

Additional context

I think if you guys are overloaded i can try to learn this OCaml and join to help, since i am programmer
But not sure yet :D

And, sorry for unrelated question: when will be next version released? I am not familiar with conventions of this project. Like, maybe you release every [xx] features or months or... is there public roadmap? Thanks forward!

[smimram]

I think that an even better solution would be to have functions so that the user can specify pretty much any dynamic placement of text. I'll try to have a look at it.

[smimram]

Ok, so you can now do:

y = ref(0)

def ty () =
  y := !y-1;
  if !y <= -100 then y := 0 end;
  !y
end

s = single("test.avi")
s = video.add_text(x=0, y=ty, speed=0, size=40, "Hello world!", s)
s = mksafe(s)

output.sdl(s)

which allows you to program whatever function for x and y. For the text it was already the case, you can use a similar logic with references to update it!

[StarveTheEgo]

Nice! So i can improve Deer Radio now!

[toots]

Thanks @sam! Would you mind adding a Changelog entry for it?