Abstraction for Cursor Movements (Issue #46)

[felixguendling]

Try to address #46 in a PoC.

[felixguendling]

I was experimenting with the library and it did not work well on Windows with multi-progress bar.
This is essentially the fix from @wolfv which seems to work well on Windows.

Regarding Codacy: I think this is a false positive. It is just a nested preprocessor #if.

Edit: I only adjusted the multi_progress_bar.cpp example but I can adjust the other examples too, if there is any interest in this PR. Otherwise, please close.

Edit 1: There are more changes because my editor automatically applies clang-format. But since there is a .clang-format file in the repository root, I assume that the files should be formatted with clang-format anyway?

[p-ranav]

Hello, I'm interested in this PR.

Can you explain the semantics of these two statements?

  indicators::enable_cursor_movement();
  indicators::show_console_cursor(false);

If I was a user, why would I need to make these calls? What happens if I don't make these calls?

[wolfv]

For our use case we ended up just calling these lines to enable VT100 escape codes on Windows:

https://github.com/QuantStack/mamba/blob/100f4de8580aab00cc9adb061949e607339ebaa0/src/output.cpp#L241-L248

You might also be interested in these to get the width of the terminal on Win & Unix:

https://github.com/QuantStack/mamba/blob/100f4de8580aab00cc9adb061949e607339ebaa0/src/output.cpp#L40-L54

And here are the cursor movements:

https://github.com/QuantStack/mamba/blob/100f4de8580aab00cc9adb061949e607339ebaa0/include/output.hpp#L17-L101

Note: since we could enable ANSI / VT100 escpae codes on Win (works from Win 10) we didn't bother with using the Win APIs for cursor movement.
I guess if you want to support older Win versions that's necessary.

[felixguendling]

If I was a user, why would I need to make these calls? What happens if I don't make these calls?

I thought that the show_console_cursor(false) call was a more comprehensible way than std::cout << "\e[?25l"; which is used elsewhere. I hoped that the naming was clear: show_console_cursor(false) hides the cursor, show_console_cursor(true) makes it visible. If you do not make this call, you have some flicker because the cursor jumps between the lines. It's not absolutely necessary but I find the jumping cursor a bit annoying.

enable_cursor_movement() is not required if we use the Windows SetConsoleCursorPosition API. I removed it. If supporting older versions of Windows is not a goal, it is probably easier to enable output processing on Windows and not use the SetConsoleCursorPosition function. The current implementation in the PR targets older Windows versions, too.

[p-ranav]

@felixguendling Do you mind updating the other samples too (and probably the README)? We can merge this.

[felixguendling]

Now, the string "\e[?25" is only used in the show_console_cursor() function. Every example/demo (including the README) uses this function now and should therefore work on Windows as well.