[Suggest] Add viewport feature

[tumashu]

We can add many viewport and split a brain map to many maps with different viewport.
the default viewport is "all" viewport.

[Kungsgeten]

Basically what this mean is supporting to have multiple *org-brain* buffers at the same time?

[tumashu]

Basically what this mean is supporting to have multiple *org-brain* buffers at the same time?

this is an approach

other approaches may:

1. adding some viewport buttons to org-brain buffer, when I click one button, i can switch to a viewport of current brain.
2. add a switch-viewport command, when run this command, brain switch viewport.

[Kungsgeten]

org-brain-visualize is currently designed to only use one buffer. However your idea of multiple viewports could still be used, but then you couldn't split the frame and have different views in different windows, which could be useful. If you want to temporarily save viewports my current suggestion would be to pin the entries you want to switch between.

[vigilancetech-com]

Would it be more involved than just making all the variables buffer local (then just letting the user rename the org-brain buffer and org-brain-visualize again)?

[vigilancetech-com]

@Kungsgeten I've made all the variables buffer local and it appears to work (being able to change the visualize buffer name and fire up another one where the two buffers work independently of each other).

Expect a PR here in a bit.