feat: Add toggle_zoom and :set-max-width with multiple :set/:toggle commands for Zen Mode like features in the future

[RokKos]

Hey, while browsing some PRs and discussion on original Helix repo I found 2 PR that came together really nicely.

This PR is based on:

• Discussion Zen Mode like
• PR: Added zoom & max-width helix-editor/helix#9838
• PR: fix(helix-term): Defer mutation of editor config to the application helix-editor/helix#14629

It adds 3 small functionalities:

• toggle_zoom: A new command that zooms the current view to take up the entire editor area.
• :set-max-width : A new command to set a maximum width for the view. This centers the view, which is perfect for focused writing! (Setting it to 0 removes the max width).
• fix for enabling multiple :set/:toggle commands

Especially with the last one, you can do some powerful commands that change the appearance of your editor.
And enable features like Zen mode. I believe this will be a great addition until we wait for the plugin system.

I was definitely looking for something like this to edit my notes in Markdown or just preview Markdown files.

My personal setup for Zen mode:

[keys.normal."space"]
# Set max width based on your terminal
z = ["toggle_zoom", ":set-max-width 80", ":set soft-wrap.enable true", ":set gutters.layout []"]
Z = ["toggle_zoom", ":set-max-width 0", ":set soft-wrap.enable false", ':set gutters.layout ["diagnostics","spacer","line-numbers","spacer","diff"]']

Preview Zen mode ON:

Preview Zen mode OFF:

[gj1118]

There is already a similar change that was already merged - helix-editor#8546 ..

[RokKos]

I checked that PR and it looks similar, at least the part about max size.
But correct me if I am wrong, it looked more for behavior when you have 2 buffers in a split to control the size of one.

Also can you hint how you would Zen mode with those commands? I am willing to remove the Zoom and Max width part and just keep this multi-command keybinding.

[gj1118]

I checked that PR and it looks similar, at least the part about max size. But correct me if I am wrong, it looked more for behavior when you have 2 buffers in a split to control the size of one.

Also can you hint how you would Zen mode with those commands? I am willing to remove the Zoom and Max width part and just keep this multi-command keybinding.

It comes with its own keybindings. I have not configured it. When I merged it initially, I thought I would use it, but I keep using tmux and hence felt no need for this feature. Perhaps , we can remove the already merged and start afresh with your pull request.

here are the keybindings.

 "A-w" => { "Alter Window"
            "A-h"|"A-left" |"h"|"left" => shrink_buffer_width,
            "A-l"|"A-right"|"l"|"right" => grow_buffer_width,
            "A-j"|"A-down" |"j"|"down" => shrink_buffer_height,
            "A-k"|"A-up"   |"k"|"up" => grow_buffer_height,
            "A-f"|"f" => toggle_focus_window,
        },