Show "resizeLeftRight" cursor when able to resize the playlist sidebar, expand activation width

[svobs]

• I have read CONTRIBUTING.md
• This implements/fixes issue #.

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Description:

Screen.Recording.2023-06-26.at.23.29.18.mov

Makes resizing the width of the Playlist sidebar easier & more intuitive:

1. Change cursor to NSCursor.resizeLeftRight when hovering inside the resize activation rect.
2. Expand width of the activation rect from 4 pts to 10 pts.

[low-batt]

Would be good to rebase this with develop to get the CI build to work.

When I tried it the cursor changed to the resize cursor at the edge of the playlist. I then moved the cursor to the left. The playlist did not change size. I ended up with a resize cursor in the middle of the window.

As can be seen in the Human Interface Guidelines here there are 3 different resize cursors. Experiments with the Dictionary app and resizing its side panel I see it switching between resizeLeftRight and resizeRight or resizeLeft once a maximum or minimum size has been reached. Testing with Preview I saw this same behavior with its side panel.

I think IINA needs to match the behavior of the Apple applications and switch between the 3 cursors different resize cursors.

[svobs]

As can be seen in the Human Interface Guidelines here there are 3 different resize cursors.

Well that's fun. Somehow I never noticed when that feature appeared.

A bit burnt out on these tweaks at the moment and have lots of non-IINA-related work piled up, but will get back to this soon.

[low-batt]

The new commit has to do with miniturizing the Music Mode window…

[svobs]

The new commit has to do with miniturizing the Music Mode window…

Sorry. Forgot I committed to develop before I branched for that one, instead of the other way around. Didn't back it out and ended up rebasing with that commit. WIll avoid that problem in the future by rebasing directly from origin/develop...

Fixed the rebase. Still need to fix the cursor though.