I created this separate issue so that icon related details don't clutter up the main discussion PR #9587 that @adzm has created. Essentially, I don't want to create any kind of noise in that discussion because it is more programming related whereas this is more image/icon related.

Microsoft Fluent UI System Icons: https://github.com/microsoft/fluentui-system-icons
Easy to navigate site for Fluent UI icons: https://bennymeg.github.io/ngx-fluent-ui/

My first WIP:

The first WIP NppFluentUI Icons for NppDarkMode was based on the regular Fluent UI icons.

My second WIP:

The second WIP focused on the filled Fluent UI icon type in the hopes that it would be softer on the eyes. I also focused more on the icons in the tab bar as well. I got rid of the constant save button icon that is always present on each tab. Instead, I made it so that the icon shows up on the tab only when changes are made, making it clear to the user that the latest changes have not yet been saved.

Challenges and Issues:

Part of the reason why I made the change on the tab bar with the saved icon is because of a problem where the saved icon was being colored constantly regardless of the color that I was using. I assume this is related to the following issue mentioned over at (#9587 (comment)):

Unfortunately, since the tab color styling has not really worked in a long
while due to windows' visual styles, pretty much every theme (including the
default notepad theme) is using incredibly jarring and garish colors for
tab styles, like bright red and green backgrounds. Ick.

So the saved icon was being color-shaded red or green depending on whether the tab was in focus or not and I believe that this is something that requires coding changes and cannot be solved with icons in tab bar.

There are also a lot of challenges with scaling SVG to tiny sizes (16x16) and converting to old BMP format. So while I could technically batch convert all icons to make the process easier for myself, the batch converted icons suffered from some imperfections and pixel related issues that show up more at 16x16. So I have to do each icon manually and give each pixel some love.

Release Challenges and Timing:

I am not a programmer and therefore have no ability to add these icons to Npp properly, such as having them automatically used when a user chooses NppDarkMode. I have only simply overwrote the old icons by same file name and compiled Npp that way to have a working example. A user would need to ability to choose the icons from settings or automatically when NppDarkMode is set.

@adzm I am only a few days or a week away from being able to complete these, at least enough for testing scenarios. Possibly we can try to time the release of these icons with the timing of your NppDarkMode merge. It will be great once your NppDarkMode is merged into official Npp branch to make collaboration easier.