I've made an "action extension" and now I need to make a glyph or template for NSExtensionServiceFinderPreviewIconName. The documentation has been useless for me.
Everything I do ends up with a generic black image overlaid with some faint template lines:
I understand a glyph ≠ template ≠ icon, but that glyph and template are both acceptable for the action extension. I've tried various ways to make my monochrome, black-and-transparent image but I'm missing something. I started with making it in Sketch. The PNG export has alpha and is black and white, though the color mode of the file is probably full color. I ran it through Icon Set Studio but Xcode warned me there were problems with it, and it came out entirely black.
I took that PNG into Pixelmator Pro and used it to make a clipping mask since one of the hallmarks of a glyph is also supposed to be an alpha mask. Re-exported this new PNG with no change or improvement. Exported it as an SVG, but still nothing helping.
The docs don't say where the image needs to be in the Xcode workspace. I've tried putting it in both the containing app's Asseets.xcassets and in the extension's Media.xcassets, but neither helps.
Once I downloaded a glyph template file (for Sketch) from Apple, but it is tremendously complicated and I hope I can get away without making a version for every font weight and size class.
A step by step guide would help a lot, so if anyone has some energy to make one I bet other indies would appreciate it. We can't all afford $$$ for a graphic artist.