Selective preview icons

[skurfer]

The icons displayed in Quicksilver should be the best available. Currently, it displays a preview icon generated by the QuickLook system, but that's not always better. Some examples:

• The “naked” icon for Preference Panes is much better than the QuickLook preview version (which is a sort of document icon with a tiny item-specific image in the center).
• Connections for Microsoft’s Remote Desktop application are stored as XML. As a result, the icon for .rdp files always appears as tiny, illegible XML text instead of the document type’s nicer icon.
• This could be personal preference, but as a general rule, previews for documents are not helpful. At that size, it can be hard to tell the difference between a text file, a Word document, or a spreadsheet. The generic type-based icon for such files is very identifiable. There’s a lot of overhead associated with the previews, too.

So what can we do about it?

1. Hard code a list of file types for which the QuickLook preview is worse than the actual icon
2. Hard code a list of types for which previews should be enabled and disable them by default
3. Add a bunch of fiddly stuff to the preferences so users can make their own list
4. Nothing

Again, this could be personal preference, but I think the only time the preview is desirable over the plain icon is for images, PDFs, and videos. If there’s general agreement on that, then option 2 makes the most sense. We should be able to simply check if a file’s UTI conforms to public.image, com.adobe.pdf, or public.movie and enable previews. Disable them otherwise.

We should also provide a way for plug-ins to enable previews for additional types or specific objects. I have some thoughts on implementation, but that can wait.