ExpanDrive

I’ve been exploring how to let users set custom drive icons for ExpanDrive 2.0, and after spending quite a while googling for any information on a cocoa/carbon framework that would help me do this, it appears there are few resources available on making .icns files. This post doesn’t add a lot of value to the subject itself, but will hopefully send a few people in the right direction.

The easiest way to create a custom icon in your code is with the (hard to find) IconFamily project. It’s a great wrapper around Icon Services, with more than a little added convenience.

IconFamily lets you:

• create a multi-representation icon family from any arbitrary NSImage
• assign an icon family as a file or folder’s custom icon resource, so it will appear in Finder views
• read and write .icns files
• copy icon data to and from the scrap (pasteboard)
• get and set the elements of an icon family in convenient, Cocoa-compatible NSBitmapImageRep form

Here are a few short examples:

Create and write an ICNS file from a NSImage:

IconFamily* iconFamily = [IconFamily iconFamilyWithThumbnailsOfImage:someNSImage
                                    usingImageInterpolation:NSImageInterpolationHigh];
[iconFamily writeToFile:@"/Some/path/file.icns"];

If you don’t want to use interpolation to create your intermediate resolutions, it’s easy to set them by hand

- (BOOL) setIconFamilyElement:(OSType)elementType fromBitmapImageRep:(NSBitmapImageRep*)bitmapImageRep

There is also built in support for setting a custom icon for a particular file or directory, which is nice if you want to spam your logo on a few resources you’re associated with.

- (BOOL) setAsCustomIconForFile:(NSString*)path
- (BOOL) setAsCustomIconForDirectory:(NSString*)path

Easy.