Asset catalogs are not fully supported in macOS 10.9 when associated with a framework. Therefore, to support macOS 10.9 and DarkAqua it requires that the images be both standalone images in the Resources directory and catalog images in the Asset catalog. FWIW If macOS 10.9 support is not needed the standalone images in the Resources directory can be removed; however, as the code has been reworked to support macOS 10.9 these have been added to the project.
'-[NSBitmapImageRep initWithFocusedViewRect:] is deprecated in macOS 10.14 and returns nil causing a runtime exception to be thrown. Code changed to use the replacement routines to get cached image of a view for macOS 10.14 and beyond while still using the old routines for macOS 10.13 and earlier.
Asset catalogs are not fully supported in macOS 10.9 when associated with a framework. Therefore, to support macOS 10.9 and DarkAqua it requires that the images be both standalone images in the Resources directory and catalog images in the Asset catalog. FWIW If macOS 10.9 support is not needed the standalone images in the Resources directory can be removed; however, as the code has been reworked to support macOS 10.9 these have been added to the project.
'-[NSBitmapImageRep initWithFocusedViewRect:] is deprecated in macOS 10.14 and returns nil causing a runtime exception to be thrown. Code changed to use the replacement routines to get cached image of a view for macOS 10.14 and beyond while still using the old routines for macOS 10.13 and earlier.