gtk-icon-set-add-source (iconset source)

iconset -- a gtk-icon-set instance
source -- a gtk-icon-source instance

This function copies source, so you can reuse the same source immediately without affecting the icon set.

Icon sets have a list of gtk-icon-source instances, which they use as base icons for rendering icons in different states and sizes. Icons are scaled, made to look insensitive, etc. in the function gtk-icon-set-render-icon, but a gtk-icon-set instance needs base images to work with. The base images and when to use them are described by a gtk-icon-source instance.

An example of when you would use this function: a web browser's "Back to Previous Page" icon might point in a different direction in Hebrew and in English. It might look different when insensitive, and it might change size depending on toolbar mode (small/large icons). So a single icon set would contain all those variants of the icon, and you might add a separate source for each one.

You should nearly always add a "default" icon source with all fields wildcarded, which will be used as a fallback if no more specific source matches. A gtk-icon-set instance always prefers more specific icon sources to more generic icon sources. The order in which you add the sources to the icon set does not matter.

The function gtk-icon-set-new-from-pixbuf creates a new icon set with a default icon source based on the given pixbuf. The function gtk-icon-set-add-source has been deprecated since version 3.10 and should not be used in newly written code. Use the gtk-icon-theme class instead.