In the GNOME 3 designs we have identified a number of places where using a symbolic variant of a standard icon is desirable. Symbolic icons are usually low color or monochrome and intended to match the foreground font color. They may be used where a high color, detailed representation isn't warranted.
Examples are provided in the Icon guidelines.
Since the icon should follow the font color of the context that the icon appears in it needs to adapt to context state changes such as item selection.
There are two primary elements of any solution.
- Ensure icon resolution fallback to non-symbolic variants
- Support styling the icon to adapt to the usage context
- Follow font size
- Follow font/foreground color
- Adapt to changes in size and color
Part of the solution is to use a method of icon name resolution that will correctly process fallbacks. For example, g_themed_icon_new_with_default_fallbacks.
There are some deficiencies in librsvg's CSS support that may need to be addressed: 614704, 614606
614711 has a proposal for how to implement this.