Sets a fallback function to generate sprites.
The fallback function is called when a texture is not found in the sprite sheet. It receives the icon name and scale factor, and should return a [class@VectorSprite], or null if the icon could not be generated. It may be called in a different thread, and it may be called multiple times for the same icon name.
If a previous fallback function was set, it will be replaced and any sprites it generated will be cleared.
fallback may be null to clear the fallback function.
| this |
a [class@VectorSpriteSheet] |
| fallback |
a [callback@ShumateVectorSpriteFallbackFunc] or null |
| notify |
a [callback@GLib.DestroyNotify] for |
| user_data |
user data to pass to |