Cell background as a #GdkRGBA
Pulse of the spinner. Increment this value to draw the next frame of the spinner animation. Usually, you would update this value in a timeout.
By default, the #GtkSpinner widget draws one full cycle of the animation, consisting of 12 frames, in 750 milliseconds.
The #GtkIconSize value that specifies the size of the rendered spinner.
Cell background as a #GdkColor