Object used to pass resources to use for the default controls.
| background | Sprite used for background elements. |
| checkmark | Sprite used for representation of an "on" state when present, such as a checkmark. |
| dropdown | Sprite used to indicate that a button will open a dropdown when clicked. |
| inputField | Sprite used as background for input fields. |
| knob | Sprite used for knobs that can be dragged, such as on a slider. |
| mask | Sprite used for masking purposes, for example to be used for the viewport of a scroll view. |
| standard | The primary sprite to be used for graphical UI elements, used by the button, toggle, and dropdown controls, among others. |