GtkPreviewType is deprecated and should not be used in newly-written code.
An enumeration which describes whether a preview contains grayscale or red-green-blue data.
Value | Symbolic name | Description |
| 0 | Gtk::PREVIEW_COLOR | The preview contains red-green-blue data. |
| 1 | Gtk::PREVIEW_GRAYSCALE | The preview contains grayscale data. |