Flags for IG_ISIS_drv_set_dialog function.

Values:

IG_ISIS_DRV_SET_DLG_BIN	Restrict the scanner settings to binary, effectively preventing the user from choosing grayscale or color modes.
IG_ISIS_DRV_SET_DLG_AREA	Show the Area button on the dialog box. When the user clicks the Area button, the Area dialog box appears. When not set, the Area button is not visible.
IG_ISIS_DRV_SET_DLG_RETURN	When set, if the user clicks Cancel, IG_ISIS_drv_set_dialog returns IG_ISIS_ERR_CANCEL. If the user clicks OK, it returns IG_ISIS_SUCCESS. If this flag is not set, IG_ISIS_drv_set_dialog always returns IG_ISIS_SUCCESS.
IG_ISIS_DRV_SET_DLG_AREAPREVIEW	When set, if the user clicks on the Area button, the dialog displayed will include a preview box where the user can set the scan area through mouse actions. The preview box may display an image if a callback function has been set with IG_ISIS_area_dialog_CB_register, otherwise it will be gray. Using this flag automatically sets the IG_ISIS_DRV_SET_DIALOG_AREA flag as well.
IG_ISIS_DRV_SET_DLG_STDFMTS	Unused.
IG_ISIS_DRV_SET_DLG_NOSAVE	Unused.
IG_ISIS_DRV_SET_DLG_PALETTE	Unused.