A rear-projection display apparatus includes a housing, a screen mounted on the housing, an optical engine mounted in the housing, and a host unit mounted in the housing and coupled to the optical engine. The host unit includes an on screen display module having an image alignment unit that is operable in an image-alignment mode to enable the optical engine to project a test pattern onto the screen. The image alignment unit is operable to adjust display of the test pattern projected by the optical engine onto the screen such that the test pattern thus displayed is within a predefined range of the screen when the image alignment unit is operated in the image-alignment mode.