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Graphics reference model


Notes:


The MHP standard contains a detailed section on the graphics reference model used. It is not clear if this is needed as it duplicates much of the work of CSS. CSS may be inadequate for this application, but producing an enhancement to that standard might be better than create a new separate standard. MHP defines three planes: background, video and graphics. A fourth "subtitle plane" is mentioned once in the standard, but no further details are given (this appears an editorial problem left over from a previous draft). Applications are provided with a contiguous rectangular region of the graphics plane in which they can place video, interface elements and graphics. It can also video on the video plane and still images or colour the background plane. Different applications can be operating in separate regions of the screen. Overlapping regions are clipped, not blended. From: Digital Video Broadcasting (DVB); Multimedia Home Platform (MHP), Specification 1.1 (ETSI 2000). A set of coordinates is defined for graphics used in Java programmes. This is in addition to the coordinate spaces defined for CSS, used in XHTML.