windows and multiple windows overlaid upon each other the present invention achieves this result by defining each window 34 36 as including a window border 38 window contents 40 a visible region 42 and a clip region 44 the window border 38 preferably comprises the rectangular frame surrounding the window contents 40 and defines the size of the window 34 36 the border 38 is preferably defined in global coordinates of a global device grid for example the border 38 may be specified in 72 dpi global coordinates the window border 38 may also include a title as shown in fig4 the window contents 40 are the image that is to be displayed the window contents 40 are preferably defined in local coordinates of local device grid relative to the global coordinates of the border 38 for example the contents 40 may be specified in port resolution local coordinates while the window border 38 is mapped to the global device grid the window contents 40 are mapped to a local grid this means that there may be overlap between the two grids i e there may be contention for a device pixel between a content 39 s local grid and the global grid of the window border 38 the present invention eliminates this contention through a region called the visible region 42 the visible region 42 is defined in global coordinates and delineates the content pixels of a window 34 36 that are visible any drawing to a window 39.