Some of the display information is initialized in ROM for each mode such as recommended nominal (or default) dimensions. Even though this information is presumably static, it would still be a mistake to hardcode assumptions about these nominal values into your code. Gathering information about the nominal dimensions of various modes is handled in a fashion similar to to the basic queries above. Here is an example of how to query the nominal dimensions of a given mode from a displayinfohandle. #include <graphics/displayinfo.h> check_dimensions( handle ) DisplayInfoHandle handle; { struct DimensionInfo query; /* fill the buffer with Mode dimension information */ if(GetDisplayInfoData(handle, (UBYTE *)&query,sizeof(query), DTAG_DIMS,NULL))) { /* display Nominal dimensions of this Mode */ printf("nominal width = %ld", query.Nominal.MaxX - query.Nominal.MinX + 1); printf("nominal height = %ld", query.Nominal.MaxY - query.Nominal.MinY + 1); } }