Combined World-to-Page Space Transformations
The five world-to-page transformations can be combined into a single 3-by-3 matrix. The CombineTransform function can be used to combine two world-space to page-space transformations. The combined transformations can be used to alter output associated with a particular device context (DC) by calling the SetWorldTransform function and supplying the elements for this matrix. When an application calls SetWorldTransform, it stores the elements of the 3-by-3 matrix in an XFORM structure. The members of this structure correspond to the first two columns of a 3-by-3 matrix; the last column of the matrix is not required because its values are constant.