============================================================= PEG transform_concatInverse--tjl: ============================================================= :Author: Tuomas J. Lukka :Last-Modified: $Date: 2003/08/05 08:26:38 $ :Revision: $Revision: 1.1 $ :Status: Current The ``transform_concat--tjl`` PEG left one type of concatenation out, which will make things slightly more efficient. Concatenating the inverse of one coordinate system to another can be done in a single operation instead of two. This is a useful operation in, e.g., the View2D stuff in FenPDF. Issues ====== Changes ======= The OpenGL libvob already implements invert as :: public int invert(int f) { return concatInverse(0, f); } This peg proposes to add concatInverse into the official VobScene definition. Add into VobScene:: public int concatInverseCS(int into, Object key, int other) ; and VobCoorder:: /** Create a new transformation that is the concatenation * of an existing transformation and the inverse of another * transformation. * If we look at the transformations as x' = f(x) and x' = g(x) then * the result of this operation is a transformation h, * for which h(x) = f(g^-1(x)) always. */ public int concatInverse(int f, int g) ;