Appends the receiver's matrix to the current transformation matrix stored in the current graphics context, replacing the current transformation matrix with the result. If this method is invoked from within an NSView's drawRect method, then the current transformation matrix is an accumulation of the screen, window and any superview's transformation matrices. Invoking this method defines a new user coordinate system whose coordinates are mapped into the former coordinate system according to the receiver's transformation matrix. To undo the concatenation, you must invert the receiver's matrix and invoke this method again. Replaces the receiver's matrix with its inverse matrix.
Inverse matrices are useful for undoing the effects of a matrix.
You can also use them in conjunction with the concat method to remove the effects of concatenating the matrix to the current transformation matrix of the current graphic context. Prepends the matrix of aTransform to the receiver's matrix. Multiplies aTransform and the receiver's matrix, and replaces the receiver's matrix with the result. This has the effect of applying aTransform before the receiver's transform. Replaces the receiver's transformation matrix with a matrix that applies a rotation of angle degrees.