The keyword you would need to looking for is "affine transformation"
https://en.wikipedia.org/wiki/Affine_transformation Where image rotation is just a special case [ cos(theta) -sin(theta) 0 ] [ sin(theta) cos(theta) 0 ] [ 0 0 1 ] And you can combine with other linear transformations by matrix multiplication, so rotate around a different origin would work. Also see https://math.stackexchange.com/questions/2093314/rotation-matrix-of-rotation-around-a-point-other-than-the-origin >>>>> In <e214b056-7318-755c-8d5b-a95ec3356...@eskimo.com> >>>>> "'PMA' via Programming" <programm...@jsoftware.com> wrote: > Dear J-Programming Forum, > I want to make a script that, given the X/Y values of a 2D > dot-graph, will rotate the graph around its designated origin, > looking for instances of 2 or more points coming into new horizontal > &/or vertical alignment, and at each such instance output the full > set of current X/Y values (integer-rounded). > Could you point me to the main needed ingredients? > Thanks in advance, > Peter Armstrong > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
