Hi Al. Yes. I saw this mistake several times. The misleading thing is, TMHO, the name "transformation matrix" for [a,b,c,d,e,f] (because the listing is pairwise for columns, as you now describe, and not for rows).
Let me explain that a bit simpler for readers who don't know or forgot linear/matrix algebra. It would be better to name it, what it is, a "transformation list". [a,b,c,d,e,f] lists the factors [a,b,c,d] and the summands [e,f] that define the "affine transformation" of a point (x_old,y_old) to a point (x_new,y_new): x_new = a*x_old + c*y_old + e y_new = b*x_old + d*y_old + f [a,d] are the scaling factors for (x_old,y_old), [b,c] are the shearing factors for (x_old,y_old), [e,f] are the translation summands for (x_old,y_old). So [1,0,0,1,0,0] defines the identity: x_new = x_old and y_new = y_old. Every scaling, shearing, translation or rotation of a point (x_old,y_old) can be built by ONE single set of such a list [a,b,c,d,e,f]. Hermann p.s. These were the first two minutes of my talk at LC Global in Nov 2017. Now I can start after that, describing how to find that single set, without matrix algebra ;-) _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
