math questions

[jjhesk]

After reading the tutorials from you @flavienlaurent from your web I have a similar matrix problem implementing on both scaling and rotation. Assume that I have two fingers touching on the screen and need to make a scale of 4x and rotate it by two finger movements. It finally got 45 degrees. How do you go about with the scaling matrix that will able to get the adjustment of deposition of the centrical point for both fingers.