Hi
You have to know wich is the center of rotation, suppose, it's the center of the image (10.5 , 9.5 use real numbers, round at final stage)
then, the coords 4,2 relative to the center: -6.5 , 7.5
that's are OldX = -6.5, OldY = 7.5 after a rotation of "alfa" degrees NewX and NewY (respect to the center) are:
NewX = (OldX*Cos(alfa)) - (OldY*Sin(alfa))
NewY = (OldY*Cos(alfa)) + (OldX*Sin(alfa))
if alfa = 10 degrees then: NewX = -7.70361, NewY = 6.25735
(10 degrees anticlockwise, -10 if you want clockwise!)
I hope, someone has a better way (or easyer) but this should work
(remember to translate the newx and newy from center to the correct point)
Juan
You have to know wich is the center of rotation, suppose, it's the center of the image (10.5 , 9.5 use real numbers, round at final stage)
then, the coords 4,2 relative to the center: -6.5 , 7.5
that's are OldX = -6.5, OldY = 7.5 after a rotation of "alfa" degrees NewX and NewY (respect to the center) are:
NewX = (OldX*Cos(alfa)) - (OldY*Sin(alfa))
NewY = (OldY*Cos(alfa)) + (OldX*Sin(alfa))
if alfa = 10 degrees then: NewX = -7.70361, NewY = 6.25735
(10 degrees anticlockwise, -10 if you want clockwise!)
I hope, someone has a better way (or easyer) but this should work
(remember to translate the newx and newy from center to the correct point)
Juan