ROTATE a drawing on a picture box??? !

hi,
i have a picture box,and i can draw on it.

how can i get rotate 360 degree ???? whats the algorithm???
i don't want any API, i want it pure algorithm.???


another question,am building an OCR system, but when
reading from a scanner,and testing each pixel,the performance
goes down....is there any way rather than searching the
picutre sequentially??

to rotate 360 degres is the same as not rotating at all. to rotate (x,y) a degrees:
newx=x*c-y*s
newy=x*s+y*s
where
c=cos(a/180*3.1415)
s=sin(a/180*3.1415)