R/math-rotate.R

In yikeshu0611/ggrose: Plot Nightingale Rose Map

rotate <- function(df,center,angle){
    angle=angle/180*pi
    x=df[,1]
    y=df[,2]
    expr_x=paste0('(','x','-',center[1],')*',cos(angle),'-(','y','-',center[2],')*',sin(angle),'+',center[1])
    expr_y=paste0('(','x','-',center[1],') * ',sin(angle),'+(','y','-',center[2],')*',cos(angle),'+',center[2])
    df[,1]=eval(parse(text = expr_x))
    df[,2]=eval(parse(text = expr_y))
    df
}