USING: images.loader grouping colors images.bitmap sequences accessors kernel math 
combinators fry ;

IN: image-rotate

: (rotate-90) ( seq^3 -- seq^3 )
    flip [ reverse ] map ;

: (rotate-180) ( seq^3 -- seq^3 )
    reverse [ reverse ] map ;
    
: (rotate-270) ( seq^3 -- seq^3 )
    flip reverse ;
    
: pixel-list ( image length -- seq )
    [ bitmap>> ] dip group ;
    
: image>rows ( image component-length -- rows )
    [ pixel-list ] 
    [ drop dim>> first ] 2bi group ;
    
: (n-rotate) ( seq n -- image )
    360 mod
    {
        { 0   [ ]              }
        { 90  [ (rotate-90) ]  }
        { 180 [ (rotate-180) ] }
        { 270 [ (rotate-270) ] }
        [ "unsupported rotation" throw ]
    } case ;

: rotate ( image rgba n -- image ) 
    [ dupd length image>rows ] dip (n-rotate)
    concat concat >>bitmap ;
    
: rotate-90 ( image rgba -- image ) 
    90 rotate ;